neovim

ops.c (128392B)

---

// ops.c: implementation of various operators: op_shift, op_delete, op_tilde,
//        op_change, op_yank, do_join

#include <assert.h>
#include <ctype.h>
#include <inttypes.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <uv.h>

#include "nvim/api/private/defs.h"
#include "nvim/api/private/helpers.h"
#include "nvim/ascii_defs.h"
#include "nvim/assert_defs.h"
#include "nvim/autocmd.h"
#include "nvim/autocmd_defs.h"
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/buffer_updates.h"
#include "nvim/change.h"
#include "nvim/charset.h"
#include "nvim/clipboard.h"
#include "nvim/cursor.h"
#include "nvim/drawscreen.h"
#include "nvim/edit.h"
#include "nvim/errors.h"
#include "nvim/eval.h"
#include "nvim/eval/typval.h"
#include "nvim/eval/typval_defs.h"
#include "nvim/ex_cmds2.h"
#include "nvim/ex_cmds_defs.h"
#include "nvim/ex_getln.h"
#include "nvim/extmark.h"
#include "nvim/file_search.h"
#include "nvim/fold.h"
#include "nvim/garray.h"
#include "nvim/garray_defs.h"
#include "nvim/getchar.h"
#include "nvim/getchar_defs.h"
#include "nvim/gettext_defs.h"
#include "nvim/globals.h"
#include "nvim/highlight_defs.h"
#include "nvim/indent.h"
#include "nvim/indent_c.h"
#include "nvim/keycodes.h"
#include "nvim/macros_defs.h"
#include "nvim/mark.h"
#include "nvim/mark_defs.h"
#include "nvim/math.h"
#include "nvim/mbyte.h"
#include "nvim/mbyte_defs.h"
#include "nvim/memline.h"
#include "nvim/memline_defs.h"
#include "nvim/memory.h"
#include "nvim/message.h"
#include "nvim/mouse.h"
#include "nvim/move.h"
#include "nvim/normal.h"
#include "nvim/ops.h"
#include "nvim/option.h"
#include "nvim/option_defs.h"
#include "nvim/option_vars.h"
#include "nvim/os/input.h"
#include "nvim/os/time.h"
#include "nvim/plines.h"
#include "nvim/register.h"
#include "nvim/search.h"
#include "nvim/state.h"
#include "nvim/state_defs.h"
#include "nvim/strings.h"
#include "nvim/terminal.h"
#include "nvim/textformat.h"
#include "nvim/types_defs.h"
#include "nvim/ui.h"
#include "nvim/ui_defs.h"
#include "nvim/undo.h"
#include "nvim/vim_defs.h"

#include "ops.c.generated.h"

// Flags for third item in "opchars".
#define OPF_LINES  1  // operator always works on lines
#define OPF_CHANGE 2  // operator changes text

/// The names of operators.
/// IMPORTANT: Index must correspond with defines in ops.h!!!
/// The third field indicates whether the operator always works on lines.
static const char opchars[][3] = {
 { NUL, NUL, 0 },                       // OP_NOP
 { 'd', NUL, OPF_CHANGE },              // OP_DELETE
 { 'y', NUL, 0 },                       // OP_YANK
 { 'c', NUL, OPF_CHANGE },              // OP_CHANGE
 { '<', NUL, OPF_LINES | OPF_CHANGE },  // OP_LSHIFT
 { '>', NUL, OPF_LINES | OPF_CHANGE },  // OP_RSHIFT
 { '!', NUL, OPF_LINES | OPF_CHANGE },  // OP_FILTER
 { 'g', '~', OPF_CHANGE },              // OP_TILDE
 { '=', NUL, OPF_LINES | OPF_CHANGE },  // OP_INDENT
 { 'g', 'q', OPF_LINES | OPF_CHANGE },  // OP_FORMAT
 { ':', NUL, OPF_LINES },               // OP_COLON
 { 'g', 'U', OPF_CHANGE },              // OP_UPPER
 { 'g', 'u', OPF_CHANGE },              // OP_LOWER
 { 'J', NUL, OPF_LINES | OPF_CHANGE },  // DO_JOIN
 { 'g', 'J', OPF_LINES | OPF_CHANGE },  // DO_JOIN_NS
 { 'g', '?', OPF_CHANGE },              // OP_ROT13
 { 'r', NUL, OPF_CHANGE },              // OP_REPLACE
 { 'I', NUL, OPF_CHANGE },              // OP_INSERT
 { 'A', NUL, OPF_CHANGE },              // OP_APPEND
 { 'z', 'f', 0         },               // OP_FOLD
 { 'z', 'o', OPF_LINES },               // OP_FOLDOPEN
 { 'z', 'O', OPF_LINES },               // OP_FOLDOPENREC
 { 'z', 'c', OPF_LINES },               // OP_FOLDCLOSE
 { 'z', 'C', OPF_LINES },               // OP_FOLDCLOSEREC
 { 'z', 'd', OPF_LINES },               // OP_FOLDDEL
 { 'z', 'D', OPF_LINES },               // OP_FOLDDELREC
 { 'g', 'w', OPF_LINES | OPF_CHANGE },  // OP_FORMAT2
 { 'g', '@', OPF_CHANGE },              // OP_FUNCTION
 { Ctrl_A, NUL, OPF_CHANGE },           // OP_NR_ADD
 { Ctrl_X, NUL, OPF_CHANGE },           // OP_NR_SUB
};

/// Translate a command name into an operator type.
/// Must only be called with a valid operator name!
int get_op_type(int char1, int char2)
{
 int i;

 if (char1 == 'r') {
   // ignore second character
   return OP_REPLACE;
 }
 if (char1 == '~') {
   // when tilde is an operator
   return OP_TILDE;
 }
 if (char1 == 'g' && char2 == Ctrl_A) {
   // add
   return OP_NR_ADD;
 }
 if (char1 == 'g' && char2 == Ctrl_X) {
   // subtract
   return OP_NR_SUB;
 }
 if (char1 == 'z' && char2 == 'y') {  // OP_YANK
   return OP_YANK;
 }
 for (i = 0;; i++) {
   if (opchars[i][0] == char1 && opchars[i][1] == char2) {
     break;
   }
   if (i == (int)(ARRAY_SIZE(opchars) - 1)) {
     internal_error("get_op_type()");
     break;
   }
 }
 return i;
}

/// @return  true if operator "op" always works on whole lines.
int op_on_lines(int op)
{
 return opchars[op][2] & OPF_LINES;
}

/// @return  true if operator "op" changes text.
int op_is_change(int op)
{
 return opchars[op][2] & OPF_CHANGE;
}

/// Get first operator command character.
///
/// @return  'g' or 'z' if there is another command character.
int get_op_char(int optype)
{
 return opchars[optype][0];
}

/// Get second operator command character.
int get_extra_op_char(int optype)
{
 return opchars[optype][1];
}

/// handle a shift operation
void op_shift(oparg_T *oap, bool curs_top, int amount)
{
 int block_col = 0;

 if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL) {
   return;
 }

 if (oap->motion_type == kMTBlockWise) {
   block_col = curwin->w_cursor.col;
 }

 for (int i = oap->line_count - 1; i >= 0; i--) {
   int first_char = (uint8_t)(*get_cursor_line_ptr());
   if (first_char == NUL) {  // empty line
     curwin->w_cursor.col = 0;
   } else if (oap->motion_type == kMTBlockWise) {
     shift_block(oap, amount);
   } else if (first_char != '#' || !preprocs_left()) {
     // Move the line right if it doesn't start with '#', 'smartindent'
     // isn't set or 'cindent' isn't set or '#' isn't in 'cino'.
     shift_line(oap->op_type == OP_LSHIFT, p_sr, amount, false);
   }
   curwin->w_cursor.lnum++;
 }

 if (oap->motion_type == kMTBlockWise) {
   curwin->w_cursor.lnum = oap->start.lnum;
   curwin->w_cursor.col = block_col;
 } else if (curs_top) {  // put cursor on first line, for ">>"
   curwin->w_cursor.lnum = oap->start.lnum;
   beginline(BL_SOL | BL_FIX);       // shift_line() may have set cursor.col
 } else {
   curwin->w_cursor.lnum--;            // put cursor on last line, for ":>"
 }
 // The cursor line is not in a closed fold
 foldOpenCursor();

 if (oap->line_count > p_report) {
   char *op = oap->op_type == OP_RSHIFT ? ">" : "<";

   char *msg_line_single = NGETTEXT("%" PRId64 " line %sed %d time",
                                    "%" PRId64 " line %sed %d times", amount);
   char *msg_line_plural = NGETTEXT("%" PRId64 " lines %sed %d time",
                                    "%" PRId64 " lines %sed %d times", amount);
   vim_snprintf(IObuff, IOSIZE,
                NGETTEXT(msg_line_single, msg_line_plural, oap->line_count),
                (int64_t)oap->line_count, op, amount);
   msg_keep(IObuff, 0, true, false);
 }

 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   // Set "'[" and "']" marks.
   curbuf->b_op_start = oap->start;
   curbuf->b_op_end.lnum = oap->end.lnum;
   curbuf->b_op_end.col = ml_get_len(oap->end.lnum);
   if (curbuf->b_op_end.col > 0) {
     curbuf->b_op_end.col--;
   }
 }

 changed_lines(curbuf, oap->start.lnum, 0, oap->end.lnum + 1, 0, true);
}

/// Return the tabstop width at the index of the variable tabstop array.  If an
/// index greater than the length of the array is given, the last tabstop width
/// in the array is returned.
static int get_vts(const int *vts_array, int index)
{
 int ts;

 if (index < 1) {
   ts = 0;
 } else if (index <= vts_array[0]) {
   ts = vts_array[index];
 } else {
   ts = vts_array[vts_array[0]];
 }

 return ts;
}

/// Return the sum of all the tabstops through the index-th.
static int get_vts_sum(const int *vts_array, int index)
{
 int sum = 0;
 int i;

 // Perform the summation for indices within the actual array.
 for (i = 1; i <= index && i <= vts_array[0]; i++) {
   sum += vts_array[i];
 }

 // Add tabstops whose indices exceed the actual array.
 if (i <= index) {
   sum += vts_array[vts_array[0]] * (index - vts_array[0]);
 }

 return sum;
}

/// @param left    true if shift is to the left
/// @param count   true if new indent is to be to a tabstop
/// @param amount  number of shifts
static int64_t get_new_sw_indent(bool left, bool round, int64_t amount, int64_t sw_val)
{
 int64_t count = get_indent();  // get current indent

 if (round) {  // round off indent
   int64_t i = trim_to_int(count / sw_val);  // number of 'shiftwidth' rounded down
   int64_t j = trim_to_int(count % sw_val);  // extra spaces
   if (j && left) {  // first remove extra spaces
     amount--;
   }
   if (left) {
     i = MAX(i - amount, 0);
   } else {
     i += amount;
   }
   count = i * sw_val;
 } else {  // original vi indent
   if (left) {
     count = MAX(count - sw_val * amount, 0);
   } else {
     count += sw_val * amount;
   }
 }

 return count;
}

/// @param left    true if shift is to the left
/// @param count   true if new indent is to be to a tabstop
/// @param amount  number of shifts
static int64_t get_new_vts_indent(bool left, bool round, int amount, int *vts_array)
{
 int64_t indent = get_indent();
 int vtsi = 0;
 int vts_indent = 0;
 int ts = 0;         // Silence uninitialized variable warning.

 // Find the tabstop at or to the left of the current indent.
 while (vts_indent <= indent) {
   vtsi++;
   ts = get_vts(vts_array, vtsi);
   vts_indent += ts;
 }
 vts_indent -= ts;
 vtsi--;

 // Extra indent spaces to the right of the tabstop
 int64_t offset = indent - vts_indent;

 if (round) {
   if (left) {
     if (offset == 0) {
       indent = get_vts_sum(vts_array, vtsi - amount);
     } else {
       indent = get_vts_sum(vts_array, vtsi - (amount - 1));
     }
   } else {
     indent = get_vts_sum(vts_array, vtsi + amount);
   }
 } else {
   if (left) {
     if (amount > vtsi) {
       indent = 0;
     } else {
       indent = get_vts_sum(vts_array, vtsi - amount) + offset;
     }
   } else {
     indent = get_vts_sum(vts_array, vtsi + amount) + offset;
   }
 }

 return indent;
}

/// Shift the current line 'amount' shiftwidth(s) left (if 'left' is true) or
/// right.
///
/// The rules for choosing a shiftwidth are:  If 'shiftwidth' is non-zero, use
/// 'shiftwidth'; else if 'vartabstop' is not empty, use 'vartabstop'; else use
/// 'tabstop'.  The Vim documentation says nothing about 'softtabstop' or
/// 'varsofttabstop' affecting the shiftwidth, and neither affects the
/// shiftwidth in current versions of Vim, so they are not considered here.
///
/// @param left                true if shift is to the left
/// @param count               true if new indent is to be to a tabstop
/// @param amount              number of shifts
/// @param call_changed_bytes  call changed_bytes()
void shift_line(bool left, bool round, int amount, int call_changed_bytes)
{
 int64_t count;
 int64_t sw_val = curbuf->b_p_sw;
 int64_t ts_val = curbuf->b_p_ts;
 int *vts_array = curbuf->b_p_vts_array;

 if (sw_val != 0) {
   // 'shiftwidth' is not zero; use it as the shift size.
   count = get_new_sw_indent(left, round, amount, sw_val);
 } else if ((vts_array == NULL) || (vts_array[0] == 0)) {
   // 'shiftwidth' is zero and 'vartabstop' is empty; use 'tabstop' as the
   // shift size.
   count = get_new_sw_indent(left, round, amount, ts_val);
 } else {
   // 'shiftwidth' is zero and 'vartabstop' is defined; use 'vartabstop'
   // to determine the new indent.
   count = get_new_vts_indent(left, round, amount, vts_array);
 }

 // Set new indent
 if (State & VREPLACE_FLAG) {
   change_indent(INDENT_SET, trim_to_int(count), false, call_changed_bytes);
 } else {
   set_indent(trim_to_int(count), call_changed_bytes ? SIN_CHANGED : 0);
 }
}

/// Shift one line of the current block one shiftwidth right or left.
/// Leaves cursor on first character in block.
static void shift_block(oparg_T *oap, int amount)
{
 const bool left = (oap->op_type == OP_LSHIFT);
 const int oldstate = State;
 char *newp;
 const int oldcol = curwin->w_cursor.col;
 const int sw_val = get_sw_value_indent(curbuf, left);
 const int ts_val = (int)curbuf->b_p_ts;
 struct block_def bd;
 int incr;
 const int old_p_ri = p_ri;

 p_ri = 0;                     // don't want revins in indent

 State = MODE_INSERT;          // don't want MODE_REPLACE for State
 block_prep(oap, &bd, curwin->w_cursor.lnum, true);
 if (bd.is_short) {
   return;
 }

 // total is number of screen columns to be inserted/removed
 int total = (int)((unsigned)amount * (unsigned)sw_val);
 if ((total / sw_val) != amount) {
   return;   // multiplication overflow
 }

 char *const oldp = get_cursor_line_ptr();
 const int old_line_len = get_cursor_line_len();

 int startcol, oldlen, newlen;

 if (!left) {
   //  1. Get start vcol
   //  2. Total ws vcols
   //  3. Divvy into TABs & spp
   //  4. Construct new string
   total += bd.pre_whitesp;    // all virtual WS up to & incl a split TAB
   colnr_T ws_vcol = bd.start_vcol - bd.pre_whitesp;
   char *old_textstart = bd.textstart;
   if (bd.startspaces) {
     if (utfc_ptr2len(bd.textstart) == 1) {
       bd.textstart++;
     } else {
       ws_vcol = 0;
       bd.startspaces = 0;
     }
   }

   // TODO(vim): is passing bd.textstart for start of the line OK?
   CharsizeArg csarg;
   CSType cstype = init_charsize_arg(&csarg, curwin, curwin->w_cursor.lnum, bd.textstart);
   StrCharInfo ci = utf_ptr2StrCharInfo(bd.textstart);
   int vcol = bd.start_vcol;
   while (ascii_iswhite(ci.chr.value)) {
     incr = win_charsize(cstype, vcol, ci.ptr, ci.chr.value, &csarg).width;
     ci = utfc_next(ci);
     total += incr;
     vcol += incr;
   }
   bd.textstart = ci.ptr;
   bd.start_vcol = vcol;

   int tabs = 0;
   int spaces = 0;
   // OK, now total=all the VWS reqd, and textstart points at the 1st
   // non-ws char in the block.
   if (!curbuf->b_p_et) {
     tabstop_fromto(ws_vcol, ws_vcol + total,
                    ts_val, curbuf->b_p_vts_array, &tabs, &spaces);
   } else {
     spaces = total;
   }

   // if we're splitting a TAB, allow for it
   const int col_pre = bd.pre_whitesp_c - (bd.startspaces != 0);
   bd.textcol -= col_pre;

   const int new_line_len  // the length of the line after the block shift
     = bd.textcol + tabs + spaces + (old_line_len - (int)(bd.textstart - oldp));
   newp = xmalloc((size_t)new_line_len + 1);
   memmove(newp, oldp, (size_t)bd.textcol);
   startcol = bd.textcol;
   oldlen = (int)(bd.textstart - old_textstart) + col_pre;
   newlen = tabs + spaces;
   memset(newp + bd.textcol, TAB, (size_t)tabs);
   memset(newp + bd.textcol + tabs, ' ', (size_t)spaces);
   STRCPY(newp + bd.textcol + tabs + spaces, bd.textstart);
   assert(newlen - oldlen == new_line_len - old_line_len);
 } else {  // left
   char *verbatim_copy_end;      // end of the part of the line which is
                                 // copied verbatim
   colnr_T verbatim_copy_width;  // the (displayed) width of this part
                                 // of line
   char *non_white = bd.textstart;

   // Firstly, let's find the first non-whitespace character that is
   // displayed after the block's start column and the character's column
   // number. Also, let's calculate the width of all the whitespace
   // characters that are displayed in the block and precede the searched
   // non-whitespace character.

   // If "bd.startspaces" is set, "bd.textstart" points to the character,
   // the part of which is displayed at the block's beginning. Let's start
   // searching from the next character.
   if (bd.startspaces) {
     MB_PTR_ADV(non_white);
   }

   // The character's column is in "bd.start_vcol".
   colnr_T non_white_col = bd.start_vcol;

   CharsizeArg csarg;
   CSType cstype = init_charsize_arg(&csarg, curwin, curwin->w_cursor.lnum, bd.textstart);
   while (ascii_iswhite(*non_white)) {
     incr = win_charsize(cstype, non_white_col, non_white, (uint8_t)(*non_white), &csarg).width;
     non_white_col += incr;
     non_white++;
   }

   const colnr_T block_space_width = non_white_col - oap->start_vcol;
   // We will shift by "total" or "block_space_width", whichever is less.
   const colnr_T shift_amount = MIN(block_space_width, total);
   // The column to which we will shift the text.
   const colnr_T destination_col = non_white_col - shift_amount;

   // Now let's find out how much of the beginning of the line we can
   // reuse without modification.
   verbatim_copy_end = bd.textstart;
   verbatim_copy_width = bd.start_vcol;

   // If "bd.startspaces" is set, "bd.textstart" points to the character
   // preceding the block. We have to subtract its width to obtain its
   // column number.
   if (bd.startspaces) {
     verbatim_copy_width -= bd.start_char_vcols;
   }
   cstype = init_charsize_arg(&csarg, curwin, 0, bd.textstart);
   StrCharInfo ci = utf_ptr2StrCharInfo(verbatim_copy_end);
   while (verbatim_copy_width < destination_col) {
     incr = win_charsize(cstype, verbatim_copy_width, ci.ptr, ci.chr.value, &csarg).width;
     if (verbatim_copy_width + incr > destination_col) {
       break;
     }
     verbatim_copy_width += incr;
     ci = utfc_next(ci);
   }
   verbatim_copy_end = ci.ptr;

   // If "destination_col" is different from the width of the initial
   // part of the line that will be copied, it means we encountered a tab
   // character, which we will have to partly replace with spaces.
   assert(destination_col - verbatim_copy_width >= 0);
   const int fill  // nr of spaces that replace a TAB
     = destination_col - verbatim_copy_width;

   assert(verbatim_copy_end - oldp >= 0);
   // length of string left of the shift position (ie the string not being shifted)
   const int fixedlen = (int)(verbatim_copy_end - oldp);
   // The replacement line will consist of:
   // - the beginning of the original line up to "verbatim_copy_end",
   // - "fill" number of spaces,
   // - the rest of the line, pointed to by non_white.
   const int new_line_len  // the length of the line after the block shift
     = fixedlen + fill + (old_line_len - (int)(non_white - oldp));

   newp = xmalloc((size_t)new_line_len + 1);
   startcol = fixedlen;
   oldlen = bd.textcol + (int)(non_white - bd.textstart) - fixedlen;
   newlen = fill;
   memmove(newp, oldp, (size_t)fixedlen);
   memset(newp + fixedlen, ' ', (size_t)fill);
   STRCPY(newp + fixedlen + fill, non_white);
   assert(newlen - oldlen == new_line_len - old_line_len);
 }
 // replace the line
 ml_replace(curwin->w_cursor.lnum, newp, false);
 changed_bytes(curwin->w_cursor.lnum, bd.textcol);
 extmark_splice_cols(curbuf, (int)curwin->w_cursor.lnum - 1, startcol,
                     oldlen, newlen,
                     kExtmarkUndo);
 State = oldstate;
 curwin->w_cursor.col = oldcol;
 p_ri = old_p_ri;
}

/// Insert string "s" (b_insert ? before : after) block :AKelly
/// Caller must prepare for undo.
static void block_insert(oparg_T *oap, const char *s, size_t slen, bool b_insert,
                        struct block_def *bdp)
{
 int ts_val;
 int count = 0;                // extra spaces to replace a cut TAB
 int spaces = 0;               // non-zero if cutting a TAB
 colnr_T offset;               // pointer along new line
 char *newp, *oldp;            // new, old lines
 int oldstate = State;
 State = MODE_INSERT;          // don't want MODE_REPLACE for State

 for (linenr_T lnum = oap->start.lnum + 1; lnum <= oap->end.lnum; lnum++) {
   block_prep(oap, bdp, lnum, true);
   if (bdp->is_short && b_insert) {
     continue;  // OP_INSERT, line ends before block start
   }

   oldp = ml_get(lnum);

   if (b_insert) {
     ts_val = bdp->start_char_vcols;
     spaces = bdp->startspaces;
     if (spaces != 0) {
       count = ts_val - 1;         // we're cutting a TAB
     }
     offset = bdp->textcol;
   } else {  // append
     ts_val = bdp->end_char_vcols;
     if (!bdp->is_short) {     // spaces = padding after block
       spaces = (bdp->endspaces ? ts_val - bdp->endspaces : 0);
       if (spaces != 0) {
         count = ts_val - 1;           // we're cutting a TAB
       }
       offset = bdp->textcol + bdp->textlen - (spaces != 0);
     } else {  // spaces = padding to block edge
               // if $ used, just append to EOL (ie spaces==0)
       if (!bdp->is_MAX) {
         spaces = (oap->end_vcol - bdp->end_vcol) + 1;
       }
       count = spaces;
       offset = bdp->textcol + bdp->textlen;
     }
   }

   if (spaces > 0) {
     // avoid copying part of a multi-byte character
     offset -= utf_head_off(oldp, oldp + offset);
   }
   spaces = MAX(spaces, 0);  // can happen when the cursor was moved

   assert(count >= 0);
   // Make sure the allocated size matches what is actually copied below.
   newp = xmalloc((size_t)ml_get_len(lnum) + (size_t)spaces + slen
                  + (spaces > 0 && !bdp->is_short ? (size_t)(ts_val - spaces) : 0)
                  + (size_t)count + 1);

   // copy up to shifted part
   memmove(newp, oldp, (size_t)offset);
   oldp += offset;
   int startcol = offset;

   // insert pre-padding
   memset(newp + offset, ' ', (size_t)spaces);

   // copy the new text
   memmove(newp + offset + spaces, s, slen);
   offset += (int)slen;

   int skipped = 0;
   if (spaces > 0 && !bdp->is_short) {
     if (*oldp == TAB) {
       // insert post-padding
       memset(newp + offset + spaces, ' ', (size_t)(ts_val - spaces));
       // We're splitting a TAB, don't copy it.
       oldp++;
       // We allowed for that TAB, remember this now
       count++;
       skipped = 1;
     } else {
       // Not a TAB, no extra spaces
       count = spaces;
     }
   }

   if (spaces > 0) {
     offset += count;
   }
   STRCPY(newp + offset, oldp);

   ml_replace(lnum, newp, false);
   extmark_splice_cols(curbuf, (int)lnum - 1, startcol,
                       skipped, offset - startcol, kExtmarkUndo);

   if (lnum == oap->end.lnum) {
     // Set "']" mark to the end of the block instead of the end of
     // the insert in the first line.
     curbuf->b_op_end.lnum = oap->end.lnum;
     curbuf->b_op_end.col = offset;
     if (curbuf->b_visual.vi_end.coladd) {
       curbuf->b_visual.vi_end.col += curbuf->b_visual.vi_end.coladd;
       curbuf->b_visual.vi_end.coladd = 0;
     }
   }
 }   // for all lnum

 State = oldstate;

 // Only call changed_lines if we actually modified additional lines beyond the first
 // This matches the condition for the for loop above: start + 1 <= end
 if (oap->start.lnum < oap->end.lnum) {
   changed_lines(curbuf, oap->start.lnum + 1, 0, oap->end.lnum + 1, 0, true);
 }
}

/// Handle a delete operation.
///
/// @return  FAIL if undo failed, OK otherwise.
int op_delete(oparg_T *oap)
{
 linenr_T lnum;
 struct block_def bd = { 0 };
 linenr_T old_lcount = curbuf->b_ml.ml_line_count;

 if (curbuf->b_ml.ml_flags & ML_EMPTY) {  // nothing to do
   return OK;
 }

 // Nothing to delete, return here. Do prepare undo, for op_change().
 if (oap->empty) {
   return u_save_cursor();
 }

 if (!MODIFIABLE(curbuf)) {
   emsg(_(e_modifiable));
   return FAIL;
 }

 if (VIsual_select && oap->is_VIsual) {
   // Use the register given with CTRL_R, defaults to zero
   oap->regname = VIsual_select_reg;
 }

 mb_adjust_opend(oap);

 // Imitate the strange Vi behaviour: If the delete spans more than one
 // line and motion_type == kMTCharWise and the result is a blank line, make the
 // delete linewise.  Don't do this for the change command or Visual mode.
 if (oap->motion_type == kMTCharWise
     && !oap->is_VIsual
     && oap->line_count > 1
     && oap->motion_force == NUL
     && oap->op_type == OP_DELETE) {
   char *ptr = ml_get(oap->end.lnum) + oap->end.col;
   if (*ptr != NUL) {
     ptr += oap->inclusive;
   }
   ptr = skipwhite(ptr);
   if (*ptr == NUL && inindent(0)) {
     oap->motion_type = kMTLineWise;
   }
 }

 // Check for trying to delete (e.g. "D") in an empty line.
 // Note: For the change operator it is ok.
 if (oap->motion_type != kMTLineWise
     && oap->line_count == 1
     && oap->op_type == OP_DELETE
     && *ml_get(oap->start.lnum) == NUL) {
   // It's an error to operate on an empty region, when 'E' included in
   // 'cpoptions' (Vi compatible).
   if (virtual_op) {
     // Virtual editing: Nothing gets deleted, but we set the '[ and ']
     // marks as if it happened.
     goto setmarks;
   }
   if (vim_strchr(p_cpo, CPO_EMPTYREGION) != NULL) {
     beep_flush();
   }
   return OK;
 }

 // Do a yank of whatever we're about to delete.
 // If a yank register was specified, put the deleted text into that
 // register.  For the black hole register '_' don't yank anything.
 if (oap->regname != '_') {
   yankreg_T *reg = NULL;
   bool did_yank = false;
   if (oap->regname != 0) {
     // check for read-only register
     if (!valid_yank_reg(oap->regname, true)) {
       beep_flush();
       return OK;
     }
     reg = get_yank_register(oap->regname, YREG_YANK);  // yank into specif'd reg
     op_yank_reg(oap, false, reg, is_append_register(oap->regname));  // yank without message
     did_yank = true;
   }

   // Put deleted text into register 1 and shift number registers if the
   // delete contains a line break, or when using a specific operator (Vi
   // compatible)

   if (oap->motion_type == kMTLineWise || oap->line_count > 1 || oap->use_reg_one) {
     shift_delete_registers(is_append_register(oap->regname));
     reg = get_y_register(1);
     op_yank_reg(oap, false, reg, false);
     did_yank = true;
   }

   // Yank into small delete register when no named register specified
   // and the delete is within one line.
   if (oap->regname == 0 && oap->motion_type != kMTLineWise
       && oap->line_count == 1) {
     reg = get_yank_register('-', YREG_YANK);
     op_yank_reg(oap, false, reg, false);
     did_yank = true;
   }

   if (did_yank || oap->regname == 0) {
     if (reg == NULL) {
       abort();
     }
     set_clipboard(oap->regname, reg);
     do_autocmd_textyankpost(oap, reg);
   }
 }

 // block mode delete
 if (oap->motion_type == kMTBlockWise) {
   if (u_save((linenr_T)(oap->start.lnum - 1),
              (linenr_T)(oap->end.lnum + 1)) == FAIL) {
     return FAIL;
   }

   for (lnum = curwin->w_cursor.lnum; lnum <= oap->end.lnum; lnum++) {
     block_prep(oap, &bd, lnum, true);
     if (bd.textlen == 0) {            // nothing to delete
       continue;
     }

     // Adjust cursor position for tab replaced by spaces and 'lbr'.
     if (lnum == curwin->w_cursor.lnum) {
       curwin->w_cursor.col = bd.textcol + bd.startspaces;
       curwin->w_cursor.coladd = 0;
     }

     // "n" == number of chars deleted
     // If we delete a TAB, it may be replaced by several characters.
     // Thus the number of characters may increase!
     int n = bd.textlen - bd.startspaces - bd.endspaces;
     char *oldp = ml_get(lnum);
     char *newp = xmalloc((size_t)ml_get_len(lnum) - (size_t)n + 1);
     // copy up to deleted part
     memmove(newp, oldp, (size_t)bd.textcol);
     // insert spaces
     memset(newp + bd.textcol, ' ', (size_t)bd.startspaces +
            (size_t)bd.endspaces);
     // copy the part after the deleted part
     STRCPY(newp + bd.textcol + bd.startspaces + bd.endspaces,
            oldp + bd.textcol + bd.textlen);
     // replace the line
     ml_replace(lnum, newp, false);

     extmark_splice_cols(curbuf, (int)lnum - 1, bd.textcol,
                         bd.textlen, bd.startspaces + bd.endspaces,
                         kExtmarkUndo);
   }

   check_cursor_col(curwin);
   changed_lines(curbuf, curwin->w_cursor.lnum, curwin->w_cursor.col,
                 oap->end.lnum + 1, 0, true);
   oap->line_count = 0;  // no lines deleted
 } else if (oap->motion_type == kMTLineWise) {
   if (oap->op_type == OP_CHANGE) {
     // Delete the lines except the first one.  Temporarily move the
     // cursor to the next line.  Save the current line number, if the
     // last line is deleted it may be changed.

     if (oap->line_count > 1) {
       lnum = curwin->w_cursor.lnum;
       curwin->w_cursor.lnum++;
       del_lines(oap->line_count - 1, true);
       curwin->w_cursor.lnum = lnum;
     }
     if (u_save_cursor() == FAIL) {
       return FAIL;
     }
     if (curbuf->b_p_ai) {                 // don't delete indent
       beginline(BL_WHITE);                // cursor on first non-white
       did_ai = true;                      // delete the indent when ESC hit
       ai_col = curwin->w_cursor.col;
     } else {
       beginline(0);                       // cursor in column 0
     }
     truncate_line(false);         // delete the rest of the line,
                                   // leaving cursor past last char in line
     if (oap->line_count > 1) {
       u_clearline(curbuf);  // "U" command not possible after "2cc"
     }
   } else {
     del_lines(oap->line_count, true);
     beginline(BL_WHITE | BL_FIX);
     u_clearline(curbuf);  //  "U" command not possible after "dd"
   }
 } else {
   if (virtual_op) {
     // For virtualedit: break the tabs that are partly included.
     if (gchar_pos(&oap->start) == '\t') {
       int endcol = 0;
       if (u_save_cursor() == FAIL) {          // save first line for undo
         return FAIL;
       }
       if (oap->line_count == 1) {
         endcol = getviscol2(oap->end.col, oap->end.coladd);
       }
       coladvance_force(getviscol2(oap->start.col, oap->start.coladd));
       oap->start = curwin->w_cursor;
       if (oap->line_count == 1) {
         coladvance(curwin, endcol);
         oap->end.col = curwin->w_cursor.col;
         oap->end.coladd = curwin->w_cursor.coladd;
         curwin->w_cursor = oap->start;
       }
     }

     // Break a tab only when it's included in the area.
     if (gchar_pos(&oap->end) == '\t'
         && oap->end.coladd == 0
         && oap->inclusive) {
       // save last line for undo
       if (u_save((linenr_T)(oap->end.lnum - 1),
                  (linenr_T)(oap->end.lnum + 1)) == FAIL) {
         return FAIL;
       }
       curwin->w_cursor = oap->end;
       coladvance_force(getviscol2(oap->end.col, oap->end.coladd));
       oap->end = curwin->w_cursor;
       curwin->w_cursor = oap->start;
     }
     mb_adjust_opend(oap);
   }

   if (oap->line_count == 1) {         // delete characters within one line
     if (u_save_cursor() == FAIL) {            // save line for undo
       return FAIL;
     }

     // if 'cpoptions' contains '$', display '$' at end of change
     if (vim_strchr(p_cpo, CPO_DOLLAR) != NULL
         && oap->op_type == OP_CHANGE
         && oap->end.lnum == curwin->w_cursor.lnum
         && !oap->is_VIsual) {
       display_dollar(oap->end.col - !oap->inclusive);
     }

     int n = oap->end.col - oap->start.col + 1 - !oap->inclusive;

     if (virtual_op) {
       // fix up things for virtualedit-delete:
       // break the tabs which are going to get in our way
       int len = get_cursor_line_len();

       if (oap->end.coladd != 0
           && (int)oap->end.col >= len - 1
           && !(oap->start.coladd && (int)oap->end.col >= len - 1)) {
         n++;
       }
       // Delete at least one char (e.g, when on a control char).
       if (n == 0 && oap->start.coladd != oap->end.coladd) {
         n = 1;
       }

       // When deleted a char in the line, reset coladd.
       if (gchar_cursor() != NUL) {
         curwin->w_cursor.coladd = 0;
       }
     }

     del_bytes((colnr_T)n, !virtual_op,
               oap->op_type == OP_DELETE && !oap->is_VIsual);
   } else {
     // delete characters between lines
     pos_T curpos;

     // save deleted and changed lines for undo
     if (u_save(curwin->w_cursor.lnum - 1,
                curwin->w_cursor.lnum + oap->line_count) == FAIL) {
       return FAIL;
     }

     curbuf_splice_pending++;
     pos_T startpos = curwin->w_cursor;  // start position for delete
     bcount_t deleted_bytes = get_region_bytecount(curbuf, startpos.lnum, oap->end.lnum,
                                                   startpos.col,
                                                   oap->end.col) + oap->inclusive;
     truncate_line(true);        // delete from cursor to end of line

     curpos = curwin->w_cursor;  // remember curwin->w_cursor
     curwin->w_cursor.lnum++;

     del_lines(oap->line_count - 2, false);

     // delete from start of line until op_end
     int n = (oap->end.col + 1 - !oap->inclusive);
     curwin->w_cursor.col = 0;
     del_bytes((colnr_T)n, !virtual_op,
               oap->op_type == OP_DELETE && !oap->is_VIsual);
     curwin->w_cursor = curpos;  // restore curwin->w_cursor
     do_join(2, false, false, false, false);
     curbuf_splice_pending--;
     extmark_splice(curbuf, (int)startpos.lnum - 1, startpos.col,
                    (int)oap->line_count - 1, n, deleted_bytes,
                    0, 0, 0, kExtmarkUndo);
   }
   if (oap->op_type == OP_DELETE) {
     auto_format(false, true);
   }
 }

 msgmore(curbuf->b_ml.ml_line_count - old_lcount);

setmarks:
 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   if (oap->motion_type == kMTBlockWise) {
     curbuf->b_op_end.lnum = oap->end.lnum;
     curbuf->b_op_end.col = oap->start.col;
   } else {
     curbuf->b_op_end = oap->start;
   }
   curbuf->b_op_start = oap->start;
 }

 return OK;
}

/// Adjust end of operating area for ending on a multi-byte character.
/// Used for deletion.
static void mb_adjust_opend(oparg_T *oap)
{
 if (!oap->inclusive) {
   return;
 }

 const char *line = ml_get(oap->end.lnum);
 const char *ptr = line + oap->end.col;
 if (*ptr != NUL) {
   ptr -= utf_head_off(line, ptr);
   ptr += utfc_ptr2len(ptr) - 1;
   oap->end.col = (colnr_T)(ptr - line);
 }
}

/// put byte 'c' at position 'lp', but
/// verify, that the position to place
/// is actually safe
static void pbyte(pos_T lp, int c)
{
 assert(c <= UCHAR_MAX);
 char *p = ml_get_buf_mut(curbuf, lp.lnum);
 colnr_T len = curbuf->b_ml.ml_line_textlen;

 // safety check
 if (lp.col >= len) {
   lp.col = (len > 1 ? len - 2 : 0);
 }
 *(p + lp.col) = (char)c;
 if (!curbuf_splice_pending) {
   extmark_splice_cols(curbuf, (int)lp.lnum - 1, lp.col, 1, 1, kExtmarkUndo);
 }
}

/// Replace the character under the cursor with "c".
/// This takes care of multi-byte characters.
static void replace_character(int c)
{
 const int n = State;

 State = MODE_REPLACE;
 ins_char(c);
 State = n;
 // Backup to the replaced character.
 dec_cursor();
}

/// Replace a whole area with one character.
static int op_replace(oparg_T *oap, int c)
{
 int n;
 struct block_def bd;
 char *after_p = NULL;
 bool had_ctrl_v_cr = false;

 if ((curbuf->b_ml.ml_flags & ML_EMPTY) || oap->empty) {
   return OK;              // nothing to do
 }
 if (c == REPLACE_CR_NCHAR) {
   had_ctrl_v_cr = true;
   c = CAR;
 } else if (c == REPLACE_NL_NCHAR) {
   had_ctrl_v_cr = true;
   c = NL;
 }

 mb_adjust_opend(oap);

 if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL) {
   return FAIL;
 }

 // block mode replace
 if (oap->motion_type == kMTBlockWise) {
   bd.is_MAX = (curwin->w_curswant == MAXCOL);
   for (; curwin->w_cursor.lnum <= oap->end.lnum; curwin->w_cursor.lnum++) {
     curwin->w_cursor.col = 0;       // make sure cursor position is valid
     block_prep(oap, &bd, curwin->w_cursor.lnum, true);
     if (bd.textlen == 0 && (!virtual_op || bd.is_MAX)) {
       continue;                     // nothing to replace
     }

     // n == number of extra chars required
     // If we split a TAB, it may be replaced by several characters.
     // Thus the number of characters may increase!
     // If the range starts in virtual space, count the initial
     // coladd offset as part of "startspaces"
     if (virtual_op && bd.is_short && *bd.textstart == NUL) {
       pos_T vpos;

       vpos.lnum = curwin->w_cursor.lnum;
       getvpos(curwin, &vpos, oap->start_vcol);
       bd.startspaces += vpos.coladd;
       n = bd.startspaces;
     } else {
       // allow for pre spaces
       n = (bd.startspaces ? bd.start_char_vcols - 1 : 0);
     }

     // allow for post spp
     n += (bd.endspaces
           && !bd.is_oneChar
           && bd.end_char_vcols > 0) ? bd.end_char_vcols - 1 : 0;
     // Figure out how many characters to replace.
     int numc = oap->end_vcol - oap->start_vcol + 1;
     if (bd.is_short && (!virtual_op || bd.is_MAX)) {
       numc -= (oap->end_vcol - bd.end_vcol) + 1;
     }

     // A double-wide character can be replaced only up to half the
     // times.
     if (utf_char2cells(c) > 1) {
       if ((numc & 1) && !bd.is_short) {
         bd.endspaces++;
         n++;
       }
       numc = numc / 2;
     }

     // Compute bytes needed, move character count to num_chars.
     int num_chars = numc;
     numc *= utf_char2len(c);

     char *oldp = get_cursor_line_ptr();
     colnr_T oldlen = get_cursor_line_len();

     size_t newp_size = (size_t)bd.textcol + (size_t)bd.startspaces;
     if (had_ctrl_v_cr || (c != '\r' && c != '\n')) {
       newp_size += (size_t)numc;
       if (!bd.is_short) {
         newp_size += (size_t)(bd.endspaces + oldlen
                               - bd.textcol - bd.textlen);
       }
     }
     char *newp = xmallocz(newp_size);
     // copy up to deleted part
     memmove(newp, oldp, (size_t)bd.textcol);
     oldp += bd.textcol + bd.textlen;
     // insert pre-spaces
     memset(newp + bd.textcol, ' ', (size_t)bd.startspaces);
     // insert replacement chars CHECK FOR ALLOCATED SPACE
     // REPLACE_CR_NCHAR/REPLACE_NL_NCHAR is used for entering CR literally.
     size_t after_p_len = 0;
     int col = oldlen - bd.textcol - bd.textlen + 1;
     assert(col >= 0);
     int newrows = 0;
     int newcols = 0;
     if (had_ctrl_v_cr || (c != '\r' && c != '\n')) {
       // strlen(newp) at this point
       int newp_len = bd.textcol + bd.startspaces;
       while (--num_chars >= 0) {
         newp_len += utf_char2bytes(c, newp + newp_len);
       }
       if (!bd.is_short) {
         // insert post-spaces
         memset(newp + newp_len, ' ', (size_t)bd.endspaces);
         newp_len += bd.endspaces;
         // copy the part after the changed part
         memmove(newp + newp_len, oldp, (size_t)col);
       }
       newcols = newp_len - bd.textcol;
     } else {
       // Replacing with \r or \n means splitting the line.
       after_p_len = (size_t)col;
       after_p = xmalloc(after_p_len);
       memmove(after_p, oldp, after_p_len);
       newrows = 1;
     }
     // replace the line
     ml_replace(curwin->w_cursor.lnum, newp, false);
     curbuf_splice_pending++;
     linenr_T baselnum = curwin->w_cursor.lnum;
     if (after_p != NULL) {
       ml_append(curwin->w_cursor.lnum++, after_p, (int)after_p_len, false);
       appended_lines_mark(curwin->w_cursor.lnum, 1);
       oap->end.lnum++;
       xfree(after_p);
     }
     curbuf_splice_pending--;
     extmark_splice(curbuf, (int)baselnum - 1, bd.textcol,
                    0, bd.textlen, bd.textlen,
                    newrows, newcols, newrows + newcols, kExtmarkUndo);
   }
 } else {
   // Characterwise or linewise motion replace.
   if (oap->motion_type == kMTLineWise) {
     oap->start.col = 0;
     curwin->w_cursor.col = 0;
     oap->end.col = ml_get_len(oap->end.lnum);
     if (oap->end.col) {
       oap->end.col--;
     }
   } else if (!oap->inclusive) {
     dec(&(oap->end));
   }

   // TODO(bfredl): we could batch all the splicing
   // done on the same line, at least
   while (ltoreq(curwin->w_cursor, oap->end)) {
     bool done = false;

     n = gchar_cursor();
     if (n != NUL) {
       int new_byte_len = utf_char2len(c);
       int old_byte_len = utfc_ptr2len(get_cursor_pos_ptr());

       if (new_byte_len > 1 || old_byte_len > 1) {
         // This is slow, but it handles replacing a single-byte
         // with a multi-byte and the other way around.
         if (curwin->w_cursor.lnum == oap->end.lnum) {
           oap->end.col += new_byte_len - old_byte_len;
         }
         replace_character(c);
         done = true;
       } else {
         if (n == TAB) {
           int end_vcol = 0;

           if (curwin->w_cursor.lnum == oap->end.lnum) {
             // oap->end has to be recalculated when
             // the tab breaks
             end_vcol = getviscol2(oap->end.col,
                                   oap->end.coladd);
           }
           coladvance_force(getviscol());
           if (curwin->w_cursor.lnum == oap->end.lnum) {
             getvpos(curwin, &oap->end, end_vcol);
           }
         }
         // with "coladd" set may move to just after a TAB
         if (gchar_cursor() != NUL) {
           pbyte(curwin->w_cursor, c);
           done = true;
         }
       }
     }
     if (!done && virtual_op && curwin->w_cursor.lnum == oap->end.lnum) {
       int virtcols = oap->end.coladd;

       if (curwin->w_cursor.lnum == oap->start.lnum
           && oap->start.col == oap->end.col && oap->start.coladd) {
         virtcols -= oap->start.coladd;
       }

       // oap->end has been trimmed so it's effectively inclusive;
       // as a result an extra +1 must be counted so we don't
       // trample the NUL byte.
       coladvance_force(getviscol2(oap->end.col, oap->end.coladd) + 1);
       curwin->w_cursor.col -= (virtcols + 1);
       for (; virtcols >= 0; virtcols--) {
         if (utf_char2len(c) > 1) {
           replace_character(c);
         } else {
           pbyte(curwin->w_cursor, c);
         }
         if (inc(&curwin->w_cursor) == -1) {
           break;
         }
       }
     }

     // Advance to next character, stop at the end of the file.
     if (inc_cursor() == -1) {
       break;
     }
   }
 }

 curwin->w_cursor = oap->start;
 check_cursor(curwin);
 changed_lines(curbuf, oap->start.lnum, oap->start.col, oap->end.lnum + 1, 0, true);

 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   // Set "'[" and "']" marks.
   curbuf->b_op_start = oap->start;
   curbuf->b_op_end = oap->end;
 }

 return OK;
}

/// Handle the (non-standard vi) tilde operator.  Also for "gu", "gU" and "g?".
void op_tilde(oparg_T *oap)
{
 struct block_def bd;
 bool did_change = false;

 if (u_save((linenr_T)(oap->start.lnum - 1),
            (linenr_T)(oap->end.lnum + 1)) == FAIL) {
   return;
 }

 pos_T pos = oap->start;
 if (oap->motion_type == kMTBlockWise) {  // Visual block mode
   for (; pos.lnum <= oap->end.lnum; pos.lnum++) {
     block_prep(oap, &bd, pos.lnum, false);
     pos.col = bd.textcol;
     bool one_change = swapchars(oap->op_type, &pos, bd.textlen);
     did_change |= one_change;
   }
   if (did_change) {
     changed_lines(curbuf, oap->start.lnum, 0, oap->end.lnum + 1, 0, true);
   }
 } else {  // not block mode
   if (oap->motion_type == kMTLineWise) {
     oap->start.col = 0;
     pos.col = 0;
     oap->end.col = ml_get_len(oap->end.lnum);
     if (oap->end.col) {
       oap->end.col--;
     }
   } else if (!oap->inclusive) {
     dec(&(oap->end));
   }

   if (pos.lnum == oap->end.lnum) {
     did_change = swapchars(oap->op_type, &pos,
                            oap->end.col - pos.col + 1);
   } else {
     while (true) {
       did_change |= swapchars(oap->op_type, &pos,
                               pos.lnum == oap->end.lnum ? oap->end.col + 1
                                                         : ml_get_pos_len(&pos));
       if (ltoreq(oap->end, pos) || inc(&pos) == -1) {
         break;
       }
     }
   }
   if (did_change) {
     changed_lines(curbuf, oap->start.lnum, oap->start.col, oap->end.lnum + 1,
                   0, true);
   }
 }

 if (!did_change && oap->is_VIsual) {
   // No change: need to remove the Visual selection
   redraw_curbuf_later(UPD_INVERTED);
 }

 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   // Set '[ and '] marks.
   curbuf->b_op_start = oap->start;
   curbuf->b_op_end = oap->end;
 }

 if (oap->line_count > p_report) {
   smsg(0, NGETTEXT("%" PRId64 " line changed", "%" PRId64 " lines changed", oap->line_count),
        (int64_t)oap->line_count);
 }
}

/// Invoke swapchar() on "length" bytes at position "pos".
///
/// @param pos     is advanced to just after the changed characters.
/// @param length  is rounded up to include the whole last multi-byte character.
/// Also works correctly when the number of bytes changes.
///
/// @return  true if some character was changed.
static int swapchars(int op_type, pos_T *pos, int length)
 FUNC_ATTR_NONNULL_ALL
{
 int did_change = 0;

 for (int todo = length; todo > 0; todo--) {
   const int len = utfc_ptr2len(ml_get_pos(pos));

   // we're counting bytes, not characters
   if (len > 0) {
     todo -= len - 1;
   }
   did_change |= swapchar(op_type, pos);
   if (inc(pos) == -1) {      // at end of file
     break;
   }
 }
 return did_change;
}

/// @param op_type
///                 == OP_UPPER: make uppercase,
///                 == OP_LOWER: make lowercase,
///                 == OP_ROT13: do rot13 encoding,
///                 else swap case of character at 'pos'
///
/// @return  true when something actually changed.
bool swapchar(int op_type, pos_T *pos)
 FUNC_ATTR_NONNULL_ARG(2)
{
 const int c = gchar_pos(pos);

 // Only do rot13 encoding for ASCII characters.
 if (c >= 0x80 && op_type == OP_ROT13) {
   return false;
 }

 int nc = c;
 if (mb_islower(c)) {
   if (op_type == OP_ROT13) {
     nc = ROT13(c, 'a');
   } else if (op_type != OP_LOWER) {
     nc = mb_toupper(c);
   }
 } else if (mb_isupper(c)) {
   if (op_type == OP_ROT13) {
     nc = ROT13(c, 'A');
   } else if (op_type != OP_UPPER) {
     nc = mb_tolower(c);
   }
 }
 if (nc != c) {
   if (c >= 0x80 || nc >= 0x80) {
     pos_T sp = curwin->w_cursor;

     curwin->w_cursor = *pos;
     // don't use del_char(), it also removes composing chars
     del_bytes(utf_ptr2len(get_cursor_pos_ptr()), false, false);
     ins_char(nc);
     curwin->w_cursor = sp;
   } else {
     pbyte(*pos, nc);
   }
   return true;
 }
 return false;
}

/// Insert and append operators for Visual mode.
void op_insert(oparg_T *oap, int count1)
{
 int pre_textlen = 0;
 colnr_T ind_pre_col = 0;
 int ind_pre_vcol = 0;
 struct block_def bd;

 // edit() changes this - record it for OP_APPEND
 bd.is_MAX = (curwin->w_curswant == MAXCOL);

 // vis block is still marked. Get rid of it now.
 curwin->w_cursor.lnum = oap->start.lnum;
 redraw_curbuf_later(UPD_INVERTED);
 update_screen();

 if (oap->motion_type == kMTBlockWise) {
   // When 'virtualedit' is used, need to insert the extra spaces before
   // doing block_prep().  When only "block" is used, virtual edit is
   // already disabled, but still need it when calling
   // coladvance_force().
   // coladvance_force() uses get_ve_flags() to get the 'virtualedit'
   // state for the current window.  To override that state, we need to
   // set the window-local value of ve_flags rather than the global value.
   if (curwin->w_cursor.coladd > 0) {
     unsigned old_ve_flags = curwin->w_ve_flags;

     if (u_save_cursor() == FAIL) {
       return;
     }
     curwin->w_ve_flags = kOptVeFlagAll;
     coladvance_force(oap->op_type == OP_APPEND
                      ? oap->end_vcol + 1 : getviscol());
     if (oap->op_type == OP_APPEND) {
       curwin->w_cursor.col--;
     }
     curwin->w_ve_flags = old_ve_flags;
   }
   // Get the info about the block before entering the text
   block_prep(oap, &bd, oap->start.lnum, true);
   // Get indent information
   ind_pre_col = (colnr_T)getwhitecols_curline();
   ind_pre_vcol = get_indent();
   pre_textlen = ml_get_len(oap->start.lnum) - bd.textcol;
   if (oap->op_type == OP_APPEND) {
     pre_textlen -= bd.textlen;
   }
 }

 if (oap->op_type == OP_APPEND) {
   if (oap->motion_type == kMTBlockWise
       && curwin->w_cursor.coladd == 0) {
     // Move the cursor to the character right of the block.
     curwin->w_set_curswant = true;
     while (*get_cursor_pos_ptr() != NUL
            && (curwin->w_cursor.col < bd.textcol + bd.textlen)) {
       curwin->w_cursor.col++;
     }
     if (bd.is_short && !bd.is_MAX) {
       // First line was too short, make it longer and adjust the
       // values in "bd".
       if (u_save_cursor() == FAIL) {
         return;
       }
       for (int i = 0; i < bd.endspaces; i++) {
         ins_char(' ');
       }
       bd.textlen += bd.endspaces;
     }
   } else {
     curwin->w_cursor = oap->end;
     check_cursor_col(curwin);

     // Works just like an 'i'nsert on the next character.
     if (!LINEEMPTY(curwin->w_cursor.lnum)
         && oap->start_vcol != oap->end_vcol) {
       inc_cursor();
     }
   }
 }

 pos_T t1 = oap->start;
 const pos_T start_insert = curwin->w_cursor;
 edit(NUL, false, (linenr_T)count1);

 // When a tab was inserted, and the characters in front of the tab
 // have been converted to a tab as well, the column of the cursor
 // might have actually been reduced, so need to adjust here.
 if (t1.lnum == curbuf->b_op_start_orig.lnum
     && lt(curbuf->b_op_start_orig, t1)) {
   oap->start = curbuf->b_op_start_orig;
 }

 // If user has moved off this line, we don't know what to do, so do
 // nothing.
 // Also don't repeat the insert when Insert mode ended with CTRL-C.
 if (curwin->w_cursor.lnum != oap->start.lnum || got_int) {
   return;
 }

 if (oap->motion_type == kMTBlockWise) {
   int ind_post_vcol = 0;
   struct block_def bd2;
   bool did_indent = false;

   // if indent kicked in, the firstline might have changed
   // but only do that, if the indent actually increased
   colnr_T ind_post_col = (colnr_T)getwhitecols_curline();
   if (curbuf->b_op_start.col > ind_pre_col && ind_post_col > ind_pre_col) {
     bd.textcol += ind_post_col - ind_pre_col;
     ind_post_vcol = get_indent();
     bd.start_vcol += ind_post_vcol - ind_pre_vcol;
     did_indent = true;
   }

   // The user may have moved the cursor before inserting something, try
   // to adjust the block for that.  But only do it, if the difference
   // does not come from indent kicking in.
   if (oap->start.lnum == curbuf->b_op_start_orig.lnum && !bd.is_MAX && !did_indent) {
     const int t = getviscol2(curbuf->b_op_start_orig.col, curbuf->b_op_start_orig.coladd);

     if (oap->op_type == OP_INSERT
         && oap->start.col + oap->start.coladd
         != curbuf->b_op_start_orig.col + curbuf->b_op_start_orig.coladd) {
       oap->start.col = curbuf->b_op_start_orig.col;
       pre_textlen -= t - oap->start_vcol;
       oap->start_vcol = t;
     } else if (oap->op_type == OP_APPEND
                && oap->start.col + oap->start.coladd
                >= curbuf->b_op_start_orig.col + curbuf->b_op_start_orig.coladd) {
       oap->start.col = curbuf->b_op_start_orig.col;
       // reset pre_textlen to the value of OP_INSERT
       pre_textlen += bd.textlen;
       pre_textlen -= t - oap->start_vcol;
       oap->start_vcol = t;
       oap->op_type = OP_INSERT;
     }
   }

   // Spaces and tabs in the indent may have changed to other spaces and
   // tabs.  Get the starting column again and correct the length.
   // Don't do this when "$" used, end-of-line will have changed.
   //
   // if indent was added and the inserted text was after the indent,
   // correct the selection for the new indent.
   if (did_indent && bd.textcol - ind_post_col > 0) {
     oap->start.col += ind_post_col - ind_pre_col;
     oap->start_vcol += ind_post_vcol - ind_pre_vcol;
     oap->end.col += ind_post_col - ind_pre_col;
     oap->end_vcol += ind_post_vcol - ind_pre_vcol;
   }
   block_prep(oap, &bd2, oap->start.lnum, true);
   if (did_indent && bd.textcol - ind_post_col > 0) {
     // undo for where "oap" is used below
     oap->start.col -= ind_post_col - ind_pre_col;
     oap->start_vcol -= ind_post_vcol - ind_pre_vcol;
     oap->end.col -= ind_post_col - ind_pre_col;
     oap->end_vcol -= ind_post_vcol - ind_pre_vcol;
   }
   if (!bd.is_MAX || bd2.textlen < bd.textlen) {
     if (oap->op_type == OP_APPEND) {
       pre_textlen += bd2.textlen - bd.textlen;
       if (bd2.endspaces) {
         bd2.textlen--;
       }
     }
     bd.textcol = bd2.textcol;
     bd.textlen = bd2.textlen;
   }

   // Subsequent calls to ml_get() flush the firstline data - take a
   // copy of the required string.
   char *firstline = ml_get(oap->start.lnum);
   colnr_T len = ml_get_len(oap->start.lnum);
   colnr_T add = bd.textcol;
   colnr_T offset = 0;  // offset when cursor was moved in insert mode
   if (oap->op_type == OP_APPEND) {
     add += bd.textlen;
     // account for pressing cursor in insert mode when '$' was used
     if (bd.is_MAX && start_insert.lnum == Insstart.lnum && start_insert.col > Insstart.col) {
       offset = start_insert.col - Insstart.col;
       add -= offset;
       if (oap->end_vcol > offset) {
         oap->end_vcol -= offset + 1;
       } else {
         // moved outside of the visual block, what to do?
         return;
       }
     }
   }
   add = MIN(add, len);  // short line, point to the NUL
   firstline += add;
   len -= add;
   int ins_len = len - pre_textlen - offset;
   if (pre_textlen >= 0 && ins_len > 0) {
     char *ins_text = xmemdupz(firstline, (size_t)ins_len);
     // block handled here
     if (u_save(oap->start.lnum, (linenr_T)(oap->end.lnum + 1)) == OK) {
       block_insert(oap, ins_text, (size_t)ins_len, (oap->op_type == OP_INSERT), &bd);
     }

     curwin->w_cursor.col = oap->start.col;
     check_cursor(curwin);
     xfree(ins_text);
   }
 }
}

/// handle a change operation
///
/// @return  true if edit() returns because of a CTRL-O command
int op_change(oparg_T *oap)
{
 int pre_textlen = 0;
 int pre_indent = 0;
 char *firstline;
 struct block_def bd;

 colnr_T l = oap->start.col;
 if (oap->motion_type == kMTLineWise) {
   l = 0;
   can_si = may_do_si();  // Like opening a new line, do smart indent
 }

 // First delete the text in the region.  In an empty buffer only need to
 // save for undo
 if (curbuf->b_ml.ml_flags & ML_EMPTY) {
   if (u_save_cursor() == FAIL) {
     return false;
   }
 } else if (op_delete(oap) == FAIL) {
   return false;
 }

 if ((l > curwin->w_cursor.col) && !LINEEMPTY(curwin->w_cursor.lnum)
     && !virtual_op) {
   inc_cursor();
 }

 // check for still on same line (<CR> in inserted text meaningless)
 // skip blank lines too
 if (oap->motion_type == kMTBlockWise) {
   // Add spaces before getting the current line length.
   if (virtual_op && (curwin->w_cursor.coladd > 0
                      || gchar_cursor() == NUL)) {
     coladvance_force(getviscol());
   }
   firstline = ml_get(oap->start.lnum);
   pre_textlen = ml_get_len(oap->start.lnum);
   pre_indent = (int)getwhitecols(firstline);
   bd.textcol = curwin->w_cursor.col;
 }

 if (oap->motion_type == kMTLineWise) {
   fix_indent();
 }

 // Reset finish_op now, don't want it set inside edit().
 const bool save_finish_op = finish_op;
 finish_op = false;

 int retval = edit(NUL, false, 1);

 finish_op = save_finish_op;

 // In Visual block mode, handle copying the new text to all lines of the
 // block.
 // Don't repeat the insert when Insert mode ended with CTRL-C.
 if (oap->motion_type == kMTBlockWise
     && oap->start.lnum != oap->end.lnum && !got_int) {
   // Auto-indenting may have changed the indent.  If the cursor was past
   // the indent, exclude that indent change from the inserted text.
   firstline = ml_get(oap->start.lnum);
   if (bd.textcol > (colnr_T)pre_indent) {
     int new_indent = (int)getwhitecols(firstline);

     pre_textlen += new_indent - pre_indent;
     bd.textcol += (colnr_T)(new_indent - pre_indent);
   }

   int ins_len = ml_get_len(oap->start.lnum) - pre_textlen;
   if (ins_len > 0) {
     // Subsequent calls to ml_get() flush the firstline data - take a
     // copy of the inserted text.
     char *ins_text = xmalloc((size_t)ins_len + 1);
     xmemcpyz(ins_text, firstline + bd.textcol, (size_t)ins_len);
     for (linenr_T linenr = oap->start.lnum + 1; linenr <= oap->end.lnum;
          linenr++) {
       block_prep(oap, &bd, linenr, true);
       if (!bd.is_short || virtual_op) {
         pos_T vpos;

         // If the block starts in virtual space, count the
         // initial coladd offset as part of "startspaces"
         if (bd.is_short) {
           vpos.lnum = linenr;
           getvpos(curwin, &vpos, oap->start_vcol);
         } else {
           vpos.coladd = 0;
         }
         char *oldp = ml_get(linenr);
         char *newp = xmalloc((size_t)ml_get_len(linenr)
                              + (size_t)vpos.coladd + (size_t)ins_len + 1);
         // copy up to block start
         memmove(newp, oldp, (size_t)bd.textcol);
         int newlen = bd.textcol;
         memset(newp + newlen, ' ', (size_t)vpos.coladd);
         newlen += vpos.coladd;
         memmove(newp + newlen, ins_text, (size_t)ins_len);
         newlen += ins_len;
         STRCPY(newp + newlen, oldp + bd.textcol);
         ml_replace(linenr, newp, false);
         extmark_splice_cols(curbuf, (int)linenr - 1, bd.textcol,
                             0, vpos.coladd + ins_len, kExtmarkUndo);
       }
     }
     check_cursor(curwin);
     changed_lines(curbuf, oap->start.lnum + 1, 0, oap->end.lnum + 1, 0, true);
     xfree(ins_text);
   }
 }
 auto_format(false, true);

 return retval;
}

/// When the cursor is on the NUL past the end of the line and it should not be
/// there move it left.
void adjust_cursor_eol(void)
{
 unsigned cur_ve_flags = get_ve_flags(curwin);

 const bool adj_cursor = (curwin->w_cursor.col > 0
                          && gchar_cursor() == NUL
                          && (cur_ve_flags & kOptVeFlagOnemore) == 0
                          && (cur_ve_flags & kOptVeFlagAll) == 0
                          && !(restart_edit || (State & MODE_INSERT)));
 if (!adj_cursor) {
   return;
 }

 // Put the cursor on the last character in the line.
 dec_cursor();

 if (cur_ve_flags == kOptVeFlagAll) {
   colnr_T scol, ecol;

   // Coladd is set to the width of the last character.
   getvcol(curwin, &curwin->w_cursor, &scol, NULL, &ecol);
   curwin->w_cursor.coladd = ecol - scol + 1;
 }
}

/// If \p "process" is true and the line begins with a comment leader (possibly
/// after some white space), return a pointer to the text after it.
/// Put a boolean value indicating whether the line ends with an unclosed
/// comment in "is_comment".
///
/// @param line - line to be processed
/// @param process - if false, will only check whether the line ends
///         with an unclosed comment,
/// @param include_space - whether to skip space following the comment leader
/// @param[out] is_comment - whether the current line ends with an unclosed
///  comment.
char *skip_comment(char *line, bool process, bool include_space, bool *is_comment)
{
 char *comment_flags = NULL;
 int leader_offset = get_last_leader_offset(line, &comment_flags);

 *is_comment = false;
 if (leader_offset != -1) {
   // Let's check whether the line ends with an unclosed comment.
   // If the last comment leader has COM_END in flags, there's no comment.
   while (*comment_flags) {
     if (*comment_flags == COM_END
         || *comment_flags == ':') {
       break;
     }
     comment_flags++;
   }
   if (*comment_flags != COM_END) {
     *is_comment = true;
   }
 }

 if (process == false) {
   return line;
 }

 int lead_len = get_leader_len(line, &comment_flags, false, include_space);

 if (lead_len == 0) {
   return line;
 }

 // Find:
 // - COM_END,
 // - colon,
 // whichever comes first.
 while (*comment_flags) {
   if (*comment_flags == COM_END
       || *comment_flags == ':') {
     break;
   }
   comment_flags++;
 }

 // If we found a colon, it means that we are not processing a line
 // starting with a closing part of a three-part comment. That's good,
 // because we don't want to remove those as this would be annoying.
 if (*comment_flags == ':' || *comment_flags == NUL) {
   line += lead_len;
 }

 return line;
}

/// @param count              number of lines (minimal 2) to join at the cursor position.
/// @param save_undo          when true, save lines for undo first.
/// @param use_formatoptions  set to false when e.g. processing backspace and comment
///                           leaders should not be removed.
/// @param setmark            when true, sets the '[ and '] mark, else, the caller is expected
///                           to set those marks.
///
/// @return  FAIL for failure, OK otherwise
int do_join(size_t count, bool insert_space, bool save_undo, bool use_formatoptions, bool setmark)
{
 char *curr = NULL;
 char *curr_start = NULL;
 char *cend;
 int endcurr1 = NUL;
 int endcurr2 = NUL;
 int currsize = 0;             // size of the current line
 int sumsize = 0;              // size of the long new line
 int ret = OK;
 int *comments = NULL;
 bool remove_comments = use_formatoptions && has_format_option(FO_REMOVE_COMS);
 bool prev_was_comment = false;
 assert(count >= 1);

 if (save_undo && u_save(curwin->w_cursor.lnum - 1,
                         curwin->w_cursor.lnum + (linenr_T)count) == FAIL) {
   return FAIL;
 }
 // Allocate an array to store the number of spaces inserted before each
 // line.  We will use it to pre-compute the length of the new line and the
 // proper placement of each original line in the new one.
 char *spaces = xcalloc(count, 1);  // number of spaces inserted before a line
 if (remove_comments) {
   comments = xcalloc(count, sizeof(*comments));
 }

 // Don't move anything yet, just compute the final line length
 // and setup the array of space strings lengths
 // This loops forward over joined lines.
 for (linenr_T t = 0; t < (linenr_T)count; t++) {
   curr_start = ml_get(curwin->w_cursor.lnum + t);
   curr = curr_start;
   if (t == 0 && setmark && (cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
     // Set the '[ mark.
     curwin->w_buffer->b_op_start.lnum = curwin->w_cursor.lnum;
     curwin->w_buffer->b_op_start.col = (colnr_T)strlen(curr);
   }
   if (remove_comments) {
     // We don't want to remove the comment leader if the
     // previous line is not a comment.
     if (t > 0 && prev_was_comment) {
       char *new_curr = skip_comment(curr, true, insert_space, &prev_was_comment);
       comments[t] = (int)(new_curr - curr);
       curr = new_curr;
     } else {
       curr = skip_comment(curr, false, insert_space, &prev_was_comment);
     }
   }

   if (insert_space && t > 0) {
     curr = skipwhite(curr);
     if (*curr != NUL
         && *curr != ')'
         && sumsize != 0
         && endcurr1 != TAB
         && (!has_format_option(FO_MBYTE_JOIN)
             || (utf_ptr2char(curr) < 0x100 && endcurr1 < 0x100))
         && (!has_format_option(FO_MBYTE_JOIN2)
             || (utf_ptr2char(curr) < 0x100 && !utf_eat_space(endcurr1))
             || (endcurr1 < 0x100
                 && !utf_eat_space(utf_ptr2char(curr))))) {
       // don't add a space if the line is ending in a space
       if (endcurr1 == ' ') {
         endcurr1 = endcurr2;
       } else {
         spaces[t]++;
       }
       // Extra space when 'joinspaces' set and line ends in '.', '?', or '!'.
       if (p_js && (endcurr1 == '.' || endcurr1 == '?' || endcurr1 == '!')) {
         spaces[t]++;
       }
     }
   }

   if (t > 0 && curbuf_splice_pending == 0) {
     colnr_T removed = (int)(curr - curr_start);
     extmark_splice(curbuf, (int)curwin->w_cursor.lnum - 1, sumsize,
                    1, removed, removed + 1,
                    0, spaces[t], spaces[t],
                    kExtmarkUndo);
   }
   currsize = (int)strlen(curr);
   sumsize += currsize + spaces[t];
   endcurr1 = endcurr2 = NUL;
   if (insert_space && currsize > 0) {
     cend = curr + currsize;
     MB_PTR_BACK(curr, cend);
     endcurr1 = utf_ptr2char(cend);
     if (cend > curr) {
       MB_PTR_BACK(curr, cend);
       endcurr2 = utf_ptr2char(cend);
     }
   }
   line_breakcheck();
   if (got_int) {
     ret = FAIL;
     goto theend;
   }
 }

 // store the column position before last line
 colnr_T col = sumsize - currsize - spaces[count - 1];

 // allocate the space for the new line
 size_t newp_len = (size_t)sumsize;
 char *newp = xmallocz(newp_len);
 cend = newp + sumsize;

 // Move affected lines to the new long one.
 // This loops backwards over the joined lines, including the original line.
 //
 // Move marks from each deleted line to the joined line, adjusting the
 // column.  This is not Vi compatible, but Vi deletes the marks, thus that
 // should not really be a problem.

 curbuf_splice_pending++;

 for (linenr_T t = (linenr_T)count - 1;; t--) {
   cend -= currsize;
   memmove(cend, curr, (size_t)currsize);

   if (spaces[t] > 0) {
     cend -= spaces[t];
     memset(cend, ' ', (size_t)(spaces[t]));
   }

   // If deleting more spaces than adding, the cursor moves no more than
   // what is added if it is inside these spaces.
   const int spaces_removed = (int)((curr - curr_start) - spaces[t]);
   linenr_T lnum = curwin->w_cursor.lnum + t;
   colnr_T mincol = 0;
   linenr_T lnum_amount = -t;
   colnr_T col_amount = (colnr_T)(cend - newp - spaces_removed);

   mark_col_adjust(lnum, mincol, lnum_amount, col_amount, spaces_removed);

   if (t == 0) {
     break;
   }

   curr_start = ml_get((linenr_T)(curwin->w_cursor.lnum + t - 1));
   curr = curr_start;
   if (remove_comments) {
     curr += comments[t - 1];
   }
   if (insert_space && t > 1) {
     curr = skipwhite(curr);
   }
   currsize = (int)strlen(curr);
 }

 ml_replace_len(curwin->w_cursor.lnum, newp, newp_len, false);

 if (setmark && (cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   // Set the '] mark.
   curwin->w_buffer->b_op_end.lnum = curwin->w_cursor.lnum;
   curwin->w_buffer->b_op_end.col = sumsize;
 }

 // Only report the change in the first line here, del_lines() will report
 // the deleted line.
 changed_lines(curbuf, curwin->w_cursor.lnum, currsize,
               curwin->w_cursor.lnum + 1, 0, true);

 // Delete following lines. To do this we move the cursor there
 // briefly, and then move it back. After del_lines() the cursor may
 // have moved up (last line deleted), so the current lnum is kept in t.
 linenr_T t = curwin->w_cursor.lnum;
 curwin->w_cursor.lnum++;
 del_lines((int)count - 1, false);
 curwin->w_cursor.lnum = t;
 curbuf_splice_pending--;
 curbuf->deleted_bytes2 = 0;

 // Set the cursor column:
 // Vi compatible: use the column of the first join
 // vim:             use the column of the last join
 curwin->w_cursor.col =
   (vim_strchr(p_cpo, CPO_JOINCOL) != NULL ? currsize : col);
 check_cursor_col(curwin);

 curwin->w_cursor.coladd = 0;
 curwin->w_set_curswant = true;

theend:
 xfree(spaces);
 if (remove_comments) {
   xfree(comments);
 }
 return ret;
}

/// Reset 'linebreak' and take care of side effects.
/// @return  the previous value, to be passed to restore_lbr().
bool reset_lbr(void)
{
 if (!curwin->w_p_lbr) {
   return false;
 }
 // changing 'linebreak' may require w_virtcol to be updated
 curwin->w_p_lbr = false;
 curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
 return true;
}

/// Restore 'linebreak' and take care of side effects.
void restore_lbr(bool lbr_saved)
{
 if (curwin->w_p_lbr || !lbr_saved) {
   return;
 }

 // changing 'linebreak' may require w_virtcol to be updated
 curwin->w_p_lbr = true;
 curwin->w_valid &= ~(VALID_WROW|VALID_WCOL|VALID_VIRTCOL);
}

/// prepare a few things for block mode yank/delete/tilde
///
/// for delete:
/// - textlen includes the first/last char to be (partly) deleted
/// - start/endspaces is the number of columns that are taken by the
///   first/last deleted char minus the number of columns that have to be
///   deleted.
/// for yank and tilde:
/// - textlen includes the first/last char to be wholly yanked
/// - start/endspaces is the number of columns of the first/last yanked char
///   that are to be yanked.
void block_prep(oparg_T *oap, struct block_def *bdp, linenr_T lnum, bool is_del)
{
 int incr = 0;
 // Avoid a problem with unwanted linebreaks in block mode.
 const bool lbr_saved = reset_lbr();

 bdp->startspaces = 0;
 bdp->endspaces = 0;
 bdp->textlen = 0;
 bdp->start_vcol = 0;
 bdp->end_vcol = 0;
 bdp->is_short = false;
 bdp->is_oneChar = false;
 bdp->pre_whitesp = 0;
 bdp->pre_whitesp_c = 0;
 bdp->end_char_vcols = 0;
 bdp->start_char_vcols = 0;

 char *line = ml_get(lnum);
 char *prev_pstart = line;

 CharsizeArg csarg;
 CSType cstype = init_charsize_arg(&csarg, curwin, lnum, line);
 StrCharInfo ci = utf_ptr2StrCharInfo(line);
 int vcol = bdp->start_vcol;
 while (vcol < oap->start_vcol && *ci.ptr != NUL) {
   incr = win_charsize(cstype, vcol, ci.ptr, ci.chr.value, &csarg).width;
   vcol += incr;
   if (ascii_iswhite(ci.chr.value)) {
     bdp->pre_whitesp += incr;
     bdp->pre_whitesp_c++;
   } else {
     bdp->pre_whitesp = 0;
     bdp->pre_whitesp_c = 0;
   }
   prev_pstart = ci.ptr;
   ci = utfc_next(ci);
 }
 bdp->start_vcol = vcol;
 char *pstart = ci.ptr;

 bdp->start_char_vcols = incr;
 if (bdp->start_vcol < oap->start_vcol) {      // line too short
   bdp->end_vcol = bdp->start_vcol;
   bdp->is_short = true;
   if (!is_del || oap->op_type == OP_APPEND) {
     bdp->endspaces = oap->end_vcol - oap->start_vcol + 1;
   }
 } else {
   // notice: this converts partly selected Multibyte characters to
   // spaces, too.
   bdp->startspaces = bdp->start_vcol - oap->start_vcol;
   if (is_del && bdp->startspaces) {
     bdp->startspaces = bdp->start_char_vcols - bdp->startspaces;
   }
   char *pend = pstart;
   bdp->end_vcol = bdp->start_vcol;
   if (bdp->end_vcol > oap->end_vcol) {  // it's all in one character
     bdp->is_oneChar = true;
     if (oap->op_type == OP_INSERT) {
       bdp->endspaces = bdp->start_char_vcols - bdp->startspaces;
     } else if (oap->op_type == OP_APPEND) {
       bdp->startspaces += oap->end_vcol - oap->start_vcol + 1;
       bdp->endspaces = bdp->start_char_vcols - bdp->startspaces;
     } else {
       bdp->startspaces = oap->end_vcol - oap->start_vcol + 1;
       if (is_del && oap->op_type != OP_LSHIFT) {
         // just putting the sum of those two into
         // bdp->startspaces doesn't work for Visual replace,
         // so we have to split the tab in two
         bdp->startspaces = bdp->start_char_vcols
                            - (bdp->start_vcol - oap->start_vcol);
         bdp->endspaces = bdp->end_vcol - oap->end_vcol - 1;
       }
     }
   } else {
     cstype = init_charsize_arg(&csarg, curwin, lnum, line);
     ci = utf_ptr2StrCharInfo(pend);
     vcol = bdp->end_vcol;
     char *prev_pend = pend;
     while (vcol <= oap->end_vcol && *ci.ptr != NUL) {
       prev_pend = ci.ptr;
       incr = win_charsize(cstype, vcol, ci.ptr, ci.chr.value, &csarg).width;
       vcol += incr;
       ci = utfc_next(ci);
     }
     bdp->end_vcol = vcol;
     pend = ci.ptr;

     if (bdp->end_vcol <= oap->end_vcol
         && (!is_del
             || oap->op_type == OP_APPEND
             || oap->op_type == OP_REPLACE)) {  // line too short
       bdp->is_short = true;
       // Alternative: include spaces to fill up the block.
       // Disadvantage: can lead to trailing spaces when the line is
       // short where the text is put
       // if (!is_del || oap->op_type == OP_APPEND)
       if (oap->op_type == OP_APPEND || virtual_op) {
         bdp->endspaces = oap->end_vcol - bdp->end_vcol
                          + oap->inclusive;
       }
     } else if (bdp->end_vcol > oap->end_vcol) {
       bdp->endspaces = bdp->end_vcol - oap->end_vcol - 1;
       if (!is_del && bdp->endspaces) {
         bdp->endspaces = incr - bdp->endspaces;
         if (pend != pstart) {
           pend = prev_pend;
         }
       }
     }
   }
   bdp->end_char_vcols = incr;
   if (is_del && bdp->startspaces) {
     pstart = prev_pstart;
   }
   bdp->textlen = (int)(pend - pstart);
 }
 bdp->textcol = (colnr_T)(pstart - line);
 bdp->textstart = pstart;
 restore_lbr(lbr_saved);
}

/// Get block text from "start" to "end"
void charwise_block_prep(pos_T start, pos_T end, struct block_def *bdp, linenr_T lnum,
                        bool inclusive)
{
 colnr_T startcol = 0;
 colnr_T endcol = MAXCOL;
 colnr_T cs, ce;
 char *p = ml_get(lnum);
 int plen = ml_get_len(lnum);

 bdp->startspaces = 0;
 bdp->endspaces = 0;
 bdp->is_oneChar = false;
 bdp->start_char_vcols = 0;

 if (lnum == start.lnum) {
   startcol = start.col;
   if (virtual_op) {
     getvcol(curwin, &start, &cs, NULL, &ce);
     if (ce != cs && start.coladd > 0) {
       // Part of a tab selected -- but don't double-count it.
       bdp->start_char_vcols = ce - cs + 1;
       bdp->startspaces = MAX(bdp->start_char_vcols - start.coladd, 0);
       startcol++;
     }
   }
 }

 if (lnum == end.lnum) {
   endcol = end.col;
   if (virtual_op) {
     getvcol(curwin, &end, &cs, NULL, &ce);
     if (p[endcol] == NUL || (cs + end.coladd < ce
                              // Don't add space for double-wide
                              // char; endcol will be on last byte
                              // of multi-byte char.
                              && utf_head_off(p, p + endcol) == 0)) {
       if (start.lnum == end.lnum && start.col == end.col) {
         // Special case: inside a single char
         bdp->is_oneChar = true;
         bdp->startspaces = end.coladd - start.coladd + inclusive;
         endcol = startcol;
       } else {
         bdp->endspaces = end.coladd + inclusive;
         endcol -= inclusive;
       }
     }
   }
 }
 if (endcol == MAXCOL) {
   endcol = ml_get_len(lnum);
 }
 if (startcol > endcol || bdp->is_oneChar) {
   bdp->textlen = 0;
 } else {
   bdp->textlen = endcol - startcol + inclusive;
 }
 bdp->textcol = startcol;
 bdp->textstart = startcol <= plen ? p + startcol : p;
}

/// Handle the add/subtract operator.
///
/// @param[in]  oap      Arguments of operator.
/// @param[in]  Prenum1  Amount of addition or subtraction.
/// @param[in]  g_cmd    Prefixed with `g`.
void op_addsub(oparg_T *oap, linenr_T Prenum1, bool g_cmd)
{
 struct block_def bd;
 ssize_t change_cnt = 0;
 linenr_T amount = Prenum1;

 // do_addsub() might trigger re-evaluation of 'foldexpr' halfway, when the
 // buffer is not completely updated yet. Postpone updating folds until before
 // the call to changed_lines().
 disable_fold_update++;

 if (!VIsual_active) {
   pos_T pos = curwin->w_cursor;
   if (u_save_cursor() == FAIL) {
     disable_fold_update--;
     return;
   }
   change_cnt = do_addsub(oap->op_type, &pos, 0, amount);
   disable_fold_update--;
   if (change_cnt) {
     changed_lines(curbuf, pos.lnum, 0, pos.lnum + 1, 0, true);
   }
 } else {
   int length;
   pos_T startpos;

   if (u_save((linenr_T)(oap->start.lnum - 1),
              (linenr_T)(oap->end.lnum + 1)) == FAIL) {
     disable_fold_update--;
     return;
   }

   pos_T pos = oap->start;
   for (; pos.lnum <= oap->end.lnum; pos.lnum++) {
     if (oap->motion_type == kMTBlockWise) {
       // Visual block mode
       block_prep(oap, &bd, pos.lnum, false);
       pos.col = bd.textcol;
       length = bd.textlen;
     } else if (oap->motion_type == kMTLineWise) {
       curwin->w_cursor.col = 0;
       pos.col = 0;
       length = ml_get_len(pos.lnum);
     } else {
       // oap->motion_type == kMTCharWise
       if (pos.lnum == oap->start.lnum && !oap->inclusive) {
         dec(&(oap->end));
       }
       length = ml_get_len(pos.lnum);
       pos.col = 0;
       if (pos.lnum == oap->start.lnum) {
         pos.col += oap->start.col;
         length -= oap->start.col;
       }
       if (pos.lnum == oap->end.lnum) {
         length = ml_get_len(oap->end.lnum);
         oap->end.col = MIN(oap->end.col, length - 1);
         length = oap->end.col - pos.col + 1;
       }
     }
     bool one_change = do_addsub(oap->op_type, &pos, length, amount);
     if (one_change) {
       // Remember the start position of the first change.
       if (change_cnt == 0) {
         startpos = curbuf->b_op_start;
       }
       change_cnt++;
     }

     if (g_cmd && one_change) {
       amount += Prenum1;
     }
   }

   disable_fold_update--;
   if (change_cnt) {
     changed_lines(curbuf, oap->start.lnum, 0, oap->end.lnum + 1, 0, true);
   }

   if (!change_cnt && oap->is_VIsual) {
     // No change: need to remove the Visual selection
     redraw_curbuf_later(UPD_INVERTED);
   }

   // Set '[ mark if something changed. Keep the last end
   // position from do_addsub().
   if (change_cnt > 0 && (cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
     curbuf->b_op_start = startpos;
   }

   if (change_cnt > p_report) {
     smsg(0, NGETTEXT("%" PRId64 " lines changed", "%" PRId64 " lines changed", change_cnt),
          (int64_t)change_cnt);
   }
 }
}

/// Add or subtract from a number in a line.
///
/// @param op_type OP_NR_ADD or OP_NR_SUB.
/// @param pos     Cursor position.
/// @param length  Target number length.
/// @param Prenum1 Amount of addition or subtraction.
///
/// @return true if some character was changed.
bool do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
{
 int pre;  // 'X' or 'x': hex; '0': octal; 'B' or 'b': bin
 static bool hexupper = false;  // 0xABC
 uvarnumber_T n;
 bool blank_unsigned = false;  // blank: treat as unsigned?
 bool negative = false;
 bool was_positive = true;
 bool visual = VIsual_active;
 bool did_change = false;
 pos_T save_cursor = curwin->w_cursor;
 int maxlen = 0;
 pos_T startpos;
 pos_T endpos;
 colnr_T save_coladd = 0;

 const bool do_hex = vim_strchr(curbuf->b_p_nf, 'x') != NULL;       // "heX"
 const bool do_oct = vim_strchr(curbuf->b_p_nf, 'o') != NULL;       // "Octal"
 const bool do_bin = vim_strchr(curbuf->b_p_nf, 'b') != NULL;       // "Bin"
 const bool do_alpha = vim_strchr(curbuf->b_p_nf, 'p') != NULL;     // "alPha"
 const bool do_unsigned = vim_strchr(curbuf->b_p_nf, 'u') != NULL;  // "Unsigned"
 const bool do_blank = vim_strchr(curbuf->b_p_nf, 'k') != NULL;     // "blanK"

 if (virtual_active(curwin)) {
   save_coladd = pos->coladd;
   pos->coladd = 0;
 }

 curwin->w_cursor = *pos;
 char *ptr = ml_get(pos->lnum);
 int linelen = ml_get_len(pos->lnum);
 int col = pos->col;

 if (col + !!save_coladd >= linelen) {
   goto theend;
 }

 // First check if we are on a hexadecimal number, after the "0x".
 if (!VIsual_active) {
   if (do_bin) {
     while (col > 0 && ascii_isbdigit(ptr[col])) {
       col--;
       col -= utf_head_off(ptr, ptr + col);
     }
   }

   if (do_hex) {
     while (col > 0 && ascii_isxdigit(ptr[col])) {
       col--;
       col -= utf_head_off(ptr, ptr + col);
     }
   }
   if (do_bin
       && do_hex
       && !((col > 0
             && (ptr[col] == 'X' || ptr[col] == 'x')
             && ptr[col - 1] == '0'
             && !utf_head_off(ptr, ptr + col - 1)
             && ascii_isxdigit(ptr[col + 1])))) {
     // In case of binary/hexadecimal pattern overlap match, rescan

     col = curwin->w_cursor.col;

     while (col > 0 && ascii_isdigit(ptr[col])) {
       col--;
       col -= utf_head_off(ptr, ptr + col);
     }
   }

   if ((do_hex
        && col > 0
        && (ptr[col] == 'X' || ptr[col] == 'x')
        && ptr[col - 1] == '0'
        && !utf_head_off(ptr, ptr + col - 1)
        && ascii_isxdigit(ptr[col + 1]))
       || (do_bin
           && col > 0
           && (ptr[col] == 'B' || ptr[col] == 'b')
           && ptr[col - 1] == '0'
           && !utf_head_off(ptr, ptr + col - 1)
           && ascii_isbdigit(ptr[col + 1]))) {
     // Found hexadecimal or binary number, move to its start.
     col--;
     col -= utf_head_off(ptr, ptr + col);
   } else {
     // Search forward and then backward to find the start of number.
     col = pos->col;

     while (ptr[col] != NUL
            && !ascii_isdigit(ptr[col])
            && !(do_alpha && ASCII_ISALPHA(ptr[col]))) {
       col++;
     }

     while (col > 0
            && ascii_isdigit(ptr[col - 1])
            && !(do_alpha && ASCII_ISALPHA(ptr[col]))) {
       col--;
     }
   }
 }

 if (visual) {
   while (ptr[col] != NUL && length > 0 && !ascii_isdigit(ptr[col])
          && !(do_alpha && ASCII_ISALPHA(ptr[col]))) {
     int mb_len = utfc_ptr2len(ptr + col);

     col += mb_len;
     length -= mb_len;
   }

   if (length == 0) {
     goto theend;
   }

   if (col > pos->col && ptr[col - 1] == '-'
       && !utf_head_off(ptr, ptr + col - 1)
       && !do_unsigned) {
     if (do_blank && col >= 2 && !ascii_iswhite(ptr[col - 2])) {
       blank_unsigned = true;
     } else {
       negative = true;
       was_positive = false;
     }
   }
 }

 // If a number was found, and saving for undo works, replace the number.
 int firstdigit = (uint8_t)ptr[col];
 if (!ascii_isdigit(firstdigit) && !(do_alpha && ASCII_ISALPHA(firstdigit))) {
   beep_flush();
   goto theend;
 }

 if (do_alpha && ASCII_ISALPHA(firstdigit)) {
   // decrement or increment alphabetic character
   if (op_type == OP_NR_SUB) {
     if (CHAR_ORD(firstdigit) < Prenum1) {
       firstdigit = isupper(firstdigit) ? 'A' : 'a';
     } else {
       firstdigit -= (int)Prenum1;
     }
   } else {
     if (26 - CHAR_ORD(firstdigit) - 1 < Prenum1) {
       firstdigit = isupper(firstdigit) ? 'Z' : 'z';
     } else {
       firstdigit += (int)Prenum1;
     }
   }
   curwin->w_cursor.col = col;
   startpos = curwin->w_cursor;
   did_change = true;
   del_char(false);
   ins_char(firstdigit);
   endpos = curwin->w_cursor;
   curwin->w_cursor.col = col;
 } else {
   if (col > 0 && ptr[col - 1] == '-'
       && !utf_head_off(ptr, ptr + col - 1)
       && !visual
       && !do_unsigned) {
     if (do_blank && col >= 2 && !ascii_iswhite(ptr[col - 2])) {
       blank_unsigned = true;
     } else {
       // negative number
       col--;
       negative = true;
     }
   }

   // get the number value (unsigned)
   if (visual && VIsual_mode != 'V') {
     maxlen = curbuf->b_visual.vi_curswant == MAXCOL ? linelen - col : length;
   }

   bool overflow = false;
   vim_str2nr(ptr + col, &pre, &length,
              0 + (do_bin ? STR2NR_BIN : 0)
              + (do_oct ? STR2NR_OCT : 0)
              + (do_hex ? STR2NR_HEX : 0),
              NULL, &n, maxlen, false, &overflow);

   // ignore leading '-' for hex, octal and bin numbers
   if (pre && negative) {
     col++;
     length--;
     negative = false;
   }

   // add or subtract
   bool subtract = false;
   if (op_type == OP_NR_SUB) {
     subtract ^= true;
   }
   if (negative) {
     subtract ^= true;
   }

   uvarnumber_T oldn = n;

   if (!overflow) {  // if number is too big don't add/subtract
     n = subtract ? n - (uvarnumber_T)Prenum1
                  : n + (uvarnumber_T)Prenum1;
   }

   // handle wraparound for decimal numbers
   if (!pre) {
     if (subtract) {
       if (n > oldn) {
         n = 1 + (n ^ (uvarnumber_T)(-1));
         negative ^= true;
       }
     } else {
       // add
       if (n < oldn) {
         n = (n ^ (uvarnumber_T)(-1));
         negative ^= true;
       }
     }
     if (n == 0) {
       negative = false;
     }
   }

   if ((do_unsigned || blank_unsigned) && negative) {
     if (subtract) {
       // sticking at zero.
       n = 0;
     } else {
       // sticking at 2^64 - 1.
       n = (uvarnumber_T)(-1);
     }
     negative = false;
   }

   if (visual && !was_positive && !negative && col > 0) {
     // need to remove the '-'
     col--;
     length++;
   }

   // Delete the old number.
   curwin->w_cursor.col = col;
   startpos = curwin->w_cursor;
   did_change = true;
   int todel = length;
   int c = gchar_cursor();

   // Don't include the '-' in the length, only the length of the part
   // after it is kept the same.
   if (c == '-') {
     length--;
   }
   while (todel-- > 0) {
     if (c < 0x100 && isalpha(c)) {
       hexupper = isupper(c);
     }
     // del_char() will mark line needing displaying
     del_char(false);
     c = gchar_cursor();
   }

   // Prepare the leading characters in buf1[].
   // When there are many leading zeros it could be very long.
   // Allocate a bit too much.
   char *buf1 = xmalloc((size_t)length + NUMBUFLEN);
   ptr = buf1;
   if (negative && (!visual || was_positive)) {
     *ptr++ = '-';
   }
   if (pre) {
     *ptr++ = '0';
     length--;
   }
   if (pre == 'b' || pre == 'B' || pre == 'x' || pre == 'X') {
     *ptr++ = (char)pre;
     length--;
   }

   // Put the number characters in buf2[].
   char buf2[NUMBUFLEN];
   int buf2len = 0;
   if (pre == 'b' || pre == 'B') {
     size_t bits = 0;

     // leading zeros
     for (bits = 8 * sizeof(n); bits > 0; bits--) {
       if ((n >> (bits - 1)) & 0x1) {
         break;
       }
     }

     while (bits > 0 && buf2len < NUMBUFLEN - 1) {
       buf2[buf2len++] = ((n >> --bits) & 0x1) ? '1' : '0';
     }

     buf2[buf2len] = NUL;
   } else if (pre == 0) {
     buf2len = vim_snprintf(buf2, ARRAY_SIZE(buf2), "%" PRIu64, (uint64_t)n);
   } else if (pre == '0') {
     buf2len = vim_snprintf(buf2, ARRAY_SIZE(buf2), "%" PRIo64, (uint64_t)n);
   } else if (hexupper) {
     buf2len = vim_snprintf(buf2, ARRAY_SIZE(buf2), "%" PRIX64, (uint64_t)n);
   } else {
     buf2len = vim_snprintf(buf2, ARRAY_SIZE(buf2), "%" PRIx64, (uint64_t)n);
   }
   length -= buf2len;

   // Adjust number of zeros to the new number of digits, so the
   // total length of the number remains the same.
   // Don't do this when
   // the result may look like an octal number.
   if (firstdigit == '0' && !(do_oct && pre == 0)) {
     while (length-- > 0) {
       *ptr++ = '0';
     }
   }
   *ptr = NUL;
   int buf1len = (int)(ptr - buf1);

   STRCPY(buf1 + buf1len, buf2);
   buf1len += buf2len;

   ins_str(buf1, (size_t)buf1len);  // insert the new number
   xfree(buf1);

   endpos = curwin->w_cursor;
   if (curwin->w_cursor.col) {
     curwin->w_cursor.col--;
   }
 }

 if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0) {
   // set the '[ and '] marks
   curbuf->b_op_start = startpos;
   curbuf->b_op_end = endpos;
   if (curbuf->b_op_end.col > 0) {
     curbuf->b_op_end.col--;
   }
 }

theend:
 if (visual) {
   curwin->w_cursor = save_cursor;
 } else if (did_change) {
   curwin->w_set_curswant = true;
 } else if (virtual_active(curwin)) {
   curwin->w_cursor.coladd = save_coladd;
 }

 return did_change;
}

void clear_oparg(oparg_T *oap)
{
 CLEAR_POINTER(oap);
}

///  Count the number of bytes, characters and "words" in a line.
///
///  "Words" are counted by looking for boundaries between non-space and
///  space characters.  (it seems to produce results that match 'wc'.)
///
///  Return value is byte count; word count for the line is added to "*wc".
///  Char count is added to "*cc".
///
///  The function will only examine the first "limit" characters in the
///  line, stopping if it encounters an end-of-line (NUL byte).  In that
///  case, eol_size will be added to the character count to account for
///  the size of the EOL character.
static varnumber_T line_count_info(char *line, varnumber_T *wc, varnumber_T *cc, varnumber_T limit,
                                  int eol_size)
{
 varnumber_T i;
 varnumber_T words = 0;
 varnumber_T chars = 0;
 bool is_word = false;

 for (i = 0; i < limit && line[i] != NUL;) {
   if (is_word) {
     if (ascii_isspace(line[i])) {
       words++;
       is_word = false;
     }
   } else if (!ascii_isspace(line[i])) {
     is_word = true;
   }
   chars++;
   i += utfc_ptr2len(line + i);
 }

 if (is_word) {
   words++;
 }
 *wc += words;

 // Add eol_size if the end of line was reached before hitting limit.
 if (i < limit && line[i] == NUL) {
   i += eol_size;
   chars += eol_size;
 }
 *cc += chars;
 return i;
}

/// Give some info about the position of the cursor (for "g CTRL-G").
/// In Visual mode, give some info about the selected region.  (In this case,
/// the *_count_cursor variables store running totals for the selection.)
///
/// @param dict  when not NULL, store the info there instead of showing it.
void cursor_pos_info(dict_T *dict)
{
 char buf1[50];
 char buf2[40];
 varnumber_T byte_count = 0;
 varnumber_T bom_count = 0;
 varnumber_T byte_count_cursor = 0;
 varnumber_T char_count = 0;
 varnumber_T char_count_cursor = 0;
 varnumber_T word_count = 0;
 varnumber_T word_count_cursor = 0;
 pos_T min_pos, max_pos;
 oparg_T oparg;
 struct block_def bd;
 const int l_VIsual_active = VIsual_active;
 const int l_VIsual_mode = VIsual_mode;

 // Compute the length of the file in characters.
 if (curbuf->b_ml.ml_flags & ML_EMPTY) {
   if (dict == NULL) {
     msg(_(no_lines_msg), 0);
     return;
   }
 } else {
   int eol_size;
   varnumber_T last_check = 100000;
   int line_count_selected = 0;
   if (get_fileformat(curbuf) == EOL_DOS) {
     eol_size = 2;
   } else {
     eol_size = 1;
   }

   if (l_VIsual_active) {
     if (lt(VIsual, curwin->w_cursor)) {
       min_pos = VIsual;
       max_pos = curwin->w_cursor;
     } else {
       min_pos = curwin->w_cursor;
       max_pos = VIsual;
     }
     if (*p_sel == 'e' && max_pos.col > 0) {
       max_pos.col--;
     }

     if (l_VIsual_mode == Ctrl_V) {
       char *const saved_sbr = p_sbr;
       char *const saved_w_sbr = curwin->w_p_sbr;

       // Make 'sbr' empty for a moment to get the correct size.
       p_sbr = empty_string_option;
       curwin->w_p_sbr = empty_string_option;
       oparg.is_VIsual = true;
       oparg.motion_type = kMTBlockWise;
       oparg.op_type = OP_NOP;
       getvcols(curwin, &min_pos, &max_pos, &oparg.start_vcol, &oparg.end_vcol);
       p_sbr = saved_sbr;
       curwin->w_p_sbr = saved_w_sbr;
       if (curwin->w_curswant == MAXCOL) {
         oparg.end_vcol = MAXCOL;
       }
       // Swap the start, end vcol if needed
       if (oparg.end_vcol < oparg.start_vcol) {
         oparg.end_vcol += oparg.start_vcol;
         oparg.start_vcol = oparg.end_vcol - oparg.start_vcol;
         oparg.end_vcol -= oparg.start_vcol;
       }
     }
     line_count_selected = max_pos.lnum - min_pos.lnum + 1;
   }

   for (linenr_T lnum = 1; lnum <= curbuf->b_ml.ml_line_count; lnum++) {
     // Check for a CTRL-C every 100000 characters.
     if (byte_count > last_check) {
       os_breakcheck();
       if (got_int) {
         return;
       }
       last_check = byte_count + 100000;
     }

     // Do extra processing for VIsual mode.
     if (l_VIsual_active
         && lnum >= min_pos.lnum && lnum <= max_pos.lnum) {
       char *s = NULL;
       int len = 0;

       switch (l_VIsual_mode) {
       case Ctrl_V:
         virtual_op = virtual_active(curwin);
         block_prep(&oparg, &bd, lnum, false);
         virtual_op = kNone;
         s = bd.textstart;
         len = bd.textlen;
         break;
       case 'V':
         s = ml_get(lnum);
         len = MAXCOL;
         break;
       case 'v': {
         colnr_T start_col = (lnum == min_pos.lnum)
                             ? min_pos.col : 0;
         colnr_T end_col = (lnum == max_pos.lnum)
                           ? max_pos.col - start_col + 1 : MAXCOL;

         s = ml_get(lnum) + start_col;
         len = end_col;
       }
       break;
       }
       if (s != NULL) {
         byte_count_cursor += line_count_info(s, &word_count_cursor,
                                              &char_count_cursor, len, eol_size);
         if (lnum == curbuf->b_ml.ml_line_count
             && !curbuf->b_p_eol
             && (curbuf->b_p_bin || !curbuf->b_p_fixeol)
             && (int)strlen(s) < len) {
           byte_count_cursor -= eol_size;
         }
       }
     } else {
       // In non-visual mode, check for the line the cursor is on
       if (lnum == curwin->w_cursor.lnum) {
         word_count_cursor += word_count;
         char_count_cursor += char_count;
         byte_count_cursor = byte_count
                             + line_count_info(ml_get(lnum), &word_count_cursor,
                                               &char_count_cursor,
                                               (varnumber_T)curwin->w_cursor.col + 1,
                                               eol_size);
       }
     }
     // Add to the running totals
     byte_count += line_count_info(ml_get(lnum), &word_count, &char_count,
                                   (varnumber_T)MAXCOL, eol_size);
   }

   // Correction for when last line doesn't have an EOL.
   if (!curbuf->b_p_eol && (curbuf->b_p_bin || !curbuf->b_p_fixeol)) {
     byte_count -= eol_size;
   }

   if (dict == NULL) {
     if (l_VIsual_active) {
       if (l_VIsual_mode == Ctrl_V && curwin->w_curswant < MAXCOL) {
         getvcols(curwin, &min_pos, &max_pos, &min_pos.col, &max_pos.col);
         int64_t cols;
         STRICT_SUB(oparg.end_vcol + 1, oparg.start_vcol, &cols, int64_t);
         vim_snprintf(buf1, sizeof(buf1), _("%" PRId64 " Cols; "),
                      cols);
       } else {
         buf1[0] = NUL;
       }

       if (char_count_cursor == byte_count_cursor
           && char_count == byte_count) {
         vim_snprintf(IObuff, IOSIZE,
                      _("Selected %s%" PRId64 " of %" PRId64 " Lines;"
                        " %" PRId64 " of %" PRId64 " Words;"
                        " %" PRId64 " of %" PRId64 " Bytes"),
                      buf1, (int64_t)line_count_selected,
                      (int64_t)curbuf->b_ml.ml_line_count,
                      (int64_t)word_count_cursor, (int64_t)word_count,
                      (int64_t)byte_count_cursor, (int64_t)byte_count);
       } else {
         vim_snprintf(IObuff, IOSIZE,
                      _("Selected %s%" PRId64 " of %" PRId64 " Lines;"
                        " %" PRId64 " of %" PRId64 " Words;"
                        " %" PRId64 " of %" PRId64 " Chars;"
                        " %" PRId64 " of %" PRId64 " Bytes"),
                      buf1, (int64_t)line_count_selected,
                      (int64_t)curbuf->b_ml.ml_line_count,
                      (int64_t)word_count_cursor, (int64_t)word_count,
                      (int64_t)char_count_cursor, (int64_t)char_count,
                      (int64_t)byte_count_cursor, (int64_t)byte_count);
       }
     } else {
       char *p = get_cursor_line_ptr();
       validate_virtcol(curwin);
       col_print(buf1, sizeof(buf1), (int)curwin->w_cursor.col + 1,
                 (int)curwin->w_virtcol + 1);
       col_print(buf2, sizeof(buf2), get_cursor_line_len(), linetabsize_str(p));

       if (char_count_cursor == byte_count_cursor
           && char_count == byte_count) {
         vim_snprintf(IObuff, IOSIZE,
                      _("Col %s of %s; Line %" PRId64 " of %" PRId64 ";"
                        " Word %" PRId64 " of %" PRId64 ";"
                        " Byte %" PRId64 " of %" PRId64 ""),
                      buf1, buf2,
                      (int64_t)curwin->w_cursor.lnum,
                      (int64_t)curbuf->b_ml.ml_line_count,
                      (int64_t)word_count_cursor, (int64_t)word_count,
                      (int64_t)byte_count_cursor, (int64_t)byte_count);
       } else {
         vim_snprintf(IObuff, IOSIZE,
                      _("Col %s of %s; Line %" PRId64 " of %" PRId64 ";"
                        " Word %" PRId64 " of %" PRId64 ";"
                        " Char %" PRId64 " of %" PRId64 ";"
                        " Byte %" PRId64 " of %" PRId64 ""),
                      buf1, buf2,
                      (int64_t)curwin->w_cursor.lnum,
                      (int64_t)curbuf->b_ml.ml_line_count,
                      (int64_t)word_count_cursor, (int64_t)word_count,
                      (int64_t)char_count_cursor, (int64_t)char_count,
                      (int64_t)byte_count_cursor, (int64_t)byte_count);
       }
     }
   }

   bom_count = bomb_size();
   if (dict == NULL && bom_count > 0) {
     const size_t len = strlen(IObuff);
     vim_snprintf(IObuff + len, IOSIZE - len,
                  _("(+%" PRId64 " for BOM)"), (int64_t)bom_count);
   }
   if (dict == NULL) {
     // Don't shorten this message, the user asked for it.
     char *p = p_shm;
     p_shm = "";
     if (p_ch < 1) {
       msg_start();
       msg_scroll = true;
     }
     msg(IObuff, 0);
     p_shm = p;
   }
 }

 if (dict != NULL) {
   // Don't shorten this message, the user asked for it.
   tv_dict_add_nr(dict, S_LEN("words"), word_count);
   tv_dict_add_nr(dict, S_LEN("chars"), char_count);
   tv_dict_add_nr(dict, S_LEN("bytes"), byte_count + bom_count);

   STATIC_ASSERT(sizeof("visual") == sizeof("cursor"),
                 "key_len argument in tv_dict_add_nr is wrong");
   tv_dict_add_nr(dict, l_VIsual_active ? "visual_bytes" : "cursor_bytes",
                  sizeof("visual_bytes") - 1, byte_count_cursor);
   tv_dict_add_nr(dict, l_VIsual_active ? "visual_chars" : "cursor_chars",
                  sizeof("visual_chars") - 1, char_count_cursor);
   tv_dict_add_nr(dict, l_VIsual_active ? "visual_words" : "cursor_words",
                  sizeof("visual_words") - 1, word_count_cursor);
 }
}

/// Handle indent and format operators and visual mode ":".
static void op_colon(oparg_T *oap)
{
 stuffcharReadbuff(':');
 if (oap->is_VIsual) {
   stuffReadbuff("'<,'>");
 } else {
   // Make the range look nice, so it can be repeated.
   if (oap->start.lnum == curwin->w_cursor.lnum) {
     stuffcharReadbuff('.');
   } else {
     stuffnumReadbuff(oap->start.lnum);
   }

   // When using !! on a closed fold the range ".!" works best to operate
   // on, it will be made the whole closed fold later.
   linenr_T endOfStartFold = oap->start.lnum;
   hasFolding(curwin, oap->start.lnum, NULL, &endOfStartFold);
   if (oap->end.lnum != oap->start.lnum && oap->end.lnum != endOfStartFold) {
     // Make it a range with the end line.
     stuffcharReadbuff(',');
     if (oap->end.lnum == curwin->w_cursor.lnum) {
       stuffcharReadbuff('.');
     } else if (oap->end.lnum == curbuf->b_ml.ml_line_count) {
       stuffcharReadbuff('$');
     } else if (oap->start.lnum == curwin->w_cursor.lnum
                // do not use ".+number" for a closed fold, it would count
                // folded lines twice
                && !hasFolding(curwin, oap->end.lnum, NULL, NULL)) {
       stuffReadbuff(".+");
       stuffnumReadbuff(oap->line_count - 1);
     } else {
       stuffnumReadbuff(oap->end.lnum);
     }
   }
 }
 if (oap->op_type != OP_COLON) {
   stuffReadbuff("!");
 }
 if (oap->op_type == OP_INDENT) {
   stuffReadbuff(get_equalprg());
   stuffReadbuff("\n");
 } else if (oap->op_type == OP_FORMAT) {
   if (*curbuf->b_p_fp != NUL) {
     stuffReadbuff(curbuf->b_p_fp);
   } else if (*p_fp != NUL) {
     stuffReadbuff(p_fp);
   } else {
     stuffReadbuff("fmt");
   }
   stuffReadbuff("\n']");
 }

 // do_cmdline() does the rest
}

/// callback function for 'operatorfunc'
static Callback opfunc_cb;

/// Process the 'operatorfunc' option value.
const char *did_set_operatorfunc(optset_T *args FUNC_ATTR_UNUSED)
{
 if (option_set_callback_func(p_opfunc, &opfunc_cb) == FAIL) {
   return e_invarg;
 }
 return NULL;
}

#if defined(EXITFREE)
void free_operatorfunc_option(void)
{
 callback_free(&opfunc_cb);
}
#endif

/// Mark the global 'operatorfunc' callback with "copyID" so that it is not
/// garbage collected.
bool set_ref_in_opfunc(int copyID)
{
 return set_ref_in_callback(&opfunc_cb, copyID, NULL, NULL);
}

/// Handle the "g@" operator: call 'operatorfunc'.
static void op_function(const oparg_T *oap)
 FUNC_ATTR_NONNULL_ALL
{
 const pos_T orig_start = curbuf->b_op_start;
 const pos_T orig_end = curbuf->b_op_end;

 if (*p_opfunc == NUL) {
   emsg(_("E774: 'operatorfunc' is empty"));
 } else {
   // Set '[ and '] marks to text to be operated on.
   curbuf->b_op_start = oap->start;
   curbuf->b_op_end = oap->end;
   if (oap->motion_type != kMTLineWise && !oap->inclusive) {
     // Exclude the end position.
     decl(&curbuf->b_op_end);
   }

   typval_T argv[2];
   argv[0].v_type = VAR_STRING;
   argv[1].v_type = VAR_UNKNOWN;
   argv[0].vval.v_string =
     (char *)(((const char *const[]) {
     [kMTBlockWise] = "block",
     [kMTLineWise] = "line",
     [kMTCharWise] = "char",
   })[oap->motion_type]);

   // Reset virtual_op so that 'virtualedit' can be changed in the
   // function.
   const TriState save_virtual_op = virtual_op;
   virtual_op = kNone;

   // Reset finish_op so that mode() returns the right value.
   const bool save_finish_op = finish_op;
   finish_op = false;

   typval_T rettv;
   if (callback_call(&opfunc_cb, 1, argv, &rettv)) {
     tv_clear(&rettv);
   }

   virtual_op = save_virtual_op;
   finish_op = save_finish_op;
   if (cmdmod.cmod_flags & CMOD_LOCKMARKS) {
     curbuf->b_op_start = orig_start;
     curbuf->b_op_end = orig_end;
   }
 }
}

/// Calculate start/end virtual columns for operating in block mode.
///
/// @param initial  when true: adjust position for 'selectmode'
static void get_op_vcol(oparg_T *oap, colnr_T redo_VIsual_vcol, bool initial)
{
 colnr_T start;
 colnr_T end;

 if (VIsual_mode != Ctrl_V
     || (!initial && oap->end.col < curwin->w_view_width)) {
   return;
 }

 oap->motion_type = kMTBlockWise;

 // prevent from moving onto a trail byte
 mark_mb_adjustpos(curwin->w_buffer, &oap->end);

 getvvcol(curwin, &(oap->start), &oap->start_vcol, NULL, &oap->end_vcol);
 if (!redo_VIsual_busy) {
   getvvcol(curwin, &(oap->end), &start, NULL, &end);

   oap->start_vcol = MIN(oap->start_vcol, start);
   if (end > oap->end_vcol) {
     if (initial && *p_sel == 'e'
         && start >= 1
         && start - 1 >= oap->end_vcol) {
       oap->end_vcol = start - 1;
     } else {
       oap->end_vcol = end;
     }
   }
 }

 // if '$' was used, get oap->end_vcol from longest line
 if (curwin->w_curswant == MAXCOL) {
   curwin->w_cursor.col = MAXCOL;
   oap->end_vcol = 0;
   for (curwin->w_cursor.lnum = oap->start.lnum;
        curwin->w_cursor.lnum <= oap->end.lnum; curwin->w_cursor.lnum++) {
     getvvcol(curwin, &curwin->w_cursor, NULL, NULL, &end);
     oap->end_vcol = MAX(oap->end_vcol, end);
   }
 } else if (redo_VIsual_busy) {
   oap->end_vcol = oap->start_vcol + redo_VIsual_vcol - 1;
 }

 // Correct oap->end.col and oap->start.col to be the
 // upper-left and lower-right corner of the block area.
 //
 // (Actually, this does convert column positions into character
 // positions)
 curwin->w_cursor.lnum = oap->end.lnum;
 coladvance(curwin, oap->end_vcol);
 oap->end = curwin->w_cursor;

 curwin->w_cursor = oap->start;
 coladvance(curwin, oap->start_vcol);
 oap->start = curwin->w_cursor;
}

/// Information for redoing the previous Visual selection.
typedef struct {
 int rv_mode;             ///< 'v', 'V', or Ctrl-V
 linenr_T rv_line_count;  ///< number of lines
 colnr_T rv_vcol;         ///< number of cols or end column
 int rv_count;            ///< count for Visual operator
 int rv_arg;              ///< extra argument
} redo_VIsual_T;

static bool is_ex_cmdchar(cmdarg_T *cap)
{
 return cap->cmdchar == ':' || cap->cmdchar == K_COMMAND;
}

/// Handle an operator after Visual mode or when the movement is finished.
/// "gui_yank" is true when yanking text for the clipboard.
void do_pending_operator(cmdarg_T *cap, int old_col, bool gui_yank)
{
 oparg_T *oap = cap->oap;
 int lbr_saved = curwin->w_p_lbr;

 // The visual area is remembered for redo
 static redo_VIsual_T redo_VIsual = { NUL, 0, 0, 0, 0 };

 pos_T old_cursor = curwin->w_cursor;

 // If an operation is pending, handle it...
 if ((finish_op
      || VIsual_active)
     && oap->op_type != OP_NOP) {
   bool empty_region_error;
   int restart_edit_save;
   bool include_line_break = false;
   // Yank can be redone when 'y' is in 'cpoptions', but not when yanking
   // for the clipboard.
   const bool redo_yank = vim_strchr(p_cpo, CPO_YANK) != NULL && !gui_yank;

   // Avoid a problem with unwanted linebreaks in block mode
   reset_lbr();
   oap->is_VIsual = VIsual_active;
   if (oap->motion_force == 'V') {
     oap->motion_type = kMTLineWise;
   } else if (oap->motion_force == 'v') {
     // If the motion was linewise, "inclusive" will not have been set.
     // Use "exclusive" to be consistent.  Makes "dvj" work nice.
     if (oap->motion_type == kMTLineWise) {
       oap->inclusive = false;
     } else if (oap->motion_type == kMTCharWise) {
       // If the motion already was charwise, toggle "inclusive"
       oap->inclusive = !oap->inclusive;
     }
     oap->motion_type = kMTCharWise;
   } else if (oap->motion_force == Ctrl_V) {
     // Change line- or charwise motion into Visual block mode.
     if (!VIsual_active) {
       VIsual_active = true;
       VIsual = oap->start;
     }
     VIsual_mode = Ctrl_V;
     VIsual_select = false;
     VIsual_reselect = false;
   }

   // Only redo yank when 'y' flag is in 'cpoptions'.
   // Never redo "zf" (define fold).
   if ((redo_yank || oap->op_type != OP_YANK)
       && ((!VIsual_active || oap->motion_force)
           // Also redo Operator-pending Visual mode mappings.
           || ((is_ex_cmdchar(cap) || cap->cmdchar == K_LUA)
               && oap->op_type != OP_COLON))
       && cap->cmdchar != 'D'
       && oap->op_type != OP_FOLD
       && oap->op_type != OP_FOLDOPEN
       && oap->op_type != OP_FOLDOPENREC
       && oap->op_type != OP_FOLDCLOSE
       && oap->op_type != OP_FOLDCLOSEREC
       && oap->op_type != OP_FOLDDEL
       && oap->op_type != OP_FOLDDELREC) {
     prep_redo(oap->regname, cap->count0,
               get_op_char(oap->op_type), get_extra_op_char(oap->op_type),
               oap->motion_force, cap->cmdchar, cap->nchar);
     if (cap->cmdchar == '/' || cap->cmdchar == '?') {     // was a search
       // If 'cpoptions' does not contain 'r', insert the search
       // pattern to really repeat the same command.
       if (vim_strchr(p_cpo, CPO_REDO) == NULL) {
         AppendToRedobuffLit(cap->searchbuf, -1);
       }
       AppendToRedobuff(NL_STR);
     } else if (is_ex_cmdchar(cap)) {
       // do_cmdline() has stored the first typed line in
       // "repeat_cmdline".  When several lines are typed repeating
       // won't be possible.
       if (repeat_cmdline == NULL) {
         ResetRedobuff();
       } else {
         if (cap->cmdchar == ':') {
           AppendToRedobuffLit(repeat_cmdline, -1);
         } else {
           AppendToRedobuffSpec(repeat_cmdline);
         }
         AppendToRedobuff(NL_STR);
         XFREE_CLEAR(repeat_cmdline);
       }
     } else if (cap->cmdchar == K_LUA) {
       AppendNumberToRedobuff(repeat_luaref);
       AppendToRedobuff(NL_STR);
     }
   }

   if (redo_VIsual_busy) {
     // Redo of an operation on a Visual area. Use the same size from
     // redo_VIsual.rv_line_count and redo_VIsual.rv_vcol.
     oap->start = curwin->w_cursor;
     curwin->w_cursor.lnum += redo_VIsual.rv_line_count - 1;
     curwin->w_cursor.lnum = MIN(curwin->w_cursor.lnum, curbuf->b_ml.ml_line_count);
     VIsual_mode = redo_VIsual.rv_mode;
     if (redo_VIsual.rv_vcol == MAXCOL || VIsual_mode == 'v') {
       if (VIsual_mode == 'v') {
         if (redo_VIsual.rv_line_count <= 1) {
           validate_virtcol(curwin);
           curwin->w_curswant = curwin->w_virtcol + redo_VIsual.rv_vcol - 1;
         } else {
           curwin->w_curswant = redo_VIsual.rv_vcol;
         }
       } else {
         curwin->w_curswant = MAXCOL;
       }
       coladvance(curwin, curwin->w_curswant);
     }
     cap->count0 = redo_VIsual.rv_count;
     cap->count1 = (cap->count0 == 0 ? 1 : cap->count0);
   } else if (VIsual_active) {
     if (!gui_yank) {
       // Save the current VIsual area for '< and '> marks, and "gv"
       curbuf->b_visual.vi_start = VIsual;
       curbuf->b_visual.vi_end = curwin->w_cursor;
       curbuf->b_visual.vi_mode = VIsual_mode;
       restore_visual_mode();
       curbuf->b_visual.vi_curswant = curwin->w_curswant;
       curbuf->b_visual_mode_eval = VIsual_mode;
     }

     // In Select mode, a linewise selection is operated upon like a
     // charwise selection.
     // Special case: gH<Del> deletes the last line.
     if (VIsual_select && VIsual_mode == 'V'
         && cap->oap->op_type != OP_DELETE) {
       if (lt(VIsual, curwin->w_cursor)) {
         VIsual.col = 0;
         curwin->w_cursor.col = ml_get_len(curwin->w_cursor.lnum);
       } else {
         curwin->w_cursor.col = 0;
         VIsual.col = ml_get_len(VIsual.lnum);
       }
       VIsual_mode = 'v';
     } else if (VIsual_mode == 'v') {
       // If 'selection' is "exclusive", backup one character for
       // charwise selections.
       include_line_break = unadjust_for_sel();
     }

     oap->start = VIsual;
     if (VIsual_mode == 'V') {
       oap->start.col = 0;
       oap->start.coladd = 0;
     }
   }

   // Set oap->start to the first position of the operated text, oap->end
   // to the end of the operated text.  w_cursor is equal to oap->start.
   if (lt(oap->start, curwin->w_cursor)) {
     // Include folded lines completely.
     if (!VIsual_active) {
       if (hasFolding(curwin, oap->start.lnum, &oap->start.lnum, NULL)) {
         oap->start.col = 0;
       }
       if ((curwin->w_cursor.col > 0
            || oap->inclusive
            || oap->motion_type == kMTLineWise)
           && hasFolding(curwin, curwin->w_cursor.lnum, NULL,
                         &curwin->w_cursor.lnum)) {
         curwin->w_cursor.col = get_cursor_line_len();
       }
     }
     oap->end = curwin->w_cursor;
     curwin->w_cursor = oap->start;

     // w_virtcol may have been updated; if the cursor goes back to its
     // previous position w_virtcol becomes invalid and isn't updated
     // automatically.
     curwin->w_valid &= ~VALID_VIRTCOL;
   } else {
     // Include folded lines completely.
     if (!VIsual_active && oap->motion_type == kMTLineWise) {
       if (hasFolding(curwin, curwin->w_cursor.lnum, &curwin->w_cursor.lnum,
                      NULL)) {
         curwin->w_cursor.col = 0;
       }
       if (hasFolding(curwin, oap->start.lnum, NULL, &oap->start.lnum)) {
         oap->start.col = ml_get_len(oap->start.lnum);
       }
     }
     oap->end = oap->start;
     oap->start = curwin->w_cursor;
   }

   // Just in case lines were deleted that make the position invalid.
   check_pos(curwin->w_buffer, &oap->end);
   oap->line_count = oap->end.lnum - oap->start.lnum + 1;

   // Set "virtual_op" before resetting VIsual_active.
   virtual_op = virtual_active(curwin);

   if (VIsual_active || redo_VIsual_busy) {
     get_op_vcol(oap, redo_VIsual.rv_vcol, true);

     if (!redo_VIsual_busy && !gui_yank) {
       // Prepare to reselect and redo Visual: this is based on the
       // size of the Visual text
       resel_VIsual_mode = VIsual_mode;
       if (curwin->w_curswant == MAXCOL) {
         resel_VIsual_vcol = MAXCOL;
       } else {
         if (VIsual_mode != Ctrl_V) {
           getvvcol(curwin, &(oap->end),
                    NULL, NULL, &oap->end_vcol);
         }
         if (VIsual_mode == Ctrl_V || oap->line_count <= 1) {
           if (VIsual_mode != Ctrl_V) {
             getvvcol(curwin, &(oap->start),
                      &oap->start_vcol, NULL, NULL);
           }
           resel_VIsual_vcol = oap->end_vcol - oap->start_vcol + 1;
         } else {
           resel_VIsual_vcol = oap->end_vcol;
         }
       }
       resel_VIsual_line_count = oap->line_count;
     }

     // can't redo yank (unless 'y' is in 'cpoptions') and ":"
     if ((redo_yank || oap->op_type != OP_YANK)
         && oap->op_type != OP_COLON
         && oap->op_type != OP_FOLD
         && oap->op_type != OP_FOLDOPEN
         && oap->op_type != OP_FOLDOPENREC
         && oap->op_type != OP_FOLDCLOSE
         && oap->op_type != OP_FOLDCLOSEREC
         && oap->op_type != OP_FOLDDEL
         && oap->op_type != OP_FOLDDELREC
         && oap->motion_force == NUL) {
       // Prepare for redoing.  Only use the nchar field for "r",
       // otherwise it might be the second char of the operator.
       if (cap->cmdchar == 'g' && (cap->nchar == 'n'
                                   || cap->nchar == 'N')) {
         prep_redo(oap->regname, cap->count0,
                   get_op_char(oap->op_type), get_extra_op_char(oap->op_type),
                   oap->motion_force, cap->cmdchar, cap->nchar);
       } else if (!is_ex_cmdchar(cap) && cap->cmdchar != K_LUA) {
         int opchar = get_op_char(oap->op_type);
         int extra_opchar = get_extra_op_char(oap->op_type);
         int nchar = oap->op_type == OP_REPLACE ? cap->nchar : NUL;

         // reverse what nv_replace() did
         if (nchar == REPLACE_CR_NCHAR) {
           nchar = CAR;
         } else if (nchar == REPLACE_NL_NCHAR) {
           nchar = NL;
         }

         if (opchar == 'g' && extra_opchar == '@') {
           // also repeat the count for 'operatorfunc'
           prep_redo_num2(oap->regname, 0, NUL, 'v', cap->count0, opchar, extra_opchar, nchar);
         } else {
           prep_redo(oap->regname, 0, NUL, 'v', opchar, extra_opchar, nchar);
         }
       }
       if (!redo_VIsual_busy) {
         redo_VIsual.rv_mode = resel_VIsual_mode;
         redo_VIsual.rv_vcol = resel_VIsual_vcol;
         redo_VIsual.rv_line_count = resel_VIsual_line_count;
         redo_VIsual.rv_count = cap->count0;
         redo_VIsual.rv_arg = cap->arg;
       }
     }

     // oap->inclusive defaults to true.
     // If oap->end is on a NUL (empty line) oap->inclusive becomes
     // false.  This makes "d}P" and "v}dP" work the same.
     if (oap->motion_force == NUL || oap->motion_type == kMTLineWise) {
       oap->inclusive = true;
     }
     if (VIsual_mode == 'V') {
       oap->motion_type = kMTLineWise;
     } else if (VIsual_mode == 'v') {
       oap->motion_type = kMTCharWise;
       if (*ml_get_pos(&(oap->end)) == NUL
           && (include_line_break || !virtual_op)) {
         oap->inclusive = false;
         // Try to include the newline, unless it's an operator
         // that works on lines only.
         if (*p_sel != 'o'
             && !op_on_lines(oap->op_type)
             && oap->end.lnum < curbuf->b_ml.ml_line_count) {
           oap->end.lnum++;
           oap->end.col = 0;
           oap->end.coladd = 0;
           oap->line_count++;
         }
       }
     }

     redo_VIsual_busy = false;

     // Switch Visual off now, so screen updating does
     // not show inverted text when the screen is redrawn.
     // With OP_YANK and sometimes with OP_COLON and OP_FILTER there is
     // no screen redraw, so it is done here to remove the inverted
     // part.
     if (!gui_yank) {
       VIsual_active = false;
       setmouse();
       mouse_dragging = 0;
       may_clear_cmdline();
       if ((oap->op_type == OP_YANK
            || oap->op_type == OP_COLON
            || oap->op_type == OP_FUNCTION
            || oap->op_type == OP_FILTER)
           && oap->motion_force == NUL) {
         // Make sure redrawing is correct.
         restore_lbr(lbr_saved);
         redraw_curbuf_later(UPD_INVERTED);
       }
     }
   }

   // Include the trailing byte of a multi-byte char.
   if (oap->inclusive) {
     const int l = utfc_ptr2len(ml_get_pos(&oap->end));
     if (l > 1) {
       oap->end.col += l - 1;
     }
   }
   curwin->w_set_curswant = true;

   // oap->empty is set when start and end are the same.  The inclusive
   // flag affects this too, unless yanking and the end is on a NUL.
   oap->empty = (oap->motion_type != kMTLineWise
                 && (!oap->inclusive
                     || (oap->op_type == OP_YANK
                         && gchar_pos(&oap->end) == NUL))
                 && equalpos(oap->start, oap->end)
                 && !(virtual_op && oap->start.coladd != oap->end.coladd));
   // For delete, change and yank, it's an error to operate on an
   // empty region, when 'E' included in 'cpoptions' (Vi compatible).
   empty_region_error = (oap->empty
                         && vim_strchr(p_cpo, CPO_EMPTYREGION) != NULL);

   // Force a redraw when operating on an empty Visual region, when
   // 'modifiable is off or creating a fold.
   if (oap->is_VIsual && (oap->empty || !MODIFIABLE(curbuf)
                          || oap->op_type == OP_FOLD)) {
     restore_lbr(lbr_saved);
     redraw_curbuf_later(UPD_INVERTED);
   }

   // If the end of an operator is in column one while oap->motion_type
   // is kMTCharWise and oap->inclusive is false, we put op_end after the last
   // character in the previous line. If op_start is on or before the
   // first non-blank in the line, the operator becomes linewise
   // (strange, but that's the way vi does it).
   if (oap->motion_type == kMTCharWise
       && oap->inclusive == false
       && !(cap->retval & CA_NO_ADJ_OP_END)
       && oap->end.col == 0
       && (!oap->is_VIsual || *p_sel == 'o')
       && oap->line_count > 1) {
     oap->end_adjusted = true;  // remember that we did this
     oap->line_count--;
     oap->end.lnum--;
     if (inindent(0)) {
       oap->motion_type = kMTLineWise;
     } else {
       oap->end.col = ml_get_len(oap->end.lnum);
       if (oap->end.col) {
         oap->end.col--;
         oap->inclusive = true;
       }
     }
   } else {
     oap->end_adjusted = false;
   }

   switch (oap->op_type) {
   case OP_LSHIFT:
   case OP_RSHIFT:
     op_shift(oap, true, oap->is_VIsual ? cap->count1 : 1);
     auto_format(false, true);
     break;

   case OP_JOIN_NS:
   case OP_JOIN:
     oap->line_count = MAX(oap->line_count, 2);
     if (curwin->w_cursor.lnum + oap->line_count - 1 >
         curbuf->b_ml.ml_line_count) {
       beep_flush();
     } else {
       do_join((size_t)oap->line_count, oap->op_type == OP_JOIN,
               true, true, true);
       auto_format(false, true);
     }
     break;

   case OP_DELETE:
     VIsual_reselect = false;              // don't reselect now
     if (empty_region_error) {
       vim_beep(kOptBoFlagOperator);
       CancelRedo();
     } else {
       op_delete(oap);
       // save cursor line for undo if it wasn't saved yet
       if (oap->motion_type == kMTLineWise
           && has_format_option(FO_AUTO)
           && u_save_cursor() == OK) {
         auto_format(false, true);
       }
     }
     break;

   case OP_YANK:
     if (empty_region_error) {
       if (!gui_yank) {
         vim_beep(kOptBoFlagOperator);
         CancelRedo();
       }
     } else {
       restore_lbr(lbr_saved);
       oap->excl_tr_ws = cap->cmdchar == 'z';
       op_yank(oap, !gui_yank);
     }
     check_cursor_col(curwin);
     break;

   case OP_CHANGE:
     VIsual_reselect = false;              // don't reselect now
     if (empty_region_error) {
       vim_beep(kOptBoFlagOperator);
       CancelRedo();
     } else {
       // This is a new edit command, not a restart.  Need to
       // remember it to make i_CTRL-O work with mappings for
       // Visual mode.  But do this only once and not when typed.
       if (!KeyTyped) {
         restart_edit_save = restart_edit;
       } else {
         restart_edit_save = 0;
       }
       restart_edit = 0;

       // Restore linebreak, so that when the user edits it looks as before.
       restore_lbr(lbr_saved);

       // trigger TextChangedI
       curbuf->b_last_changedtick_i = buf_get_changedtick(curbuf);

       if (op_change(oap)) {           // will call edit()
         cap->retval |= CA_COMMAND_BUSY;
       }
       if (restart_edit == 0) {
         restart_edit = restart_edit_save;
       }
     }
     break;

   case OP_FILTER:
     if (vim_strchr(p_cpo, CPO_FILTER) != NULL) {
       AppendToRedobuff("!\r");  // Use any last used !cmd.
     } else {
       bangredo = true;  // do_bang() will put cmd in redo buffer.
     }
     FALLTHROUGH;

   case OP_INDENT:
   case OP_COLON:

     // If 'equalprg' is empty, do the indenting internally.
     if (oap->op_type == OP_INDENT && *get_equalprg() == NUL) {
       if (curbuf->b_p_lisp) {
         if (use_indentexpr_for_lisp()) {
           op_reindent(oap, get_expr_indent);
         } else {
           op_reindent(oap, get_lisp_indent);
         }
         break;
       }
       op_reindent(oap,
                   *curbuf->b_p_inde != NUL ? get_expr_indent
                                            : get_c_indent);
       break;
     }

     op_colon(oap);
     break;

   case OP_TILDE:
   case OP_UPPER:
   case OP_LOWER:
   case OP_ROT13:
     if (empty_region_error) {
       vim_beep(kOptBoFlagOperator);
       CancelRedo();
     } else {
       op_tilde(oap);
     }
     check_cursor_col(curwin);
     break;

   case OP_FORMAT:
     if (*curbuf->b_p_fex != NUL) {
       op_formatexpr(oap);             // use expression
     } else {
       if (*p_fp != NUL || *curbuf->b_p_fp != NUL) {
         op_colon(oap);                // use external command
       } else {
         op_format(oap, false);        // use internal function
       }
     }
     break;

   case OP_FORMAT2:
     op_format(oap, true);             // use internal function
     break;

   case OP_FUNCTION: {
     redo_VIsual_T save_redo_VIsual = redo_VIsual;

     // Restore linebreak, so that when the user edits it looks as before.
     restore_lbr(lbr_saved);
     // call 'operatorfunc'
     op_function(oap);

     // Restore the info for redoing Visual mode, the function may
     // invoke another operator and unintentionally change it.
     redo_VIsual = save_redo_VIsual;
     break;
   }

   case OP_INSERT:
   case OP_APPEND:
     VIsual_reselect = false;          // don't reselect now
     if (empty_region_error) {
       vim_beep(kOptBoFlagOperator);
       CancelRedo();
     } else {
       // This is a new edit command, not a restart.  Need to
       // remember it to make i_CTRL-O work with mappings for
       // Visual mode.  But do this only once.
       restart_edit_save = restart_edit;
       restart_edit = 0;

       // Restore linebreak, so that when the user edits it looks as before.
       restore_lbr(lbr_saved);

       // trigger TextChangedI
       curbuf->b_last_changedtick_i = buf_get_changedtick(curbuf);

       op_insert(oap, cap->count1);

       // Reset linebreak, so that formatting works correctly.
       reset_lbr();

       // TODO(brammool): when inserting in several lines, should format all
       // the lines.
       auto_format(false, true);

       if (restart_edit == 0) {
         restart_edit = restart_edit_save;
       } else {
         cap->retval |= CA_COMMAND_BUSY;
       }
     }
     break;

   case OP_REPLACE:
     VIsual_reselect = false;          // don't reselect now
     if (empty_region_error) {
       vim_beep(kOptBoFlagOperator);
       CancelRedo();
     } else {
       // Restore linebreak, so that when the user edits it looks as before.
       restore_lbr(lbr_saved);

       op_replace(oap, cap->nchar);
     }
     break;

   case OP_FOLD:
     VIsual_reselect = false;          // don't reselect now
     foldCreate(curwin, oap->start, oap->end);
     break;

   case OP_FOLDOPEN:
   case OP_FOLDOPENREC:
   case OP_FOLDCLOSE:
   case OP_FOLDCLOSEREC:
     VIsual_reselect = false;          // don't reselect now
     opFoldRange(oap->start, oap->end,
                 oap->op_type == OP_FOLDOPEN
                 || oap->op_type == OP_FOLDOPENREC,
                 oap->op_type == OP_FOLDOPENREC
                 || oap->op_type == OP_FOLDCLOSEREC,
                 oap->is_VIsual);
     break;

   case OP_FOLDDEL:
   case OP_FOLDDELREC:
     VIsual_reselect = false;          // don't reselect now
     deleteFold(curwin, oap->start.lnum, oap->end.lnum,
                oap->op_type == OP_FOLDDELREC, oap->is_VIsual);
     break;

   case OP_NR_ADD:
   case OP_NR_SUB:
     if (empty_region_error) {
       vim_beep(kOptBoFlagOperator);
       CancelRedo();
     } else {
       VIsual_active = true;
       restore_lbr(lbr_saved);
       op_addsub(oap, (linenr_T)cap->count1, redo_VIsual.rv_arg);
       VIsual_active = false;
     }
     check_cursor_col(curwin);
     break;
   default:
     clearopbeep(oap);
   }
   virtual_op = kNone;
   if (!gui_yank) {
     // if 'sol' not set, go back to old column for some commands
     if (!p_sol && oap->motion_type == kMTLineWise && !oap->end_adjusted
         && (oap->op_type == OP_LSHIFT || oap->op_type == OP_RSHIFT
             || oap->op_type == OP_DELETE)) {
       reset_lbr();
       coladvance(curwin, curwin->w_curswant = old_col);
     }
   } else {
     curwin->w_cursor = old_cursor;
   }
   clearop(oap);
   motion_force = NUL;
 }
 restore_lbr(lbr_saved);
}

/// Get the byte count of buffer region. End-exclusive.
///
/// @return number of bytes
bcount_t get_region_bytecount(buf_T *buf, linenr_T start_lnum, linenr_T end_lnum, colnr_T start_col,
                             colnr_T end_col)
{
 linenr_T max_lnum = buf->b_ml.ml_line_count;
 if (start_lnum > max_lnum) {
   return 0;
 }
 if (start_lnum == end_lnum) {
   return end_col - start_col;
 }
 bcount_t deleted_bytes = ml_get_buf_len(buf, start_lnum) - start_col + 1;

 for (linenr_T i = 1; i <= end_lnum - start_lnum - 1; i++) {
   if (start_lnum + i > max_lnum) {
     return deleted_bytes;
   }
   deleted_bytes += ml_get_buf_len(buf, start_lnum + i) + 1;
 }
 if (end_lnum > max_lnum) {
   return deleted_bytes;
 }
 return deleted_bytes + end_col;
}