tor-browser

bprint.c (10265B)

---

/*
* Copyright (c) 2012 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/

#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include "avstring.h"
#include "bprint.h"
#include "compat/va_copy.h"
#include "error.h"
#include "macros.h"
#include "mem.h"

#define av_bprint_room(buf) ((buf)->size - FFMIN((buf)->len, (buf)->size))
#define av_bprint_is_allocated(buf) ((buf)->str != (buf)->reserved_internal_buffer)

static int av_bprint_alloc(AVBPrint *buf, unsigned room)
{
   char *old_str, *new_str;
   unsigned min_size, new_size;

   if (buf->size == buf->size_max)
       return AVERROR(EIO);
   if (!av_bprint_is_complete(buf))
       return AVERROR_INVALIDDATA; /* it is already truncated anyway */
   min_size = buf->len + 1 + FFMIN(UINT_MAX - buf->len - 1, room);
   new_size = buf->size > buf->size_max / 2 ? buf->size_max : buf->size * 2;
   if (new_size < min_size)
       new_size = FFMIN(buf->size_max, min_size);
   old_str = av_bprint_is_allocated(buf) ? buf->str : NULL;
   new_str = av_realloc(old_str, new_size);
   if (!new_str)
       return AVERROR(ENOMEM);
   if (!old_str)
       memcpy(new_str, buf->str, buf->len + 1);
   buf->str  = new_str;
   buf->size = new_size;
   return 0;
}

static void av_bprint_grow(AVBPrint *buf, unsigned extra_len)
{
   /* arbitrary margin to avoid small overflows */
   extra_len = FFMIN(extra_len, UINT_MAX - 5 - buf->len);
   buf->len += extra_len;
   if (buf->size)
       buf->str[FFMIN(buf->len, buf->size - 1)] = 0;
}

void av_bprint_init(AVBPrint *buf, unsigned size_init, unsigned size_max)
{
   unsigned size_auto = (char *)buf + sizeof(*buf) -
                        buf->reserved_internal_buffer;

   if (size_max == AV_BPRINT_SIZE_AUTOMATIC)
       size_max = size_auto;
   buf->str      = buf->reserved_internal_buffer;
   buf->len      = 0;
   buf->size     = FFMIN(size_auto, size_max);
   buf->size_max = size_max;
   *buf->str = 0;
   if (size_init > buf->size)
       av_bprint_alloc(buf, size_init - 1);
}

void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
{
   if (size == 0) {
       av_bprint_init(buf, 0, AV_BPRINT_SIZE_COUNT_ONLY);
       return;
   }

   buf->str      = buffer;
   buf->len      = 0;
   buf->size     = size;
   buf->size_max = size;
   *buf->str = 0;
}

void av_bprintf(AVBPrint *buf, const char *fmt, ...)
{
   unsigned room;
   char *dst;
   va_list vl;
   int extra_len;

   while (1) {
       room = av_bprint_room(buf);
       dst = room ? buf->str + buf->len : NULL;
       va_start(vl, fmt);
       extra_len = vsnprintf(dst, room, fmt, vl);
       va_end(vl);
       if (extra_len <= 0)
           return;
       if (extra_len < room)
           break;
       if (av_bprint_alloc(buf, extra_len))
           break;
   }
   av_bprint_grow(buf, extra_len);
}

void av_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg)
{
   unsigned room;
   char *dst;
   int extra_len;
   va_list vl;

   while (1) {
       room = av_bprint_room(buf);
       dst = room ? buf->str + buf->len : NULL;
       va_copy(vl, vl_arg);
       extra_len = vsnprintf(dst, room, fmt, vl);
       va_end(vl);
       if (extra_len <= 0)
           return;
       if (extra_len < room)
           break;
       if (av_bprint_alloc(buf, extra_len))
           break;
   }
   av_bprint_grow(buf, extra_len);
}

void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
{
   unsigned room, real_n;

   while (1) {
       room = av_bprint_room(buf);
       if (n < room)
           break;
       if (av_bprint_alloc(buf, n))
           break;
   }
   if (room) {
       real_n = FFMIN(n, room - 1);
       memset(buf->str + buf->len, c, real_n);
   }
   av_bprint_grow(buf, n);
}

void av_bprint_append_data(AVBPrint *buf, const char *data, unsigned size)
{
   unsigned room, real_n;

   while (1) {
       room = av_bprint_room(buf);
       if (size < room)
           break;
       if (av_bprint_alloc(buf, size))
           break;
   }
   if (room) {
       real_n = FFMIN(size, room - 1);
       memcpy(buf->str + buf->len, data, real_n);
   }
   av_bprint_grow(buf, size);
}

void av_bprint_strftime(AVBPrint *buf, const char *fmt, const struct tm *tm)
{
   unsigned room;
   size_t l;

   if (!*fmt)
       return;
   while (1) {
       room = av_bprint_room(buf);
       if (room && (l = strftime(buf->str + buf->len, room, fmt, tm)))
           break;
       /* strftime does not tell us how much room it would need: let us
          retry with twice as much until the buffer is large enough */
       room = !room ? strlen(fmt) + 1 :
              room <= INT_MAX / 2 ? room * 2 : INT_MAX;
       if (av_bprint_alloc(buf, room)) {
           /* impossible to grow, try to manage something useful anyway */
           room = av_bprint_room(buf);
           if (room < 1024) {
               /* if strftime fails because the buffer has (almost) reached
                  its maximum size, let us try in a local buffer; 1k should
                  be enough to format any real date+time string */
               char buf2[1024];
               if ((l = strftime(buf2, sizeof(buf2), fmt, tm))) {
                   av_bprintf(buf, "%s", buf2);
                   return;
               }
           }
           if (room) {
               /* if anything else failed and the buffer is not already
                  truncated, let us add a stock string and force truncation */
               static const char txt[] = "[truncated strftime output]";
               memset(buf->str + buf->len, '!', room);
               memcpy(buf->str + buf->len, txt, FFMIN(sizeof(txt) - 1, room));
               av_bprint_grow(buf, room); /* force truncation */
           }
           return;
       }
   }
   av_bprint_grow(buf, l);
}

void av_bprint_get_buffer(AVBPrint *buf, unsigned size,
                         unsigned char **mem, unsigned *actual_size)
{
   if (size > av_bprint_room(buf))
       av_bprint_alloc(buf, size);
   *actual_size = av_bprint_room(buf);
   *mem = *actual_size ? buf->str + buf->len : NULL;
}

void av_bprint_clear(AVBPrint *buf)
{
   if (buf->len) {
       *buf->str = 0;
       buf->len  = 0;
   }
}

int av_bprint_finalize(AVBPrint *buf, char **ret_str)
{
   unsigned real_size = FFMIN(buf->len + 1, buf->size);
   char *str;
   int ret = 0;

   if (ret_str) {
       if (av_bprint_is_allocated(buf)) {
           str = av_realloc(buf->str, real_size);
           if (!str)
               str = buf->str;
           buf->str = NULL;
       } else {
           str = av_memdup(buf->str, real_size);
           if (!str)
               ret = AVERROR(ENOMEM);
       }
       *ret_str = str;
   } else {
       if (av_bprint_is_allocated(buf))
           av_freep(&buf->str);
   }
   buf->size = real_size;
   return ret;
}

#define WHITESPACES " \n\t\r"

void av_bprint_escape(AVBPrint *dstbuf, const char *src, const char *special_chars,
                     enum AVEscapeMode mode, int flags)
{
   const char *src0 = src;

   if (mode == AV_ESCAPE_MODE_AUTO)
       mode = AV_ESCAPE_MODE_BACKSLASH; /* TODO: implement a heuristic */

   switch (mode) {
   case AV_ESCAPE_MODE_QUOTE:
       /* enclose the string between '' */
       av_bprint_chars(dstbuf, '\'', 1);
       for (; *src; src++) {
           if (*src == '\'')
               av_bprintf(dstbuf, "'\\''");
           else
               av_bprint_chars(dstbuf, *src, 1);
       }
       av_bprint_chars(dstbuf, '\'', 1);
       break;

   case AV_ESCAPE_MODE_XML:
       /* escape XML non-markup character data as per 2.4 by default: */
       /*  [^<&]* - ([^<&]* ']]>' [^<&]*) */

       /* additionally, given one of the AV_ESCAPE_FLAG_XML_* flags, */
       /* escape those specific characters as required. */
       for (; *src; src++) {
           switch (*src) {
           case '&' : av_bprintf(dstbuf, "%s", "&amp;");  break;
           case '<' : av_bprintf(dstbuf, "%s", "&lt;");   break;
           case '>' : av_bprintf(dstbuf, "%s", "&gt;");   break;
           case '\'':
               if (!(flags & AV_ESCAPE_FLAG_XML_SINGLE_QUOTES))
                   goto XML_DEFAULT_HANDLING;

               av_bprintf(dstbuf, "%s", "&apos;");
               break;
           case '"' :
               if (!(flags & AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES))
                   goto XML_DEFAULT_HANDLING;

               av_bprintf(dstbuf, "%s", "&quot;");
               break;
XML_DEFAULT_HANDLING:
           default: av_bprint_chars(dstbuf, *src, 1);
           }
       }
       break;

   /* case AV_ESCAPE_MODE_BACKSLASH or unknown mode */
   default:
       /* \-escape characters */
       for (; *src; src++) {
           int is_first_last       = src == src0 || !*(src+1);
           int is_ws               = !!strchr(WHITESPACES, *src);
           int is_strictly_special = special_chars && strchr(special_chars, *src);
           int is_special          =
               is_strictly_special || strchr("'\\", *src) ||
               (is_ws && (flags & AV_ESCAPE_FLAG_WHITESPACE));

           if (is_strictly_special ||
               (!(flags & AV_ESCAPE_FLAG_STRICT) &&
                (is_special || (is_ws && is_first_last))))
               av_bprint_chars(dstbuf, '\\', 1);
           av_bprint_chars(dstbuf, *src, 1);
       }
       break;
   }
}