tor-browser

psstack.c (9233B)

---

/****************************************************************************
*
* psstack.c
*
*   Adobe's code for emulating a CFF stack (body).
*
* Copyright 2007-2013 Adobe Systems Incorporated.
*
* This software, and all works of authorship, whether in source or
* object code form as indicated by the copyright notice(s) included
* herein (collectively, the "Work") is made available, and may only be
* used, modified, and distributed under the FreeType Project License,
* LICENSE.TXT.  Additionally, subject to the terms and conditions of the
* FreeType Project License, each contributor to the Work hereby grants
* to any individual or legal entity exercising permissions granted by
* the FreeType Project License and this section (hereafter, "You" or
* "Your") a perpetual, worldwide, non-exclusive, no-charge,
* royalty-free, irrevocable (except as stated in this section) patent
* license to make, have made, use, offer to sell, sell, import, and
* otherwise transfer the Work, where such license applies only to those
* patent claims licensable by such contributor that are necessarily
* infringed by their contribution(s) alone or by combination of their
* contribution(s) with the Work to which such contribution(s) was
* submitted.  If You institute patent litigation against any entity
* (including a cross-claim or counterclaim in a lawsuit) alleging that
* the Work or a contribution incorporated within the Work constitutes
* direct or contributory patent infringement, then any patent licenses
* granted to You under this License for that Work shall terminate as of
* the date such litigation is filed.
*
* By using, modifying, or distributing the Work you indicate that you
* have read and understood the terms and conditions of the
* FreeType Project License as well as those provided in this section,
* and you accept them fully.
*
*/


#include "psft.h"
#include <freetype/internal/ftdebug.h>

#include "psglue.h"
#include "psfont.h"
#include "psstack.h"

#include "pserror.h"


 /* Allocate and initialize an instance of CF2_Stack.       */
 /* Note: This function returns NULL on error (does not set */
 /* `error').                                               */
 FT_LOCAL_DEF( CF2_Stack )
 cf2_stack_init( FT_Memory  memory,
                 FT_Error*  e,
                 FT_UInt    stackSize )
 {
   FT_Error   error;        /* for FT_QNEW */
   CF2_Stack  stack = NULL;


   if ( FT_QNEW( stack ) )
     return NULL;

   stack->memory = memory;
   stack->error  = e;

   /* allocate the stack buffer */
   if ( FT_QNEW_ARRAY( stack->buffer, stackSize ) )
   {
     FT_FREE( stack );
     return NULL;
   }

   stack->stackSize = stackSize;
   stack->top       = stack->buffer;     /* empty stack */

   return stack;
 }


 FT_LOCAL_DEF( void )
 cf2_stack_free( CF2_Stack  stack )
 {
   if ( stack )
   {
     FT_Memory  memory = stack->memory;

     /* free the buffer */
     FT_FREE( stack->buffer );

     /* free the main structure */
     FT_FREE( stack );
   }
 }


 FT_LOCAL_DEF( CF2_UInt )
 cf2_stack_count( CF2_Stack  stack )
 {
   return (CF2_UInt)( stack->top - stack->buffer );
 }


 FT_LOCAL_DEF( void )
 cf2_stack_pushInt( CF2_Stack  stack,
                    CF2_Int    val )
 {
   if ( stack->top == stack->buffer + stack->stackSize )
   {
     CF2_SET_ERROR( stack->error, Stack_Overflow );
     return;     /* stack overflow */
   }

   stack->top->u.i  = val;
   stack->top->type = CF2_NumberInt;
   stack->top++;
 }


 FT_LOCAL_DEF( void )
 cf2_stack_pushFixed( CF2_Stack  stack,
                      CF2_Fixed  val )
 {
   if ( stack->top == stack->buffer + stack->stackSize )
   {
     CF2_SET_ERROR( stack->error, Stack_Overflow );
     return;     /* stack overflow */
   }

   stack->top->u.r  = val;
   stack->top->type = CF2_NumberFixed;
   stack->top++;
 }


 /* this function is only allowed to pop an integer type */
 FT_LOCAL_DEF( CF2_Int )
 cf2_stack_popInt( CF2_Stack  stack )
 {
   if ( stack->top == stack->buffer )
   {
     CF2_SET_ERROR( stack->error, Stack_Underflow );
     return 0;   /* underflow */
   }
   if ( stack->top[-1].type != CF2_NumberInt )
   {
     CF2_SET_ERROR( stack->error, Syntax_Error );
     return 0;   /* type mismatch */
   }

   stack->top--;

   return stack->top->u.i;
 }


 /* Note: type mismatch is silently cast */
 /* TODO: check this                     */
 FT_LOCAL_DEF( CF2_Fixed )
 cf2_stack_popFixed( CF2_Stack  stack )
 {
   if ( stack->top == stack->buffer )
   {
     CF2_SET_ERROR( stack->error, Stack_Underflow );
     return cf2_intToFixed( 0 );    /* underflow */
   }

   stack->top--;

   switch ( stack->top->type )
   {
   case CF2_NumberInt:
     return cf2_intToFixed( stack->top->u.i );
   case CF2_NumberFrac:
     return cf2_fracToFixed( stack->top->u.f );
   default:
     return stack->top->u.r;
   }
 }


 /* Note: type mismatch is silently cast */
 /* TODO: check this                     */
 FT_LOCAL_DEF( CF2_Fixed )
 cf2_stack_getReal( CF2_Stack  stack,
                    CF2_UInt   idx )
 {
   FT_ASSERT( cf2_stack_count( stack ) <= stack->stackSize );

   if ( idx >= cf2_stack_count( stack ) )
   {
     CF2_SET_ERROR( stack->error, Stack_Overflow );
     return cf2_intToFixed( 0 );    /* bounds error */
   }

   switch ( stack->buffer[idx].type )
   {
   case CF2_NumberInt:
     return cf2_intToFixed( stack->buffer[idx].u.i );
   case CF2_NumberFrac:
     return cf2_fracToFixed( stack->buffer[idx].u.f );
   default:
     return stack->buffer[idx].u.r;
   }
 }


 /* provide random access to stack */
 FT_LOCAL_DEF( void )
 cf2_stack_setReal( CF2_Stack  stack,
                    CF2_UInt   idx,
                    CF2_Fixed  val )
 {
   if ( idx > cf2_stack_count( stack ) )
   {
     CF2_SET_ERROR( stack->error, Stack_Overflow );
     return;
   }

   stack->buffer[idx].u.r  = val;
   stack->buffer[idx].type = CF2_NumberFixed;
 }


 /* discard (pop) num values from stack */
 FT_LOCAL_DEF( void )
 cf2_stack_pop( CF2_Stack  stack,
                CF2_UInt   num )
 {
   if ( num > cf2_stack_count( stack ) )
   {
     CF2_SET_ERROR( stack->error, Stack_Underflow );
     return;
   }
   stack->top -= num;
 }


 FT_LOCAL_DEF( void )
 cf2_stack_roll( CF2_Stack  stack,
                 CF2_Int    count,
                 CF2_Int    shift )
 {
   /* we initialize this variable to avoid compiler warnings */
   CF2_StackNumber  last = { { 0 }, CF2_NumberInt };

   CF2_Int  start_idx, idx, i;


   if ( count < 2 )
     return; /* nothing to do (values 0 and 1), or undefined value */

   if ( (CF2_UInt)count > cf2_stack_count( stack ) )
   {
     CF2_SET_ERROR( stack->error, Stack_Overflow );
     return;
   }

   /* before C99 it is implementation-defined whether    */
   /* the result of `%' is negative if the first operand */
   /* is negative                                        */
   if ( shift < 0 )
     shift = -( ( -shift ) % count );
   else
     shift %= count;

   if ( shift == 0 )
     return; /* nothing to do */

   /* We use the following algorithm to do the rolling, */
   /* which needs two temporary variables only.         */
   /*                                                   */
   /* Example:                                          */
   /*                                                   */
   /*   count = 8                                       */
   /*   shift = 2                                       */
   /*                                                   */
   /*   stack indices before roll:  7 6 5 4 3 2 1 0     */
   /*   stack indices after roll:   1 0 7 6 5 4 3 2     */
   /*                                                   */
   /* The value of index 0 gets moved to index 2, while */
   /* the old value of index 2 gets moved to index 4,   */
   /* and so on.  We thus have the following copying    */
   /* chains for shift value 2.                         */
   /*                                                   */
   /*   0 -> 2 -> 4 -> 6 -> 0                           */
   /*   1 -> 3 -> 5 -> 7 -> 1                           */
   /*                                                   */
   /* If `count' and `shift' are incommensurable, we    */
   /* have a single chain only.  Otherwise, increase    */
   /* the start index by 1 after the first chain, then  */
   /* do the next chain until all elements in all       */
   /* chains are handled.                               */

   start_idx = -1;
   idx       = -1;
   for ( i = 0; i < count; i++ )
   {
     CF2_StackNumber  tmp;


     if ( start_idx == idx )
     {
       start_idx++;
       idx  = start_idx;
       last = stack->buffer[idx];
     }

     idx += shift;
     if ( idx >= count )
       idx -= count;
     else if ( idx < 0 )
       idx += count;

     tmp                = stack->buffer[idx];
     stack->buffer[idx] = last;
     last               = tmp;
   }
 }


 FT_LOCAL_DEF( void )
 cf2_stack_clear( CF2_Stack  stack )
 {
   stack->top = stack->buffer;
 }


/* END */