kc3-lang/freetype/src/psaux/psstack.c

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• Hash : 3915a18b
  Author :
  Date : 2018-08-29T06:53:54
  

  [cff] Fix handling of `roll' op in old engine. Reported as https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10080 * src/psaux/cffdecode.c (cff_decoder_parse_charstrings) <cff_op_roll> [CFF_CONFIG_OPTION_OLD_ENGINE]: Use modulo for loop count, as documented in the specification.

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• src/psaux/psstack.c

• /****************************************************************************
   *
   * 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 FT_INTERNAL_DEBUG_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 = FT_Err_Ok;     /* for FT_NEW */
  
      CF2_Stack  stack = NULL;
  
  
      if ( !FT_NEW( stack ) )
      {
        /* initialize the structure; FT_NEW zeroes it */
        stack->memory = memory;
        stack->error  = e;
      }
  
      /* allocate the stack buffer */
      if ( FT_NEW_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 */
  

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