text: 
  /* pngmem.c - stub functions for memory allocation
   *
   * Last changed in libpng 1.2.37 [June 4, 2009]
   * For conditions of distribution and use, see copyright notice in png.h
   * Copyright (c) 1998-2009 Glenn Randers-Pehrson
   * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   *
   * This file provides a location for all memory allocation.  Users who
   * need special memory handling are expected to supply replacement
   * functions for png_malloc() and png_free(), and to use
   * png_create_read_struct_2() and png_create_write_struct_2() to
   * identify the replacement functions.
   */
  
  #define PNG_INTERNAL
  #include "png.h"
  #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
  
  /* Borland DOS special memory handler */
  #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
  /* If you change this, be sure to change the one in png.h also */
  
  /* Allocate memory for a png_struct.  The malloc and memset can be replaced
     by a single call to calloc() if this is thought to improve performance. */
  png_voidp /* PRIVATE */
  png_create_struct(int type)
  {
  #ifdef PNG_USER_MEM_SUPPORTED
     return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
  }
  
  /* Alternate version of png_create_struct, for use with user-defined malloc. */
  png_voidp /* PRIVATE */
  png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
  {
  #endif /* PNG_USER_MEM_SUPPORTED */
     png_size_t size;
     png_voidp struct_ptr;
  
     if (type == PNG_STRUCT_INFO)
        size = png_sizeof(png_info);
     else if (type == PNG_STRUCT_PNG)
        size = png_sizeof(png_struct);
     else
        return (png_get_copyright(NULL));
  
  #ifdef PNG_USER_MEM_SUPPORTED
     if (malloc_fn != NULL)
     {
        png_struct dummy_struct;
        png_structp png_ptr = &dummy_struct;
        png_ptr->mem_ptr=mem_ptr;
        struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
     }
     else
  #endif /* PNG_USER_MEM_SUPPORTED */
     struct_ptr = (png_voidp)farmalloc(size);
     if (struct_ptr != NULL)
        png_memset(struct_ptr, 0, size);
     return (struct_ptr);
  }
  
  /* Free memory allocated by a png_create_struct() call */
  void /* PRIVATE */
  png_destroy_struct(png_voidp struct_ptr)
  {
  #ifdef PNG_USER_MEM_SUPPORTED
     png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
  }
  
  /* Free memory allocated by a png_create_struct() call */
  void /* PRIVATE */
  png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
      png_voidp mem_ptr)
  {
  #endif
     if (struct_ptr != NULL)
     {
  #ifdef PNG_USER_MEM_SUPPORTED
        if (free_fn != NULL)
        {
           png_struct dummy_struct;
           png_structp png_ptr = &dummy_struct;
           png_ptr->mem_ptr=mem_ptr;
           (*(free_fn))(png_ptr, struct_ptr);
           return;
        }
  #endif /* PNG_USER_MEM_SUPPORTED */
        farfree (struct_ptr);
     }
  }
  
  /* Allocate memory.  For reasonable files, size should never exceed
   * 64K.  However, zlib may allocate more then 64K if you don't tell
   * it not to.  See zconf.h and png.h for more information. zlib does
   * need to allocate exactly 64K, so whatever you call here must
   * have the ability to do that.
   *
   * Borland seems to have a problem in DOS mode for exactly 64K.
   * It gives you a segment with an offset of 8 (perhaps to store its
   * memory stuff).  zlib doesn't like this at all, so we have to
   * detect and deal with it.  This code should not be needed in
   * Windows or OS/2 modes, and only in 16 bit mode.  This code has
   * been updated by Alexander Lehmann for version 0.89 to waste less
   * memory.
   *
   * Note that we can't use png_size_t for the "size" declaration,
   * since on some systems a png_size_t is a 16-bit quantity, and as a
   * result, we would be truncating potentially larger memory requests
   * (which should cause a fatal error) and introducing major problems.
   */
  
  png_voidp PNGAPI
  png_malloc(png_structp png_ptr, png_uint_32 size)
  {
     png_voidp ret;
  
     if (png_ptr == NULL || size == 0)
        return (NULL);
  
  #ifdef PNG_USER_MEM_SUPPORTED
     if (png_ptr->malloc_fn != NULL)
        ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
     else
        ret = (png_malloc_default(png_ptr, size));
     if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
         png_error(png_ptr, "Out of memory!");
     return (ret);
  }
  
  png_voidp PNGAPI
  png_malloc_default(png_structp png_ptr, png_uint_32 size)
  {
     png_voidp ret;
  #endif /* PNG_USER_MEM_SUPPORTED */
  
     if (png_ptr == NULL || size == 0)
        return (NULL);
  
  #ifdef PNG_MAX_MALLOC_64K
     if (size > (png_uint_32)65536L)
     {
        png_warning(png_ptr, "Cannot Allocate > 64K");
        ret = NULL;
     }
     else
  #endif
  
     if (size != (size_t)size)
        ret = NULL;
     else if (size == (png_uint_32)65536L)
     {
        if (png_ptr->offset_table == NULL)
        {
           /* Try to see if we need to do any of this fancy stuff */
           ret = farmalloc(size);
           if (ret == NULL || ((png_size_t)ret & 0xffff))
           {
              int num_blocks;
              png_uint_32 total_size;
              png_bytep table;
              int i;
              png_byte huge * hptr;
  
              if (ret != NULL)
              {
                 farfree(ret);
                 ret = NULL;
              }
  
              if (png_ptr->zlib_window_bits > 14)
                 num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
              else
                 num_blocks = 1;
              if (png_ptr->zlib_mem_level >= 7)
                 num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
              else
                 num_blocks++;
  
              total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
  
              table = farmalloc(total_size);
  
              if (table == NULL)
              {
  #ifndef PNG_USER_MEM_SUPPORTED
                 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                    png_error(png_ptr, "Out Of Memory."); /* Note "O" and "M" */
                 else
                    png_warning(png_ptr, "Out Of Memory.");
  #endif
                 return (NULL);
              }
  
              if ((png_size_t)table & 0xfff0)
              {
  #ifndef PNG_USER_MEM_SUPPORTED
                 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                    png_error(png_ptr,
                      "Farmalloc didn't return normalized pointer");
                 else
                    png_warning(png_ptr,
                      "Farmalloc didn't return normalized pointer");
  #endif
                 return (NULL);
              }
  
              png_ptr->offset_table = table;
              png_ptr->offset_table_ptr = farmalloc(num_blocks *
                 png_sizeof(png_bytep));
  
              if (png_ptr->offset_table_ptr == NULL)
              {
  #ifndef PNG_USER_MEM_SUPPORTED
                 if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
                    png_error(png_ptr, "Out Of memory."); /* Note "O" and "M" */
                 else
                    png_warning(png_ptr, "Out Of memory.");
  #endif
                 return (NULL);
              }
  
              hptr = (png_byte huge *)table;
              if ((png_size_t)hptr & 0xf)
              {
                 hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
                 hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
              }
              for (i = 0; i < num_blocks; i++)
              {
                 png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
                 hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
              }
  
              png_ptr->offset_table_number = num_blocks;
              png_ptr->offset_table_count = 0;
              png_ptr->offset_table_count_free = 0;
           }
        }
  
        if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
        {
  #ifndef PNG_USER_MEM_SUPPORTED
           if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
              png_error(png_ptr, "Out of Memory."); /* Note "o" and "M" */
           else
              png_warning(png_ptr, "Out of Memory.");
  #endif
           return (NULL);
        }
  
        ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
     }
     else
        ret = farmalloc(size);
  
  #ifndef PNG_USER_MEM_SUPPORTED
     if (ret == NULL)
     {
        if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
           png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
        else
           png_warning(png_ptr, "Out of memory."); /* Note "o" and "m" */
     }
  #endif
  
     return (ret);
  }
  
  /* Free a pointer allocated by png_malloc().  In the default
   * configuration, png_ptr is not used, but is passed in case it
   * is needed.  If ptr is NULL, return without taking any action.
   */
  void PNGAPI
  png_free(png_structp png_ptr, png_voidp ptr)
  {
     if (png_ptr == NULL || ptr == NULL)
        return;
  
  #ifdef PNG_USER_MEM_SUPPORTED
     if (png_ptr->free_fn != NULL)
     {
        (*(png_ptr->free_fn))(png_ptr, ptr);
        return;
     }
     else
        png_free_default(png_ptr, ptr);
  }
  
  void PNGAPI
  png_free_default(png_structp png_ptr, png_voidp ptr)
  {
  #endif /* PNG_USER_MEM_SUPPORTED */
  
     if (png_ptr == NULL || ptr == NULL)
        return;
  
     if (png_ptr->offset_table != NULL)
     {
        int i;
  
        for (i = 0; i < png_ptr->offset_table_count; i++)
        {
           if (ptr == png_ptr->offset_table_ptr[i])
           {
              ptr = NULL;
              png_ptr->offset_table_count_free++;
              break;
           }
        }
        if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
        {
           farfree(png_ptr->offset_table);
           farfree(png_ptr->offset_table_ptr);
           png_ptr->offset_table = NULL;
           png_ptr->offset_table_ptr = NULL;
        }
     }
  
     if (ptr != NULL)
     {
        farfree(ptr);
     }
  }
  
  #else /* Not the Borland DOS special memory handler */
  
  /* Allocate memory for a png_struct or a png_info.  The malloc and
     memset can be replaced by a single call to calloc() if this is thought
     to improve performance noticably. */
  png_voidp /* PRIVATE */
  png_create_struct(int type)
  {
  #ifdef PNG_USER_MEM_SUPPORTED
     return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
  }
  
  /* Allocate memory for a png_struct or a png_info.  The malloc and
     memset can be replaced by a single call to calloc() if this is thought
     to improve performance noticably. */
  png_voidp /* PRIVATE */
  png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
  {
  #endif /* PNG_USER_MEM_SUPPORTED */
     png_size_t size;
     png_voidp struct_ptr;
  
     if (type == PNG_STRUCT_INFO)
        size = png_sizeof(png_info);
     else if (type == PNG_STRUCT_PNG)
        size = png_sizeof(png_struct);
     else
        return (NULL);
  
  #ifdef PNG_USER_MEM_SUPPORTED
     if (malloc_fn != NULL)
     {
        png_struct dummy_struct;
        png_structp png_ptr = &dummy_struct;
        png_ptr->mem_ptr=mem_ptr;
        struct_ptr = (*(malloc_fn))(png_ptr, size);
        if (struct_ptr != NULL)
           png_memset(struct_ptr, 0, size);
        return (struct_ptr);
     }
  #endif /* PNG_USER_MEM_SUPPORTED */
  
  #if defined(__TURBOC__) && !defined(__FLAT__)
     struct_ptr = (png_voidp)farmalloc(size);
  #else
  # if defined(_MSC_VER) && defined(MAXSEG_64K)
     struct_ptr = (png_voidp)halloc(size, 1);
  # else
     struct_ptr = (png_voidp)malloc(size);
  # endif
  #endif
     if (struct_ptr != NULL)
        png_memset(struct_ptr, 0, size);
  
     return (struct_ptr);
  }
  
  
  /* Free memory allocated by a png_create_struct() call */
  void /* PRIVATE */
  png_destroy_struct(png_voidp struct_ptr)
  {
  #ifdef PNG_USER_MEM_SUPPORTED
     png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
  }
  
  /* Free memory allocated by a png_create_struct() call */
  void /* PRIVATE */
  png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
      png_voidp mem_ptr)
  {
  #endif /* PNG_USER_MEM_SUPPORTED */
     if (struct_ptr != NULL)
     {
  #ifdef PNG_USER_MEM_SUPPORTED
        if (free_fn != NULL)
        {
           png_struct dummy_struct;
           png_structp png_ptr = &dummy_struct;
           png_ptr->mem_ptr=mem_ptr;
           (*(free_fn))(png_ptr, struct_ptr);
           return;
        }
  #endif /* PNG_USER_MEM_SUPPORTED */
  #if defined(__TURBOC__) && !defined(__FLAT__)
        farfree(struct_ptr);
  #else
  # if defined(_MSC_VER) && defined(MAXSEG_64K)
        hfree(struct_ptr);
  # else
        free(struct_ptr);
  # endif
  #endif
     }
  }
  
  /* Allocate memory.  For reasonable files, size should never exceed
   * 64K.  However, zlib may allocate more then 64K if you don't tell
   * it not to.  See zconf.h and png.h for more information.  zlib does
   * need to allocate exactly 64K, so whatever you call here must
   * have the ability to do that.
   */
  
  
  png_voidp PNGAPI
  png_malloc(png_structp png_ptr, png_uint_32 size)
  {
     png_voidp ret;
  
  #ifdef PNG_USER_MEM_SUPPORTED
     if (png_ptr == NULL || size == 0)
        return (NULL);
  
     if (png_ptr->malloc_fn != NULL)
        ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
     else
        ret = (png_malloc_default(png_ptr, size));
     if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
         png_error(png_ptr, "Out of Memory!");
     return (ret);
  }
  
  png_voidp PNGAPI
  png_malloc_default(png_structp png_ptr, png_uint_32 size)
  {
     png_voidp ret;
  #endif /* PNG_USER_MEM_SUPPORTED */
  
     if (png_ptr == NULL || size == 0)
        return (NULL);
  
  #ifdef PNG_MAX_MALLOC_64K
     if (size > (png_uint_32)65536L)
     {
  #ifndef PNG_USER_MEM_SUPPORTED
        if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
           png_error(png_ptr, "Cannot Allocate > 64K");
        else
  #endif
           return NULL;
     }
  #endif
  
     /* Check for overflow */
  #if defined(__TURBOC__) && !defined(__FLAT__)
     if (size != (unsigned long)size)
        ret = NULL;
     else
        ret = farmalloc(size);
  #else
  # if defined(_MSC_VER) && defined(MAXSEG_64K)
     if (size != (unsigned long)size)
        ret = NULL;
     else
        ret = halloc(size, 1);
  # else
     if (size != (size_t)size)
        ret = NULL;
     else
        ret = malloc((size_t)size);
  # endif
  #endif
  
  #ifndef PNG_USER_MEM_SUPPORTED
     if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
        png_error(png_ptr, "Out of Memory");
  #endif
  
     return (ret);
  }
  
  /* Free a pointer allocated by png_malloc().  If ptr is NULL, return
   * without taking any action.
   */
  void PNGAPI
  png_free(png_structp png_ptr, png_voidp ptr)
  {
     if (png_ptr == NULL || ptr == NULL)
        return;
  
  #ifdef PNG_USER_MEM_SUPPORTED
     if (png_ptr->free_fn != NULL)
     {
        (*(png_ptr->free_fn))(png_ptr, ptr);
        return;
     }
     else
        png_free_default(png_ptr, ptr);
  }
  void PNGAPI
  png_free_default(png_structp png_ptr, png_voidp ptr)
  {
     if (png_ptr == NULL || ptr == NULL)
        return;
  
  #endif /* PNG_USER_MEM_SUPPORTED */
  
  #if defined(__TURBOC__) && !defined(__FLAT__)
     farfree(ptr);
  #else
  # if defined(_MSC_VER) && defined(MAXSEG_64K)
     hfree(ptr);
  # else
     free(ptr);
  # endif
  #endif
  }
  
  #endif /* Not Borland DOS special memory handler */
  
  #if defined(PNG_1_0_X)
  #  define png_malloc_warn png_malloc
  #else
  /* This function was added at libpng version 1.2.3.  The png_malloc_warn()
   * function will set up png_malloc() to issue a png_warning and return NULL
   * instead of issuing a png_error, if it fails to allocate the requested
   * memory.
   */
  png_voidp PNGAPI
  png_malloc_warn(png_structp png_ptr, png_uint_32 size)
  {
     png_voidp ptr;
     png_uint_32 save_flags;
     if (png_ptr == NULL)
        return (NULL);
  
     save_flags = png_ptr->flags;
     png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
     ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
     png_ptr->flags=save_flags;
     return(ptr);
  }
  #endif
  
  png_voidp PNGAPI
  png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
     png_uint_32 length)
  {
     png_size_t size;
  
     size = (png_size_t)length;
     if ((png_uint_32)size != length)
        png_error(png_ptr, "Overflow in png_memcpy_check.");
  
     return(png_memcpy (s1, s2, size));
  }
  
  png_voidp PNGAPI
  png_memset_check (png_structp png_ptr, png_voidp s1, int value,
     png_uint_32 length)
  {
     png_size_t size;
  
     size = (png_size_t)length;
     if ((png_uint_32)size != length)
        png_error(png_ptr, "Overflow in png_memset_check.");
  
     return (png_memset (s1, value, size));
  
  }
  
  #ifdef PNG_USER_MEM_SUPPORTED
  /* This function is called when the application wants to use another method
   * of allocating and freeing memory.
   */
  void PNGAPI
  png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
    malloc_fn, png_free_ptr free_fn)
  {
     if (png_ptr != NULL)
     {
        png_ptr->mem_ptr = mem_ptr;
        png_ptr->malloc_fn = malloc_fn;
        png_ptr->free_fn = free_fn;
     }
  }
  
  /* This function returns a pointer to the mem_ptr associated with the user
   * functions.  The application should free any memory associated with this
   * pointer before png_write_destroy and png_read_destroy are called.
   */
  png_voidp PNGAPI
  png_get_mem_ptr(png_structp png_ptr)
  {
     if (png_ptr == NULL)
        return (NULL);
     return ((png_voidp)png_ptr->mem_ptr);
  }
  #endif /* PNG_USER_MEM_SUPPORTED */
  #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
  