/* pngmem.c - stub functions for memory allocation

 *

 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

 *

 * This code is released under the libpng license.

 * For conditions of distribution and use, see the disclaimer

 * and license in png.h

 *

 * 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.

 */

#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

}

/* 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

}

/* 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_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)

   return (ret);

}

png_voidp PNGAPI

{

   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)

               else

#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)

               else

#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)

         else

#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)

      else

   }

#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

}

/* 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

}

/* 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_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)

   return (ret);

}

png_voidp PNGAPI

{

   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