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 *

 * Last changed in libpng 1.6.0 [February 14, 2013]

 * Copyright (c) 1998-2013 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 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.

 */

/* Free a png_struct */

void /* PRIVATE */

png_destroy_png_struct(png_structrp png_ptr)

{

   if (png_ptr != NULL)

   {

      /* png_free might call png_error and may certainly call

       * png_get_mem_ptr, so fake a temporary png_struct to support this.

       */

      png_struct dummy_struct = *png_ptr;

      memset(png_ptr, 0, (sizeof *png_ptr));

      png_free(&dummy_struct, png_ptr);

         /* We may have a jmp_buf left to deallocate. */

         png_free_jmpbuf(&dummy_struct);

#     endif

   }

}

 * 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_FUNCTION(png_voidp,PNGAPI

png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)

{

   png_voidp ret;

      memset(ret, 0, size);

}

 * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED.

 * Checking and error handling must happen outside this routine; it returns NULL

 * if the allocation cannot be done (for any reason.)

 */

PNG_FUNCTION(png_voidp /* PRIVATE */,

png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),

   PNG_ALLOCATED)

{

   /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS

    * allocators have also been removed in 1.6.0, so any 16-bit system now has

    * to implement a user memory handler.  This checks to be sure it isn't

    * called with big numbers.

    */

#ifdef PNG_USER_MEM_SUPPORTED

   PNG_UNUSED(png_ptr)

#endif

   if (size > 0 && size <= PNG_SIZE_MAX

#     ifdef PNG_MAX_MALLOC_64K

         && size <= 65536U

#     endif

      )

   {

#ifdef PNG_USER_MEM_SUPPORTED

      if (png_ptr != NULL && png_ptr->malloc_fn != NULL)

         return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);

#endif

         return malloc((size_t)size); /* checked for truncation above */

   }

      return NULL;

}

 * that arises because of the checks in png_realloc_array that are repeated in

 * png_malloc_array.

 */

static png_voidp

png_malloc_array_checked(png_const_structrp png_ptr, int nelements,

   size_t element_size)

{

   png_alloc_size_t req = nelements; /* known to be > 0 */

      return png_malloc_base(png_ptr, req * element_size);

   return NULL;

}

png_malloc_array,(png_const_structrp png_ptr, int nelements,

   size_t element_size),PNG_ALLOCATED)

{

   if (nelements <= 0 || element_size == 0)

      png_error(png_ptr, "internal error: array alloc");

}

png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,

   int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)

{

   /* These are internal errors: */

   if (add_elements <= 0 || element_size == 0 || old_elements < 0 ||

      (old_array == NULL && old_elements > 0))

      png_error(png_ptr, "internal error: array realloc");

    * check.)

    */

   if (add_elements <= INT_MAX - old_elements)

   {

      png_voidp new_array = png_malloc_array_checked(png_ptr,

         old_elements+add_elements, element_size);

      {

         /* Because png_malloc_array worked the size calculations below cannot

          * overflow.

          */

         if (old_elements > 0)

            memcpy(new_array, old_array, element_size*(unsigned)old_elements);

            element_size*(unsigned)add_elements);

      }

   }

}

 * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate

 * function png_malloc_default is also provided.

 */

PNG_FUNCTION(png_voidp,PNGAPI

png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)

{

   png_voidp ret;

      return NULL;

       png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */

}

PNG_FUNCTION(png_voidp,PNGAPI

png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),

   PNG_ALLOCATED PNG_DEPRECATED)

{

   png_voidp ret;

      return NULL;

   ret = png_malloc_base(NULL/*use malloc*/, size);

      png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */

}

#endif /* PNG_USER_MEM_SUPPORTED */

 * function will issue a png_warning and return NULL instead of issuing a

 * png_error, if it fails to allocate the requested memory.

 */

PNG_FUNCTION(png_voidp,PNGAPI

png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size),

   PNG_ALLOCATED)

{

   if (png_ptr != NULL)

   {

      png_voidp ret = png_malloc_base(png_ptr, size);

         return ret;

   }

}

 * without taking any action.

 */

void PNGAPI

png_free(png_const_structrp png_ptr, png_voidp ptr)

{

   if (png_ptr == NULL || ptr == NULL)

      return;

   if (png_ptr->free_fn != NULL)

      png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);

      png_free_default(png_ptr, ptr);

}

png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)

{

   if (png_ptr == NULL || ptr == NULL)

      return;

#endif /* 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_structrp 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;

   }

}

 * 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_const_structrp png_ptr)

{

   if (png_ptr == NULL)

      return NULL;

}

#endif /* PNG_USER_MEM_SUPPORTED */

#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */