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/* pngmem.c - stub functions for memory allocation
*
* Last changed in libpng 1.6.0 [(PENDING RELEASE)]
* Copyright (c) 1998-2011 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.
*/
#include "pngpriv.h"
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
/* Free a png_struct */
void /* PRIVATE */
png_destroy_png_struct(png_structp 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);
# ifdef PNG_SETJMP_SUPPORTED
/* We may have a jmp_buf left to deallocate. */
png_free_jmpbuf(&dummy_struct);
# 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_FUNCTION(png_voidp,PNGAPI
png_calloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
png_voidp ret;
ret = png_malloc(png_ptr, size);
if (ret != NULL)
png_memset(ret, 0, size);
return ret;
}
/* png_malloc_base, an internal function added at libpng 1.6.0, does the work of
* 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_structp 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 <= ~(size_t)0
# 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_ptr, size);
else
#endif
return malloc((size_t)size); /* checked for truncation above */
}
else
return NULL;
}
/* Various functions that have different error handling are derived from this.
* 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_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
png_voidp ret;
if (png_ptr == NULL)
return NULL;
ret = png_malloc_base(png_ptr, size);
if (ret == NULL)
png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */
return ret;
}
#ifdef PNG_USER_MEM_SUPPORTED
PNG_FUNCTION(png_voidp,PNGAPI
png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),
PNG_ALLOCATED PNG_DEPRECATED)
{
png_voidp ret;
if (png_ptr == NULL)
return NULL;
/* Passing 'NULL' here bypasses the application provided memory handler. */
ret = png_malloc_base(NULL/*use malloc*/, size);
if (ret == NULL)
png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
return ret;
}
#endif /* PNG_USER_MEM_SUPPORTED */
/* This function was added at libpng version 1.2.3. The png_malloc_warn()
* 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_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
if (png_ptr != NULL)
{
png_voidp ret = png_malloc_base(png_ptr, size);
if (ret != NULL)
return ret;
png_warning(png_ptr, "Out of memory");
}
return NULL;
}
/* 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);
else
png_free_default(png_ptr, ptr);
}
PNG_FUNCTION(void,PNGAPI
png_free_default,(png_structp png_ptr, png_voidp ptr),PNG_DEPRECATED)
{
if (png_ptr == NULL || ptr == NULL)
return;
#endif /* PNG_USER_MEM_SUPPORTED */
free(ptr);
}
#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_const_structp png_ptr)
{
if (png_ptr == NULL)
return NULL;
return png_ptr->mem_ptr;
}
#endif /* PNG_USER_MEM_SUPPORTED */
#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
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