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libpng/pngmem.c

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/* pngmem.c - stub functions for memory allocation
*
* Last changed in libpng 1.5.0 [(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)
/* 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_FUNCTION(png_voidp /* PRIVATE */,
png_create_struct,(int type),PNG_ALLOCATED)
{
# ifdef PNG_USER_MEM_SUPPORTED
return (png_create_struct_2(type, NULL, NULL));
}
/* Alternate version of png_create_struct, for use with user-defined malloc. */
PNG_FUNCTION(png_voidp /* PRIVATE */,
png_create_struct_2,(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr),
PNG_ALLOCATED)
{
# 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, NULL, 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_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,(png_size_t)size);
return (ret);
}
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 || 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_FUNCTION(png_voidp,PNGAPI
png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
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", "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", "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_FUNCTION(png_voidp /* PRIVATE */,
png_create_struct,(int type),PNG_ALLOCATED)
{
# ifdef PNG_USER_MEM_SUPPORTED
return (png_create_struct_2(type, NULL, 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_FUNCTION(png_voidp /* PRIVATE */,
png_create_struct_2,(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr),
PNG_ALLOCATED)
{
# 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, NULL, 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_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,(png_size_t)size);
return (ret);
}
PNG_FUNCTION(png_voidp,PNGAPI
png_malloc,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
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_FUNCTION(png_voidp,PNGAPI
png_malloc_default,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
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 */
/* 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_FUNCTION(png_voidp,PNGAPI
png_malloc_warn,(png_structp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
{
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);
}
#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 */
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