| |
| /* pngmem.c - stub functions for memory allocation |
| * |
| * Last changed in libpng 1.6.15 [November 20, 2014] |
| * Copyright (c) 1998-2002,2004,2006-2014 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" |
| |
| void* FXMEM_DefaultAlloc(int byte_size, int); |
| void FXMEM_DefaultFree(void* pointer, int); |
| |
| #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) |
| /* 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); |
| |
| # 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 than 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; |
| |
| ret = png_malloc(png_ptr, size); |
| |
| if (ret != NULL) |
| 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_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. |
| */ |
| #ifndef PNG_USER_MEM_SUPPORTED |
| PNG_UNUSED(png_ptr) |
| #endif |
| |
| /* Some compilers complain that this is always true. However, it |
| * can be false when integer overflow happens. |
| */ |
| 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); |
| |
| else |
| #endif |
| return FXMEM_DefaultAlloc((int)size, 0); |
| } |
| |
| else |
| return NULL; |
| } |
| |
| #if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\ |
| defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) |
| /* This is really here only to work round a spurious warning in GCC 4.6 and 4.7 |
| * 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 */ |
| |
| if (req <= PNG_SIZE_MAX/element_size) |
| return png_malloc_base(png_ptr, req * element_size); |
| |
| /* The failure case when the request is too large */ |
| return NULL; |
| } |
| |
| PNG_FUNCTION(png_voidp /* PRIVATE */, |
| 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"); |
| |
| return png_malloc_array_checked(png_ptr, nelements, element_size); |
| } |
| |
| PNG_FUNCTION(png_voidp /* PRIVATE */, |
| 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 for overflow on the elements count (so the caller does not have to |
| * check.) |
| */ |
| if (add_elements <= INT_MAX - old_elements) |
| { |
| png_voidp new_array = png_malloc_array_checked(png_ptr, |
| old_elements+add_elements, element_size); |
| |
| if (new_array != NULL) |
| { |
| /* 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); |
| |
| memset((char*)new_array + element_size*(unsigned)old_elements, 0, |
| element_size*(unsigned)add_elements); |
| |
| return new_array; |
| } |
| } |
| |
| return NULL; /* error */ |
| } |
| #endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */ |
| |
| /* 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_const_structrp 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_const_structrp 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 /* USER_MEM */ |
| |
| /* 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_const_structrp 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_const_structrp 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_constcast(png_structrp,png_ptr), ptr); |
| |
| else |
| png_free_default(png_ptr, ptr); |
| } |
| |
| PNG_FUNCTION(void,PNGAPI |
| png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED) |
| { |
| if (png_ptr == NULL || ptr == NULL) |
| return; |
| #endif /* USER_MEM */ |
| |
| FXMEM_DefaultFree(ptr, 0); |
| } |
| |
| #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_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; |
| } |
| } |
| |
| /* 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_structrp png_ptr) |
| { |
| if (png_ptr == NULL) |
| return NULL; |
| |
| return png_ptr->mem_ptr; |
| } |
| #endif /* USER_MEM */ |
| #endif /* READ || WRITE */ |