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Diffstat (limited to 'png/pngmem.c')
| -rw-r--r-- | png/pngmem.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/png/pngmem.c b/png/pngmem.c new file mode 100644 index 0000000..8ee0866 --- /dev/null +++ b/png/pngmem.c @@ -0,0 +1,281 @@ + +/* pngmem.c - stub functions for memory allocation + * + * Last changed in libpng 1.6.8 [December 19, 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. + */ + +#include "pngpriv.h" + +#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 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; + + 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 + + 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 malloc((size_t)size); /* checked for truncation above */ + } + + 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 /* 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_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 /* 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_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 /* PNG_USER_MEM_SUPPORTED */ +#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ |