386 lines
9.5 KiB
C
386 lines
9.5 KiB
C
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/* pngmem.c - stub functions for memory allocation
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libpng 1.0 beta 3 - version 0.89
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For conditions of distribution and use, see copyright notice in png.h
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Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
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May 25, 1996
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This file provides a location for all memory allocation. Users which
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need special memory handling are expected to modify the code in this file
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to meet their needs. See the instructions at each function. */
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#define PNG_INTERNAL
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#include "png.h"
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/* Borland DOS special memory handler */
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#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
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/* if you change this, be sure to change the one in png.h also */
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/* Allocate memory for a png_struct. The malloc and memset can be replaced
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* by a single call to calloc() if this is thought to improve performance.
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*/
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png_voidp
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png_create_struct(uInt type)
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{
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png_size_t type;
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png_voidp struct_ptr;
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if (type == PNG_STRUCT_INFO)
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size = sizeof(png_info);
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else if (type == PNG_STRUCT_PNG)
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size = sizeof(png_struct);
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else
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return (png_voidp)NULL;
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if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
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{
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png_memset(struct_ptr, 0, size);
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}
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return (struct_ptr);
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}
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/* Free memory allocated by a png_create_struct() call */
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void
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png_destroy_struct(png_voidp struct_ptr)
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{
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if (struct_ptr)
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farfree (struct_ptr);
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}
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/* Allocate memory. For reasonable files, size should never exceed
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64K. However, zlib may allocate more then 64K if you don't tell
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it not to. See zconf.h and png.h for more information. zlib does
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need to allocate exactly 64K, so whatever you call here must
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have the ability to do that. */
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/* Borland seems to have a problem in DOS mode for exactly 64K.
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It gives you a segment with an offset of 8 (perhaps to store it's
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memory stuff). zlib doesn't like this at all, so we have to
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detect and deal with it. This code should not be needed in
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Windows or OS/2 modes, and only in 16 bit mode. This code has
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been updated by Alexander Lehmann for version 0.89 to waste less
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memory.
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*/
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png_voidp
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png_large_malloc(png_structp png_ptr, png_uint_32 size)
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{
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png_voidp ret;
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if (!png_ptr || !size)
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return ((voidp)NULL);
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#ifdef PNG_MAX_MALLOC_64K
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if (size > (png_uint_32)65536L)
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png_error(png_ptr, "Cannot Allocate > 64K");
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#endif
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if (size == (png_uint_32)(65536L))
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{
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if (!png_ptr->offset_table)
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{
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/* try to see if we need to do any of this fancy stuff */
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ret = farmalloc(size);
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if (!ret || ((long)ret & 0xffff))
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{
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int num_blocks;
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png_uint_32 total_size;
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png_bytep table;
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int i;
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png_byte huge * hptr;
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if (ret)
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farfree(ret);
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ret = NULL;
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num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
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if (num_blocks < 1)
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num_blocks = 1;
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if (png_ptr->zlib_mem_level >= 7)
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num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
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else
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num_blocks++;
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total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
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table = farmalloc(total_size);
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if (!table)
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{
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png_error(png_ptr, "Out of Memory");
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}
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if ((long)table & 0xfff0)
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{
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png_error(png_ptr, "Farmalloc didn't return normalized pointer");
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}
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png_ptr->offset_table = table;
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png_ptr->offset_table_ptr = farmalloc(
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num_blocks * sizeof (png_bytep));
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if (!png_ptr->offset_table_ptr)
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{
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png_error(png_ptr, "Out of memory");
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}
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hptr = (png_byte huge *)table;
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if ((long)hptr & 0xf)
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{
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hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
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hptr += 16L;
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}
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for (i = 0; i < num_blocks; i++)
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{
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png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
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hptr += 65536L;
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}
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png_ptr->offset_table_number = num_blocks;
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png_ptr->offset_table_count = 0;
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png_ptr->offset_table_count_free = 0;
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}
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}
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if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
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png_error(png_ptr, "Out of Memory");
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ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
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}
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else
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ret = farmalloc(size);
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if (ret == NULL)
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{
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png_error(png_ptr, "Out of Memory");
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}
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return ret;
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}
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/* free a pointer allocated by png_large_malloc(). In the default
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configuration, png_ptr is not used, but is passed in case it
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is needed. If ptr is NULL, return without taking any action. */
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void
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png_large_free(png_structp png_ptr, png_voidp ptr)
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{
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if (!png_ptr)
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return;
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if (ptr != NULL)
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{
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if (png_ptr->offset_table)
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{
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int i;
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for (i = 0; i < png_ptr->offset_table_count; i++)
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{
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if (ptr == png_ptr->offset_table_ptr[i])
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{
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ptr = 0;
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png_ptr->offset_table_count_free++;
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break;
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}
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}
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if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
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{
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farfree(png_ptr->offset_table);
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farfree(png_ptr->offset_table_ptr);
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png_ptr->offset_table = 0;
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png_ptr->offset_table_ptr = 0;
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}
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}
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if (ptr)
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farfree(ptr);
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}
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}
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#else /* Not the Borland DOS special memory handler */
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/* Allocate memory for a png_struct or a png_info. The malloc and
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* memset can be replaced by a single call to calloc() if this is thought
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* to improve performance noticably.
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*/
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png_voidp
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png_create_struct(uInt type)
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{
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size_t size;
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png_voidp struct_ptr;
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if (type == PNG_STRUCT_INFO)
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size = sizeof(png_info);
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else if (type == PNG_STRUCT_PNG)
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size = sizeof(png_struct);
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else
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return (png_voidp)NULL;
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#if defined(__TURBOC__) && !defined(__FLAT__)
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if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
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#else
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# if defined(_MSC_VER) && defined(MAXSEG_64K)
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if ((struct_ptr = (png_voidp)halloc(size)) != NULL)
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# else
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if ((struct_ptr = (png_voidp)malloc(size)) != NULL)
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# endif
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#endif
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{
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png_memset(struct_ptr, 0, size);
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}
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return (struct_ptr);
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}
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/* Free memory allocated by a png_create_struct() call */
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void
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png_destroy_struct(png_voidp struct_ptr)
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{
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if (struct_ptr)
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#if defined(__TURBOC__) && !defined(__FLAT__)
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farfree(struct_ptr);
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#else
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# if defined(_MSC_VER) && defined(MAXSEG_64K)
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hfree(struct_ptr);
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# else
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free(struct_ptr);
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# endif
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#endif
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}
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/* Allocate memory. For reasonable files, size should never exceed
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64K. However, zlib may allocate more then 64K if you don't tell
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it not to. See zconf.h and png.h for more information. zlib does
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need to allocate exactly 64K, so whatever you call here must
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have the ability to do that. */
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png_voidp
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png_large_malloc(png_structp png_ptr, png_uint_32 size)
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{
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png_voidp ret;
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if (!png_ptr || !size)
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return ((voidp)0);
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#ifdef PNG_MAX_MALLOC_64K
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if (size > (png_uint_32)65536L)
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png_error(png_ptr, "Cannot Allocate > 64K");
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#endif
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#if defined(__TURBOC__) && !defined(__FLAT__)
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ret = farmalloc(size);
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#else
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# if defined(_MSC_VER) && defined(MAXSEG_64K)
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ret = halloc(size, 1);
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# else
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ret = malloc(size);
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# endif
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#endif
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if (ret == NULL)
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{
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png_error(png_ptr, "Out of Memory");
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}
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return ret;
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}
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/* free a pointer allocated by png_large_malloc(). In the default
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configuration, png_ptr is not used, but is passed in case it
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is needed. If ptr is NULL, return without taking any action. */
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void
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png_large_free(png_structp png_ptr, png_voidp ptr)
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{
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if (!png_ptr)
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return;
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if (ptr != NULL)
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{
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#if defined(__TURBOC__) && !defined(__FLAT__)
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farfree(ptr);
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#else
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# if defined(_MSC_VER) && defined(MAXSEG_64K)
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hfree(ptr);
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# else
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free(ptr);
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# endif
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#endif
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}
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}
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#endif /* Not Borland DOS special memory handler */
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/* Allocate memory. This is called for smallish blocks only It
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should not get anywhere near 64K. On segmented machines, this
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must come from the local heap (for zlib). Currently, zlib is
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the only one that uses this, so you should only get one call
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to this, and that a small block. */
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void *
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png_malloc(png_structp png_ptr, png_uint_32 size)
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{
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void *ret;
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if (!png_ptr || !size)
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{
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return ((void *)0);
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}
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#ifdef PNG_MAX_MALLOC_64K
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if (size > (png_uint_32)65536L)
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png_error(png_ptr, "Cannot Allocate > 64K");
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#endif
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ret = malloc((png_size_t)size);
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if (!ret)
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{
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png_error(png_ptr, "Out of Memory");
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}
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return ret;
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}
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/* Reallocate memory. This will not get near 64K on a
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even marginally reasonable file. This is not used in
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the current version of the library. */
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void *
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png_realloc(png_structp png_ptr, void * ptr, png_uint_32 size,
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png_uint_32 old_size)
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{
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void *ret;
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if (!png_ptr || !old_size || !ptr || !size)
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return ((void *)0);
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#ifdef PNG_MAX_MALLOC_64K
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if (size > (png_uint_32)65536L)
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png_error(png_ptr, "Cannot Allocate > 64K");
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#endif
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ret = realloc(ptr, (png_size_t)size);
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if (!ret)
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{
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png_error(png_ptr, "Out of Memory 7");
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}
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return ret;
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}
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/* free a pointer allocated by png_malloc(). In the default
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configuration, png_ptr is not used, but is passed incase it
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is needed. If ptr is NULL, return without taking any action. */
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void
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png_free(png_structp png_ptr, void * ptr)
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{
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if (!png_ptr)
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return;
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if (ptr != (void *)0)
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free(ptr);
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}
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