/* * jmemansi.c * * Copyright (C) 1992-1996, Thomas G. Lane. * This file is part of the Independent JPEG Group's software. * For conditions of distribution and use, see the accompanying README file. * * This file provides a simple generic implementation of the system- * dependent portion of the JPEG memory manager.  This implementation * assumes that you have the ANSI-standard library routine tmpfile(). * Also, the problem of determining the amount of memory available * is shoved onto the user. */#define JPEG_INTERNALS#include "jinclude.h"#include "jpeglib.h"#include "jmemsys.h"		/* import the system-dependent declarations */#ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare malloc(),free() */extern void * malloc JPP((size_t size));extern void free JPP((void *ptr));#endif#ifndef SEEK_SET		/* pre-ANSI systems may not define this; */#define SEEK_SET  0		/* if not, assume 0 is correct */#endif/* * Memory allocation and freeing are controlled by the regular library * routines malloc() and free(). */GLOBAL(void *)jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject){  return (void *) malloc(sizeofobject);}GLOBAL(void)jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject){  free(object);}/* * "Large" objects are treated the same as "small" ones. * NB: although we include FAR keywords in the routine declarations, * this file won't actually work in 80x86 small/medium model; at least, * you probably won't be able to process useful-size images in only 64KB. */GLOBAL(void FAR *)jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject){  return (void FAR *) malloc(sizeofobject);}GLOBAL(void)jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject){  free(object);}/* * This routine computes the total memory space available for allocation. * It's impossible to do this in a portable way; our current solution is * to make the user tell us (with a default value set at compile time). * If you can actually get the available space, it's a good idea to subtract * a slop factor of 5% or so. */#ifndef DEFAULT_MAX_MEM		/* so can override from makefile */#define DEFAULT_MAX_MEM		1000000L /* default: one megabyte */#endifGLOBAL(long)jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,		    long max_bytes_needed, long already_allocated){  return cinfo->mem->max_memory_to_use - already_allocated;}/* * Backing store (temporary file) management. * Backing store objects are only used when the value returned by * jpeg_mem_available is less than the total space needed.  You can dispense * with these routines if you have plenty of virtual memory; see jmemnobs.c. *///#if 0METHODDEF(void)read_backing_store (j_common_ptr cinfo, backing_store_ptr info,		    void FAR * buffer_address,		    long file_offset, long byte_count){/*  if (fseek(info->temp_file, file_offset, SEEK_SET))    ERREXIT(cinfo, JERR_TFILE_SEEK);  if (JFREAD(info->temp_file, buffer_address, byte_count)      != (size_t) byte_count)    ERREXIT(cinfo, JERR_TFILE_READ);*/}METHODDEF(void)write_backing_store (j_common_ptr cinfo, backing_store_ptr info,		     void FAR * buffer_address,		     long file_offset, long byte_count){/*  if (fseek(info->temp_file, file_offset, SEEK_SET))    ERREXIT(cinfo, JERR_TFILE_SEEK);  if (JFWRITE(info->temp_file, buffer_address, byte_count)      != (size_t) byte_count)    ERREXIT(cinfo, JERR_TFILE_WRITE);*/}METHODDEF(void)close_backing_store (j_common_ptr cinfo, backing_store_ptr info){  /* Since this implementation uses tmpfile() to create the file,   * no explicit file deletion is needed.   */}//#endif/* * Initial opening of a backing-store object. * * This version uses tmpfile(), which constructs a suitable file name * behind the scenes.  We don't have to use info->temp_name[] at all; * indeed, we can't even find out the actual name of the temp file. */GLOBAL(void)jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,			 long total_bytes_needed){ // if ((info->temp_file = tmpfile()) == NULL) //   ERREXITS(cinfo, JERR_TFILE_CREATE, "");  info->read_backing_store = read_backing_store;  info->write_backing_store = write_backing_store;  info->close_backing_store = close_backing_store;}/* * These routines take care of any system-dependent initialization and * cleanup required. */GLOBAL(long)jpeg_mem_init (j_common_ptr cinfo){  return DEFAULT_MAX_MEM;	/* default for max_memory_to_use */}