jmemnobs.cpp

来自「Windows 图形编程 书籍」· C++ 代码 · 共 80 行

//-------------------------------------------------------------------------//
//          Windows Graphics Programming: Win32 GDI and DirectDraw         //
//                        ISBN  0-13-086985-6                              //
//                                                                         //
//  Modified by: Yuan, Feng                             www.fengyuan.com   //
//  Changes    : C++, exception, in-memory source, BGR byte order          //
//  Version    : 1.00.000, May 31, 2000                                    //
//-------------------------------------------------------------------------//

/*
 * jmemnobs.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 really simple implementation of the system-
 * dependent portion of the JPEG memory manager.  This implementation
 * assumes that no backing-store files are needed: all required space
 * can be obtained from malloc().
 * This is very portable in the sense that it'll compile on almost anything,
 * but you'd better have lots of main memory (or virtual memory) if you want
 * to process big images.
 * Note that the max_memory_to_use option is ignored by this implementation.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jmemsys.h"		/* import the system-dependent declarations */

/*
 * Memory allocation and freeing are controlled by the regular library
 * routines malloc() and free().
 */

/*
 * This routine computes the total memory space available for allocation.
 * Here we always say, "we got all you want bud!"
 */

GLOBAL(long)
jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
		    long max_bytes_needed, long already_allocated)
{
  return max_bytes_needed;
}


/*
 * Backing store (temporary file) management.
 * Since jpeg_mem_available always promised the moon,
 * this should never be called and we can just error out.
 */

GLOBAL(void)
jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
			 long total_bytes_needed)
{
  cinfo->ERREXIT(JERR_NO_BACKING_STORE);
}


/*
 * These routines take care of any system-dependent initialization and
 * cleanup required.  Here, there isn't any.
 */

GLOBAL(long)
jpeg_mem_init (j_common_ptr cinfo)
{
  return 0;			/* just set max_memory_to_use to 0 */
}

GLOBAL(void)
jpeg_mem_term (j_common_ptr cinfo)
{
  /* no work */
}