277 строки
8.1 KiB
C
277 строки
8.1 KiB
C
/*
|
|
* jmemname.c
|
|
*
|
|
* Copyright (C) 1992-1997, 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 generic implementation of the system-dependent
|
|
* portion of the JPEG memory manager. This implementation assumes that
|
|
* you must explicitly construct a name for each temp file.
|
|
* 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
|
|
|
|
#ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */
|
|
#define READ_BINARY "r"
|
|
#define RW_BINARY "w+"
|
|
#else
|
|
#ifdef VMS /* VMS is very nonstandard */
|
|
#define READ_BINARY "rb", "ctx=stm"
|
|
#define RW_BINARY "w+b", "ctx=stm"
|
|
#else /* standard ANSI-compliant case */
|
|
#define READ_BINARY "rb"
|
|
#define RW_BINARY "w+b"
|
|
#endif
|
|
#endif
|
|
|
|
|
|
/*
|
|
* Selection of a file name for a temporary file.
|
|
* This is system-dependent!
|
|
*
|
|
* The code as given is suitable for most Unix systems, and it is easily
|
|
* modified for most non-Unix systems. Some notes:
|
|
* 1. The temp file is created in the directory named by TEMP_DIRECTORY.
|
|
* The default value is /usr/tmp, which is the conventional place for
|
|
* creating large temp files on Unix. On other systems you'll probably
|
|
* want to change the file location. You can do this by editing the
|
|
* #define, or (preferred) by defining TEMP_DIRECTORY in jconfig.h.
|
|
*
|
|
* 2. If you need to change the file name as well as its location,
|
|
* you can override the TEMP_FILE_NAME macro. (Note that this is
|
|
* actually a printf format string; it must contain %s and %d.)
|
|
* Few people should need to do this.
|
|
*
|
|
* 3. mktemp() is used to ensure that multiple processes running
|
|
* simultaneously won't select the same file names. If your system
|
|
* doesn't have mktemp(), define NO_MKTEMP to do it the hard way.
|
|
* (If you don't have <errno.h>, also define NO_ERRNO_H.)
|
|
*
|
|
* 4. You probably want to define NEED_SIGNAL_CATCHER so that cjpeg.c/djpeg.c
|
|
* will cause the temp files to be removed if you stop the program early.
|
|
*/
|
|
|
|
#ifndef TEMP_DIRECTORY /* can override from jconfig.h or Makefile */
|
|
#define TEMP_DIRECTORY "/usr/tmp/" /* recommended setting for Unix */
|
|
#endif
|
|
|
|
static int next_file_num; /* to distinguish among several temp files */
|
|
|
|
#ifdef NO_MKTEMP
|
|
|
|
#ifndef TEMP_FILE_NAME /* can override from jconfig.h or Makefile */
|
|
#define TEMP_FILE_NAME "%sJPG%03d.TMP"
|
|
#endif
|
|
|
|
#ifndef NO_ERRNO_H
|
|
#include <errno.h> /* to define ENOENT */
|
|
#endif
|
|
|
|
/* ANSI C specifies that errno is a macro, but on older systems it's more
|
|
* likely to be a plain int variable. And not all versions of errno.h
|
|
* bother to declare it, so we have to in order to be most portable. Thus:
|
|
*/
|
|
#ifndef errno
|
|
extern int errno;
|
|
#endif
|
|
|
|
|
|
LOCAL(void)
|
|
select_file_name (char * fname)
|
|
{
|
|
FILE * tfile;
|
|
|
|
/* Keep generating file names till we find one that's not in use */
|
|
for (;;) {
|
|
next_file_num++; /* advance counter */
|
|
sprintf(fname, TEMP_FILE_NAME, TEMP_DIRECTORY, next_file_num);
|
|
if ((tfile = fopen(fname, READ_BINARY)) == NULL) {
|
|
/* fopen could have failed for a reason other than the file not
|
|
* being there; for example, file there but unreadable.
|
|
* If <errno.h> isn't available, then we cannot test the cause.
|
|
*/
|
|
#ifdef ENOENT
|
|
if (errno != ENOENT)
|
|
continue;
|
|
#endif
|
|
break;
|
|
}
|
|
fclose(tfile); /* oops, it's there; close tfile & try again */
|
|
}
|
|
}
|
|
|
|
#else /* ! NO_MKTEMP */
|
|
|
|
/* Note that mktemp() requires the initial filename to end in six X's */
|
|
#ifndef TEMP_FILE_NAME /* can override from jconfig.h or Makefile */
|
|
#define TEMP_FILE_NAME "%sJPG%dXXXXXX"
|
|
#endif
|
|
|
|
LOCAL(void)
|
|
select_file_name (char * fname)
|
|
{
|
|
next_file_num++; /* advance counter */
|
|
sprintf(fname, TEMP_FILE_NAME, TEMP_DIRECTORY, next_file_num);
|
|
mktemp(fname); /* make sure file name is unique */
|
|
/* mktemp replaces the trailing XXXXXX with a unique string of characters */
|
|
}
|
|
|
|
#endif /* NO_MKTEMP */
|
|
|
|
|
|
/*
|
|
* 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 */
|
|
#endif
|
|
|
|
GLOBAL(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.
|
|
*/
|
|
|
|
|
|
METHODDEF(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)
|
|
{
|
|
fclose(info->temp_file); /* close the file */
|
|
unlink(info->temp_name); /* delete the file */
|
|
/* If your system doesn't have unlink(), use remove() instead.
|
|
* remove() is the ANSI-standard name for this function, but if
|
|
* your system was ANSI you'd be using jmemansi.c, right?
|
|
*/
|
|
TRACEMSS(cinfo, 1, JTRC_TFILE_CLOSE, info->temp_name);
|
|
}
|
|
|
|
|
|
/*
|
|
* Initial opening of a backing-store object.
|
|
*/
|
|
|
|
GLOBAL(void)
|
|
jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
|
|
long total_bytes_needed)
|
|
{
|
|
select_file_name(info->temp_name);
|
|
if ((info->temp_file = fopen(info->temp_name, RW_BINARY)) == NULL)
|
|
ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);
|
|
info->read_backing_store = read_backing_store;
|
|
info->write_backing_store = write_backing_store;
|
|
info->close_backing_store = close_backing_store;
|
|
TRACEMSS(cinfo, 1, JTRC_TFILE_OPEN, info->temp_name);
|
|
}
|
|
|
|
|
|
/*
|
|
* These routines take care of any system-dependent initialization and
|
|
* cleanup required.
|
|
*/
|
|
|
|
GLOBAL(long)
|
|
jpeg_mem_init (j_common_ptr cinfo)
|
|
{
|
|
next_file_num = 0; /* initialize temp file name generator */
|
|
return DEFAULT_MAX_MEM; /* default for max_memory_to_use */
|
|
}
|
|
|
|
GLOBAL(void)
|
|
jpeg_mem_term (j_common_ptr cinfo)
|
|
{
|
|
/* no work */
|
|
}
|