/* * 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 */#define TEMP_DIRECTORY  "./" /* modified by Leo */#endifstatic 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 errnoextern 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 */#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. */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   remove(info->temp_name);	// using remove operation under ARM processor    // unlink(info->temp_name);	// delete the file // original code    // 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 */}