PageRenderTime 19ms CodeModel.GetById 2ms app.highlight 13ms RepoModel.GetById 1ms app.codeStats 0ms

/src/FreeImage/Source/LibJPEG/jmemname.c

https://bitbucket.org/cabalistic/ogredeps/
C | 276 lines | 146 code | 46 blank | 84 comment | 13 complexity | 719f6097de742d244c6680941795fa3e MD5 | raw file
  1/*
  2 * jmemname.c
  3 *
  4 * Copyright (C) 1992-1997, Thomas G. Lane.
  5 * This file is part of the Independent JPEG Group's software.
  6 * For conditions of distribution and use, see the accompanying README file.
  7 *
  8 * This file provides a generic implementation of the system-dependent
  9 * portion of the JPEG memory manager.  This implementation assumes that
 10 * you must explicitly construct a name for each temp file.
 11 * Also, the problem of determining the amount of memory available
 12 * is shoved onto the user.
 13 */
 14
 15#define JPEG_INTERNALS
 16#include "jinclude.h"
 17#include "jpeglib.h"
 18#include "jmemsys.h"		/* import the system-dependent declarations */
 19
 20#ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare malloc(),free() */
 21extern void * malloc JPP((size_t size));
 22extern void free JPP((void *ptr));
 23#endif
 24
 25#ifndef SEEK_SET		/* pre-ANSI systems may not define this; */
 26#define SEEK_SET  0		/* if not, assume 0 is correct */
 27#endif
 28
 29#ifdef DONT_USE_B_MODE		/* define mode parameters for fopen() */
 30#define READ_BINARY	"r"
 31#define RW_BINARY	"w+"
 32#else
 33#ifdef VMS			/* VMS is very nonstandard */
 34#define READ_BINARY	"rb", "ctx=stm"
 35#define RW_BINARY	"w+b", "ctx=stm"
 36#else				/* standard ANSI-compliant case */
 37#define READ_BINARY	"rb"
 38#define RW_BINARY	"w+b"
 39#endif
 40#endif
 41
 42
 43/*
 44 * Selection of a file name for a temporary file.
 45 * This is system-dependent!
 46 *
 47 * The code as given is suitable for most Unix systems, and it is easily
 48 * modified for most non-Unix systems.  Some notes:
 49 *  1.  The temp file is created in the directory named by TEMP_DIRECTORY.
 50 *      The default value is /usr/tmp, which is the conventional place for
 51 *      creating large temp files on Unix.  On other systems you'll probably
 52 *      want to change the file location.  You can do this by editing the
 53 *      #define, or (preferred) by defining TEMP_DIRECTORY in jconfig.h.
 54 *
 55 *  2.  If you need to change the file name as well as its location,
 56 *      you can override the TEMP_FILE_NAME macro.  (Note that this is
 57 *      actually a printf format string; it must contain %s and %d.)
 58 *      Few people should need to do this.
 59 *
 60 *  3.  mktemp() is used to ensure that multiple processes running
 61 *      simultaneously won't select the same file names.  If your system
 62 *      doesn't have mktemp(), define NO_MKTEMP to do it the hard way.
 63 *      (If you don't have <errno.h>, also define NO_ERRNO_H.)
 64 *
 65 *  4.  You probably want to define NEED_SIGNAL_CATCHER so that cjpeg.c/djpeg.c
 66 *      will cause the temp files to be removed if you stop the program early.
 67 */
 68
 69#ifndef TEMP_DIRECTORY		/* can override from jconfig.h or Makefile */
 70#define TEMP_DIRECTORY  "/usr/tmp/" /* recommended setting for Unix */
 71#endif
 72
 73static int next_file_num;	/* to distinguish among several temp files */
 74
 75#ifdef NO_MKTEMP
 76
 77#ifndef TEMP_FILE_NAME		/* can override from jconfig.h or Makefile */
 78#define TEMP_FILE_NAME  "%sJPG%03d.TMP"
 79#endif
 80
 81#ifndef NO_ERRNO_H
 82#include <errno.h>		/* to define ENOENT */
 83#endif
 84
 85/* ANSI C specifies that errno is a macro, but on older systems it's more
 86 * likely to be a plain int variable.  And not all versions of errno.h
 87 * bother to declare it, so we have to in order to be most portable.  Thus:
 88 */
 89#ifndef errno
 90extern int errno;
 91#endif
 92
 93
 94LOCAL(void)
 95select_file_name (char * fname)
 96{
 97  FILE * tfile;
 98
 99  /* Keep generating file names till we find one that's not in use */
100  for (;;) {
101    next_file_num++;		/* advance counter */
102    sprintf(fname, TEMP_FILE_NAME, TEMP_DIRECTORY, next_file_num);
103    if ((tfile = fopen(fname, READ_BINARY)) == NULL) {
104      /* fopen could have failed for a reason other than the file not
105       * being there; for example, file there but unreadable.
106       * If <errno.h> isn't available, then we cannot test the cause.
107       */
108#ifdef ENOENT
109      if (errno != ENOENT)
110	continue;
111#endif
112      break;
113    }
114    fclose(tfile);		/* oops, it's there; close tfile & try again */
115  }
116}
117
118#else /* ! NO_MKTEMP */
119
120/* Note that mktemp() requires the initial filename to end in six X's */
121#ifndef TEMP_FILE_NAME		/* can override from jconfig.h or Makefile */
122#define TEMP_FILE_NAME  "%sJPG%dXXXXXX"
123#endif
124
125LOCAL(void)
126select_file_name (char * fname)
127{
128  next_file_num++;		/* advance counter */
129  sprintf(fname, TEMP_FILE_NAME, TEMP_DIRECTORY, next_file_num);
130  mktemp(fname);		/* make sure file name is unique */
131  /* mktemp replaces the trailing XXXXXX with a unique string of characters */
132}
133
134#endif /* NO_MKTEMP */
135
136
137/*
138 * Memory allocation and freeing are controlled by the regular library
139 * routines malloc() and free().
140 */
141
142GLOBAL(void *)
143jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
144{
145  return (void *) malloc(sizeofobject);
146}
147
148GLOBAL(void)
149jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject)
150{
151  free(object);
152}
153
154
155/*
156 * "Large" objects are treated the same as "small" ones.
157 * NB: although we include FAR keywords in the routine declarations,
158 * this file won't actually work in 80x86 small/medium model; at least,
159 * you probably won't be able to process useful-size images in only 64KB.
160 */
161
162GLOBAL(void FAR *)
163jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
164{
165  return (void FAR *) malloc(sizeofobject);
166}
167
168GLOBAL(void)
169jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)
170{
171  free(object);
172}
173
174
175/*
176 * This routine computes the total memory space available for allocation.
177 * It's impossible to do this in a portable way; our current solution is
178 * to make the user tell us (with a default value set at compile time).
179 * If you can actually get the available space, it's a good idea to subtract
180 * a slop factor of 5% or so.
181 */
182
183#ifndef DEFAULT_MAX_MEM		/* so can override from makefile */
184#define DEFAULT_MAX_MEM		1000000L /* default: one megabyte */
185#endif
186
187GLOBAL(long)
188jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
189		    long max_bytes_needed, long already_allocated)
190{
191  return cinfo->mem->max_memory_to_use - already_allocated;
192}
193
194
195/*
196 * Backing store (temporary file) management.
197 * Backing store objects are only used when the value returned by
198 * jpeg_mem_available is less than the total space needed.  You can dispense
199 * with these routines if you have plenty of virtual memory; see jmemnobs.c.
200 */
201
202
203METHODDEF(void)
204read_backing_store (j_common_ptr cinfo, backing_store_ptr info,
205		    void FAR * buffer_address,
206		    long file_offset, long byte_count)
207{
208  if (fseek(info->temp_file, file_offset, SEEK_SET))
209    ERREXIT(cinfo, JERR_TFILE_SEEK);
210  if (JFREAD(info->temp_file, buffer_address, byte_count)
211      != (size_t) byte_count)
212    ERREXIT(cinfo, JERR_TFILE_READ);
213}
214
215
216METHODDEF(void)
217write_backing_store (j_common_ptr cinfo, backing_store_ptr info,
218		     void FAR * buffer_address,
219		     long file_offset, long byte_count)
220{
221  if (fseek(info->temp_file, file_offset, SEEK_SET))
222    ERREXIT(cinfo, JERR_TFILE_SEEK);
223  if (JFWRITE(info->temp_file, buffer_address, byte_count)
224      != (size_t) byte_count)
225    ERREXIT(cinfo, JERR_TFILE_WRITE);
226}
227
228
229METHODDEF(void)
230close_backing_store (j_common_ptr cinfo, backing_store_ptr info)
231{
232  fclose(info->temp_file);	/* close the file */
233  unlink(info->temp_name);	/* delete the file */
234/* If your system doesn't have unlink(), use remove() instead.
235 * remove() is the ANSI-standard name for this function, but if
236 * your system was ANSI you'd be using jmemansi.c, right?
237 */
238  TRACEMSS(cinfo, 1, JTRC_TFILE_CLOSE, info->temp_name);
239}
240
241
242/*
243 * Initial opening of a backing-store object.
244 */
245
246GLOBAL(void)
247jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
248			 long total_bytes_needed)
249{
250  select_file_name(info->temp_name);
251  if ((info->temp_file = fopen(info->temp_name, RW_BINARY)) == NULL)
252    ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);
253  info->read_backing_store = read_backing_store;
254  info->write_backing_store = write_backing_store;
255  info->close_backing_store = close_backing_store;
256  TRACEMSS(cinfo, 1, JTRC_TFILE_OPEN, info->temp_name);
257}
258
259
260/*
261 * These routines take care of any system-dependent initialization and
262 * cleanup required.
263 */
264
265GLOBAL(long)
266jpeg_mem_init (j_common_ptr cinfo)
267{
268  next_file_num = 0;		/* initialize temp file name generator */
269  return DEFAULT_MAX_MEM;	/* default for max_memory_to_use */
270}
271
272GLOBAL(void)
273jpeg_mem_term (j_common_ptr cinfo)
274{
275  /* no work */
276}