--- /dev/null
+/*
+ * 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 */
+}
projects / synfig.git / blobdiff