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Diffstat (limited to 'code/jpeg-6/jmemansi.c')
| -rwxr-xr-x | code/jpeg-6/jmemansi.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/code/jpeg-6/jmemansi.c b/code/jpeg-6/jmemansi.c new file mode 100755 index 0000000..b560d20 --- /dev/null +++ b/code/jpeg-6/jmemansi.c @@ -0,0 +1,167 @@ +/*
+ * jmemansi.c
+ *
+ * Copyright (C) 1992-1994, 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 simple generic implementation of the system-
+ * dependent portion of the JPEG memory manager. This implementation
+ * assumes that you have the ANSI-standard library routine tmpfile().
+ * 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
+
+
+/*
+ * 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);
+ /* Since this implementation uses tmpfile() to create the file,
+ * no explicit file deletion is needed.
+ */
+}
+
+
+/*
+ * Initial opening of a backing-store object.
+ *
+ * This version uses tmpfile(), which constructs a suitable file name
+ * behind the scenes. We don't have to use info->temp_name[] at all;
+ * indeed, we can't even find out the actual name of the temp file.
+ */
+
+GLOBAL void
+jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
+ long total_bytes_needed)
+{
+ if ((info->temp_file = tmpfile()) == NULL)
+ ERREXITS(cinfo, JERR_TFILE_CREATE, "");
+ info->read_backing_store = read_backing_store;
+ info->write_backing_store = write_backing_store;
+ info->close_backing_store = close_backing_store;
+}
+
+
+/*
+ * These routines take care of any system-dependent initialization and
+ * cleanup required.
+ */
+
+GLOBAL long
+jpeg_mem_init (j_common_ptr cinfo)
+{
+ return DEFAULT_MAX_MEM; /* default for max_memory_to_use */
+}
+
+GLOBAL void
+jpeg_mem_term (j_common_ptr cinfo)
+{
+ /* no work */
+}
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