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Diffstat (limited to 'src/jpeg-6/jmemansi.c')
-rw-r--r-- | src/jpeg-6/jmemansi.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/jpeg-6/jmemansi.c b/src/jpeg-6/jmemansi.c new file mode 100644 index 0000000..70010f9 --- /dev/null +++ b/src/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 */ +} |