+++ /dev/null
-/*
- * jmemdos.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 an MS-DOS-compatible implementation of the system-
- * dependent portion of the JPEG memory manager. Temporary data can be
- * stored in extended or expanded memory as well as in regular DOS files.
- *
- * If you use this file, you must be sure that NEED_FAR_POINTERS is defined
- * if you compile in a small-data memory model; it should NOT be defined if
- * you use a large-data memory model. This file is not recommended if you
- * are using a flat-memory-space 386 environment such as DJGCC or Watcom C.
- * Also, this code will NOT work if struct fields are aligned on greater than
- * 2-byte boundaries.
- *
- * Based on code contributed by Ge' Weijers.
- */
-
-/*
- * If you have both extended and expanded memory, you may want to change the
- * order in which they are tried in jopen_backing_store. On a 286 machine
- * expanded memory is usually faster, since extended memory access involves
- * an expensive protected-mode-and-back switch. On 386 and better, extended
- * memory is usually faster. As distributed, the code tries extended memory
- * first (what? not everyone has a 386? :-).
- *
- * You can disable use of extended/expanded memory entirely by altering these
- * definitions or overriding them from the Makefile (eg, -DEMS_SUPPORTED=0).
- */
-
-#ifndef XMS_SUPPORTED
-#define XMS_SUPPORTED 1
-#endif
-#ifndef EMS_SUPPORTED
-#define EMS_SUPPORTED 1
-#endif
-
-
-#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 these */
-extern void * malloc JPP((size_t size));
-extern void free JPP((void *ptr));
-extern char * getenv JPP((const char * name));
-#endif
-
-#ifdef NEED_FAR_POINTERS
-
-#ifdef __TURBOC__
-/* These definitions work for Borland C (Turbo C) */
-#include <alloc.h> /* need farmalloc(), farfree() */
-#define far_malloc(x) farmalloc(x)
-#define far_free(x) farfree(x)
-#else
-/* These definitions work for Microsoft C and compatible compilers */
-#include <malloc.h> /* need _fmalloc(), _ffree() */
-#define far_malloc(x) _fmalloc(x)
-#define far_free(x) _ffree(x)
-#endif
-
-#else /* not NEED_FAR_POINTERS */
-
-#define far_malloc(x) malloc(x)
-#define far_free(x) free(x)
-
-#endif /* NEED_FAR_POINTERS */
-
-#ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */
-#define READ_BINARY "r"
-#else
-#define READ_BINARY "rb"
-#endif
-
-#ifndef USE_MSDOS_MEMMGR /* make sure user got configuration right */
- You forgot to define USE_MSDOS_MEMMGR in jconfig.h. /* deliberate syntax error */
-#endif
-
-#if MAX_ALLOC_CHUNK >= 65535L /* make sure jconfig.h got this right */
- MAX_ALLOC_CHUNK should be less than 64K. /* deliberate syntax error */
-#endif
-
-
-/*
- * Declarations for assembly-language support routines (see jmemdosa.asm).
- *
- * The functions are declared "far" as are all their pointer arguments;
- * this ensures the assembly source code will work regardless of the
- * compiler memory model. We assume "short" is 16 bits, "long" is 32.
- */
-
-typedef void far * XMSDRIVER; /* actually a pointer to code */
-typedef struct { /* registers for calling XMS driver */
- unsigned short ax, dx, bx;
- void far * ds_si;
- } XMScontext;
-typedef struct { /* registers for calling EMS driver */
- unsigned short ax, dx, bx;
- void far * ds_si;
- } EMScontext;
-
-extern short far jdos_open JPP((short far * handle, char far * filename));
-extern short far jdos_close JPP((short handle));
-extern short far jdos_seek JPP((short handle, long offset));
-extern short far jdos_read JPP((short handle, void far * buffer,
- unsigned short count));
-extern short far jdos_write JPP((short handle, void far * buffer,
- unsigned short count));
-extern void far jxms_getdriver JPP((XMSDRIVER far *));
-extern void far jxms_calldriver JPP((XMSDRIVER, XMScontext far *));
-extern short far jems_available JPP((void));
-extern void far jems_calldriver JPP((EMScontext far *));
-
-
-/*
- * Selection of a file name for a temporary file.
- * This is highly system-dependent, and you may want to customize it.
- */
-
-static int next_file_num; /* to distinguish among several temp files */
-
-LOCAL(void)
-select_file_name (char * fname)
-{
- const char * env;
- char * ptr;
- FILE * tfile;
-
- /* Keep generating file names till we find one that's not in use */
- for (;;) {
- /* Get temp directory name from environment TMP or TEMP variable;
- * if none, use "."
- */
- if ((env = (const char *) getenv("TMP")) == NULL)
- if ((env = (const char *) getenv("TEMP")) == NULL)
- env = ".";
- if (*env == '\0') /* null string means "." */
- env = ".";
- ptr = fname; /* copy name to fname */
- while (*env != '\0')
- *ptr++ = *env++;
- if (ptr[-1] != '\\' && ptr[-1] != '/')
- *ptr++ = '\\'; /* append backslash if not in env variable */
- /* Append a suitable file name */
- next_file_num++; /* advance counter */
- sprintf(ptr, "JPG%03d.TMP", next_file_num);
- /* Probe to see if file name is already in use */
- if ((tfile = fopen(fname, READ_BINARY)) == NULL)
- break;
- fclose(tfile); /* oops, it's there; close tfile & try again */
- }
-}
-
-
-/*
- * Near-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 allocated in far memory, if possible
- */
-
-GLOBAL(void FAR *)
-jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
-{
- return (void FAR *) far_malloc(sizeofobject);
-}
-
-GLOBAL(void)
-jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)
-{
- far_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 300000L /* for total usage about 450K */
-#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.
- */
-
-/*
- * For MS-DOS we support three types of backing storage:
- * 1. Conventional DOS files. We access these by direct DOS calls rather
- * than via the stdio package. This provides a bit better performance,
- * but the real reason is that the buffers to be read or written are FAR.
- * The stdio library for small-data memory models can't cope with that.
- * 2. Extended memory, accessed per the XMS V2.0 specification.
- * 3. Expanded memory, accessed per the LIM/EMS 4.0 specification.
- * You'll need copies of those specs to make sense of the related code.
- * The specs are available by Internet FTP from the SIMTEL archives
- * (oak.oakland.edu and its various mirror sites). See files
- * pub/msdos/microsoft/xms20.arc and pub/msdos/info/limems41.zip.
- */
-
-
-/*
- * Access methods for a DOS file.
- */
-
-
-METHODDEF(void)
-read_file_store (j_common_ptr cinfo, backing_store_ptr info,
- void FAR * buffer_address,
- long file_offset, long byte_count)
-{
- if (jdos_seek(info->handle.file_handle, file_offset))
- ERREXIT(cinfo, JERR_TFILE_SEEK);
- /* Since MAX_ALLOC_CHUNK is less than 64K, byte_count will be too. */
- if (byte_count > 65535L) /* safety check */
- ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
- if (jdos_read(info->handle.file_handle, buffer_address,
- (unsigned short) byte_count))
- ERREXIT(cinfo, JERR_TFILE_READ);
-}
-
-
-METHODDEF(void)
-write_file_store (j_common_ptr cinfo, backing_store_ptr info,
- void FAR * buffer_address,
- long file_offset, long byte_count)
-{
- if (jdos_seek(info->handle.file_handle, file_offset))
- ERREXIT(cinfo, JERR_TFILE_SEEK);
- /* Since MAX_ALLOC_CHUNK is less than 64K, byte_count will be too. */
- if (byte_count > 65535L) /* safety check */
- ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
- if (jdos_write(info->handle.file_handle, buffer_address,
- (unsigned short) byte_count))
- ERREXIT(cinfo, JERR_TFILE_WRITE);
-}
-
-
-METHODDEF(void)
-close_file_store (j_common_ptr cinfo, backing_store_ptr info)
-{
- jdos_close(info->handle.file_handle); /* close the file */
- remove(info->temp_name); /* delete the file */
-/* If your system doesn't have remove(), try unlink() instead.
- * remove() is the ANSI-standard name for this function, but
- * unlink() was more common in pre-ANSI systems.
- */
- TRACEMSS(cinfo, 1, JTRC_TFILE_CLOSE, info->temp_name);
-}
-
-
-LOCAL(boolean)
-open_file_store (j_common_ptr cinfo, backing_store_ptr info,
- long total_bytes_needed)
-{
- short handle;
-
- select_file_name(info->temp_name);
- if (jdos_open((short far *) & handle, (char far *) info->temp_name)) {
- /* might as well exit since jpeg_open_backing_store will fail anyway */
- ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);
- return FALSE;
- }
- info->handle.file_handle = handle;
- info->read_backing_store = read_file_store;
- info->write_backing_store = write_file_store;
- info->close_backing_store = close_file_store;
- TRACEMSS(cinfo, 1, JTRC_TFILE_OPEN, info->temp_name);
- return TRUE; /* succeeded */
-}
-
-
-/*
- * Access methods for extended memory.
- */
-
-#if XMS_SUPPORTED
-
-static XMSDRIVER xms_driver; /* saved address of XMS driver */
-
-typedef union { /* either long offset or real-mode pointer */
- long offset;
- void far * ptr;
- } XMSPTR;
-
-typedef struct { /* XMS move specification structure */
- long length;
- XMSH src_handle;
- XMSPTR src;
- XMSH dst_handle;
- XMSPTR dst;
- } XMSspec;
-
-#define ODD(X) (((X) & 1L) != 0)
-
-
-METHODDEF(void)
-read_xms_store (j_common_ptr cinfo, backing_store_ptr info,
- void FAR * buffer_address,
- long file_offset, long byte_count)
-{
- XMScontext ctx;
- XMSspec spec;
- char endbuffer[2];
-
- /* The XMS driver can't cope with an odd length, so handle the last byte
- * specially if byte_count is odd. We don't expect this to be common.
- */
-
- spec.length = byte_count & (~ 1L);
- spec.src_handle = info->handle.xms_handle;
- spec.src.offset = file_offset;
- spec.dst_handle = 0;
- spec.dst.ptr = buffer_address;
-
- ctx.ds_si = (void far *) & spec;
- ctx.ax = 0x0b00; /* EMB move */
- jxms_calldriver(xms_driver, (XMScontext far *) & ctx);
- if (ctx.ax != 1)
- ERREXIT(cinfo, JERR_XMS_READ);
-
- if (ODD(byte_count)) {
- read_xms_store(cinfo, info, (void FAR *) endbuffer,
- file_offset + byte_count - 1L, 2L);
- ((char FAR *) buffer_address)[byte_count - 1L] = endbuffer[0];
- }
-}
-
-
-METHODDEF(void)
-write_xms_store (j_common_ptr cinfo, backing_store_ptr info,
- void FAR * buffer_address,
- long file_offset, long byte_count)
-{
- XMScontext ctx;
- XMSspec spec;
- char endbuffer[2];
-
- /* The XMS driver can't cope with an odd length, so handle the last byte
- * specially if byte_count is odd. We don't expect this to be common.
- */
-
- spec.length = byte_count & (~ 1L);
- spec.src_handle = 0;
- spec.src.ptr = buffer_address;
- spec.dst_handle = info->handle.xms_handle;
- spec.dst.offset = file_offset;
-
- ctx.ds_si = (void far *) & spec;
- ctx.ax = 0x0b00; /* EMB move */
- jxms_calldriver(xms_driver, (XMScontext far *) & ctx);
- if (ctx.ax != 1)
- ERREXIT(cinfo, JERR_XMS_WRITE);
-
- if (ODD(byte_count)) {
- read_xms_store(cinfo, info, (void FAR *) endbuffer,
- file_offset + byte_count - 1L, 2L);
- endbuffer[0] = ((char FAR *) buffer_address)[byte_count - 1L];
- write_xms_store(cinfo, info, (void FAR *) endbuffer,
- file_offset + byte_count - 1L, 2L);
- }
-}
-
-
-METHODDEF(void)
-close_xms_store (j_common_ptr cinfo, backing_store_ptr info)
-{
- XMScontext ctx;
-
- ctx.dx = info->handle.xms_handle;
- ctx.ax = 0x0a00;
- jxms_calldriver(xms_driver, (XMScontext far *) & ctx);
- TRACEMS1(cinfo, 1, JTRC_XMS_CLOSE, info->handle.xms_handle);
- /* we ignore any error return from the driver */
-}
-
-
-LOCAL(boolean)
-open_xms_store (j_common_ptr cinfo, backing_store_ptr info,
- long total_bytes_needed)
-{
- XMScontext ctx;
-
- /* Get address of XMS driver */
- jxms_getdriver((XMSDRIVER far *) & xms_driver);
- if (xms_driver == NULL)
- return FALSE; /* no driver to be had */
-
- /* Get version number, must be >= 2.00 */
- ctx.ax = 0x0000;
- jxms_calldriver(xms_driver, (XMScontext far *) & ctx);
- if (ctx.ax < (unsigned short) 0x0200)
- return FALSE;
-
- /* Try to get space (expressed in kilobytes) */
- ctx.dx = (unsigned short) ((total_bytes_needed + 1023L) >> 10);
- ctx.ax = 0x0900;
- jxms_calldriver(xms_driver, (XMScontext far *) & ctx);
- if (ctx.ax != 1)
- return FALSE;
-
- /* Succeeded, save the handle and away we go */
- info->handle.xms_handle = ctx.dx;
- info->read_backing_store = read_xms_store;
- info->write_backing_store = write_xms_store;
- info->close_backing_store = close_xms_store;
- TRACEMS1(cinfo, 1, JTRC_XMS_OPEN, ctx.dx);
- return TRUE; /* succeeded */
-}
-
-#endif /* XMS_SUPPORTED */
-
-
-/*
- * Access methods for expanded memory.
- */
-
-#if EMS_SUPPORTED
-
-/* The EMS move specification structure requires word and long fields aligned
- * at odd byte boundaries. Some compilers will align struct fields at even
- * byte boundaries. While it's usually possible to force byte alignment,
- * that causes an overall performance penalty and may pose problems in merging
- * JPEG into a larger application. Instead we accept some rather dirty code
- * here. Note this code would fail if the hardware did not allow odd-byte
- * word & long accesses, but all 80x86 CPUs do.
- */
-
-typedef void far * EMSPTR;
-
-typedef union { /* EMS move specification structure */
- long length; /* It's easy to access first 4 bytes */
- char bytes[18]; /* Misaligned fields in here! */
- } EMSspec;
-
-/* Macros for accessing misaligned fields */
-#define FIELD_AT(spec,offset,type) (*((type *) &(spec.bytes[offset])))
-#define SRC_TYPE(spec) FIELD_AT(spec,4,char)
-#define SRC_HANDLE(spec) FIELD_AT(spec,5,EMSH)
-#define SRC_OFFSET(spec) FIELD_AT(spec,7,unsigned short)
-#define SRC_PAGE(spec) FIELD_AT(spec,9,unsigned short)
-#define SRC_PTR(spec) FIELD_AT(spec,7,EMSPTR)
-#define DST_TYPE(spec) FIELD_AT(spec,11,char)
-#define DST_HANDLE(spec) FIELD_AT(spec,12,EMSH)
-#define DST_OFFSET(spec) FIELD_AT(spec,14,unsigned short)
-#define DST_PAGE(spec) FIELD_AT(spec,16,unsigned short)
-#define DST_PTR(spec) FIELD_AT(spec,14,EMSPTR)
-
-#define EMSPAGESIZE 16384L /* gospel, see the EMS specs */
-
-#define HIBYTE(W) (((W) >> 8) & 0xFF)
-#define LOBYTE(W) ((W) & 0xFF)
-
-
-METHODDEF(void)
-read_ems_store (j_common_ptr cinfo, backing_store_ptr info,
- void FAR * buffer_address,
- long file_offset, long byte_count)
-{
- EMScontext ctx;
- EMSspec spec;
-
- spec.length = byte_count;
- SRC_TYPE(spec) = 1;
- SRC_HANDLE(spec) = info->handle.ems_handle;
- SRC_PAGE(spec) = (unsigned short) (file_offset / EMSPAGESIZE);
- SRC_OFFSET(spec) = (unsigned short) (file_offset % EMSPAGESIZE);
- DST_TYPE(spec) = 0;
- DST_HANDLE(spec) = 0;
- DST_PTR(spec) = buffer_address;
-
- ctx.ds_si = (void far *) & spec;
- ctx.ax = 0x5700; /* move memory region */
- jems_calldriver((EMScontext far *) & ctx);
- if (HIBYTE(ctx.ax) != 0)
- ERREXIT(cinfo, JERR_EMS_READ);
-}
-
-
-METHODDEF(void)
-write_ems_store (j_common_ptr cinfo, backing_store_ptr info,
- void FAR * buffer_address,
- long file_offset, long byte_count)
-{
- EMScontext ctx;
- EMSspec spec;
-
- spec.length = byte_count;
- SRC_TYPE(spec) = 0;
- SRC_HANDLE(spec) = 0;
- SRC_PTR(spec) = buffer_address;
- DST_TYPE(spec) = 1;
- DST_HANDLE(spec) = info->handle.ems_handle;
- DST_PAGE(spec) = (unsigned short) (file_offset / EMSPAGESIZE);
- DST_OFFSET(spec) = (unsigned short) (file_offset % EMSPAGESIZE);
-
- ctx.ds_si = (void far *) & spec;
- ctx.ax = 0x5700; /* move memory region */
- jems_calldriver((EMScontext far *) & ctx);
- if (HIBYTE(ctx.ax) != 0)
- ERREXIT(cinfo, JERR_EMS_WRITE);
-}
-
-
-METHODDEF(void)
-close_ems_store (j_common_ptr cinfo, backing_store_ptr info)
-{
- EMScontext ctx;
-
- ctx.ax = 0x4500;
- ctx.dx = info->handle.ems_handle;
- jems_calldriver((EMScontext far *) & ctx);
- TRACEMS1(cinfo, 1, JTRC_EMS_CLOSE, info->handle.ems_handle);
- /* we ignore any error return from the driver */
-}
-
-
-LOCAL(boolean)
-open_ems_store (j_common_ptr cinfo, backing_store_ptr info,
- long total_bytes_needed)
-{
- EMScontext ctx;
-
- /* Is EMS driver there? */
- if (! jems_available())
- return FALSE;
-
- /* Get status, make sure EMS is OK */
- ctx.ax = 0x4000;
- jems_calldriver((EMScontext far *) & ctx);
- if (HIBYTE(ctx.ax) != 0)
- return FALSE;
-
- /* Get version, must be >= 4.0 */
- ctx.ax = 0x4600;
- jems_calldriver((EMScontext far *) & ctx);
- if (HIBYTE(ctx.ax) != 0 || LOBYTE(ctx.ax) < 0x40)
- return FALSE;
-
- /* Try to allocate requested space */
- ctx.ax = 0x4300;
- ctx.bx = (unsigned short) ((total_bytes_needed + EMSPAGESIZE-1L) / EMSPAGESIZE);
- jems_calldriver((EMScontext far *) & ctx);
- if (HIBYTE(ctx.ax) != 0)
- return FALSE;
-
- /* Succeeded, save the handle and away we go */
- info->handle.ems_handle = ctx.dx;
- info->read_backing_store = read_ems_store;
- info->write_backing_store = write_ems_store;
- info->close_backing_store = close_ems_store;
- TRACEMS1(cinfo, 1, JTRC_EMS_OPEN, ctx.dx);
- return TRUE; /* succeeded */
-}
-
-#endif /* EMS_SUPPORTED */
-
-
-/*
- * 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)
-{
- /* Try extended memory, then expanded memory, then regular file. */
-#if XMS_SUPPORTED
- if (open_xms_store(cinfo, info, total_bytes_needed))
- return;
-#endif
-#if EMS_SUPPORTED
- if (open_ems_store(cinfo, info, total_bytes_needed))
- return;
-#endif
- if (open_file_store(cinfo, info, total_bytes_needed))
- return;
- ERREXITS(cinfo, JERR_TFILE_CREATE, "");
-}
-
-
-/*
- * 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)
-{
- /* Microsoft C, at least in v6.00A, will not successfully reclaim freed
- * blocks of size > 32Kbytes unless we give it a kick in the rear, like so:
- */
-#ifdef NEED_FHEAPMIN
- _fheapmin();
-#endif
-}
projects / synfig.git / blobdiff