--- /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