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Diffstat (limited to 'src/jpeg-6/jmemdos.c')
| -rw-r--r-- | src/jpeg-6/jmemdos.c | 634 |
1 files changed, 634 insertions, 0 deletions
diff --git a/src/jpeg-6/jmemdos.c b/src/jpeg-6/jmemdos.c new file mode 100644 index 0000000..4db8ec5 --- /dev/null +++ b/src/jpeg-6/jmemdos.c @@ -0,0 +1,634 @@ +/* + * jmemdos.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 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 + +#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 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 +} |