1 | /* |
---|
2 | * jmemdos.c |
---|
3 | * |
---|
4 | * Copyright (C) 1992-1997, Thomas G. Lane. |
---|
5 | * This file is part of the Independent JPEG Group's software. |
---|
6 | * For conditions of distribution and use, see the accompanying README file. |
---|
7 | * |
---|
8 | * This file provides an MS-DOS-compatible implementation of the system- |
---|
9 | * dependent portion of the JPEG memory manager. Temporary data can be |
---|
10 | * stored in extended or expanded memory as well as in regular DOS files. |
---|
11 | * |
---|
12 | * If you use this file, you must be sure that NEED_FAR_POINTERS is defined |
---|
13 | * if you compile in a small-data memory model; it should NOT be defined if |
---|
14 | * you use a large-data memory model. This file is not recommended if you |
---|
15 | * are using a flat-memory-space 386 environment such as DJGCC or Watcom C. |
---|
16 | * Also, this code will NOT work if struct fields are aligned on greater than |
---|
17 | * 2-byte boundaries. |
---|
18 | * |
---|
19 | * Based on code contributed by Ge' Weijers. |
---|
20 | */ |
---|
21 | |
---|
22 | /* |
---|
23 | * If you have both extended and expanded memory, you may want to change the |
---|
24 | * order in which they are tried in jopen_backing_store. On a 286 machine |
---|
25 | * expanded memory is usually faster, since extended memory access involves |
---|
26 | * an expensive protected-mode-and-back switch. On 386 and better, extended |
---|
27 | * memory is usually faster. As distributed, the code tries extended memory |
---|
28 | * first (what? not everyone has a 386? :-). |
---|
29 | * |
---|
30 | * You can disable use of extended/expanded memory entirely by altering these |
---|
31 | * definitions or overriding them from the Makefile (eg, -DEMS_SUPPORTED=0). |
---|
32 | */ |
---|
33 | |
---|
34 | #ifndef XMS_SUPPORTED |
---|
35 | #define XMS_SUPPORTED 1 |
---|
36 | #endif |
---|
37 | #ifndef EMS_SUPPORTED |
---|
38 | #define EMS_SUPPORTED 1 |
---|
39 | #endif |
---|
40 | |
---|
41 | |
---|
42 | #define JPEG_INTERNALS |
---|
43 | #include "jinclude.h" |
---|
44 | #include "jpeglib.h" |
---|
45 | #include "jmemsys.h" /* import the system-dependent declarations */ |
---|
46 | |
---|
47 | #ifndef HAVE_STDLIB_H /* <stdlib.h> should declare these */ |
---|
48 | extern void * malloc JPP((size_t size)); |
---|
49 | extern void free JPP((void *ptr)); |
---|
50 | extern char * getenv JPP((const char * name)); |
---|
51 | #endif |
---|
52 | |
---|
53 | #ifdef NEED_FAR_POINTERS |
---|
54 | |
---|
55 | #ifdef __TURBOC__ |
---|
56 | /* These definitions work for Borland C (Turbo C) */ |
---|
57 | #include <alloc.h> /* need farmalloc(), farfree() */ |
---|
58 | #define far_malloc(x) farmalloc(x) |
---|
59 | #define far_free(x) farfree(x) |
---|
60 | #else |
---|
61 | /* These definitions work for Microsoft C and compatible compilers */ |
---|
62 | #include <malloc.h> /* need _fmalloc(), _ffree() */ |
---|
63 | #define far_malloc(x) _fmalloc(x) |
---|
64 | #define far_free(x) _ffree(x) |
---|
65 | #endif |
---|
66 | |
---|
67 | #else /* not NEED_FAR_POINTERS */ |
---|
68 | |
---|
69 | #define far_malloc(x) malloc(x) |
---|
70 | #define far_free(x) free(x) |
---|
71 | |
---|
72 | #endif /* NEED_FAR_POINTERS */ |
---|
73 | |
---|
74 | #ifdef DONT_USE_B_MODE /* define mode parameters for fopen() */ |
---|
75 | #define READ_BINARY "r" |
---|
76 | #else |
---|
77 | #define READ_BINARY "rb" |
---|
78 | #endif |
---|
79 | |
---|
80 | #ifndef USE_MSDOS_MEMMGR /* make sure user got configuration right */ |
---|
81 | You forgot to define USE_MSDOS_MEMMGR in jconfig.h. /* deliberate syntax error */ |
---|
82 | #endif |
---|
83 | |
---|
84 | #if MAX_ALLOC_CHUNK >= 65535L /* make sure jconfig.h got this right */ |
---|
85 | MAX_ALLOC_CHUNK should be less than 64K. /* deliberate syntax error */ |
---|
86 | #endif |
---|
87 | |
---|
88 | |
---|
89 | /* |
---|
90 | * Declarations for assembly-language support routines (see jmemdosa.asm). |
---|
91 | * |
---|
92 | * The functions are declared "far" as are all their pointer arguments; |
---|
93 | * this ensures the assembly source code will work regardless of the |
---|
94 | * compiler memory model. We assume "short" is 16 bits, "long" is 32. |
---|
95 | */ |
---|
96 | |
---|
97 | typedef void far * XMSDRIVER; /* actually a pointer to code */ |
---|
98 | typedef struct { /* registers for calling XMS driver */ |
---|
99 | unsigned short ax, dx, bx; |
---|
100 | void far * ds_si; |
---|
101 | } XMScontext; |
---|
102 | typedef struct { /* registers for calling EMS driver */ |
---|
103 | unsigned short ax, dx, bx; |
---|
104 | void far * ds_si; |
---|
105 | } EMScontext; |
---|
106 | |
---|
107 | extern short far jdos_open JPP((short far * handle, char far * filename)); |
---|
108 | extern short far jdos_close JPP((short handle)); |
---|
109 | extern short far jdos_seek JPP((short handle, long offset)); |
---|
110 | extern short far jdos_read JPP((short handle, void far * buffer, |
---|
111 | unsigned short count)); |
---|
112 | extern short far jdos_write JPP((short handle, void far * buffer, |
---|
113 | unsigned short count)); |
---|
114 | extern void far jxms_getdriver JPP((XMSDRIVER far *)); |
---|
115 | extern void far jxms_calldriver JPP((XMSDRIVER, XMScontext far *)); |
---|
116 | extern short far jems_available JPP((void)); |
---|
117 | extern void far jems_calldriver JPP((EMScontext far *)); |
---|
118 | |
---|
119 | |
---|
120 | /* |
---|
121 | * Selection of a file name for a temporary file. |
---|
122 | * This is highly system-dependent, and you may want to customize it. |
---|
123 | */ |
---|
124 | |
---|
125 | static int next_file_num; /* to distinguish among several temp files */ |
---|
126 | |
---|
127 | LOCAL(void) |
---|
128 | select_file_name (char * fname) |
---|
129 | { |
---|
130 | const char * env; |
---|
131 | char * ptr; |
---|
132 | FILE * tfile; |
---|
133 | |
---|
134 | /* Keep generating file names till we find one that's not in use */ |
---|
135 | for (;;) { |
---|
136 | /* Get temp directory name from environment TMP or TEMP variable; |
---|
137 | * if none, use "." |
---|
138 | */ |
---|
139 | if ((env = (const char *) getenv("TMP")) == NULL) |
---|
140 | if ((env = (const char *) getenv("TEMP")) == NULL) |
---|
141 | env = "."; |
---|
142 | if (*env == '\0') /* null string means "." */ |
---|
143 | env = "."; |
---|
144 | ptr = fname; /* copy name to fname */ |
---|
145 | while (*env != '\0') |
---|
146 | *ptr++ = *env++; |
---|
147 | if (ptr[-1] != '\\' && ptr[-1] != '/') |
---|
148 | *ptr++ = '\\'; /* append backslash if not in env variable */ |
---|
149 | /* Append a suitable file name */ |
---|
150 | next_file_num++; /* advance counter */ |
---|
151 | sprintf(ptr, "JPG%03d.TMP", next_file_num); |
---|
152 | /* Probe to see if file name is already in use */ |
---|
153 | if ((tfile = fopen(fname, READ_BINARY)) == NULL) |
---|
154 | break; |
---|
155 | fclose(tfile); /* oops, it's there; close tfile & try again */ |
---|
156 | } |
---|
157 | } |
---|
158 | |
---|
159 | |
---|
160 | /* |
---|
161 | * Near-memory allocation and freeing are controlled by the regular library |
---|
162 | * routines malloc() and free(). |
---|
163 | */ |
---|
164 | |
---|
165 | GLOBAL(void *) |
---|
166 | jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject) |
---|
167 | { |
---|
168 | return (void *) malloc(sizeofobject); |
---|
169 | } |
---|
170 | |
---|
171 | GLOBAL(void) |
---|
172 | jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject) |
---|
173 | { |
---|
174 | free(object); |
---|
175 | } |
---|
176 | |
---|
177 | |
---|
178 | /* |
---|
179 | * "Large" objects are allocated in far memory, if possible |
---|
180 | */ |
---|
181 | |
---|
182 | GLOBAL(void FAR *) |
---|
183 | jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject) |
---|
184 | { |
---|
185 | return (void FAR *) far_malloc(sizeofobject); |
---|
186 | } |
---|
187 | |
---|
188 | GLOBAL(void) |
---|
189 | jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject) |
---|
190 | { |
---|
191 | far_free(object); |
---|
192 | } |
---|
193 | |
---|
194 | |
---|
195 | /* |
---|
196 | * This routine computes the total memory space available for allocation. |
---|
197 | * It's impossible to do this in a portable way; our current solution is |
---|
198 | * to make the user tell us (with a default value set at compile time). |
---|
199 | * If you can actually get the available space, it's a good idea to subtract |
---|
200 | * a slop factor of 5% or so. |
---|
201 | */ |
---|
202 | |
---|
203 | #ifndef DEFAULT_MAX_MEM /* so can override from makefile */ |
---|
204 | #define DEFAULT_MAX_MEM 300000L /* for total usage about 450K */ |
---|
205 | #endif |
---|
206 | |
---|
207 | GLOBAL(long) |
---|
208 | jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed, |
---|
209 | long max_bytes_needed, long already_allocated) |
---|
210 | { |
---|
211 | return cinfo->mem->max_memory_to_use - already_allocated; |
---|
212 | } |
---|
213 | |
---|
214 | |
---|
215 | /* |
---|
216 | * Backing store (temporary file) management. |
---|
217 | * Backing store objects are only used when the value returned by |
---|
218 | * jpeg_mem_available is less than the total space needed. You can dispense |
---|
219 | * with these routines if you have plenty of virtual memory; see jmemnobs.c. |
---|
220 | */ |
---|
221 | |
---|
222 | /* |
---|
223 | * For MS-DOS we support three types of backing storage: |
---|
224 | * 1. Conventional DOS files. We access these by direct DOS calls rather |
---|
225 | * than via the stdio package. This provides a bit better performance, |
---|
226 | * but the real reason is that the buffers to be read or written are FAR. |
---|
227 | * The stdio library for small-data memory models can't cope with that. |
---|
228 | * 2. Extended memory, accessed per the XMS V2.0 specification. |
---|
229 | * 3. Expanded memory, accessed per the LIM/EMS 4.0 specification. |
---|
230 | * You'll need copies of those specs to make sense of the related code. |
---|
231 | * The specs are available by Internet FTP from the SIMTEL archives |
---|
232 | * (oak.oakland.edu and its various mirror sites). See files |
---|
233 | * pub/msdos/microsoft/xms20.arc and pub/msdos/info/limems41.zip. |
---|
234 | */ |
---|
235 | |
---|
236 | |
---|
237 | /* |
---|
238 | * Access methods for a DOS file. |
---|
239 | */ |
---|
240 | |
---|
241 | |
---|
242 | METHODDEF(void) |
---|
243 | read_file_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
244 | void FAR * buffer_address, |
---|
245 | long file_offset, long byte_count) |
---|
246 | { |
---|
247 | if (jdos_seek(info->handle.file_handle, file_offset)) |
---|
248 | ERREXIT(cinfo, JERR_TFILE_SEEK); |
---|
249 | /* Since MAX_ALLOC_CHUNK is less than 64K, byte_count will be too. */ |
---|
250 | if (byte_count > 65535L) /* safety check */ |
---|
251 | ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK); |
---|
252 | if (jdos_read(info->handle.file_handle, buffer_address, |
---|
253 | (unsigned short) byte_count)) |
---|
254 | ERREXIT(cinfo, JERR_TFILE_READ); |
---|
255 | } |
---|
256 | |
---|
257 | |
---|
258 | METHODDEF(void) |
---|
259 | write_file_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
260 | void FAR * buffer_address, |
---|
261 | long file_offset, long byte_count) |
---|
262 | { |
---|
263 | if (jdos_seek(info->handle.file_handle, file_offset)) |
---|
264 | ERREXIT(cinfo, JERR_TFILE_SEEK); |
---|
265 | /* Since MAX_ALLOC_CHUNK is less than 64K, byte_count will be too. */ |
---|
266 | if (byte_count > 65535L) /* safety check */ |
---|
267 | ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK); |
---|
268 | if (jdos_write(info->handle.file_handle, buffer_address, |
---|
269 | (unsigned short) byte_count)) |
---|
270 | ERREXIT(cinfo, JERR_TFILE_WRITE); |
---|
271 | } |
---|
272 | |
---|
273 | |
---|
274 | METHODDEF(void) |
---|
275 | close_file_store (j_common_ptr cinfo, backing_store_ptr info) |
---|
276 | { |
---|
277 | jdos_close(info->handle.file_handle); /* close the file */ |
---|
278 | remove(info->temp_name); /* delete the file */ |
---|
279 | /* If your system doesn't have remove(), try unlink() instead. |
---|
280 | * remove() is the ANSI-standard name for this function, but |
---|
281 | * unlink() was more common in pre-ANSI systems. |
---|
282 | */ |
---|
283 | TRACEMSS(cinfo, 1, JTRC_TFILE_CLOSE, info->temp_name); |
---|
284 | } |
---|
285 | |
---|
286 | |
---|
287 | LOCAL(boolean) |
---|
288 | open_file_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
289 | long total_bytes_needed) |
---|
290 | { |
---|
291 | short handle; |
---|
292 | |
---|
293 | select_file_name(info->temp_name); |
---|
294 | if (jdos_open((short far *) & handle, (char far *) info->temp_name)) { |
---|
295 | /* might as well exit since jpeg_open_backing_store will fail anyway */ |
---|
296 | ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name); |
---|
297 | return FALSE; |
---|
298 | } |
---|
299 | info->handle.file_handle = handle; |
---|
300 | info->read_backing_store = read_file_store; |
---|
301 | info->write_backing_store = write_file_store; |
---|
302 | info->close_backing_store = close_file_store; |
---|
303 | TRACEMSS(cinfo, 1, JTRC_TFILE_OPEN, info->temp_name); |
---|
304 | return TRUE; /* succeeded */ |
---|
305 | } |
---|
306 | |
---|
307 | |
---|
308 | /* |
---|
309 | * Access methods for extended memory. |
---|
310 | */ |
---|
311 | |
---|
312 | #if XMS_SUPPORTED |
---|
313 | |
---|
314 | static XMSDRIVER xms_driver; /* saved address of XMS driver */ |
---|
315 | |
---|
316 | typedef union { /* either long offset or real-mode pointer */ |
---|
317 | long offset; |
---|
318 | void far * ptr; |
---|
319 | } XMSPTR; |
---|
320 | |
---|
321 | typedef struct { /* XMS move specification structure */ |
---|
322 | long length; |
---|
323 | XMSH src_handle; |
---|
324 | XMSPTR src; |
---|
325 | XMSH dst_handle; |
---|
326 | XMSPTR dst; |
---|
327 | } XMSspec; |
---|
328 | |
---|
329 | #define ODD(X) (((X) & 1L) != 0) |
---|
330 | |
---|
331 | |
---|
332 | METHODDEF(void) |
---|
333 | read_xms_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
334 | void FAR * buffer_address, |
---|
335 | long file_offset, long byte_count) |
---|
336 | { |
---|
337 | XMScontext ctx; |
---|
338 | XMSspec spec; |
---|
339 | char endbuffer[2]; |
---|
340 | |
---|
341 | /* The XMS driver can't cope with an odd length, so handle the last byte |
---|
342 | * specially if byte_count is odd. We don't expect this to be common. |
---|
343 | */ |
---|
344 | |
---|
345 | spec.length = byte_count & (~ 1L); |
---|
346 | spec.src_handle = info->handle.xms_handle; |
---|
347 | spec.src.offset = file_offset; |
---|
348 | spec.dst_handle = 0; |
---|
349 | spec.dst.ptr = buffer_address; |
---|
350 | |
---|
351 | ctx.ds_si = (void far *) & spec; |
---|
352 | ctx.ax = 0x0b00; /* EMB move */ |
---|
353 | jxms_calldriver(xms_driver, (XMScontext far *) & ctx); |
---|
354 | if (ctx.ax != 1) |
---|
355 | ERREXIT(cinfo, JERR_XMS_READ); |
---|
356 | |
---|
357 | if (ODD(byte_count)) { |
---|
358 | read_xms_store(cinfo, info, (void FAR *) endbuffer, |
---|
359 | file_offset + byte_count - 1L, 2L); |
---|
360 | ((char FAR *) buffer_address)[byte_count - 1L] = endbuffer[0]; |
---|
361 | } |
---|
362 | } |
---|
363 | |
---|
364 | |
---|
365 | METHODDEF(void) |
---|
366 | write_xms_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
367 | void FAR * buffer_address, |
---|
368 | long file_offset, long byte_count) |
---|
369 | { |
---|
370 | XMScontext ctx; |
---|
371 | XMSspec spec; |
---|
372 | char endbuffer[2]; |
---|
373 | |
---|
374 | /* The XMS driver can't cope with an odd length, so handle the last byte |
---|
375 | * specially if byte_count is odd. We don't expect this to be common. |
---|
376 | */ |
---|
377 | |
---|
378 | spec.length = byte_count & (~ 1L); |
---|
379 | spec.src_handle = 0; |
---|
380 | spec.src.ptr = buffer_address; |
---|
381 | spec.dst_handle = info->handle.xms_handle; |
---|
382 | spec.dst.offset = file_offset; |
---|
383 | |
---|
384 | ctx.ds_si = (void far *) & spec; |
---|
385 | ctx.ax = 0x0b00; /* EMB move */ |
---|
386 | jxms_calldriver(xms_driver, (XMScontext far *) & ctx); |
---|
387 | if (ctx.ax != 1) |
---|
388 | ERREXIT(cinfo, JERR_XMS_WRITE); |
---|
389 | |
---|
390 | if (ODD(byte_count)) { |
---|
391 | read_xms_store(cinfo, info, (void FAR *) endbuffer, |
---|
392 | file_offset + byte_count - 1L, 2L); |
---|
393 | endbuffer[0] = ((char FAR *) buffer_address)[byte_count - 1L]; |
---|
394 | write_xms_store(cinfo, info, (void FAR *) endbuffer, |
---|
395 | file_offset + byte_count - 1L, 2L); |
---|
396 | } |
---|
397 | } |
---|
398 | |
---|
399 | |
---|
400 | METHODDEF(void) |
---|
401 | close_xms_store (j_common_ptr cinfo, backing_store_ptr info) |
---|
402 | { |
---|
403 | XMScontext ctx; |
---|
404 | |
---|
405 | ctx.dx = info->handle.xms_handle; |
---|
406 | ctx.ax = 0x0a00; |
---|
407 | jxms_calldriver(xms_driver, (XMScontext far *) & ctx); |
---|
408 | TRACEMS1(cinfo, 1, JTRC_XMS_CLOSE, info->handle.xms_handle); |
---|
409 | /* we ignore any error return from the driver */ |
---|
410 | } |
---|
411 | |
---|
412 | |
---|
413 | LOCAL(boolean) |
---|
414 | open_xms_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
415 | long total_bytes_needed) |
---|
416 | { |
---|
417 | XMScontext ctx; |
---|
418 | |
---|
419 | /* Get address of XMS driver */ |
---|
420 | jxms_getdriver((XMSDRIVER far *) & xms_driver); |
---|
421 | if (xms_driver == NULL) |
---|
422 | return FALSE; /* no driver to be had */ |
---|
423 | |
---|
424 | /* Get version number, must be >= 2.00 */ |
---|
425 | ctx.ax = 0x0000; |
---|
426 | jxms_calldriver(xms_driver, (XMScontext far *) & ctx); |
---|
427 | if (ctx.ax < (unsigned short) 0x0200) |
---|
428 | return FALSE; |
---|
429 | |
---|
430 | /* Try to get space (expressed in kilobytes) */ |
---|
431 | ctx.dx = (unsigned short) ((total_bytes_needed + 1023L) >> 10); |
---|
432 | ctx.ax = 0x0900; |
---|
433 | jxms_calldriver(xms_driver, (XMScontext far *) & ctx); |
---|
434 | if (ctx.ax != 1) |
---|
435 | return FALSE; |
---|
436 | |
---|
437 | /* Succeeded, save the handle and away we go */ |
---|
438 | info->handle.xms_handle = ctx.dx; |
---|
439 | info->read_backing_store = read_xms_store; |
---|
440 | info->write_backing_store = write_xms_store; |
---|
441 | info->close_backing_store = close_xms_store; |
---|
442 | TRACEMS1(cinfo, 1, JTRC_XMS_OPEN, ctx.dx); |
---|
443 | return TRUE; /* succeeded */ |
---|
444 | } |
---|
445 | |
---|
446 | #endif /* XMS_SUPPORTED */ |
---|
447 | |
---|
448 | |
---|
449 | /* |
---|
450 | * Access methods for expanded memory. |
---|
451 | */ |
---|
452 | |
---|
453 | #if EMS_SUPPORTED |
---|
454 | |
---|
455 | /* The EMS move specification structure requires word and long fields aligned |
---|
456 | * at odd byte boundaries. Some compilers will align struct fields at even |
---|
457 | * byte boundaries. While it's usually possible to force byte alignment, |
---|
458 | * that causes an overall performance penalty and may pose problems in merging |
---|
459 | * JPEG into a larger application. Instead we accept some rather dirty code |
---|
460 | * here. Note this code would fail if the hardware did not allow odd-byte |
---|
461 | * word & long accesses, but all 80x86 CPUs do. |
---|
462 | */ |
---|
463 | |
---|
464 | typedef void far * EMSPTR; |
---|
465 | |
---|
466 | typedef union { /* EMS move specification structure */ |
---|
467 | long length; /* It's easy to access first 4 bytes */ |
---|
468 | char bytes[18]; /* Misaligned fields in here! */ |
---|
469 | } EMSspec; |
---|
470 | |
---|
471 | /* Macros for accessing misaligned fields */ |
---|
472 | #define FIELD_AT(spec,offset,type) (*((type *) &(spec.bytes[offset]))) |
---|
473 | #define SRC_TYPE(spec) FIELD_AT(spec,4,char) |
---|
474 | #define SRC_HANDLE(spec) FIELD_AT(spec,5,EMSH) |
---|
475 | #define SRC_OFFSET(spec) FIELD_AT(spec,7,unsigned short) |
---|
476 | #define SRC_PAGE(spec) FIELD_AT(spec,9,unsigned short) |
---|
477 | #define SRC_PTR(spec) FIELD_AT(spec,7,EMSPTR) |
---|
478 | #define DST_TYPE(spec) FIELD_AT(spec,11,char) |
---|
479 | #define DST_HANDLE(spec) FIELD_AT(spec,12,EMSH) |
---|
480 | #define DST_OFFSET(spec) FIELD_AT(spec,14,unsigned short) |
---|
481 | #define DST_PAGE(spec) FIELD_AT(spec,16,unsigned short) |
---|
482 | #define DST_PTR(spec) FIELD_AT(spec,14,EMSPTR) |
---|
483 | |
---|
484 | #define EMSPAGESIZE 16384L /* gospel, see the EMS specs */ |
---|
485 | |
---|
486 | #define HIBYTE(W) (((W) >> 8) & 0xFF) |
---|
487 | #define LOBYTE(W) ((W) & 0xFF) |
---|
488 | |
---|
489 | |
---|
490 | METHODDEF(void) |
---|
491 | read_ems_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
492 | void FAR * buffer_address, |
---|
493 | long file_offset, long byte_count) |
---|
494 | { |
---|
495 | EMScontext ctx; |
---|
496 | EMSspec spec; |
---|
497 | |
---|
498 | spec.length = byte_count; |
---|
499 | SRC_TYPE(spec) = 1; |
---|
500 | SRC_HANDLE(spec) = info->handle.ems_handle; |
---|
501 | SRC_PAGE(spec) = (unsigned short) (file_offset / EMSPAGESIZE); |
---|
502 | SRC_OFFSET(spec) = (unsigned short) (file_offset % EMSPAGESIZE); |
---|
503 | DST_TYPE(spec) = 0; |
---|
504 | DST_HANDLE(spec) = 0; |
---|
505 | DST_PTR(spec) = buffer_address; |
---|
506 | |
---|
507 | ctx.ds_si = (void far *) & spec; |
---|
508 | ctx.ax = 0x5700; /* move memory region */ |
---|
509 | jems_calldriver((EMScontext far *) & ctx); |
---|
510 | if (HIBYTE(ctx.ax) != 0) |
---|
511 | ERREXIT(cinfo, JERR_EMS_READ); |
---|
512 | } |
---|
513 | |
---|
514 | |
---|
515 | METHODDEF(void) |
---|
516 | write_ems_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
517 | void FAR * buffer_address, |
---|
518 | long file_offset, long byte_count) |
---|
519 | { |
---|
520 | EMScontext ctx; |
---|
521 | EMSspec spec; |
---|
522 | |
---|
523 | spec.length = byte_count; |
---|
524 | SRC_TYPE(spec) = 0; |
---|
525 | SRC_HANDLE(spec) = 0; |
---|
526 | SRC_PTR(spec) = buffer_address; |
---|
527 | DST_TYPE(spec) = 1; |
---|
528 | DST_HANDLE(spec) = info->handle.ems_handle; |
---|
529 | DST_PAGE(spec) = (unsigned short) (file_offset / EMSPAGESIZE); |
---|
530 | DST_OFFSET(spec) = (unsigned short) (file_offset % EMSPAGESIZE); |
---|
531 | |
---|
532 | ctx.ds_si = (void far *) & spec; |
---|
533 | ctx.ax = 0x5700; /* move memory region */ |
---|
534 | jems_calldriver((EMScontext far *) & ctx); |
---|
535 | if (HIBYTE(ctx.ax) != 0) |
---|
536 | ERREXIT(cinfo, JERR_EMS_WRITE); |
---|
537 | } |
---|
538 | |
---|
539 | |
---|
540 | METHODDEF(void) |
---|
541 | close_ems_store (j_common_ptr cinfo, backing_store_ptr info) |
---|
542 | { |
---|
543 | EMScontext ctx; |
---|
544 | |
---|
545 | ctx.ax = 0x4500; |
---|
546 | ctx.dx = info->handle.ems_handle; |
---|
547 | jems_calldriver((EMScontext far *) & ctx); |
---|
548 | TRACEMS1(cinfo, 1, JTRC_EMS_CLOSE, info->handle.ems_handle); |
---|
549 | /* we ignore any error return from the driver */ |
---|
550 | } |
---|
551 | |
---|
552 | |
---|
553 | LOCAL(boolean) |
---|
554 | open_ems_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
555 | long total_bytes_needed) |
---|
556 | { |
---|
557 | EMScontext ctx; |
---|
558 | |
---|
559 | /* Is EMS driver there? */ |
---|
560 | if (! jems_available()) |
---|
561 | return FALSE; |
---|
562 | |
---|
563 | /* Get status, make sure EMS is OK */ |
---|
564 | ctx.ax = 0x4000; |
---|
565 | jems_calldriver((EMScontext far *) & ctx); |
---|
566 | if (HIBYTE(ctx.ax) != 0) |
---|
567 | return FALSE; |
---|
568 | |
---|
569 | /* Get version, must be >= 4.0 */ |
---|
570 | ctx.ax = 0x4600; |
---|
571 | jems_calldriver((EMScontext far *) & ctx); |
---|
572 | if (HIBYTE(ctx.ax) != 0 || LOBYTE(ctx.ax) < 0x40) |
---|
573 | return FALSE; |
---|
574 | |
---|
575 | /* Try to allocate requested space */ |
---|
576 | ctx.ax = 0x4300; |
---|
577 | ctx.bx = (unsigned short) ((total_bytes_needed + EMSPAGESIZE-1L) / EMSPAGESIZE); |
---|
578 | jems_calldriver((EMScontext far *) & ctx); |
---|
579 | if (HIBYTE(ctx.ax) != 0) |
---|
580 | return FALSE; |
---|
581 | |
---|
582 | /* Succeeded, save the handle and away we go */ |
---|
583 | info->handle.ems_handle = ctx.dx; |
---|
584 | info->read_backing_store = read_ems_store; |
---|
585 | info->write_backing_store = write_ems_store; |
---|
586 | info->close_backing_store = close_ems_store; |
---|
587 | TRACEMS1(cinfo, 1, JTRC_EMS_OPEN, ctx.dx); |
---|
588 | return TRUE; /* succeeded */ |
---|
589 | } |
---|
590 | |
---|
591 | #endif /* EMS_SUPPORTED */ |
---|
592 | |
---|
593 | |
---|
594 | /* |
---|
595 | * Initial opening of a backing-store object. |
---|
596 | */ |
---|
597 | |
---|
598 | GLOBAL(void) |
---|
599 | jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info, |
---|
600 | long total_bytes_needed) |
---|
601 | { |
---|
602 | /* Try extended memory, then expanded memory, then regular file. */ |
---|
603 | #if XMS_SUPPORTED |
---|
604 | if (open_xms_store(cinfo, info, total_bytes_needed)) |
---|
605 | return; |
---|
606 | #endif |
---|
607 | #if EMS_SUPPORTED |
---|
608 | if (open_ems_store(cinfo, info, total_bytes_needed)) |
---|
609 | return; |
---|
610 | #endif |
---|
611 | if (open_file_store(cinfo, info, total_bytes_needed)) |
---|
612 | return; |
---|
613 | ERREXITS(cinfo, JERR_TFILE_CREATE, ""); |
---|
614 | } |
---|
615 | |
---|
616 | |
---|
617 | /* |
---|
618 | * These routines take care of any system-dependent initialization and |
---|
619 | * cleanup required. |
---|
620 | */ |
---|
621 | |
---|
622 | GLOBAL(long) |
---|
623 | jpeg_mem_init (j_common_ptr cinfo) |
---|
624 | { |
---|
625 | next_file_num = 0; /* initialize temp file name generator */ |
---|
626 | return DEFAULT_MAX_MEM; /* default for max_memory_to_use */ |
---|
627 | } |
---|
628 | |
---|
629 | GLOBAL(void) |
---|
630 | jpeg_mem_term (j_common_ptr cinfo) |
---|
631 | { |
---|
632 | /* Microsoft C, at least in v6.00A, will not successfully reclaim freed |
---|
633 | * blocks of size > 32Kbytes unless we give it a kick in the rear, like so: |
---|
634 | */ |
---|
635 | #ifdef NEED_FHEAPMIN |
---|
636 | _fheapmin(); |
---|
637 | #endif |
---|
638 | } |
---|