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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 | } |