• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * jmemmgr.c
3  *
4  * Copyright (C) 1991-1997, 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 contains the JPEG system-independent memory management
9  * routines.  This code is usable across a wide variety of machines; most
10  * of the system dependencies have been isolated in a separate file.
11  * The major functions provided here are:
12  *   * pool-based allocation and freeing of memory;
13  *   * policy decisions about how to divide available memory among the
14  *     virtual arrays;
15  *   * control logic for swapping virtual arrays between main memory and
16  *     backing storage.
17  * The separate system-dependent file provides the actual backing-storage
18  * access code, and it contains the policy decision about how much total
19  * main memory to use.
20  * This file is system-dependent in the sense that some of its functions
21  * are unnecessary in some systems.  For example, if there is enough virtual
22  * memory so that backing storage will never be used, much of the virtual
23  * array control logic could be removed.  (Of course, if you have that much
24  * memory then you shouldn't care about a little bit of unused code...)
25  */
26 
27 #define JPEG_INTERNALS
28 #define AM_MEMORY_MANAGER	/* we define jvirt_Xarray_control structs */
29 #include "jinclude.h"
30 #include "jpeglib.h"
31 #include "jmemsys.h"		/* import the system-dependent declarations */
32 
33 #ifndef NO_GETENV
34 #ifndef HAVE_STDLIB_H		/* <stdlib.h> should declare getenv() */
35 extern char * getenv JPP((const char * name));
36 #endif
37 #endif
38 
39 
40 /*
41  * Some important notes:
42  *   The allocation routines provided here must never return NULL.
43  *   They should exit to error_exit if unsuccessful.
44  *
45  *   It's not a good idea to try to merge the sarray and barray routines,
46  *   even though they are textually almost the same, because samples are
47  *   usually stored as bytes while coefficients are shorts or ints.  Thus,
48  *   in machines where byte pointers have a different representation from
49  *   word pointers, the resulting machine code could not be the same.
50  */
51 
52 
53 /*
54  * Many machines require storage alignment: longs must start on 4-byte
55  * boundaries, doubles on 8-byte boundaries, etc.  On such machines, malloc()
56  * always returns pointers that are multiples of the worst-case alignment
57  * requirement, and we had better do so too.
58  * There isn't any really portable way to determine the worst-case alignment
59  * requirement.  This module assumes that the alignment requirement is
60  * multiples of sizeof(ALIGN_TYPE).
61  * By default, we define ALIGN_TYPE as double.  This is necessary on some
62  * workstations (where doubles really do need 8-byte alignment) and will work
63  * fine on nearly everything.  If your machine has lesser alignment needs,
64  * you can save a few bytes by making ALIGN_TYPE smaller.
65  * The only place I know of where this will NOT work is certain Macintosh
66  * 680x0 compilers that define double as a 10-byte IEEE extended float.
67  * Doing 10-byte alignment is counterproductive because longwords won't be
68  * aligned well.  Put "#define ALIGN_TYPE long" in jconfig.h if you have
69  * such a compiler.
70  */
71 
72 #ifndef ALIGN_TYPE		/* so can override from jconfig.h */
73 #define ALIGN_TYPE  double
74 #endif
75 
76 
77 /*
78  * We allocate objects from "pools", where each pool is gotten with a single
79  * request to jpeg_get_small() or jpeg_get_large().  There is no per-object
80  * overhead within a pool, except for alignment padding.  Each pool has a
81  * header with a link to the next pool of the same class.
82  * Small and large pool headers are identical except that the latter's
83  * link pointer must be FAR on 80x86 machines.
84  * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
85  * field.  This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
86  * of the alignment requirement of ALIGN_TYPE.
87  */
88 
89 typedef union small_pool_struct * small_pool_ptr;
90 
91 typedef union small_pool_struct {
92   struct {
93     small_pool_ptr next;	/* next in list of pools */
94     size_t bytes_used;		/* how many bytes already used within pool */
95     size_t bytes_left;		/* bytes still available in this pool */
96   } hdr;
97   ALIGN_TYPE dummy;		/* included in union to ensure alignment */
98 } small_pool_hdr;
99 
100 typedef union large_pool_struct FAR * large_pool_ptr;
101 
102 typedef union large_pool_struct {
103   struct {
104     large_pool_ptr next;	/* next in list of pools */
105     size_t bytes_used;		/* how many bytes already used within pool */
106     size_t bytes_left;		/* bytes still available in this pool */
107   } hdr;
108   ALIGN_TYPE dummy;		/* included in union to ensure alignment */
109 } large_pool_hdr;
110 
111 
112 /*
113  * Here is the full definition of a memory manager object.
114  */
115 
116 typedef struct {
117   struct jpeg_memory_mgr pub;	/* public fields */
118 
119   /* Each pool identifier (lifetime class) names a linked list of pools. */
120   small_pool_ptr small_list[JPOOL_NUMPOOLS];
121   large_pool_ptr large_list[JPOOL_NUMPOOLS];
122 
123   /* Since we only have one lifetime class of virtual arrays, only one
124    * linked list is necessary (for each datatype).  Note that the virtual
125    * array control blocks being linked together are actually stored somewhere
126    * in the small-pool list.
127    */
128   jvirt_sarray_ptr virt_sarray_list;
129   jvirt_barray_ptr virt_barray_list;
130 
131   /* This counts total space obtained from jpeg_get_small/large */
132   long total_space_allocated;
133 
134   /* alloc_sarray and alloc_barray set this value for use by virtual
135    * array routines.
136    */
137   JDIMENSION last_rowsperchunk;	/* from most recent alloc_sarray/barray */
138 } my_memory_mgr;
139 
140 typedef my_memory_mgr * my_mem_ptr;
141 
142 
143 /*
144  * The control blocks for virtual arrays.
145  * Note that these blocks are allocated in the "small" pool area.
146  * System-dependent info for the associated backing store (if any) is hidden
147  * inside the backing_store_info struct.
148  */
149 
150 struct jvirt_sarray_control {
151   JSAMPARRAY mem_buffer;	/* => the in-memory buffer */
152   JDIMENSION rows_in_array;	/* total virtual array height */
153   JDIMENSION samplesperrow;	/* width of array (and of memory buffer) */
154   JDIMENSION maxaccess;		/* max rows accessed by access_virt_sarray */
155   JDIMENSION rows_in_mem;	/* height of memory buffer */
156   JDIMENSION rowsperchunk;	/* allocation chunk size in mem_buffer */
157   JDIMENSION cur_start_row;	/* first logical row # in the buffer */
158   JDIMENSION first_undef_row;	/* row # of first uninitialized row */
159   boolean pre_zero;		/* pre-zero mode requested? */
160   boolean dirty;		/* do current buffer contents need written? */
161   boolean b_s_open;		/* is backing-store data valid? */
162   jvirt_sarray_ptr next;	/* link to next virtual sarray control block */
163   backing_store_info b_s_info;	/* System-dependent control info */
164 };
165 
166 struct jvirt_barray_control {
167   JBLOCKARRAY mem_buffer;	/* => the in-memory buffer */
168   JDIMENSION rows_in_array;	/* total virtual array height */
169   JDIMENSION blocksperrow;	/* width of array (and of memory buffer) */
170   JDIMENSION maxaccess;		/* max rows accessed by access_virt_barray */
171   JDIMENSION rows_in_mem;	/* height of memory buffer */
172   JDIMENSION rowsperchunk;	/* allocation chunk size in mem_buffer */
173   JDIMENSION cur_start_row;	/* first logical row # in the buffer */
174   JDIMENSION first_undef_row;	/* row # of first uninitialized row */
175   boolean pre_zero;		/* pre-zero mode requested? */
176   boolean dirty;		/* do current buffer contents need written? */
177   boolean b_s_open;		/* is backing-store data valid? */
178   jvirt_barray_ptr next;	/* link to next virtual barray control block */
179   backing_store_info b_s_info;	/* System-dependent control info */
180 };
181 
182 
183 #ifdef MEM_STATS		/* optional extra stuff for statistics */
184 
185 LOCAL(void)
print_mem_stats(j_common_ptr cinfo,int pool_id)186 print_mem_stats (j_common_ptr cinfo, int pool_id)
187 {
188   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
189   small_pool_ptr shdr_ptr;
190   large_pool_ptr lhdr_ptr;
191 
192   /* Since this is only a debugging stub, we can cheat a little by using
193    * fprintf directly rather than going through the trace message code.
194    * This is helpful because message parm array can't handle longs.
195    */
196   fprintf(stderr, "Freeing pool %d, total space = %ld\n",
197 	  pool_id, mem->total_space_allocated);
198 
199   for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
200        lhdr_ptr = lhdr_ptr->hdr.next) {
201     fprintf(stderr, "  Large chunk used %ld\n",
202 	    (long) lhdr_ptr->hdr.bytes_used);
203   }
204 
205   for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
206        shdr_ptr = shdr_ptr->hdr.next) {
207     fprintf(stderr, "  Small chunk used %ld free %ld\n",
208 	    (long) shdr_ptr->hdr.bytes_used,
209 	    (long) shdr_ptr->hdr.bytes_left);
210   }
211 }
212 
213 #endif /* MEM_STATS */
214 
215 
216 LOCAL(void)
out_of_memory(j_common_ptr cinfo,int which)217 out_of_memory (j_common_ptr cinfo, int which)
218 /* Report an out-of-memory error and stop execution */
219 /* If we compiled MEM_STATS support, report alloc requests before dying */
220 {
221 #ifdef MEM_STATS
222   cinfo->err->trace_level = 2;	/* force self_destruct to report stats */
223 #endif
224   ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
225 }
226 
227 
228 /*
229  * Allocation of "small" objects.
230  *
231  * For these, we use pooled storage.  When a new pool must be created,
232  * we try to get enough space for the current request plus a "slop" factor,
233  * where the slop will be the amount of leftover space in the new pool.
234  * The speed vs. space tradeoff is largely determined by the slop values.
235  * A different slop value is provided for each pool class (lifetime),
236  * and we also distinguish the first pool of a class from later ones.
237  * NOTE: the values given work fairly well on both 16- and 32-bit-int
238  * machines, but may be too small if longs are 64 bits or more.
239  */
240 
241 static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
242 {
243 	1600,			/* first PERMANENT pool */
244 	16000			/* first IMAGE pool */
245 };
246 
247 static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
248 {
249 	0,			/* additional PERMANENT pools */
250 	5000			/* additional IMAGE pools */
251 };
252 
253 #define MIN_SLOP  50		/* greater than 0 to avoid futile looping */
254 
255 
256 METHODDEF(void *)
alloc_small(j_common_ptr cinfo,int pool_id,size_t sizeofobject)257 alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
258 /* Allocate a "small" object */
259 {
260   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
261   small_pool_ptr hdr_ptr, prev_hdr_ptr;
262   char * data_ptr;
263   size_t odd_bytes, min_request, slop;
264 
265   /* Check for unsatisfiable request (do now to ensure no overflow below) */
266   if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
267     out_of_memory(cinfo, 1);	/* request exceeds malloc's ability */
268 
269   /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
270   odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
271   if (odd_bytes > 0)
272     sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
273 
274   /* See if space is available in any existing pool */
275   if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
276     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */
277   prev_hdr_ptr = NULL;
278   hdr_ptr = mem->small_list[pool_id];
279   while (hdr_ptr != NULL) {
280     if (hdr_ptr->hdr.bytes_left >= sizeofobject)
281       break;			/* found pool with enough space */
282     prev_hdr_ptr = hdr_ptr;
283     hdr_ptr = hdr_ptr->hdr.next;
284   }
285 
286   /* Time to make a new pool? */
287   if (hdr_ptr == NULL) {
288     /* min_request is what we need now, slop is what will be leftover */
289     min_request = sizeofobject + SIZEOF(small_pool_hdr);
290     if (prev_hdr_ptr == NULL)	/* first pool in class? */
291       slop = first_pool_slop[pool_id];
292     else
293       slop = extra_pool_slop[pool_id];
294     /* Don't ask for more than MAX_ALLOC_CHUNK */
295     if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
296       slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
297     /* Try to get space, if fail reduce slop and try again */
298     for (;;) {
299       hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
300       if (hdr_ptr != NULL)
301 	break;
302       slop /= 2;
303       if (slop < MIN_SLOP)	/* give up when it gets real small */
304 	out_of_memory(cinfo, 2); /* jpeg_get_small failed */
305     }
306     mem->total_space_allocated += min_request + slop;
307     /* Success, initialize the new pool header and add to end of list */
308     hdr_ptr->hdr.next = NULL;
309     hdr_ptr->hdr.bytes_used = 0;
310     hdr_ptr->hdr.bytes_left = sizeofobject + slop;
311     if (prev_hdr_ptr == NULL)	/* first pool in class? */
312       mem->small_list[pool_id] = hdr_ptr;
313     else
314       prev_hdr_ptr->hdr.next = hdr_ptr;
315   }
316 
317   /* OK, allocate the object from the current pool */
318   data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
319   data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
320   hdr_ptr->hdr.bytes_used += sizeofobject;
321   hdr_ptr->hdr.bytes_left -= sizeofobject;
322 
323   return (void *) data_ptr;
324 }
325 
326 
327 /*
328  * Allocation of "large" objects.
329  *
330  * The external semantics of these are the same as "small" objects,
331  * except that FAR pointers are used on 80x86.  However the pool
332  * management heuristics are quite different.  We assume that each
333  * request is large enough that it may as well be passed directly to
334  * jpeg_get_large; the pool management just links everything together
335  * so that we can free it all on demand.
336  * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
337  * structures.  The routines that create these structures (see below)
338  * deliberately bunch rows together to ensure a large request size.
339  */
340 
341 METHODDEF(void FAR *)
alloc_large(j_common_ptr cinfo,int pool_id,size_t sizeofobject)342 alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
343 /* Allocate a "large" object */
344 {
345   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
346   large_pool_ptr hdr_ptr;
347   size_t odd_bytes;
348 
349   /* Check for unsatisfiable request (do now to ensure no overflow below) */
350   if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
351     out_of_memory(cinfo, 3);	/* request exceeds malloc's ability */
352 
353   /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
354   odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
355   if (odd_bytes > 0)
356     sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
357 
358   /* Always make a new pool */
359   if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
360     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */
361 
362   hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
363 					    SIZEOF(large_pool_hdr));
364   if (hdr_ptr == NULL)
365     out_of_memory(cinfo, 4);	/* jpeg_get_large failed */
366   mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr);
367 
368   /* Success, initialize the new pool header and add to list */
369   hdr_ptr->hdr.next = mem->large_list[pool_id];
370   /* We maintain space counts in each pool header for statistical purposes,
371    * even though they are not needed for allocation.
372    */
373   hdr_ptr->hdr.bytes_used = sizeofobject;
374   hdr_ptr->hdr.bytes_left = 0;
375   mem->large_list[pool_id] = hdr_ptr;
376 
377   return (void FAR *) (hdr_ptr + 1); /* point to first data byte in pool */
378 }
379 
380 
381 /*
382  * Creation of 2-D sample arrays.
383  * The pointers are in near heap, the samples themselves in FAR heap.
384  *
385  * To minimize allocation overhead and to allow I/O of large contiguous
386  * blocks, we allocate the sample rows in groups of as many rows as possible
387  * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
388  * NB: the virtual array control routines, later in this file, know about
389  * this chunking of rows.  The rowsperchunk value is left in the mem manager
390  * object so that it can be saved away if this sarray is the workspace for
391  * a virtual array.
392  */
393 
394 METHODDEF(JSAMPARRAY)
alloc_sarray(j_common_ptr cinfo,int pool_id,JDIMENSION samplesperrow,JDIMENSION numrows)395 alloc_sarray (j_common_ptr cinfo, int pool_id,
396 	      JDIMENSION samplesperrow, JDIMENSION numrows)
397 /* Allocate a 2-D sample array */
398 {
399   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
400   JSAMPARRAY result;
401   JSAMPROW workspace;
402   JDIMENSION rowsperchunk, currow, i;
403   long ltemp;
404 
405   /* Calculate max # of rows allowed in one allocation chunk */
406   ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
407 	  ((long) samplesperrow * SIZEOF(JSAMPLE));
408   if (ltemp <= 0)
409     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
410   if (ltemp < (long) numrows)
411     rowsperchunk = (JDIMENSION) ltemp;
412   else
413     rowsperchunk = numrows;
414   mem->last_rowsperchunk = rowsperchunk;
415 
416   /* Get space for row pointers (small object) */
417   result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
418 				    (size_t) (numrows * SIZEOF(JSAMPROW)));
419 
420   /* Get the rows themselves (large objects) */
421   currow = 0;
422   while (currow < numrows) {
423     rowsperchunk = MIN(rowsperchunk, numrows - currow);
424     workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
425 	(size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
426 		  * SIZEOF(JSAMPLE)));
427     for (i = rowsperchunk; i > 0; i--) {
428       result[currow++] = workspace;
429       workspace += samplesperrow;
430     }
431   }
432 
433   return result;
434 }
435 
436 
437 /*
438  * Creation of 2-D coefficient-block arrays.
439  * This is essentially the same as the code for sample arrays, above.
440  */
441 
442 METHODDEF(JBLOCKARRAY)
alloc_barray(j_common_ptr cinfo,int pool_id,JDIMENSION blocksperrow,JDIMENSION numrows)443 alloc_barray (j_common_ptr cinfo, int pool_id,
444 	      JDIMENSION blocksperrow, JDIMENSION numrows)
445 /* Allocate a 2-D coefficient-block array */
446 {
447   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
448   JBLOCKARRAY result;
449   JBLOCKROW workspace;
450   JDIMENSION rowsperchunk, currow, i;
451   long ltemp;
452 
453   /* Calculate max # of rows allowed in one allocation chunk */
454   ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
455 	  ((long) blocksperrow * SIZEOF(JBLOCK));
456   if (ltemp <= 0)
457     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
458   if (ltemp < (long) numrows)
459     rowsperchunk = (JDIMENSION) ltemp;
460   else
461     rowsperchunk = numrows;
462   mem->last_rowsperchunk = rowsperchunk;
463 
464   /* Get space for row pointers (small object) */
465   result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
466 				     (size_t) (numrows * SIZEOF(JBLOCKROW)));
467 
468   /* Get the rows themselves (large objects) */
469   currow = 0;
470   while (currow < numrows) {
471     rowsperchunk = MIN(rowsperchunk, numrows - currow);
472     workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
473 	(size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
474 		  * SIZEOF(JBLOCK)));
475     for (i = rowsperchunk; i > 0; i--) {
476       result[currow++] = workspace;
477       workspace += blocksperrow;
478     }
479   }
480 
481   return result;
482 }
483 
484 
485 /*
486  * About virtual array management:
487  *
488  * The above "normal" array routines are only used to allocate strip buffers
489  * (as wide as the image, but just a few rows high).  Full-image-sized buffers
490  * are handled as "virtual" arrays.  The array is still accessed a strip at a
491  * time, but the memory manager must save the whole array for repeated
492  * accesses.  The intended implementation is that there is a strip buffer in
493  * memory (as high as is possible given the desired memory limit), plus a
494  * backing file that holds the rest of the array.
495  *
496  * The request_virt_array routines are told the total size of the image and
497  * the maximum number of rows that will be accessed at once.  The in-memory
498  * buffer must be at least as large as the maxaccess value.
499  *
500  * The request routines create control blocks but not the in-memory buffers.
501  * That is postponed until realize_virt_arrays is called.  At that time the
502  * total amount of space needed is known (approximately, anyway), so free
503  * memory can be divided up fairly.
504  *
505  * The access_virt_array routines are responsible for making a specific strip
506  * area accessible (after reading or writing the backing file, if necessary).
507  * Note that the access routines are told whether the caller intends to modify
508  * the accessed strip; during a read-only pass this saves having to rewrite
509  * data to disk.  The access routines are also responsible for pre-zeroing
510  * any newly accessed rows, if pre-zeroing was requested.
511  *
512  * In current usage, the access requests are usually for nonoverlapping
513  * strips; that is, successive access start_row numbers differ by exactly
514  * num_rows = maxaccess.  This means we can get good performance with simple
515  * buffer dump/reload logic, by making the in-memory buffer be a multiple
516  * of the access height; then there will never be accesses across bufferload
517  * boundaries.  The code will still work with overlapping access requests,
518  * but it doesn't handle bufferload overlaps very efficiently.
519  */
520 
521 
522 METHODDEF(jvirt_sarray_ptr)
request_virt_sarray(j_common_ptr cinfo,int pool_id,boolean pre_zero,JDIMENSION samplesperrow,JDIMENSION numrows,JDIMENSION maxaccess)523 request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
524 		     JDIMENSION samplesperrow, JDIMENSION numrows,
525 		     JDIMENSION maxaccess)
526 /* Request a virtual 2-D sample array */
527 {
528   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
529   jvirt_sarray_ptr result;
530 
531   /* Only IMAGE-lifetime virtual arrays are currently supported */
532   if (pool_id != JPOOL_IMAGE)
533     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */
534 
535   /* get control block */
536   result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
537 					  SIZEOF(struct jvirt_sarray_control));
538 
539   result->mem_buffer = NULL;	/* marks array not yet realized */
540   result->rows_in_array = numrows;
541   result->samplesperrow = samplesperrow;
542   result->maxaccess = maxaccess;
543   result->pre_zero = pre_zero;
544   result->b_s_open = FALSE;	/* no associated backing-store object */
545   result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
546   mem->virt_sarray_list = result;
547 
548   return result;
549 }
550 
551 
552 METHODDEF(jvirt_barray_ptr)
request_virt_barray(j_common_ptr cinfo,int pool_id,boolean pre_zero,JDIMENSION blocksperrow,JDIMENSION numrows,JDIMENSION maxaccess)553 request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
554 		     JDIMENSION blocksperrow, JDIMENSION numrows,
555 		     JDIMENSION maxaccess)
556 /* Request a virtual 2-D coefficient-block array */
557 {
558   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
559   jvirt_barray_ptr result;
560 
561   /* Only IMAGE-lifetime virtual arrays are currently supported */
562   if (pool_id != JPOOL_IMAGE)
563     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */
564 
565   /* get control block */
566   result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
567 					  SIZEOF(struct jvirt_barray_control));
568 
569   result->mem_buffer = NULL;	/* marks array not yet realized */
570   result->rows_in_array = numrows;
571   result->blocksperrow = blocksperrow;
572   result->maxaccess = maxaccess;
573   result->pre_zero = pre_zero;
574   result->b_s_open = FALSE;	/* no associated backing-store object */
575   result->next = mem->virt_barray_list; /* add to list of virtual arrays */
576   mem->virt_barray_list = result;
577 
578   return result;
579 }
580 
581 
582 METHODDEF(void)
realize_virt_arrays(j_common_ptr cinfo)583 realize_virt_arrays (j_common_ptr cinfo)
584 /* Allocate the in-memory buffers for any unrealized virtual arrays */
585 {
586   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
587   long space_per_minheight, maximum_space, avail_mem;
588   long minheights, max_minheights;
589   jvirt_sarray_ptr sptr;
590   jvirt_barray_ptr bptr;
591 
592   /* Compute the minimum space needed (maxaccess rows in each buffer)
593    * and the maximum space needed (full image height in each buffer).
594    * These may be of use to the system-dependent jpeg_mem_available routine.
595    */
596   space_per_minheight = 0;
597   maximum_space = 0;
598   for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
599     if (sptr->mem_buffer == NULL) { /* if not realized yet */
600       space_per_minheight += (long) sptr->maxaccess *
601 			     (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
602       maximum_space += (long) sptr->rows_in_array *
603 		       (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
604     }
605   }
606   for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
607     if (bptr->mem_buffer == NULL) { /* if not realized yet */
608       space_per_minheight += (long) bptr->maxaccess *
609 			     (long) bptr->blocksperrow * SIZEOF(JBLOCK);
610       maximum_space += (long) bptr->rows_in_array *
611 		       (long) bptr->blocksperrow * SIZEOF(JBLOCK);
612     }
613   }
614 
615   if (space_per_minheight <= 0)
616     return;			/* no unrealized arrays, no work */
617 
618   /* Determine amount of memory to actually use; this is system-dependent. */
619   avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space,
620 				 mem->total_space_allocated);
621 
622   /* If the maximum space needed is available, make all the buffers full
623    * height; otherwise parcel it out with the same number of minheights
624    * in each buffer.
625    */
626   if (avail_mem >= maximum_space)
627     max_minheights = 1000000000L;
628   else {
629     max_minheights = avail_mem / space_per_minheight;
630     /* If there doesn't seem to be enough space, try to get the minimum
631      * anyway.  This allows a "stub" implementation of jpeg_mem_available().
632      */
633     if (max_minheights <= 0)
634       max_minheights = 1;
635   }
636 
637   /* Allocate the in-memory buffers and initialize backing store as needed. */
638 
639   for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
640     if (sptr->mem_buffer == NULL) { /* if not realized yet */
641       minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L;
642       if (minheights <= max_minheights) {
643 	/* This buffer fits in memory */
644 	sptr->rows_in_mem = sptr->rows_in_array;
645       } else {
646 	/* It doesn't fit in memory, create backing store. */
647 	sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess);
648 	jpeg_open_backing_store(cinfo, & sptr->b_s_info,
649 				(long) sptr->rows_in_array *
650 				(long) sptr->samplesperrow *
651 				(long) SIZEOF(JSAMPLE));
652 	sptr->b_s_open = TRUE;
653       }
654       sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
655 				      sptr->samplesperrow, sptr->rows_in_mem);
656       sptr->rowsperchunk = mem->last_rowsperchunk;
657       sptr->cur_start_row = 0;
658       sptr->first_undef_row = 0;
659       sptr->dirty = FALSE;
660     }
661   }
662 
663   for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
664     if (bptr->mem_buffer == NULL) { /* if not realized yet */
665       minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
666       if (minheights <= max_minheights) {
667 	/* This buffer fits in memory */
668 	bptr->rows_in_mem = bptr->rows_in_array;
669       } else {
670 	/* It doesn't fit in memory, create backing store. */
671 	bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess);
672 	jpeg_open_backing_store(cinfo, & bptr->b_s_info,
673 				(long) bptr->rows_in_array *
674 				(long) bptr->blocksperrow *
675 				(long) SIZEOF(JBLOCK));
676 	bptr->b_s_open = TRUE;
677       }
678       bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
679 				      bptr->blocksperrow, bptr->rows_in_mem);
680       bptr->rowsperchunk = mem->last_rowsperchunk;
681       bptr->cur_start_row = 0;
682       bptr->first_undef_row = 0;
683       bptr->dirty = FALSE;
684     }
685   }
686 }
687 
688 
689 LOCAL(void)
do_sarray_io(j_common_ptr cinfo,jvirt_sarray_ptr ptr,boolean writing)690 do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
691 /* Do backing store read or write of a virtual sample array */
692 {
693   long bytesperrow, file_offset, byte_count, rows, thisrow, i;
694 
695   bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
696   file_offset = ptr->cur_start_row * bytesperrow;
697   /* Loop to read or write each allocation chunk in mem_buffer */
698   for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
699     /* One chunk, but check for short chunk at end of buffer */
700     rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
701     /* Transfer no more than is currently defined */
702     thisrow = (long) ptr->cur_start_row + i;
703     rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
704     /* Transfer no more than fits in file */
705     rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
706     if (rows <= 0)		/* this chunk might be past end of file! */
707       break;
708     byte_count = rows * bytesperrow;
709     if (writing)
710       (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
711 					    (void FAR *) ptr->mem_buffer[i],
712 					    file_offset, byte_count);
713     else
714       (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
715 					   (void FAR *) ptr->mem_buffer[i],
716 					   file_offset, byte_count);
717     file_offset += byte_count;
718   }
719 }
720 
721 
722 LOCAL(void)
do_barray_io(j_common_ptr cinfo,jvirt_barray_ptr ptr,boolean writing)723 do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
724 /* Do backing store read or write of a virtual coefficient-block array */
725 {
726   long bytesperrow, file_offset, byte_count, rows, thisrow, i;
727 
728   bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
729   file_offset = ptr->cur_start_row * bytesperrow;
730   /* Loop to read or write each allocation chunk in mem_buffer */
731   for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
732     /* One chunk, but check for short chunk at end of buffer */
733     rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
734     /* Transfer no more than is currently defined */
735     thisrow = (long) ptr->cur_start_row + i;
736     rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
737     /* Transfer no more than fits in file */
738     rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
739     if (rows <= 0)		/* this chunk might be past end of file! */
740       break;
741     byte_count = rows * bytesperrow;
742     if (writing)
743       (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
744 					    (void FAR *) ptr->mem_buffer[i],
745 					    file_offset, byte_count);
746     else
747       (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
748 					   (void FAR *) ptr->mem_buffer[i],
749 					   file_offset, byte_count);
750     file_offset += byte_count;
751   }
752 }
753 
754 
755 METHODDEF(JSAMPARRAY)
access_virt_sarray(j_common_ptr cinfo,jvirt_sarray_ptr ptr,JDIMENSION start_row,JDIMENSION num_rows,boolean writable)756 access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
757 		    JDIMENSION start_row, JDIMENSION num_rows,
758 		    boolean writable)
759 /* Access the part of a virtual sample array starting at start_row */
760 /* and extending for num_rows rows.  writable is true if  */
761 /* caller intends to modify the accessed area. */
762 {
763   JDIMENSION end_row = start_row + num_rows;
764   JDIMENSION undef_row;
765 
766   /* debugging check */
767   if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
768       ptr->mem_buffer == NULL)
769     ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
770 
771   /* Make the desired part of the virtual array accessible */
772   if (start_row < ptr->cur_start_row ||
773       end_row > ptr->cur_start_row+ptr->rows_in_mem) {
774     if (! ptr->b_s_open)
775       ERREXIT(cinfo, JERR_VIRTUAL_BUG);
776     /* Flush old buffer contents if necessary */
777     if (ptr->dirty) {
778       do_sarray_io(cinfo, ptr, TRUE);
779       ptr->dirty = FALSE;
780     }
781     /* Decide what part of virtual array to access.
782      * Algorithm: if target address > current window, assume forward scan,
783      * load starting at target address.  If target address < current window,
784      * assume backward scan, load so that target area is top of window.
785      * Note that when switching from forward write to forward read, will have
786      * start_row = 0, so the limiting case applies and we load from 0 anyway.
787      */
788     if (start_row > ptr->cur_start_row) {
789       ptr->cur_start_row = start_row;
790     } else {
791       /* use long arithmetic here to avoid overflow & unsigned problems */
792       long ltemp;
793 
794       ltemp = (long) end_row - (long) ptr->rows_in_mem;
795       if (ltemp < 0)
796 	ltemp = 0;		/* don't fall off front end of file */
797       ptr->cur_start_row = (JDIMENSION) ltemp;
798     }
799     /* Read in the selected part of the array.
800      * During the initial write pass, we will do no actual read
801      * because the selected part is all undefined.
802      */
803     do_sarray_io(cinfo, ptr, FALSE);
804   }
805   /* Ensure the accessed part of the array is defined; prezero if needed.
806    * To improve locality of access, we only prezero the part of the array
807    * that the caller is about to access, not the entire in-memory array.
808    */
809   if (ptr->first_undef_row < end_row) {
810     if (ptr->first_undef_row < start_row) {
811       if (writable)		/* writer skipped over a section of array */
812 	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
813       undef_row = start_row;	/* but reader is allowed to read ahead */
814     } else {
815       undef_row = ptr->first_undef_row;
816     }
817     if (writable)
818       ptr->first_undef_row = end_row;
819     if (ptr->pre_zero) {
820       size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
821       undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
822       end_row -= ptr->cur_start_row;
823       while (undef_row < end_row) {
824 	jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
825 	undef_row++;
826       }
827     } else {
828       if (! writable)		/* reader looking at undefined data */
829 	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
830     }
831   }
832   /* Flag the buffer dirty if caller will write in it */
833   if (writable)
834     ptr->dirty = TRUE;
835   /* Return address of proper part of the buffer */
836   return ptr->mem_buffer + (start_row - ptr->cur_start_row);
837 }
838 
839 
840 METHODDEF(JBLOCKARRAY)
access_virt_barray(j_common_ptr cinfo,jvirt_barray_ptr ptr,JDIMENSION start_row,JDIMENSION num_rows,boolean writable)841 access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
842 		    JDIMENSION start_row, JDIMENSION num_rows,
843 		    boolean writable)
844 /* Access the part of a virtual block array starting at start_row */
845 /* and extending for num_rows rows.  writable is true if  */
846 /* caller intends to modify the accessed area. */
847 {
848   JDIMENSION end_row = start_row + num_rows;
849   JDIMENSION undef_row;
850 
851   /* debugging check */
852   if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
853       ptr->mem_buffer == NULL)
854     ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
855 
856   /* Make the desired part of the virtual array accessible */
857   if (start_row < ptr->cur_start_row ||
858       end_row > ptr->cur_start_row+ptr->rows_in_mem) {
859     if (! ptr->b_s_open)
860       ERREXIT(cinfo, JERR_VIRTUAL_BUG);
861     /* Flush old buffer contents if necessary */
862     if (ptr->dirty) {
863       do_barray_io(cinfo, ptr, TRUE);
864       ptr->dirty = FALSE;
865     }
866     /* Decide what part of virtual array to access.
867      * Algorithm: if target address > current window, assume forward scan,
868      * load starting at target address.  If target address < current window,
869      * assume backward scan, load so that target area is top of window.
870      * Note that when switching from forward write to forward read, will have
871      * start_row = 0, so the limiting case applies and we load from 0 anyway.
872      */
873     if (start_row > ptr->cur_start_row) {
874       ptr->cur_start_row = start_row;
875     } else {
876       /* use long arithmetic here to avoid overflow & unsigned problems */
877       long ltemp;
878 
879       ltemp = (long) end_row - (long) ptr->rows_in_mem;
880       if (ltemp < 0)
881 	ltemp = 0;		/* don't fall off front end of file */
882       ptr->cur_start_row = (JDIMENSION) ltemp;
883     }
884     /* Read in the selected part of the array.
885      * During the initial write pass, we will do no actual read
886      * because the selected part is all undefined.
887      */
888     do_barray_io(cinfo, ptr, FALSE);
889   }
890   /* Ensure the accessed part of the array is defined; prezero if needed.
891    * To improve locality of access, we only prezero the part of the array
892    * that the caller is about to access, not the entire in-memory array.
893    */
894   if (ptr->first_undef_row < end_row) {
895     if (ptr->first_undef_row < start_row) {
896       if (writable)		/* writer skipped over a section of array */
897 	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
898       undef_row = start_row;	/* but reader is allowed to read ahead */
899     } else {
900       undef_row = ptr->first_undef_row;
901     }
902     if (writable)
903       ptr->first_undef_row = end_row;
904     if (ptr->pre_zero) {
905       size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
906       undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
907       end_row -= ptr->cur_start_row;
908       while (undef_row < end_row) {
909 	jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
910 	undef_row++;
911       }
912     } else {
913       if (! writable)		/* reader looking at undefined data */
914 	ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
915     }
916   }
917   /* Flag the buffer dirty if caller will write in it */
918   if (writable)
919     ptr->dirty = TRUE;
920   /* Return address of proper part of the buffer */
921   return ptr->mem_buffer + (start_row - ptr->cur_start_row);
922 }
923 
924 
925 /*
926  * Release all objects belonging to a specified pool.
927  */
928 
929 METHODDEF(void)
free_pool(j_common_ptr cinfo,int pool_id)930 free_pool (j_common_ptr cinfo, int pool_id)
931 {
932   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
933   small_pool_ptr shdr_ptr;
934   large_pool_ptr lhdr_ptr;
935   size_t space_freed;
936 
937   if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
938     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id);	/* safety check */
939 
940 #ifdef MEM_STATS
941   if (cinfo->err->trace_level > 1)
942     print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
943 #endif
944 
945   /* If freeing IMAGE pool, close any virtual arrays first */
946   if (pool_id == JPOOL_IMAGE) {
947     jvirt_sarray_ptr sptr;
948     jvirt_barray_ptr bptr;
949 
950     for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
951       if (sptr->b_s_open) {	/* there may be no backing store */
952 	sptr->b_s_open = FALSE;	/* prevent recursive close if error */
953 	(*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
954       }
955     }
956     mem->virt_sarray_list = NULL;
957     for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
958       if (bptr->b_s_open) {	/* there may be no backing store */
959 	bptr->b_s_open = FALSE;	/* prevent recursive close if error */
960 	(*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
961       }
962     }
963     mem->virt_barray_list = NULL;
964   }
965 
966   /* Release large objects */
967   lhdr_ptr = mem->large_list[pool_id];
968   mem->large_list[pool_id] = NULL;
969 
970   while (lhdr_ptr != NULL) {
971     large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
972     space_freed = lhdr_ptr->hdr.bytes_used +
973 		  lhdr_ptr->hdr.bytes_left +
974 		  SIZEOF(large_pool_hdr);
975     jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
976     mem->total_space_allocated -= space_freed;
977     lhdr_ptr = next_lhdr_ptr;
978   }
979 
980   /* Release small objects */
981   shdr_ptr = mem->small_list[pool_id];
982   mem->small_list[pool_id] = NULL;
983 
984   while (shdr_ptr != NULL) {
985     small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
986     space_freed = shdr_ptr->hdr.bytes_used +
987 		  shdr_ptr->hdr.bytes_left +
988 		  SIZEOF(small_pool_hdr);
989     jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
990     mem->total_space_allocated -= space_freed;
991     shdr_ptr = next_shdr_ptr;
992   }
993 }
994 
995 
996 /*
997  * Close up shop entirely.
998  * Note that this cannot be called unless cinfo->mem is non-NULL.
999  */
1000 
1001 METHODDEF(void)
self_destruct(j_common_ptr cinfo)1002 self_destruct (j_common_ptr cinfo)
1003 {
1004   int pool;
1005 
1006   /* Close all backing store, release all memory.
1007    * Releasing pools in reverse order might help avoid fragmentation
1008    * with some (brain-damaged) malloc libraries.
1009    */
1010   for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1011     free_pool(cinfo, pool);
1012   }
1013 
1014   /* Release the memory manager control block too. */
1015   jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
1016   cinfo->mem = NULL;		/* ensures I will be called only once */
1017 
1018   jpeg_mem_term(cinfo);		/* system-dependent cleanup */
1019 }
1020 
1021 
1022 /*
1023  * Memory manager initialization.
1024  * When this is called, only the error manager pointer is valid in cinfo!
1025  */
1026 
1027 GLOBAL(void)
jinit_memory_mgr(j_common_ptr cinfo)1028 jinit_memory_mgr (j_common_ptr cinfo)
1029 {
1030   my_mem_ptr mem;
1031   long max_to_use;
1032   int pool;
1033   size_t test_mac;
1034 
1035   cinfo->mem = NULL;		/* for safety if init fails */
1036 
1037   /* Check for configuration errors.
1038    * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
1039    * doesn't reflect any real hardware alignment requirement.
1040    * The test is a little tricky: for X>0, X and X-1 have no one-bits
1041    * in common if and only if X is a power of 2, ie has only one one-bit.
1042    * Some compilers may give an "unreachable code" warning here; ignore it.
1043    */
1044   if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
1045     ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
1046   /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
1047    * a multiple of SIZEOF(ALIGN_TYPE).
1048    * Again, an "unreachable code" warning may be ignored here.
1049    * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
1050    */
1051   test_mac = (size_t) MAX_ALLOC_CHUNK;
1052   if ((long) test_mac != MAX_ALLOC_CHUNK ||
1053       (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
1054     ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
1055 
1056   max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
1057 
1058   /* Attempt to allocate memory manager's control block */
1059   mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
1060 
1061   if (mem == NULL) {
1062     jpeg_mem_term(cinfo);	/* system-dependent cleanup */
1063     ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
1064   }
1065 
1066   /* OK, fill in the method pointers */
1067   mem->pub.alloc_small = alloc_small;
1068   mem->pub.alloc_large = alloc_large;
1069   mem->pub.alloc_sarray = alloc_sarray;
1070   mem->pub.alloc_barray = alloc_barray;
1071   mem->pub.request_virt_sarray = request_virt_sarray;
1072   mem->pub.request_virt_barray = request_virt_barray;
1073   mem->pub.realize_virt_arrays = realize_virt_arrays;
1074   mem->pub.access_virt_sarray = access_virt_sarray;
1075   mem->pub.access_virt_barray = access_virt_barray;
1076   mem->pub.free_pool = free_pool;
1077   mem->pub.self_destruct = self_destruct;
1078 
1079   /* Make MAX_ALLOC_CHUNK accessible to other modules */
1080   mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
1081 
1082   /* Initialize working state */
1083   mem->pub.max_memory_to_use = max_to_use;
1084 
1085   for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1086     mem->small_list[pool] = NULL;
1087     mem->large_list[pool] = NULL;
1088   }
1089   mem->virt_sarray_list = NULL;
1090   mem->virt_barray_list = NULL;
1091 
1092   mem->total_space_allocated = SIZEOF(my_memory_mgr);
1093 
1094   /* Declare ourselves open for business */
1095   cinfo->mem = & mem->pub;
1096 
1097   /* Check for an environment variable JPEGMEM; if found, override the
1098    * default max_memory setting from jpeg_mem_init.  Note that the
1099    * surrounding application may again override this value.
1100    * If your system doesn't support getenv(), define NO_GETENV to disable
1101    * this feature.
1102    */
1103 #ifndef NO_GETENV
1104   { char * memenv;
1105 
1106     if ((memenv = getenv("JPEGMEM")) != NULL) {
1107       char ch = 'x';
1108 
1109       if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
1110 	if (ch == 'm' || ch == 'M')
1111 	  max_to_use *= 1000L;
1112 	mem->pub.max_memory_to_use = max_to_use * 1000L;
1113       }
1114     }
1115   }
1116 #endif
1117 
1118 }
1119