LCOV - app.info - media/libjpeg/jmemmgr.c

LCOV - code coverage report
| Current view: | directory - media/libjpeg - jmemmgr.c (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 380 | 138 | 36.3 %
| Date: | 2012-06-02 | Functions: | 16 | 8 | 50.0 %

           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                 : LOCAL(size_t)
          41             373 : round_up_pow2 (size_t a, size_t b)
          42                 : /* a rounded up to the next multiple of b, i.e. ceil(a/b)*b */
          43                 : /* Assumes a >= 0, b > 0, and b is a power of 2 */
          44                 : {
          45             373 :   return ((a + b - 1) & (~(b - 1)));
          46                 : }
          47                 :
          48                 :
          49                 : /*
          50                 :  * Some important notes:
          51                 :  *   The allocation routines provided here must never return NULL.
          52                 :  *   They should exit to error_exit if unsuccessful.
          53                 :  *
          54                 :  *   It's not a good idea to try to merge the sarray and barray routines,
          55                 :  *   even though they are textually almost the same, because samples are
          56                 :  *   usually stored as bytes while coefficients are shorts or ints.  Thus,
          57                 :  *   in machines where byte pointers have a different representation from
          58                 :  *   word pointers, the resulting machine code could not be the same.
          59                 :  */
          60                 :
          61                 :
          62                 : /*
          63                 :  * Many machines require storage alignment: longs must start on 4-byte
          64                 :  * boundaries, doubles on 8-byte boundaries, etc.  On such machines, malloc()
          65                 :  * always returns pointers that are multiples of the worst-case alignment
          66                 :  * requirement, and we had better do so too.
          67                 :  * There isn't any really portable way to determine the worst-case alignment
          68                 :  * requirement.  This module assumes that the alignment requirement is
          69                 :  * multiples of ALIGN_SIZE.
          70                 :  * By default, we define ALIGN_SIZE as sizeof(double).  This is necessary on some
          71                 :  * workstations (where doubles really do need 8-byte alignment) and will work
          72                 :  * fine on nearly everything.  If your machine has lesser alignment needs,
          73                 :  * you can save a few bytes by making ALIGN_SIZE smaller.
          74                 :  * The only place I know of where this will NOT work is certain Macintosh
          75                 :  * 680x0 compilers that define double as a 10-byte IEEE extended float.
          76                 :  * Doing 10-byte alignment is counterproductive because longwords won't be
          77                 :  * aligned well.  Put "#define ALIGN_SIZE 4" in jconfig.h if you have
          78                 :  * such a compiler.
          79                 :  */
          80                 :
          81                 : #ifndef ALIGN_SIZE              /* so can override from jconfig.h */
          82                 : #ifndef WITH_SIMD
          83                 : #define ALIGN_SIZE  SIZEOF(double)
          84                 : #else
          85                 : #define ALIGN_SIZE  16 /* Most SIMD implementations require this */
          86                 : #endif
          87                 : #endif
          88                 :
          89                 : /*
          90                 :  * We allocate objects from "pools", where each pool is gotten with a single
          91                 :  * request to jpeg_get_small() or jpeg_get_large().  There is no per-object
          92                 :  * overhead within a pool, except for alignment padding.  Each pool has a
          93                 :  * header with a link to the next pool of the same class.
          94                 :  * Small and large pool headers are identical except that the latter's
          95                 :  * link pointer must be FAR on 80x86 machines.
          96                 :  */
          97                 :
          98                 : typedef struct small_pool_struct * small_pool_ptr;
          99                 :
         100                 : typedef struct small_pool_struct {
         101                 :   small_pool_ptr next;  /* next in list of pools */
         102                 :   size_t bytes_used;            /* how many bytes already used within pool */
         103                 :   size_t bytes_left;            /* bytes still available in this pool */
         104                 : } small_pool_hdr;
         105                 :
         106                 : typedef struct large_pool_struct FAR * large_pool_ptr;
         107                 :
         108                 : typedef struct large_pool_struct {
         109                 :   large_pool_ptr next;  /* next in list of pools */
         110                 :   size_t bytes_used;            /* how many bytes already used within pool */
         111                 :   size_t bytes_left;            /* bytes still available in this pool */
         112                 : } large_pool_hdr;
         113                 :
         114                 : /*
         115                 :  * Here is the full definition of a memory manager object.
         116                 :  */
         117                 :
         118                 : typedef struct {
         119                 :   struct jpeg_memory_mgr pub;   /* public fields */
         120                 :
         121                 :   /* Each pool identifier (lifetime class) names a linked list of pools. */
         122                 :   small_pool_ptr small_list[JPOOL_NUMPOOLS];
         123                 :   large_pool_ptr large_list[JPOOL_NUMPOOLS];
         124                 :
         125                 :   /* Since we only have one lifetime class of virtual arrays, only one
         126                 :    * linked list is necessary (for each datatype).  Note that the virtual
         127                 :    * array control blocks being linked together are actually stored somewhere
         128                 :    * in the small-pool list.
         129                 :    */
         130                 :   jvirt_sarray_ptr virt_sarray_list;
         131                 :   jvirt_barray_ptr virt_barray_list;
         132                 :
         133                 :   /* This counts total space obtained from jpeg_get_small/large */
         134                 :   size_t total_space_allocated;
         135                 :
         136                 :   /* alloc_sarray and alloc_barray set this value for use by virtual
         137                 :    * array routines.
         138                 :    */
         139                 :   JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
         140                 : } my_memory_mgr;
         141                 :
         142                 : typedef my_memory_mgr * my_mem_ptr;
         143                 :
         144                 :
         145                 : /*
         146                 :  * The control blocks for virtual arrays.
         147                 :  * Note that these blocks are allocated in the "small" pool area.
         148                 :  * System-dependent info for the associated backing store (if any) is hidden
         149                 :  * inside the backing_store_info struct.
         150                 :  */
         151                 :
         152                 : struct jvirt_sarray_control {
         153                 :   JSAMPARRAY mem_buffer;        /* => the in-memory buffer */
         154                 :   JDIMENSION rows_in_array;     /* total virtual array height */
         155                 :   JDIMENSION samplesperrow;     /* width of array (and of memory buffer) */
         156                 :   JDIMENSION maxaccess;         /* max rows accessed by access_virt_sarray */
         157                 :   JDIMENSION rows_in_mem;       /* height of memory buffer */
         158                 :   JDIMENSION rowsperchunk;      /* allocation chunk size in mem_buffer */
         159                 :   JDIMENSION cur_start_row;     /* first logical row # in the buffer */
         160                 :   JDIMENSION first_undef_row;   /* row # of first uninitialized row */
         161                 :   boolean pre_zero;             /* pre-zero mode requested? */
         162                 :   boolean dirty;                /* do current buffer contents need written? */
         163                 :   boolean b_s_open;             /* is backing-store data valid? */
         164                 :   jvirt_sarray_ptr next;        /* link to next virtual sarray control block */
         165                 :   backing_store_info b_s_info;  /* System-dependent control info */
         166                 : };
         167                 :
         168                 : struct jvirt_barray_control {
         169                 :   JBLOCKARRAY mem_buffer;       /* => the in-memory buffer */
         170                 :   JDIMENSION rows_in_array;     /* total virtual array height */
         171                 :   JDIMENSION blocksperrow;      /* width of array (and of memory buffer) */
         172                 :   JDIMENSION maxaccess;         /* max rows accessed by access_virt_barray */
         173                 :   JDIMENSION rows_in_mem;       /* height of memory buffer */
         174                 :   JDIMENSION rowsperchunk;      /* allocation chunk size in mem_buffer */
         175                 :   JDIMENSION cur_start_row;     /* first logical row # in the buffer */
         176                 :   JDIMENSION first_undef_row;   /* row # of first uninitialized row */
         177                 :   boolean pre_zero;             /* pre-zero mode requested? */
         178                 :   boolean dirty;                /* do current buffer contents need written? */
         179                 :   boolean b_s_open;             /* is backing-store data valid? */
         180                 :   jvirt_barray_ptr next;        /* link to next virtual barray control block */
         181                 :   backing_store_info b_s_info;  /* System-dependent control info */
         182                 : };
         183                 :
         184                 :
         185                 : #ifdef MEM_STATS                /* optional extra stuff for statistics */
         186                 :
         187                 : LOCAL(void)
         188                 : print_mem_stats (j_common_ptr cinfo, int pool_id)
         189                 : {
         190                 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         191                 :   small_pool_ptr shdr_ptr;
         192                 :   large_pool_ptr lhdr_ptr;
         193                 :
         194                 :   /* Since this is only a debugging stub, we can cheat a little by using
         195                 :    * fprintf directly rather than going through the trace message code.
         196                 :    * This is helpful because message parm array can't handle longs.
         197                 :    */
         198                 :   fprintf(stderr, "Freeing pool %d, total space = %ld\n",
         199                 :           pool_id, mem->total_space_allocated);
         200                 :
         201                 :   for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
         202                 :        lhdr_ptr = lhdr_ptr->next) {
         203                 :     fprintf(stderr, "  Large chunk used %ld\n",
         204                 :             (long) lhdr_ptr->bytes_used);
         205                 :   }
         206                 :
         207                 :   for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
         208                 :        shdr_ptr = shdr_ptr->next) {
         209                 :     fprintf(stderr, "  Small chunk used %ld free %ld\n",
         210                 :             (long) shdr_ptr->bytes_used,
         211                 :             (long) shdr_ptr->bytes_left);
         212                 :   }
         213                 : }
         214                 :
         215                 : #endif /* MEM_STATS */
         216                 :
         217                 :
         218                 : LOCAL(void)
         219               0 : out_of_memory (j_common_ptr cinfo, int which)
         220                 : /* Report an out-of-memory error and stop execution */
         221                 : /* If we compiled MEM_STATS support, report alloc requests before dying */
         222                 : {
         223                 : #ifdef MEM_STATS
         224                 :   cinfo->err->trace_level = 2;    /* force self_destruct to report stats */
         225                 : #endif
         226               0 :   ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
         227               0 : }
         228                 :
         229                 :
         230                 : /*
         231                 :  * Allocation of "small" objects.
         232                 :  *
         233                 :  * For these, we use pooled storage.  When a new pool must be created,
         234                 :  * we try to get enough space for the current request plus a "slop" factor,
         235                 :  * where the slop will be the amount of leftover space in the new pool.
         236                 :  * The speed vs. space tradeoff is largely determined by the slop values.
         237                 :  * A different slop value is provided for each pool class (lifetime),
         238                 :  * and we also distinguish the first pool of a class from later ones.
         239                 :  * NOTE: the values given work fairly well on both 16- and 32-bit-int
         240                 :  * machines, but may be too small if longs are 64 bits or more.
         241                 :  *
         242                 :  * Since we do not know what alignment malloc() gives us, we have to
         243                 :  * allocate ALIGN_SIZE-1 extra space per pool to have room for alignment
         244                 :  * adjustment.
         245                 :  */
         246                 :
         247                 : static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
         248                 : {
         249                 :         1600,                   /* first PERMANENT pool */
         250                 :         16000                   /* first IMAGE pool */
         251                 : };
         252                 :
         253                 : static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
         254                 : {
         255                 :         0,                      /* additional PERMANENT pools */
         256                 :         5000                    /* additional IMAGE pools */
         257                 : };
         258                 :
         259                 : #define MIN_SLOP  50            /* greater than 0 to avoid futile looping */
         260                 :
         261                 :
         262                 : METHODDEF(void *)
         263             269 : alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
         264                 : /* Allocate a "small" object */
         265                 : {
         266             269 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         267                 :   small_pool_ptr hdr_ptr, prev_hdr_ptr;
         268                 :   char * data_ptr;
         269                 :   size_t min_request, slop;
         270                 :
         271                 :   /*
         272                 :    * Round up the requested size to a multiple of ALIGN_SIZE in order
         273                 :    * to assure alignment for the next object allocated in the same pool
         274                 :    * and so that algorithms can straddle outside the proper area up
         275                 :    * to the next alignment.
         276                 :    */
         277             269 :   sizeofobject = round_up_pow2(sizeofobject, ALIGN_SIZE);
         278                 :
         279                 :   /* Check for unsatisfiable request (do now to ensure no overflow below) */
         280             269 :   if ((SIZEOF(small_pool_hdr) + sizeofobject + ALIGN_SIZE - 1) > MAX_ALLOC_CHUNK)
         281               0 :     out_of_memory(cinfo, 1);    /* request exceeds malloc's ability */
         282                 :
         283                 :   /* See if space is available in any existing pool */
         284             269 :   if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
         285               0 :     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
         286             269 :   prev_hdr_ptr = NULL;
         287             269 :   hdr_ptr = mem->small_list[pool_id];
         288             538 :   while (hdr_ptr != NULL) {
         289             253 :     if (hdr_ptr->bytes_left >= sizeofobject)
         290             253 :       break;                    /* found pool with enough space */
         291               0 :     prev_hdr_ptr = hdr_ptr;
         292               0 :     hdr_ptr = hdr_ptr->next;
         293                 :   }
         294                 :
         295                 :   /* Time to make a new pool? */
         296             269 :   if (hdr_ptr == NULL) {
         297                 :     /* min_request is what we need now, slop is what will be leftover */
         298              16 :     min_request = SIZEOF(small_pool_hdr) + sizeofobject + ALIGN_SIZE - 1;
         299              16 :     if (prev_hdr_ptr == NULL)   /* first pool in class? */
         300              16 :       slop = first_pool_slop[pool_id];
         301                 :     else
         302               0 :       slop = extra_pool_slop[pool_id];
         303                 :     /* Don't ask for more than MAX_ALLOC_CHUNK */
         304              16 :     if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
         305               0 :       slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
         306                 :     /* Try to get space, if fail reduce slop and try again */
         307                 :     for (;;) {
         308              16 :       hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
         309              16 :       if (hdr_ptr != NULL)
         310                 :         break;
         311               0 :       slop /= 2;
         312               0 :       if (slop < MIN_SLOP)   /* give up when it gets real small */
         313               0 :         out_of_memory(cinfo, 2); /* jpeg_get_small failed */
         314               0 :     }
         315              16 :     mem->total_space_allocated += min_request + slop;
         316                 :     /* Success, initialize the new pool header and add to end of list */
         317              16 :     hdr_ptr->next = NULL;
         318              16 :     hdr_ptr->bytes_used = 0;
         319              16 :     hdr_ptr->bytes_left = sizeofobject + slop;
         320              16 :     if (prev_hdr_ptr == NULL)   /* first pool in class? */
         321              16 :       mem->small_list[pool_id] = hdr_ptr;
         322                 :     else
         323               0 :       prev_hdr_ptr->next = hdr_ptr;
         324                 :   }
         325                 :
         326                 :   /* OK, allocate the object from the current pool */
         327             269 :   data_ptr = (char *) hdr_ptr; /* point to first data byte in pool... */
         328             269 :   data_ptr += SIZEOF(small_pool_hdr); /* ...by skipping the header... */
         329             269 :   if ((size_t)data_ptr % ALIGN_SIZE) /* ...and adjust for alignment */
         330             269 :     data_ptr += ALIGN_SIZE - (size_t)data_ptr % ALIGN_SIZE;
         331             269 :   data_ptr += hdr_ptr->bytes_used; /* point to place for object */
         332             269 :   hdr_ptr->bytes_used += sizeofobject;
         333             269 :   hdr_ptr->bytes_left -= sizeofobject;
         334                 :
         335             269 :   return (void *) data_ptr;
         336                 : }
         337                 :
         338                 :
         339                 : /*
         340                 :  * Allocation of "large" objects.
         341                 :  *
         342                 :  * The external semantics of these are the same as "small" objects,
         343                 :  * except that FAR pointers are used on 80x86.  However the pool
         344                 :  * management heuristics are quite different.  We assume that each
         345                 :  * request is large enough that it may as well be passed directly to
         346                 :  * jpeg_get_large; the pool management just links everything together
         347                 :  * so that we can free it all on demand.
         348                 :  * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
         349                 :  * structures.  The routines that create these structures (see below)
         350                 :  * deliberately bunch rows together to ensure a large request size.
         351                 :  */
         352                 :
         353                 : METHODDEF(void FAR *)
         354              61 : alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
         355                 : /* Allocate a "large" object */
         356                 : {
         357              61 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         358                 :   large_pool_ptr hdr_ptr;
         359                 :   char FAR * data_ptr;
         360                 :
         361                 :   /*
         362                 :    * Round up the requested size to a multiple of ALIGN_SIZE so that
         363                 :    * algorithms can straddle outside the proper area up to the next
         364                 :    * alignment.
         365                 :    */
         366              61 :   sizeofobject = round_up_pow2(sizeofobject, ALIGN_SIZE);
         367                 :
         368                 :   /* Check for unsatisfiable request (do now to ensure no overflow below) */
         369              61 :   if ((SIZEOF(large_pool_hdr) + sizeofobject + ALIGN_SIZE - 1) > MAX_ALLOC_CHUNK)
         370               0 :     out_of_memory(cinfo, 3);    /* request exceeds malloc's ability */
         371                 :
         372                 :   /* Always make a new pool */
         373              61 :   if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
         374               0 :     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
         375                 :
         376              61 :   hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
         377                 :                                             SIZEOF(large_pool_hdr) +
         378                 :                                             ALIGN_SIZE - 1);
         379              61 :   if (hdr_ptr == NULL)
         380               0 :     out_of_memory(cinfo, 4);    /* jpeg_get_large failed */
         381              61 :   mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr) + ALIGN_SIZE - 1;
         382                 :
         383                 :   /* Success, initialize the new pool header and add to list */
         384              61 :   hdr_ptr->next = mem->large_list[pool_id];
         385                 :   /* We maintain space counts in each pool header for statistical purposes,
         386                 :    * even though they are not needed for allocation.
         387                 :    */
         388              61 :   hdr_ptr->bytes_used = sizeofobject;
         389              61 :   hdr_ptr->bytes_left = 0;
         390              61 :   mem->large_list[pool_id] = hdr_ptr;
         391                 :
         392              61 :   data_ptr = (char *) hdr_ptr; /* point to first data byte in pool... */
         393              61 :   data_ptr += SIZEOF(small_pool_hdr); /* ...by skipping the header... */
         394              61 :   if ((size_t)data_ptr % ALIGN_SIZE) /* ...and adjust for alignment */
         395              61 :     data_ptr += ALIGN_SIZE - (size_t)data_ptr % ALIGN_SIZE;
         396                 :
         397              61 :   return (void FAR *) data_ptr;
         398                 : }
         399                 :
         400                 :
         401                 : /*
         402                 :  * Creation of 2-D sample arrays.
         403                 :  * The pointers are in near heap, the samples themselves in FAR heap.
         404                 :  *
         405                 :  * To minimize allocation overhead and to allow I/O of large contiguous
         406                 :  * blocks, we allocate the sample rows in groups of as many rows as possible
         407                 :  * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
         408                 :  * NB: the virtual array control routines, later in this file, know about
         409                 :  * this chunking of rows.  The rowsperchunk value is left in the mem manager
         410                 :  * object so that it can be saved away if this sarray is the workspace for
         411                 :  * a virtual array.
         412                 :  *
         413                 :  * Since we are often upsampling with a factor 2, we align the size (not
         414                 :  * the start) to 2 * ALIGN_SIZE so that the upsampling routines don't have
         415                 :  * to be as careful about size.
         416                 :  */
         417                 :
         418                 : METHODDEF(JSAMPARRAY)
         419              43 : alloc_sarray (j_common_ptr cinfo, int pool_id,
         420                 :               JDIMENSION samplesperrow, JDIMENSION numrows)
         421                 : /* Allocate a 2-D sample array */
         422                 : {
         423              43 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         424                 :   JSAMPARRAY result;
         425                 :   JSAMPROW workspace;
         426                 :   JDIMENSION rowsperchunk, currow, i;
         427                 :   long ltemp;
         428                 :
         429                 :   /* Make sure each row is properly aligned */
         430                 :   if ((ALIGN_SIZE % SIZEOF(JSAMPLE)) != 0)
         431                 :     out_of_memory(cinfo, 5);    /* safety check */
         432              43 :   samplesperrow = (JDIMENSION)round_up_pow2(samplesperrow, (2 * ALIGN_SIZE) / SIZEOF(JSAMPLE));
         433                 :
         434                 :   /* Calculate max # of rows allowed in one allocation chunk */
         435              43 :   ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
         436                 :           ((long) samplesperrow * SIZEOF(JSAMPLE));
         437              43 :   if (ltemp <= 0)
         438               0 :     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
         439              43 :   if (ltemp < (long) numrows)
         440               0 :     rowsperchunk = (JDIMENSION) ltemp;
         441                 :   else
         442              43 :     rowsperchunk = numrows;
         443              43 :   mem->last_rowsperchunk = rowsperchunk;
         444                 :
         445                 :   /* Get space for row pointers (small object) */
         446              43 :   result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
         447                 :                                     (size_t) (numrows * SIZEOF(JSAMPROW)));
         448                 :
         449                 :   /* Get the rows themselves (large objects) */
         450              43 :   currow = 0;
         451             129 :   while (currow < numrows) {
         452              43 :     rowsperchunk = MIN(rowsperchunk, numrows - currow);
         453              43 :     workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
         454                 :         (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
         455                 :                   * SIZEOF(JSAMPLE)));
         456             328 :     for (i = rowsperchunk; i > 0; i--) {
         457             285 :       result[currow++] = workspace;
         458             285 :       workspace += samplesperrow;
         459                 :     }
         460                 :   }
         461                 :
         462              43 :   return result;
         463                 : }
         464                 :
         465                 :
         466                 : /*
         467                 :  * Creation of 2-D coefficient-block arrays.
         468                 :  * This is essentially the same as the code for sample arrays, above.
         469                 :  */
         470                 :
         471                 : METHODDEF(JBLOCKARRAY)
         472               0 : alloc_barray (j_common_ptr cinfo, int pool_id,
         473                 :               JDIMENSION blocksperrow, JDIMENSION numrows)
         474                 : /* Allocate a 2-D coefficient-block array */
         475                 : {
         476               0 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         477                 :   JBLOCKARRAY result;
         478                 :   JBLOCKROW workspace;
         479                 :   JDIMENSION rowsperchunk, currow, i;
         480                 :   long ltemp;
         481                 :
         482                 :   /* Make sure each row is properly aligned */
         483                 :   if ((SIZEOF(JBLOCK) % ALIGN_SIZE) != 0)
         484                 :     out_of_memory(cinfo, 6);    /* safety check */
         485                 :
         486                 :   /* Calculate max # of rows allowed in one allocation chunk */
         487               0 :   ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
         488               0 :           ((long) blocksperrow * SIZEOF(JBLOCK));
         489               0 :   if (ltemp <= 0)
         490               0 :     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
         491               0 :   if (ltemp < (long) numrows)
         492               0 :     rowsperchunk = (JDIMENSION) ltemp;
         493                 :   else
         494               0 :     rowsperchunk = numrows;
         495               0 :   mem->last_rowsperchunk = rowsperchunk;
         496                 :
         497                 :   /* Get space for row pointers (small object) */
         498               0 :   result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
         499                 :                                      (size_t) (numrows * SIZEOF(JBLOCKROW)));
         500                 :
         501                 :   /* Get the rows themselves (large objects) */
         502               0 :   currow = 0;
         503               0 :   while (currow < numrows) {
         504               0 :     rowsperchunk = MIN(rowsperchunk, numrows - currow);
         505               0 :     workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
         506               0 :         (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
         507                 :                   * SIZEOF(JBLOCK)));
         508               0 :     for (i = rowsperchunk; i > 0; i--) {
         509               0 :       result[currow++] = workspace;
         510               0 :       workspace += blocksperrow;
         511                 :     }
         512                 :   }
         513                 :
         514               0 :   return result;
         515                 : }
         516                 :
         517                 :
         518                 : /*
         519                 :  * About virtual array management:
         520                 :  *
         521                 :  * The above "normal" array routines are only used to allocate strip buffers
         522                 :  * (as wide as the image, but just a few rows high).  Full-image-sized buffers
         523                 :  * are handled as "virtual" arrays.  The array is still accessed a strip at a
         524                 :  * time, but the memory manager must save the whole array for repeated
         525                 :  * accesses.  The intended implementation is that there is a strip buffer in
         526                 :  * memory (as high as is possible given the desired memory limit), plus a
         527                 :  * backing file that holds the rest of the array.
         528                 :  *
         529                 :  * The request_virt_array routines are told the total size of the image and
         530                 :  * the maximum number of rows that will be accessed at once.  The in-memory
         531                 :  * buffer must be at least as large as the maxaccess value.
         532                 :  *
         533                 :  * The request routines create control blocks but not the in-memory buffers.
         534                 :  * That is postponed until realize_virt_arrays is called.  At that time the
         535                 :  * total amount of space needed is known (approximately, anyway), so free
         536                 :  * memory can be divided up fairly.
         537                 :  *
         538                 :  * The access_virt_array routines are responsible for making a specific strip
         539                 :  * area accessible (after reading or writing the backing file, if necessary).
         540                 :  * Note that the access routines are told whether the caller intends to modify
         541                 :  * the accessed strip; during a read-only pass this saves having to rewrite
         542                 :  * data to disk.  The access routines are also responsible for pre-zeroing
         543                 :  * any newly accessed rows, if pre-zeroing was requested.
         544                 :  *
         545                 :  * In current usage, the access requests are usually for nonoverlapping
         546                 :  * strips; that is, successive access start_row numbers differ by exactly
         547                 :  * num_rows = maxaccess.  This means we can get good performance with simple
         548                 :  * buffer dump/reload logic, by making the in-memory buffer be a multiple
         549                 :  * of the access height; then there will never be accesses across bufferload
         550                 :  * boundaries.  The code will still work with overlapping access requests,
         551                 :  * but it doesn't handle bufferload overlaps very efficiently.
         552                 :  */
         553                 :
         554                 :
         555                 : METHODDEF(jvirt_sarray_ptr)
         556               0 : request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
         557                 :                      JDIMENSION samplesperrow, JDIMENSION numrows,
         558                 :                      JDIMENSION maxaccess)
         559                 : /* Request a virtual 2-D sample array */
         560                 : {
         561               0 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         562                 :   jvirt_sarray_ptr result;
         563                 :
         564                 :   /* Only IMAGE-lifetime virtual arrays are currently supported */
         565               0 :   if (pool_id != JPOOL_IMAGE)
         566               0 :     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
         567                 :
         568                 :   /* get control block */
         569               0 :   result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
         570                 :                                           SIZEOF(struct jvirt_sarray_control));
         571                 :
         572               0 :   result->mem_buffer = NULL; /* marks array not yet realized */
         573               0 :   result->rows_in_array = numrows;
         574               0 :   result->samplesperrow = samplesperrow;
         575               0 :   result->maxaccess = maxaccess;
         576               0 :   result->pre_zero = pre_zero;
         577               0 :   result->b_s_open = FALSE;  /* no associated backing-store object */
         578               0 :   result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
         579               0 :   mem->virt_sarray_list = result;
         580                 :
         581               0 :   return result;
         582                 : }
         583                 :
         584                 :
         585                 : METHODDEF(jvirt_barray_ptr)
         586               0 : request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
         587                 :                      JDIMENSION blocksperrow, JDIMENSION numrows,
         588                 :                      JDIMENSION maxaccess)
         589                 : /* Request a virtual 2-D coefficient-block array */
         590                 : {
         591               0 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         592                 :   jvirt_barray_ptr result;
         593                 :
         594                 :   /* Only IMAGE-lifetime virtual arrays are currently supported */
         595               0 :   if (pool_id != JPOOL_IMAGE)
         596               0 :     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
         597                 :
         598                 :   /* get control block */
         599               0 :   result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
         600                 :                                           SIZEOF(struct jvirt_barray_control));
         601                 :
         602               0 :   result->mem_buffer = NULL; /* marks array not yet realized */
         603               0 :   result->rows_in_array = numrows;
         604               0 :   result->blocksperrow = blocksperrow;
         605               0 :   result->maxaccess = maxaccess;
         606               0 :   result->pre_zero = pre_zero;
         607               0 :   result->b_s_open = FALSE;  /* no associated backing-store object */
         608               0 :   result->next = mem->virt_barray_list; /* add to list of virtual arrays */
         609               0 :   mem->virt_barray_list = result;
         610                 :
         611               0 :   return result;
         612                 : }
         613                 :
         614                 :
         615                 : METHODDEF(void)
         616               8 : realize_virt_arrays (j_common_ptr cinfo)
         617                 : /* Allocate the in-memory buffers for any unrealized virtual arrays */
         618                 : {
         619               8 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         620                 :   size_t space_per_minheight, maximum_space, avail_mem;
         621                 :   size_t minheights, max_minheights;
         622                 :   jvirt_sarray_ptr sptr;
         623                 :   jvirt_barray_ptr bptr;
         624                 :
         625                 :   /* Compute the minimum space needed (maxaccess rows in each buffer)
         626                 :    * and the maximum space needed (full image height in each buffer).
         627                 :    * These may be of use to the system-dependent jpeg_mem_available routine.
         628                 :    */
         629               8 :   space_per_minheight = 0;
         630               8 :   maximum_space = 0;
         631               8 :   for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
         632               0 :     if (sptr->mem_buffer == NULL) { /* if not realized yet */
         633               0 :       space_per_minheight += (long) sptr->maxaccess *
         634               0 :                              (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
         635               0 :       maximum_space += (long) sptr->rows_in_array *
         636               0 :                        (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
         637                 :     }
         638                 :   }
         639               8 :   for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
         640               0 :     if (bptr->mem_buffer == NULL) { /* if not realized yet */
         641               0 :       space_per_minheight += (long) bptr->maxaccess *
         642               0 :                              (long) bptr->blocksperrow * SIZEOF(JBLOCK);
         643               0 :       maximum_space += (long) bptr->rows_in_array *
         644               0 :                        (long) bptr->blocksperrow * SIZEOF(JBLOCK);
         645                 :     }
         646                 :   }
         647                 :
         648               8 :   if (space_per_minheight <= 0)
         649               8 :     return;                     /* no unrealized arrays, no work */
         650                 :
         651                 :   /* Determine amount of memory to actually use; this is system-dependent. */
         652               0 :   avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space,
         653                 :                                  mem->total_space_allocated);
         654                 :
         655                 :   /* If the maximum space needed is available, make all the buffers full
         656                 :    * height; otherwise parcel it out with the same number of minheights
         657                 :    * in each buffer.
         658                 :    */
         659               0 :   if (avail_mem >= maximum_space)
         660               0 :     max_minheights = 1000000000L;
         661                 :   else {
         662               0 :     max_minheights = avail_mem / space_per_minheight;
         663                 :     /* If there doesn't seem to be enough space, try to get the minimum
         664                 :      * anyway.  This allows a "stub" implementation of jpeg_mem_available().
         665                 :      */
         666               0 :     if (max_minheights <= 0)
         667               0 :       max_minheights = 1;
         668                 :   }
         669                 :
         670                 :   /* Allocate the in-memory buffers and initialize backing store as needed. */
         671                 :
         672               0 :   for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
         673               0 :     if (sptr->mem_buffer == NULL) { /* if not realized yet */
         674               0 :       minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L;
         675               0 :       if (minheights <= max_minheights) {
         676                 :         /* This buffer fits in memory */
         677               0 :         sptr->rows_in_mem = sptr->rows_in_array;
         678                 :       } else {
         679                 :         /* It doesn't fit in memory, create backing store. */
         680               0 :         sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess);
         681               0 :         jpeg_open_backing_store(cinfo, & sptr->b_s_info,
         682               0 :                                 (long) sptr->rows_in_array *
         683               0 :                                 (long) sptr->samplesperrow *
         684                 :                                 (long) SIZEOF(JSAMPLE));
         685               0 :         sptr->b_s_open = TRUE;
         686                 :       }
         687               0 :       sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
         688                 :                                       sptr->samplesperrow, sptr->rows_in_mem);
         689               0 :       sptr->rowsperchunk = mem->last_rowsperchunk;
         690               0 :       sptr->cur_start_row = 0;
         691               0 :       sptr->first_undef_row = 0;
         692               0 :       sptr->dirty = FALSE;
         693                 :     }
         694                 :   }
         695                 :
         696               0 :   for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
         697               0 :     if (bptr->mem_buffer == NULL) { /* if not realized yet */
         698               0 :       minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
         699               0 :       if (minheights <= max_minheights) {
         700                 :         /* This buffer fits in memory */
         701               0 :         bptr->rows_in_mem = bptr->rows_in_array;
         702                 :       } else {
         703                 :         /* It doesn't fit in memory, create backing store. */
         704               0 :         bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess);
         705               0 :         jpeg_open_backing_store(cinfo, & bptr->b_s_info,
         706               0 :                                 (long) bptr->rows_in_array *
         707               0 :                                 (long) bptr->blocksperrow *
         708                 :                                 (long) SIZEOF(JBLOCK));
         709               0 :         bptr->b_s_open = TRUE;
         710                 :       }
         711               0 :       bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
         712                 :                                       bptr->blocksperrow, bptr->rows_in_mem);
         713               0 :       bptr->rowsperchunk = mem->last_rowsperchunk;
         714               0 :       bptr->cur_start_row = 0;
         715               0 :       bptr->first_undef_row = 0;
         716               0 :       bptr->dirty = FALSE;
         717                 :     }
         718                 :   }
         719                 : }
         720                 :
         721                 :
         722                 : LOCAL(void)
         723               0 : do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
         724                 : /* Do backing store read or write of a virtual sample array */
         725                 : {
         726                 :   long bytesperrow, file_offset, byte_count, rows, thisrow, i;
         727                 :
         728               0 :   bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
         729               0 :   file_offset = ptr->cur_start_row * bytesperrow;
         730                 :   /* Loop to read or write each allocation chunk in mem_buffer */
         731               0 :   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               0 :     rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
         734                 :     /* Transfer no more than is currently defined */
         735               0 :     thisrow = (long) ptr->cur_start_row + i;
         736               0 :     rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
         737                 :     /* Transfer no more than fits in file */
         738               0 :     rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
         739               0 :     if (rows <= 0)           /* this chunk might be past end of file! */
         740               0 :       break;
         741               0 :     byte_count = rows * bytesperrow;
         742               0 :     if (writing)
         743               0 :       (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
         744               0 :                                             (void FAR *) ptr->mem_buffer[i],
         745                 :                                             file_offset, byte_count);
         746                 :     else
         747               0 :       (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
         748               0 :                                            (void FAR *) ptr->mem_buffer[i],
         749                 :                                            file_offset, byte_count);
         750               0 :     file_offset += byte_count;
         751                 :   }
         752               0 : }
         753                 :
         754                 :
         755                 : LOCAL(void)
         756               0 : do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
         757                 : /* Do backing store read or write of a virtual coefficient-block array */
         758                 : {
         759                 :   long bytesperrow, file_offset, byte_count, rows, thisrow, i;
         760                 :
         761               0 :   bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
         762               0 :   file_offset = ptr->cur_start_row * bytesperrow;
         763                 :   /* Loop to read or write each allocation chunk in mem_buffer */
         764               0 :   for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
         765                 :     /* One chunk, but check for short chunk at end of buffer */
         766               0 :     rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
         767                 :     /* Transfer no more than is currently defined */
         768               0 :     thisrow = (long) ptr->cur_start_row + i;
         769               0 :     rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
         770                 :     /* Transfer no more than fits in file */
         771               0 :     rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
         772               0 :     if (rows <= 0)           /* this chunk might be past end of file! */
         773               0 :       break;
         774               0 :     byte_count = rows * bytesperrow;
         775               0 :     if (writing)
         776               0 :       (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
         777               0 :                                             (void FAR *) ptr->mem_buffer[i],
         778                 :                                             file_offset, byte_count);
         779                 :     else
         780               0 :       (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
         781               0 :                                            (void FAR *) ptr->mem_buffer[i],
         782                 :                                            file_offset, byte_count);
         783               0 :     file_offset += byte_count;
         784                 :   }
         785               0 : }
         786                 :
         787                 :
         788                 : METHODDEF(JSAMPARRAY)
         789               0 : access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
         790                 :                     JDIMENSION start_row, JDIMENSION num_rows,
         791                 :                     boolean writable)
         792                 : /* Access the part of a virtual sample array starting at start_row */
         793                 : /* and extending for num_rows rows.  writable is true if  */
         794                 : /* caller intends to modify the accessed area. */
         795                 : {
         796               0 :   JDIMENSION end_row = start_row + num_rows;
         797                 :   JDIMENSION undef_row;
         798                 :
         799                 :   /* debugging check */
         800               0 :   if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
         801               0 :       ptr->mem_buffer == NULL)
         802               0 :     ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
         803                 :
         804                 :   /* Make the desired part of the virtual array accessible */
         805               0 :   if (start_row < ptr->cur_start_row ||
         806               0 :       end_row > ptr->cur_start_row+ptr->rows_in_mem) {
         807               0 :     if (! ptr->b_s_open)
         808               0 :       ERREXIT(cinfo, JERR_VIRTUAL_BUG);
         809                 :     /* Flush old buffer contents if necessary */
         810               0 :     if (ptr->dirty) {
         811               0 :       do_sarray_io(cinfo, ptr, TRUE);
         812               0 :       ptr->dirty = FALSE;
         813                 :     }
         814                 :     /* Decide what part of virtual array to access.
         815                 :      * Algorithm: if target address > current window, assume forward scan,
         816                 :      * load starting at target address.  If target address < current window,
         817                 :      * assume backward scan, load so that target area is top of window.
         818                 :      * Note that when switching from forward write to forward read, will have
         819                 :      * start_row = 0, so the limiting case applies and we load from 0 anyway.
         820                 :      */
         821               0 :     if (start_row > ptr->cur_start_row) {
         822               0 :       ptr->cur_start_row = start_row;
         823                 :     } else {
         824                 :       /* use long arithmetic here to avoid overflow & unsigned problems */
         825                 :       long ltemp;
         826                 :
         827               0 :       ltemp = (long) end_row - (long) ptr->rows_in_mem;
         828               0 :       if (ltemp < 0)
         829               0 :         ltemp = 0;              /* don't fall off front end of file */
         830               0 :       ptr->cur_start_row = (JDIMENSION) ltemp;
         831                 :     }
         832                 :     /* Read in the selected part of the array.
         833                 :      * During the initial write pass, we will do no actual read
         834                 :      * because the selected part is all undefined.
         835                 :      */
         836               0 :     do_sarray_io(cinfo, ptr, FALSE);
         837                 :   }
         838                 :   /* Ensure the accessed part of the array is defined; prezero if needed.
         839                 :    * To improve locality of access, we only prezero the part of the array
         840                 :    * that the caller is about to access, not the entire in-memory array.
         841                 :    */
         842               0 :   if (ptr->first_undef_row < end_row) {
         843               0 :     if (ptr->first_undef_row < start_row) {
         844               0 :       if (writable)             /* writer skipped over a section of array */
         845               0 :         ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
         846               0 :       undef_row = start_row;    /* but reader is allowed to read ahead */
         847                 :     } else {
         848               0 :       undef_row = ptr->first_undef_row;
         849                 :     }
         850               0 :     if (writable)
         851               0 :       ptr->first_undef_row = end_row;
         852               0 :     if (ptr->pre_zero) {
         853               0 :       size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
         854               0 :       undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
         855               0 :       end_row -= ptr->cur_start_row;
         856               0 :       while (undef_row < end_row) {
         857               0 :         jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
         858               0 :         undef_row++;
         859                 :       }
         860                 :     } else {
         861               0 :       if (! writable)           /* reader looking at undefined data */
         862               0 :         ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
         863                 :     }
         864                 :   }
         865                 :   /* Flag the buffer dirty if caller will write in it */
         866               0 :   if (writable)
         867               0 :     ptr->dirty = TRUE;
         868                 :   /* Return address of proper part of the buffer */
         869               0 :   return ptr->mem_buffer + (start_row - ptr->cur_start_row);
         870                 : }
         871                 :
         872                 :
         873                 : METHODDEF(JBLOCKARRAY)
         874               0 : access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
         875                 :                     JDIMENSION start_row, JDIMENSION num_rows,
         876                 :                     boolean writable)
         877                 : /* Access the part of a virtual block array starting at start_row */
         878                 : /* and extending for num_rows rows.  writable is true if  */
         879                 : /* caller intends to modify the accessed area. */
         880                 : {
         881               0 :   JDIMENSION end_row = start_row + num_rows;
         882                 :   JDIMENSION undef_row;
         883                 :
         884                 :   /* debugging check */
         885               0 :   if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
         886               0 :       ptr->mem_buffer == NULL)
         887               0 :     ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
         888                 :
         889                 :   /* Make the desired part of the virtual array accessible */
         890               0 :   if (start_row < ptr->cur_start_row ||
         891               0 :       end_row > ptr->cur_start_row+ptr->rows_in_mem) {
         892               0 :     if (! ptr->b_s_open)
         893               0 :       ERREXIT(cinfo, JERR_VIRTUAL_BUG);
         894                 :     /* Flush old buffer contents if necessary */
         895               0 :     if (ptr->dirty) {
         896               0 :       do_barray_io(cinfo, ptr, TRUE);
         897               0 :       ptr->dirty = FALSE;
         898                 :     }
         899                 :     /* Decide what part of virtual array to access.
         900                 :      * Algorithm: if target address > current window, assume forward scan,
         901                 :      * load starting at target address.  If target address < current window,
         902                 :      * assume backward scan, load so that target area is top of window.
         903                 :      * Note that when switching from forward write to forward read, will have
         904                 :      * start_row = 0, so the limiting case applies and we load from 0 anyway.
         905                 :      */
         906               0 :     if (start_row > ptr->cur_start_row) {
         907               0 :       ptr->cur_start_row = start_row;
         908                 :     } else {
         909                 :       /* use long arithmetic here to avoid overflow & unsigned problems */
         910                 :       long ltemp;
         911                 :
         912               0 :       ltemp = (long) end_row - (long) ptr->rows_in_mem;
         913               0 :       if (ltemp < 0)
         914               0 :         ltemp = 0;              /* don't fall off front end of file */
         915               0 :       ptr->cur_start_row = (JDIMENSION) ltemp;
         916                 :     }
         917                 :     /* Read in the selected part of the array.
         918                 :      * During the initial write pass, we will do no actual read
         919                 :      * because the selected part is all undefined.
         920                 :      */
         921               0 :     do_barray_io(cinfo, ptr, FALSE);
         922                 :   }
         923                 :   /* Ensure the accessed part of the array is defined; prezero if needed.
         924                 :    * To improve locality of access, we only prezero the part of the array
         925                 :    * that the caller is about to access, not the entire in-memory array.
         926                 :    */
         927               0 :   if (ptr->first_undef_row < end_row) {
         928               0 :     if (ptr->first_undef_row < start_row) {
         929               0 :       if (writable)             /* writer skipped over a section of array */
         930               0 :         ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
         931               0 :       undef_row = start_row;    /* but reader is allowed to read ahead */
         932                 :     } else {
         933               0 :       undef_row = ptr->first_undef_row;
         934                 :     }
         935               0 :     if (writable)
         936               0 :       ptr->first_undef_row = end_row;
         937               0 :     if (ptr->pre_zero) {
         938               0 :       size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
         939               0 :       undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
         940               0 :       end_row -= ptr->cur_start_row;
         941               0 :       while (undef_row < end_row) {
         942               0 :         jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
         943               0 :         undef_row++;
         944                 :       }
         945                 :     } else {
         946               0 :       if (! writable)           /* reader looking at undefined data */
         947               0 :         ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
         948                 :     }
         949                 :   }
         950                 :   /* Flag the buffer dirty if caller will write in it */
         951               0 :   if (writable)
         952               0 :     ptr->dirty = TRUE;
         953                 :   /* Return address of proper part of the buffer */
         954               0 :   return ptr->mem_buffer + (start_row - ptr->cur_start_row);
         955                 : }
         956                 :
         957                 :
         958                 : /*
         959                 :  * Release all objects belonging to a specified pool.
         960                 :  */
         961                 :
         962                 : METHODDEF(void)
         963              24 : free_pool (j_common_ptr cinfo, int pool_id)
         964                 : {
         965              24 :   my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
         966                 :   small_pool_ptr shdr_ptr;
         967                 :   large_pool_ptr lhdr_ptr;
         968                 :   size_t space_freed;
         969                 :
         970              24 :   if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
         971               0 :     ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
         972                 :
         973                 : #ifdef MEM_STATS
         974                 :   if (cinfo->err->trace_level > 1)
         975                 :     print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
         976                 : #endif
         977                 :
         978                 :   /* If freeing IMAGE pool, close any virtual arrays first */
         979              24 :   if (pool_id == JPOOL_IMAGE) {
         980                 :     jvirt_sarray_ptr sptr;
         981                 :     jvirt_barray_ptr bptr;
         982                 :
         983              16 :     for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
         984               0 :       if (sptr->b_s_open) {  /* there may be no backing store */
         985               0 :         sptr->b_s_open = FALSE;      /* prevent recursive close if error */
         986               0 :         (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
         987                 :       }
         988                 :     }
         989              16 :     mem->virt_sarray_list = NULL;
         990              16 :     for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
         991               0 :       if (bptr->b_s_open) {  /* there may be no backing store */
         992               0 :         bptr->b_s_open = FALSE;      /* prevent recursive close if error */
         993               0 :         (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
         994                 :       }
         995                 :     }
         996              16 :     mem->virt_barray_list = NULL;
         997                 :   }
         998                 :
         999                 :   /* Release large objects */
        1000              24 :   lhdr_ptr = mem->large_list[pool_id];
        1001              24 :   mem->large_list[pool_id] = NULL;
        1002                 :
        1003             109 :   while (lhdr_ptr != NULL) {
        1004              61 :     large_pool_ptr next_lhdr_ptr = lhdr_ptr->next;
        1005             122 :     space_freed = lhdr_ptr->bytes_used +
        1006              61 :                   lhdr_ptr->bytes_left +
        1007                 :                   SIZEOF(large_pool_hdr);
        1008              61 :     jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
        1009              61 :     mem->total_space_allocated -= space_freed;
        1010              61 :     lhdr_ptr = next_lhdr_ptr;
        1011                 :   }
        1012                 :
        1013                 :   /* Release small objects */
        1014              24 :   shdr_ptr = mem->small_list[pool_id];
        1015              24 :   mem->small_list[pool_id] = NULL;
        1016                 :
        1017              64 :   while (shdr_ptr != NULL) {
        1018              16 :     small_pool_ptr next_shdr_ptr = shdr_ptr->next;
        1019              32 :     space_freed = shdr_ptr->bytes_used +
        1020              16 :                   shdr_ptr->bytes_left +
        1021                 :                   SIZEOF(small_pool_hdr);
        1022              16 :     jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
        1023              16 :     mem->total_space_allocated -= space_freed;
        1024              16 :     shdr_ptr = next_shdr_ptr;
        1025                 :   }
        1026              24 : }
        1027                 :
        1028                 :
        1029                 : /*
        1030                 :  * Close up shop entirely.
        1031                 :  * Note that this cannot be called unless cinfo->mem is non-NULL.
        1032                 :  */
        1033                 :
        1034                 : METHODDEF(void)
        1035               8 : self_destruct (j_common_ptr cinfo)
        1036                 : {
        1037                 :   int pool;
        1038                 :
        1039                 :   /* Close all backing store, release all memory.
        1040                 :    * Releasing pools in reverse order might help avoid fragmentation
        1041                 :    * with some (brain-damaged) malloc libraries.
        1042                 :    */
        1043              24 :   for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
        1044              16 :     free_pool(cinfo, pool);
        1045                 :   }
        1046                 :
        1047                 :   /* Release the memory manager control block too. */
        1048               8 :   jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
        1049               8 :   cinfo->mem = NULL;         /* ensures I will be called only once */
        1050                 :
        1051               8 :   jpeg_mem_term(cinfo);         /* system-dependent cleanup */
        1052               8 : }
        1053                 :
        1054                 :
        1055                 : /*
        1056                 :  * Memory manager initialization.
        1057                 :  * When this is called, only the error manager pointer is valid in cinfo!
        1058                 :  */
        1059                 :
        1060                 : GLOBAL(void)
        1061               8 : jinit_memory_mgr (j_common_ptr cinfo)
        1062                 : {
        1063                 :   my_mem_ptr mem;
        1064                 :   long max_to_use;
        1065                 :   int pool;
        1066                 :   size_t test_mac;
        1067                 :
        1068               8 :   cinfo->mem = NULL;         /* for safety if init fails */
        1069                 :
        1070                 :   /* Check for configuration errors.
        1071                 :    * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
        1072                 :    * doesn't reflect any real hardware alignment requirement.
        1073                 :    * The test is a little tricky: for X>0, X and X-1 have no one-bits
        1074                 :    * in common if and only if X is a power of 2, ie has only one one-bit.
        1075                 :    * Some compilers may give an "unreachable code" warning here; ignore it.
        1076                 :    */
        1077                 :   if ((ALIGN_SIZE & (ALIGN_SIZE-1)) != 0)
        1078                 :     ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
        1079                 :   /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
        1080                 :    * a multiple of ALIGN_SIZE.
        1081                 :    * Again, an "unreachable code" warning may be ignored here.
        1082                 :    * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
        1083                 :    */
        1084               8 :   test_mac = (size_t) MAX_ALLOC_CHUNK;
        1085               8 :   if ((long) test_mac != MAX_ALLOC_CHUNK ||
        1086                 :       (MAX_ALLOC_CHUNK % ALIGN_SIZE) != 0)
        1087               0 :     ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
        1088                 :
        1089               8 :   max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
        1090                 :
        1091                 :   /* Attempt to allocate memory manager's control block */
        1092               8 :   mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
        1093                 :
        1094               8 :   if (mem == NULL) {
        1095               0 :     jpeg_mem_term(cinfo);       /* system-dependent cleanup */
        1096               0 :     ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
        1097                 :   }
        1098                 :
        1099                 :   /* OK, fill in the method pointers */
        1100               8 :   mem->pub.alloc_small = alloc_small;
        1101               8 :   mem->pub.alloc_large = alloc_large;
        1102               8 :   mem->pub.alloc_sarray = alloc_sarray;
        1103               8 :   mem->pub.alloc_barray = alloc_barray;
        1104               8 :   mem->pub.request_virt_sarray = request_virt_sarray;
        1105               8 :   mem->pub.request_virt_barray = request_virt_barray;
        1106               8 :   mem->pub.realize_virt_arrays = realize_virt_arrays;
        1107               8 :   mem->pub.access_virt_sarray = access_virt_sarray;
        1108               8 :   mem->pub.access_virt_barray = access_virt_barray;
        1109               8 :   mem->pub.free_pool = free_pool;
        1110               8 :   mem->pub.self_destruct = self_destruct;
        1111                 :
        1112                 :   /* Make MAX_ALLOC_CHUNK accessible to other modules */
        1113               8 :   mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
        1114                 :
        1115                 :   /* Initialize working state */
        1116               8 :   mem->pub.max_memory_to_use = max_to_use;
        1117                 :
        1118              24 :   for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
        1119              16 :     mem->small_list[pool] = NULL;
        1120              16 :     mem->large_list[pool] = NULL;
        1121                 :   }
        1122               8 :   mem->virt_sarray_list = NULL;
        1123               8 :   mem->virt_barray_list = NULL;
        1124                 :
        1125               8 :   mem->total_space_allocated = SIZEOF(my_memory_mgr);
        1126                 :
        1127                 :   /* Declare ourselves open for business */
        1128               8 :   cinfo->mem = & mem->pub;
        1129                 :
        1130                 :   /* Check for an environment variable JPEGMEM; if found, override the
        1131                 :    * default max_memory setting from jpeg_mem_init.  Note that the
        1132                 :    * surrounding application may again override this value.
        1133                 :    * If your system doesn't support getenv(), define NO_GETENV to disable
        1134                 :    * this feature.
        1135                 :    */
        1136                 : #ifndef NO_GETENV
        1137                 :   { char * memenv;
        1138                 :
        1139               8 :     if ((memenv = getenv("JPEGMEM")) != NULL) {
        1140               0 :       char ch = 'x';
        1141                 :
        1142               0 :       if (sscanf(memenv, "%ld%c", &max_to_use, &ch) > 0) {
        1143               0 :         if (ch == 'm' || ch == 'M')
        1144               0 :           max_to_use *= 1000L;
        1145               0 :         mem->pub.max_memory_to_use = max_to_use * 1000L;
        1146                 :       }
        1147                 :     }
        1148                 :   }
        1149                 : #endif
        1150                 :
        1151               8 : }

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