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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