jdk

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/*
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 * reserved comment block
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 * DO NOT REMOVE OR ALTER!
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 */
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/*
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 * jmemmgr.c
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 *
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 * Copyright (C) 1991-1997, Thomas G. Lane.
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 * This file is part of the Independent JPEG Group's software.
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 * For conditions of distribution and use, see the accompanying README file.
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 *
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 * This file contains the JPEG system-independent memory management
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 * routines.  This code is usable across a wide variety of machines; most
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 * of the system dependencies have been isolated in a separate file.
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 * The major functions provided here are:
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 *   * pool-based allocation and freeing of memory;
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 *   * policy decisions about how to divide available memory among the
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 *     virtual arrays;
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 *   * control logic for swapping virtual arrays between main memory and
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 *     backing storage.
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 * The separate system-dependent file provides the actual backing-storage
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 * access code, and it contains the policy decision about how much total
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 * main memory to use.
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 * This file is system-dependent in the sense that some of its functions
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 * are unnecessary in some systems.  For example, if there is enough virtual
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 * memory so that backing storage will never be used, much of the virtual
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 * array control logic could be removed.  (Of course, if you have that much
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 * memory then you shouldn't care about a little bit of unused code...)
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 */
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#define JPEG_INTERNALS
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#define AM_MEMORY_MANAGER       /* we define jvirt_Xarray_control structs */
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#include "jinclude.h"
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#include "jpeglib.h"
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#include "jmemsys.h"            /* import the system-dependent declarations */
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#ifndef NO_GETENV
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#ifndef HAVE_STDLIB_H           /* <stdlib.h> should declare getenv() */
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extern char * getenv JPP((const char * name));
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#endif
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#endif
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43

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/*
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 * Some important notes:
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 *   The allocation routines provided here must never return NULL.
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 *   They should exit to error_exit if unsuccessful.
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 *
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 *   It's not a good idea to try to merge the sarray and barray routines,
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 *   even though they are textually almost the same, because samples are
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 *   usually stored as bytes while coefficients are shorts or ints.  Thus,
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 *   in machines where byte pointers have a different representation from
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 *   word pointers, the resulting machine code could not be the same.
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 */
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56

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/*
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 * Many machines require storage alignment: longs must start on 4-byte
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 * boundaries, doubles on 8-byte boundaries, etc.  On such machines, malloc()
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 * always returns pointers that are multiples of the worst-case alignment
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 * requirement, and we had better do so too.
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 * There isn't any really portable way to determine the worst-case alignment
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 * requirement.  This module assumes that the alignment requirement is
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 * multiples of sizeof(ALIGN_TYPE).
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 * By default, we define ALIGN_TYPE as double.  This is necessary on some
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 * workstations (where doubles really do need 8-byte alignment) and will work
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 * fine on nearly everything.  If your machine has lesser alignment needs,
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 * you can save a few bytes by making ALIGN_TYPE smaller.
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 * The only place I know of where this will NOT work is certain Macintosh
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 * 680x0 compilers that define double as a 10-byte IEEE extended float.
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 * Doing 10-byte alignment is counterproductive because longwords won't be
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 * aligned well.  Put "#define ALIGN_TYPE long" in jconfig.h if you have
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 * such a compiler.
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 */
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#ifndef ALIGN_TYPE              /* so can override from jconfig.h */
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#define ALIGN_TYPE  double
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#endif
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80

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/*
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 * We allocate objects from "pools", where each pool is gotten with a single
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 * request to jpeg_get_small() or jpeg_get_large().  There is no per-object
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 * overhead within a pool, except for alignment padding.  Each pool has a
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 * header with a link to the next pool of the same class.
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 * Small and large pool headers are identical except that the latter's
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 * link pointer must be FAR on 80x86 machines.
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 * Notice that the "real" header fields are union'ed with a dummy ALIGN_TYPE
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 * field.  This forces the compiler to make SIZEOF(small_pool_hdr) a multiple
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 * of the alignment requirement of ALIGN_TYPE.
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 */
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typedef union small_pool_struct * small_pool_ptr;
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typedef union small_pool_struct {
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  struct {
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    small_pool_ptr next;        /* next in list of pools */
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    size_t bytes_used;          /* how many bytes already used within pool */
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    size_t bytes_left;          /* bytes still available in this pool */
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  } hdr;
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  ALIGN_TYPE dummy;             /* included in union to ensure alignment */
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} small_pool_hdr;
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typedef union large_pool_struct FAR * large_pool_ptr;
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typedef union large_pool_struct {
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  struct {
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    large_pool_ptr next;        /* next in list of pools */
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    size_t bytes_used;          /* how many bytes already used within pool */
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    size_t bytes_left;          /* bytes still available in this pool */
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  } hdr;
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  ALIGN_TYPE dummy;             /* included in union to ensure alignment */
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} large_pool_hdr;
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115

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/*
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 * Here is the full definition of a memory manager object.
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 */
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typedef struct {
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  struct jpeg_memory_mgr pub;   /* public fields */
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  /* Each pool identifier (lifetime class) names a linked list of pools. */
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  small_pool_ptr small_list[JPOOL_NUMPOOLS];
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  large_pool_ptr large_list[JPOOL_NUMPOOLS];
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  /* Since we only have one lifetime class of virtual arrays, only one
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   * linked list is necessary (for each datatype).  Note that the virtual
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   * array control blocks being linked together are actually stored somewhere
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   * in the small-pool list.
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   */
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  jvirt_sarray_ptr virt_sarray_list;
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  jvirt_barray_ptr virt_barray_list;
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  /* This counts total space obtained from jpeg_get_small/large */
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  size_t total_space_allocated;
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  /* alloc_sarray and alloc_barray set this value for use by virtual
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   * array routines.
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   */
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  JDIMENSION last_rowsperchunk; /* from most recent alloc_sarray/barray */
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} my_memory_mgr;
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typedef my_memory_mgr * my_mem_ptr;
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146

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/*
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 * The control blocks for virtual arrays.
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 * Note that these blocks are allocated in the "small" pool area.
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 * System-dependent info for the associated backing store (if any) is hidden
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 * inside the backing_store_info struct.
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 */
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struct jvirt_sarray_control {
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  JSAMPARRAY mem_buffer;        /* => the in-memory buffer */
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  JDIMENSION rows_in_array;     /* total virtual array height */
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  JDIMENSION samplesperrow;     /* width of array (and of memory buffer) */
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  JDIMENSION maxaccess;         /* max rows accessed by access_virt_sarray */
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  JDIMENSION rows_in_mem;       /* height of memory buffer */
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  JDIMENSION rowsperchunk;      /* allocation chunk size in mem_buffer */
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  JDIMENSION cur_start_row;     /* first logical row # in the buffer */
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  JDIMENSION first_undef_row;   /* row # of first uninitialized row */
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  boolean pre_zero;             /* pre-zero mode requested? */
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  boolean dirty;                /* do current buffer contents need written? */
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  boolean b_s_open;             /* is backing-store data valid? */
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  jvirt_sarray_ptr next;        /* link to next virtual sarray control block */
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  backing_store_info b_s_info;  /* System-dependent control info */
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};
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struct jvirt_barray_control {
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  JBLOCKARRAY mem_buffer;       /* => the in-memory buffer */
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  JDIMENSION rows_in_array;     /* total virtual array height */
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  JDIMENSION blocksperrow;      /* width of array (and of memory buffer) */
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  JDIMENSION maxaccess;         /* max rows accessed by access_virt_barray */
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  JDIMENSION rows_in_mem;       /* height of memory buffer */
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  JDIMENSION rowsperchunk;      /* allocation chunk size in mem_buffer */
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  JDIMENSION cur_start_row;     /* first logical row # in the buffer */
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  JDIMENSION first_undef_row;   /* row # of first uninitialized row */
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  boolean pre_zero;             /* pre-zero mode requested? */
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  boolean dirty;                /* do current buffer contents need written? */
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  boolean b_s_open;             /* is backing-store data valid? */
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  jvirt_barray_ptr next;        /* link to next virtual barray control block */
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  backing_store_info b_s_info;  /* System-dependent control info */
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};
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186

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#ifdef MEM_STATS                /* optional extra stuff for statistics */
188

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LOCAL(void)
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print_mem_stats (j_common_ptr cinfo, int pool_id)
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{
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  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
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  small_pool_ptr shdr_ptr;
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  large_pool_ptr lhdr_ptr;
195

196
  /* Since this is only a debugging stub, we can cheat a little by using
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   * fprintf directly rather than going through the trace message code.
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   * This is helpful because message parm array can't handle longs.
199
   */
200
  fprintf(stderr, "Freeing pool %d, total space = %ld\n",
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          pool_id, mem->total_space_allocated);
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203
  for (lhdr_ptr = mem->large_list[pool_id]; lhdr_ptr != NULL;
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       lhdr_ptr = lhdr_ptr->hdr.next) {
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    fprintf(stderr, "  Large chunk used %ld\n",
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            (long) lhdr_ptr->hdr.bytes_used);
207
  }
208

209
  for (shdr_ptr = mem->small_list[pool_id]; shdr_ptr != NULL;
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       shdr_ptr = shdr_ptr->hdr.next) {
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    fprintf(stderr, "  Small chunk used %ld free %ld\n",
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            (long) shdr_ptr->hdr.bytes_used,
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            (long) shdr_ptr->hdr.bytes_left);
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  }
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}
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#endif /* MEM_STATS */
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LOCAL(void)
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out_of_memory (j_common_ptr cinfo, int which)
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/* Report an out-of-memory error and stop execution */
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/* If we compiled MEM_STATS support, report alloc requests before dying */
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{
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#ifdef MEM_STATS
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  cinfo->err->trace_level = 2;  /* force self_destruct to report stats */
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#endif
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  ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, which);
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}
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/*
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 * Allocation of "small" objects.
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 *
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 * For these, we use pooled storage.  When a new pool must be created,
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 * we try to get enough space for the current request plus a "slop" factor,
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 * where the slop will be the amount of leftover space in the new pool.
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 * The speed vs. space tradeoff is largely determined by the slop values.
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 * A different slop value is provided for each pool class (lifetime),
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 * and we also distinguish the first pool of a class from later ones.
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 * NOTE: the values given work fairly well on both 16- and 32-bit-int
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 * machines, but may be too small if longs are 64 bits or more.
243
 */
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static const size_t first_pool_slop[JPOOL_NUMPOOLS] =
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{
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        1600,                   /* first PERMANENT pool */
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        16000                   /* first IMAGE pool */
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};
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static const size_t extra_pool_slop[JPOOL_NUMPOOLS] =
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{
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        0,                      /* additional PERMANENT pools */
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        5000                    /* additional IMAGE pools */
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};
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#define MIN_SLOP  50            /* greater than 0 to avoid futile looping */
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METHODDEF(void *)
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alloc_small (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
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/* Allocate a "small" object */
263
{
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  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
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  small_pool_ptr hdr_ptr, prev_hdr_ptr;
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  char * data_ptr;
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  size_t odd_bytes, min_request, slop;
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269
  /* Check for unsatisfiable request (do now to ensure no overflow below) */
270
  if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(small_pool_hdr)))
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    out_of_memory(cinfo, 1);    /* request exceeds malloc's ability */
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  /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
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  odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
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  if (odd_bytes > 0)
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    sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
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  /* See if space is available in any existing pool */
279
  if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
280
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
281
  prev_hdr_ptr = NULL;
282
  hdr_ptr = mem->small_list[pool_id];
283
  while (hdr_ptr != NULL) {
284
    if (hdr_ptr->hdr.bytes_left >= sizeofobject)
285
      break;                    /* found pool with enough space */
286
    prev_hdr_ptr = hdr_ptr;
287
    hdr_ptr = hdr_ptr->hdr.next;
288
  }
289

290
  /* Time to make a new pool? */
291
  if (hdr_ptr == NULL) {
292
    /* min_request is what we need now, slop is what will be leftover */
293
    min_request = sizeofobject + SIZEOF(small_pool_hdr);
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    if (prev_hdr_ptr == NULL)   /* first pool in class? */
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      slop = first_pool_slop[pool_id];
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    else
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      slop = extra_pool_slop[pool_id];
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    /* Don't ask for more than MAX_ALLOC_CHUNK */
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    if (slop > (size_t) (MAX_ALLOC_CHUNK-min_request))
300
      slop = (size_t) (MAX_ALLOC_CHUNK-min_request);
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    /* Try to get space, if fail reduce slop and try again */
302
    for (;;) {
303
      hdr_ptr = (small_pool_ptr) jpeg_get_small(cinfo, min_request + slop);
304
      if (hdr_ptr != NULL)
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        break;
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      slop /= 2;
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      if (slop < MIN_SLOP)      /* give up when it gets real small */
308
        out_of_memory(cinfo, 2); /* jpeg_get_small failed */
309
    }
310
    mem->total_space_allocated += min_request + slop;
311
    /* Success, initialize the new pool header and add to end of list */
312
    hdr_ptr->hdr.next = NULL;
313
    hdr_ptr->hdr.bytes_used = 0;
314
    hdr_ptr->hdr.bytes_left = sizeofobject + slop;
315
    if (prev_hdr_ptr == NULL)   /* first pool in class? */
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      mem->small_list[pool_id] = hdr_ptr;
317
    else
318
      prev_hdr_ptr->hdr.next = hdr_ptr;
319
  }
320

321
  /* OK, allocate the object from the current pool */
322
  data_ptr = (char *) (hdr_ptr + 1); /* point to first data byte in pool */
323
  data_ptr += hdr_ptr->hdr.bytes_used; /* point to place for object */
324
  hdr_ptr->hdr.bytes_used += sizeofobject;
325
  hdr_ptr->hdr.bytes_left -= sizeofobject;
326

327
  return (void *) data_ptr;
328
}
329

330

331
/*
332
 * Allocation of "large" objects.
333
 *
334
 * The external semantics of these are the same as "small" objects,
335
 * except that FAR pointers are used on 80x86.  However the pool
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 * management heuristics are quite different.  We assume that each
337
 * request is large enough that it may as well be passed directly to
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 * jpeg_get_large; the pool management just links everything together
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 * so that we can free it all on demand.
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 * Note: the major use of "large" objects is in JSAMPARRAY and JBLOCKARRAY
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 * structures.  The routines that create these structures (see below)
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 * deliberately bunch rows together to ensure a large request size.
343
 */
344

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METHODDEF(void FAR *)
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alloc_large (j_common_ptr cinfo, int pool_id, size_t sizeofobject)
347
/* Allocate a "large" object */
348
{
349
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
350
  large_pool_ptr hdr_ptr;
351
  size_t odd_bytes;
352

353
  /* Check for unsatisfiable request (do now to ensure no overflow below) */
354
  if (sizeofobject > (size_t) (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)))
355
    out_of_memory(cinfo, 3);    /* request exceeds malloc's ability */
356

357
  /* Round up the requested size to a multiple of SIZEOF(ALIGN_TYPE) */
358
  odd_bytes = sizeofobject % SIZEOF(ALIGN_TYPE);
359
  if (odd_bytes > 0)
360
    sizeofobject += SIZEOF(ALIGN_TYPE) - odd_bytes;
361

362
  /* Always make a new pool */
363
  if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
364
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
365

366
  hdr_ptr = (large_pool_ptr) jpeg_get_large(cinfo, sizeofobject +
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                                            SIZEOF(large_pool_hdr));
368
  if (hdr_ptr == NULL)
369
    out_of_memory(cinfo, 4);    /* jpeg_get_large failed */
370
  mem->total_space_allocated += sizeofobject + SIZEOF(large_pool_hdr);
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372
  /* Success, initialize the new pool header and add to list */
373
  hdr_ptr->hdr.next = mem->large_list[pool_id];
374
  /* We maintain space counts in each pool header for statistical purposes,
375
   * even though they are not needed for allocation.
376
   */
377
  hdr_ptr->hdr.bytes_used = sizeofobject;
378
  hdr_ptr->hdr.bytes_left = 0;
379
  mem->large_list[pool_id] = hdr_ptr;
380

381
  return (void FAR *) (hdr_ptr + 1); /* point to first data byte in pool */
382
}
383

384

385
/*
386
 * Creation of 2-D sample arrays.
387
 * The pointers are in near heap, the samples themselves in FAR heap.
388
 *
389
 * To minimize allocation overhead and to allow I/O of large contiguous
390
 * blocks, we allocate the sample rows in groups of as many rows as possible
391
 * without exceeding MAX_ALLOC_CHUNK total bytes per allocation request.
392
 * NB: the virtual array control routines, later in this file, know about
393
 * this chunking of rows.  The rowsperchunk value is left in the mem manager
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 * object so that it can be saved away if this sarray is the workspace for
395
 * a virtual array.
396
 */
397

398
METHODDEF(JSAMPARRAY)
399
alloc_sarray (j_common_ptr cinfo, int pool_id,
400
              JDIMENSION samplesperrow, JDIMENSION numrows)
401
/* Allocate a 2-D sample array */
402
{
403
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
404
  JSAMPARRAY result;
405
  JSAMPROW workspace;
406
  JDIMENSION rowsperchunk, currow, i;
407
  long ltemp;
408

409
  if (samplesperrow == 0) {
410
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
411
  }
412
  /* Calculate max # of rows allowed in one allocation chunk */
413
  ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
414
          ((long) samplesperrow * SIZEOF(JSAMPLE));
415
  if (ltemp <= 0)
416
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
417
  if (ltemp < (long) numrows)
418
    rowsperchunk = (JDIMENSION) ltemp;
419
  else
420
    rowsperchunk = numrows;
421
  mem->last_rowsperchunk = rowsperchunk;
422

423
  /* Get space for row pointers (small object) */
424
  result = (JSAMPARRAY) alloc_small(cinfo, pool_id,
425
                                    (size_t) (numrows * SIZEOF(JSAMPROW)));
426

427
  /* Get the rows themselves (large objects) */
428
  currow = 0;
429
  while (currow < numrows) {
430
    rowsperchunk = MIN(rowsperchunk, numrows - currow);
431
    workspace = (JSAMPROW) alloc_large(cinfo, pool_id,
432
        (size_t) ((size_t) rowsperchunk * (size_t) samplesperrow
433
                  * SIZEOF(JSAMPLE)));
434
    for (i = rowsperchunk; i > 0; i--) {
435
      result[currow++] = workspace;
436
      workspace += samplesperrow;
437
    }
438
  }
439

440
  return result;
441
}
442

443

444
/*
445
 * Creation of 2-D coefficient-block arrays.
446
 * This is essentially the same as the code for sample arrays, above.
447
 */
448

449
METHODDEF(JBLOCKARRAY)
450
alloc_barray (j_common_ptr cinfo, int pool_id,
451
              JDIMENSION blocksperrow, JDIMENSION numrows)
452
/* Allocate a 2-D coefficient-block array */
453
{
454
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
455
  JBLOCKARRAY result;
456
  JBLOCKROW workspace;
457
  JDIMENSION rowsperchunk, currow, i;
458
  long ltemp;
459

460
  if (blocksperrow == 0) {
461
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
462
  }
463

464
  /* Calculate max # of rows allowed in one allocation chunk */
465
  ltemp = (MAX_ALLOC_CHUNK-SIZEOF(large_pool_hdr)) /
466
          ((long) blocksperrow * SIZEOF(JBLOCK));
467
  if (ltemp <= 0)
468
    ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
469
  if (ltemp < (long) numrows)
470
    rowsperchunk = (JDIMENSION) ltemp;
471
  else
472
    rowsperchunk = numrows;
473
  mem->last_rowsperchunk = rowsperchunk;
474

475
  /* Get space for row pointers (small object) */
476
  result = (JBLOCKARRAY) alloc_small(cinfo, pool_id,
477
                                     (size_t) (numrows * SIZEOF(JBLOCKROW)));
478

479
  /* Get the rows themselves (large objects) */
480
  currow = 0;
481
  while (currow < numrows) {
482
    rowsperchunk = MIN(rowsperchunk, numrows - currow);
483
    workspace = (JBLOCKROW) alloc_large(cinfo, pool_id,
484
        (size_t) ((size_t) rowsperchunk * (size_t) blocksperrow
485
                  * SIZEOF(JBLOCK)));
486
    for (i = rowsperchunk; i > 0; i--) {
487
      result[currow++] = workspace;
488
      workspace += blocksperrow;
489
    }
490
  }
491

492
  return result;
493
}
494

495

496
/*
497
 * About virtual array management:
498
 *
499
 * The above "normal" array routines are only used to allocate strip buffers
500
 * (as wide as the image, but just a few rows high).  Full-image-sized buffers
501
 * are handled as "virtual" arrays.  The array is still accessed a strip at a
502
 * time, but the memory manager must save the whole array for repeated
503
 * accesses.  The intended implementation is that there is a strip buffer in
504
 * memory (as high as is possible given the desired memory limit), plus a
505
 * backing file that holds the rest of the array.
506
 *
507
 * The request_virt_array routines are told the total size of the image and
508
 * the maximum number of rows that will be accessed at once.  The in-memory
509
 * buffer must be at least as large as the maxaccess value.
510
 *
511
 * The request routines create control blocks but not the in-memory buffers.
512
 * That is postponed until realize_virt_arrays is called.  At that time the
513
 * total amount of space needed is known (approximately, anyway), so free
514
 * memory can be divided up fairly.
515
 *
516
 * The access_virt_array routines are responsible for making a specific strip
517
 * area accessible (after reading or writing the backing file, if necessary).
518
 * Note that the access routines are told whether the caller intends to modify
519
 * the accessed strip; during a read-only pass this saves having to rewrite
520
 * data to disk.  The access routines are also responsible for pre-zeroing
521
 * any newly accessed rows, if pre-zeroing was requested.
522
 *
523
 * In current usage, the access requests are usually for nonoverlapping
524
 * strips; that is, successive access start_row numbers differ by exactly
525
 * num_rows = maxaccess.  This means we can get good performance with simple
526
 * buffer dump/reload logic, by making the in-memory buffer be a multiple
527
 * of the access height; then there will never be accesses across bufferload
528
 * boundaries.  The code will still work with overlapping access requests,
529
 * but it doesn't handle bufferload overlaps very efficiently.
530
 */
531

532

533
METHODDEF(jvirt_sarray_ptr)
534
request_virt_sarray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
535
                     JDIMENSION samplesperrow, JDIMENSION numrows,
536
                     JDIMENSION maxaccess)
537
/* Request a virtual 2-D sample array */
538
{
539
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
540
  jvirt_sarray_ptr result;
541

542
  /* Only IMAGE-lifetime virtual arrays are currently supported */
543
  if (pool_id != JPOOL_IMAGE)
544
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
545

546
  /* get control block */
547
  result = (jvirt_sarray_ptr) alloc_small(cinfo, pool_id,
548
                                          SIZEOF(struct jvirt_sarray_control));
549

550
  result->mem_buffer = NULL;    /* marks array not yet realized */
551
  result->rows_in_array = numrows;
552
  result->samplesperrow = samplesperrow;
553
  result->maxaccess = maxaccess;
554
  result->pre_zero = pre_zero;
555
  result->b_s_open = FALSE;     /* no associated backing-store object */
556
  result->next = mem->virt_sarray_list; /* add to list of virtual arrays */
557
  mem->virt_sarray_list = result;
558

559
  return result;
560
}
561

562

563
METHODDEF(jvirt_barray_ptr)
564
request_virt_barray (j_common_ptr cinfo, int pool_id, boolean pre_zero,
565
                     JDIMENSION blocksperrow, JDIMENSION numrows,
566
                     JDIMENSION maxaccess)
567
/* Request a virtual 2-D coefficient-block array */
568
{
569
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
570
  jvirt_barray_ptr result;
571

572
  /* Only IMAGE-lifetime virtual arrays are currently supported */
573
  if (pool_id != JPOOL_IMAGE)
574
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
575

576
  /* get control block */
577
  result = (jvirt_barray_ptr) alloc_small(cinfo, pool_id,
578
                                          SIZEOF(struct jvirt_barray_control));
579

580
  result->mem_buffer = NULL;    /* marks array not yet realized */
581
  result->rows_in_array = numrows;
582
  result->blocksperrow = blocksperrow;
583
  result->maxaccess = maxaccess;
584
  result->pre_zero = pre_zero;
585
  result->b_s_open = FALSE;     /* no associated backing-store object */
586
  result->next = mem->virt_barray_list; /* add to list of virtual arrays */
587
  mem->virt_barray_list = result;
588

589
  return result;
590
}
591

592

593
METHODDEF(void)
594
realize_virt_arrays (j_common_ptr cinfo)
595
/* Allocate the in-memory buffers for any unrealized virtual arrays */
596
{
597
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
598
  size_t space_per_minheight, maximum_space, avail_mem;
599
  size_t minheights, max_minheights;
600
  jvirt_sarray_ptr sptr;
601
  jvirt_barray_ptr bptr;
602

603
  /* Compute the minimum space needed (maxaccess rows in each buffer)
604
   * and the maximum space needed (full image height in each buffer).
605
   * These may be of use to the system-dependent jpeg_mem_available routine.
606
   */
607
  space_per_minheight = 0;
608
  maximum_space = 0;
609
  for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
610
    if (sptr->mem_buffer == NULL) { /* if not realized yet */
611
      space_per_minheight += (long) sptr->maxaccess *
612
                             (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
613
      maximum_space += (long) sptr->rows_in_array *
614
                       (long) sptr->samplesperrow * SIZEOF(JSAMPLE);
615
    }
616
  }
617
  for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
618
    if (bptr->mem_buffer == NULL) { /* if not realized yet */
619
      space_per_minheight += (long) bptr->maxaccess *
620
                             (long) bptr->blocksperrow * SIZEOF(JBLOCK);
621
      maximum_space += (long) bptr->rows_in_array *
622
                       (long) bptr->blocksperrow * SIZEOF(JBLOCK);
623
    }
624
  }
625

626
  if (space_per_minheight <= 0)
627
    return;                     /* no unrealized arrays, no work */
628

629
  /* Determine amount of memory to actually use; this is system-dependent. */
630
  avail_mem = jpeg_mem_available(cinfo, space_per_minheight, maximum_space,
631
                                 mem->total_space_allocated);
632

633
  /* If the maximum space needed is available, make all the buffers full
634
   * height; otherwise parcel it out with the same number of minheights
635
   * in each buffer.
636
   */
637
  if (avail_mem >= maximum_space)
638
    max_minheights = 1000000000L;
639
  else {
640
    max_minheights = avail_mem / space_per_minheight;
641
    /* If there doesn't seem to be enough space, try to get the minimum
642
     * anyway.  This allows a "stub" implementation of jpeg_mem_available().
643
     */
644
    if (max_minheights <= 0)
645
      max_minheights = 1;
646
  }
647

648
  /* Allocate the in-memory buffers and initialize backing store as needed. */
649

650
  for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
651
    if (sptr->mem_buffer == NULL) { /* if not realized yet */
652
      minheights = ((long) sptr->rows_in_array - 1L) / sptr->maxaccess + 1L;
653
      if (minheights <= max_minheights) {
654
        /* This buffer fits in memory */
655
        sptr->rows_in_mem = sptr->rows_in_array;
656
      } else {
657
        /* It doesn't fit in memory, create backing store. */
658
        sptr->rows_in_mem = (JDIMENSION) (max_minheights * sptr->maxaccess);
659
        jpeg_open_backing_store(cinfo, & sptr->b_s_info,
660
                                (long) sptr->rows_in_array *
661
                                (long) sptr->samplesperrow *
662
                                (long) SIZEOF(JSAMPLE));
663
        sptr->b_s_open = TRUE;
664
      }
665
      sptr->mem_buffer = alloc_sarray(cinfo, JPOOL_IMAGE,
666
                                      sptr->samplesperrow, sptr->rows_in_mem);
667
      sptr->rowsperchunk = mem->last_rowsperchunk;
668
      sptr->cur_start_row = 0;
669
      sptr->first_undef_row = 0;
670
      sptr->dirty = FALSE;
671
    }
672
  }
673

674
  for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
675
    if (bptr->mem_buffer == NULL) { /* if not realized yet */
676
      minheights = ((long) bptr->rows_in_array - 1L) / bptr->maxaccess + 1L;
677
      if (minheights <= max_minheights) {
678
        /* This buffer fits in memory */
679
        bptr->rows_in_mem = bptr->rows_in_array;
680
      } else {
681
        /* It doesn't fit in memory, create backing store. */
682
        bptr->rows_in_mem = (JDIMENSION) (max_minheights * bptr->maxaccess);
683
        jpeg_open_backing_store(cinfo, & bptr->b_s_info,
684
                                (long) bptr->rows_in_array *
685
                                (long) bptr->blocksperrow *
686
                                (long) SIZEOF(JBLOCK));
687
        bptr->b_s_open = TRUE;
688
      }
689
      bptr->mem_buffer = alloc_barray(cinfo, JPOOL_IMAGE,
690
                                      bptr->blocksperrow, bptr->rows_in_mem);
691
      bptr->rowsperchunk = mem->last_rowsperchunk;
692
      bptr->cur_start_row = 0;
693
      bptr->first_undef_row = 0;
694
      bptr->dirty = FALSE;
695
    }
696
  }
697
}
698

699

700
LOCAL(void)
701
do_sarray_io (j_common_ptr cinfo, jvirt_sarray_ptr ptr, boolean writing)
702
/* Do backing store read or write of a virtual sample array */
703
{
704
  long bytesperrow, file_offset, byte_count, rows, thisrow, i;
705

706
  bytesperrow = (long) ptr->samplesperrow * SIZEOF(JSAMPLE);
707
  file_offset = ptr->cur_start_row * bytesperrow;
708
  /* Loop to read or write each allocation chunk in mem_buffer */
709
  for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
710
    /* One chunk, but check for short chunk at end of buffer */
711
    rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
712
    /* Transfer no more than is currently defined */
713
    thisrow = (long) ptr->cur_start_row + i;
714
    rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
715
    /* Transfer no more than fits in file */
716
    rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
717
    if (rows <= 0)              /* this chunk might be past end of file! */
718
      break;
719
    byte_count = rows * bytesperrow;
720
    if (writing)
721
      (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
722
                                            (void FAR *) ptr->mem_buffer[i],
723
                                            file_offset, byte_count);
724
    else
725
      (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
726
                                           (void FAR *) ptr->mem_buffer[i],
727
                                           file_offset, byte_count);
728
    file_offset += byte_count;
729
  }
730
}
731

732

733
LOCAL(void)
734
do_barray_io (j_common_ptr cinfo, jvirt_barray_ptr ptr, boolean writing)
735
/* Do backing store read or write of a virtual coefficient-block array */
736
{
737
  long bytesperrow, file_offset, byte_count, rows, thisrow, i;
738

739
  bytesperrow = (long) ptr->blocksperrow * SIZEOF(JBLOCK);
740
  file_offset = ptr->cur_start_row * bytesperrow;
741
  /* Loop to read or write each allocation chunk in mem_buffer */
742
  for (i = 0; i < (long) ptr->rows_in_mem; i += ptr->rowsperchunk) {
743
    /* One chunk, but check for short chunk at end of buffer */
744
    rows = MIN((long) ptr->rowsperchunk, (long) ptr->rows_in_mem - i);
745
    /* Transfer no more than is currently defined */
746
    thisrow = (long) ptr->cur_start_row + i;
747
    rows = MIN(rows, (long) ptr->first_undef_row - thisrow);
748
    /* Transfer no more than fits in file */
749
    rows = MIN(rows, (long) ptr->rows_in_array - thisrow);
750
    if (rows <= 0)              /* this chunk might be past end of file! */
751
      break;
752
    byte_count = rows * bytesperrow;
753
    if (writing)
754
      (*ptr->b_s_info.write_backing_store) (cinfo, & ptr->b_s_info,
755
                                            (void FAR *) ptr->mem_buffer[i],
756
                                            file_offset, byte_count);
757
    else
758
      (*ptr->b_s_info.read_backing_store) (cinfo, & ptr->b_s_info,
759
                                           (void FAR *) ptr->mem_buffer[i],
760
                                           file_offset, byte_count);
761
    file_offset += byte_count;
762
  }
763
}
764

765

766
METHODDEF(JSAMPARRAY)
767
access_virt_sarray (j_common_ptr cinfo, jvirt_sarray_ptr ptr,
768
                    JDIMENSION start_row, JDIMENSION num_rows,
769
                    boolean writable)
770
/* Access the part of a virtual sample array starting at start_row */
771
/* and extending for num_rows rows.  writable is true if  */
772
/* caller intends to modify the accessed area. */
773
{
774
  JDIMENSION end_row = start_row + num_rows;
775
  JDIMENSION undef_row;
776

777
  /* debugging check */
778
  if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
779
      ptr->mem_buffer == NULL)
780
    ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
781

782
  /* Make the desired part of the virtual array accessible */
783
  if (start_row < ptr->cur_start_row ||
784
      end_row > ptr->cur_start_row+ptr->rows_in_mem) {
785
    if (! ptr->b_s_open)
786
      ERREXIT(cinfo, JERR_VIRTUAL_BUG);
787
    /* Flush old buffer contents if necessary */
788
    if (ptr->dirty) {
789
      do_sarray_io(cinfo, ptr, TRUE);
790
      ptr->dirty = FALSE;
791
    }
792
    /* Decide what part of virtual array to access.
793
     * Algorithm: if target address > current window, assume forward scan,
794
     * load starting at target address.  If target address < current window,
795
     * assume backward scan, load so that target area is top of window.
796
     * Note that when switching from forward write to forward read, will have
797
     * start_row = 0, so the limiting case applies and we load from 0 anyway.
798
     */
799
    if (start_row > ptr->cur_start_row) {
800
      ptr->cur_start_row = start_row;
801
    } else {
802
      /* use long arithmetic here to avoid overflow & unsigned problems */
803
      long ltemp;
804

805
      ltemp = (long) end_row - (long) ptr->rows_in_mem;
806
      if (ltemp < 0)
807
        ltemp = 0;              /* don't fall off front end of file */
808
      ptr->cur_start_row = (JDIMENSION) ltemp;
809
    }
810
    /* Read in the selected part of the array.
811
     * During the initial write pass, we will do no actual read
812
     * because the selected part is all undefined.
813
     */
814
    do_sarray_io(cinfo, ptr, FALSE);
815
  }
816
  /* Ensure the accessed part of the array is defined; prezero if needed.
817
   * To improve locality of access, we only prezero the part of the array
818
   * that the caller is about to access, not the entire in-memory array.
819
   */
820
  if (ptr->first_undef_row < end_row) {
821
    if (ptr->first_undef_row < start_row) {
822
      if (writable)             /* writer skipped over a section of array */
823
        ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
824
      undef_row = start_row;    /* but reader is allowed to read ahead */
825
    } else {
826
      undef_row = ptr->first_undef_row;
827
    }
828
    if (writable)
829
      ptr->first_undef_row = end_row;
830
    if (ptr->pre_zero) {
831
      size_t bytesperrow = (size_t) ptr->samplesperrow * SIZEOF(JSAMPLE);
832
      undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
833
      end_row -= ptr->cur_start_row;
834
      while (undef_row < end_row) {
835
        jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
836
        undef_row++;
837
      }
838
    } else {
839
      if (! writable)           /* reader looking at undefined data */
840
        ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
841
    }
842
  }
843
  /* Flag the buffer dirty if caller will write in it */
844
  if (writable)
845
    ptr->dirty = TRUE;
846
  /* Return address of proper part of the buffer */
847
  return ptr->mem_buffer + (start_row - ptr->cur_start_row);
848
}
849

850

851
METHODDEF(JBLOCKARRAY)
852
access_virt_barray (j_common_ptr cinfo, jvirt_barray_ptr ptr,
853
                    JDIMENSION start_row, JDIMENSION num_rows,
854
                    boolean writable)
855
/* Access the part of a virtual block array starting at start_row */
856
/* and extending for num_rows rows.  writable is true if  */
857
/* caller intends to modify the accessed area. */
858
{
859
  JDIMENSION end_row = start_row + num_rows;
860
  JDIMENSION undef_row;
861

862
  /* debugging check */
863
  if (end_row > ptr->rows_in_array || num_rows > ptr->maxaccess ||
864
      ptr->mem_buffer == NULL)
865
    ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
866

867
  /* Make the desired part of the virtual array accessible */
868
  if (start_row < ptr->cur_start_row ||
869
      end_row > ptr->cur_start_row+ptr->rows_in_mem) {
870
    if (! ptr->b_s_open)
871
      ERREXIT(cinfo, JERR_VIRTUAL_BUG);
872
    /* Flush old buffer contents if necessary */
873
    if (ptr->dirty) {
874
      do_barray_io(cinfo, ptr, TRUE);
875
      ptr->dirty = FALSE;
876
    }
877
    /* Decide what part of virtual array to access.
878
     * Algorithm: if target address > current window, assume forward scan,
879
     * load starting at target address.  If target address < current window,
880
     * assume backward scan, load so that target area is top of window.
881
     * Note that when switching from forward write to forward read, will have
882
     * start_row = 0, so the limiting case applies and we load from 0 anyway.
883
     */
884
    if (start_row > ptr->cur_start_row) {
885
      ptr->cur_start_row = start_row;
886
    } else {
887
      /* use long arithmetic here to avoid overflow & unsigned problems */
888
      long ltemp;
889

890
      ltemp = (long) end_row - (long) ptr->rows_in_mem;
891
      if (ltemp < 0)
892
        ltemp = 0;              /* don't fall off front end of file */
893
      ptr->cur_start_row = (JDIMENSION) ltemp;
894
    }
895
    /* Read in the selected part of the array.
896
     * During the initial write pass, we will do no actual read
897
     * because the selected part is all undefined.
898
     */
899
    do_barray_io(cinfo, ptr, FALSE);
900
  }
901
  /* Ensure the accessed part of the array is defined; prezero if needed.
902
   * To improve locality of access, we only prezero the part of the array
903
   * that the caller is about to access, not the entire in-memory array.
904
   */
905
  if (ptr->first_undef_row < end_row) {
906
    if (ptr->first_undef_row < start_row) {
907
      if (writable)             /* writer skipped over a section of array */
908
        ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
909
      undef_row = start_row;    /* but reader is allowed to read ahead */
910
    } else {
911
      undef_row = ptr->first_undef_row;
912
    }
913
    if (writable)
914
      ptr->first_undef_row = end_row;
915
    if (ptr->pre_zero) {
916
      size_t bytesperrow = (size_t) ptr->blocksperrow * SIZEOF(JBLOCK);
917
      undef_row -= ptr->cur_start_row; /* make indexes relative to buffer */
918
      end_row -= ptr->cur_start_row;
919
      while (undef_row < end_row) {
920
        jzero_far((void FAR *) ptr->mem_buffer[undef_row], bytesperrow);
921
        undef_row++;
922
      }
923
    } else {
924
      if (! writable)           /* reader looking at undefined data */
925
        ERREXIT(cinfo, JERR_BAD_VIRTUAL_ACCESS);
926
    }
927
  }
928
  /* Flag the buffer dirty if caller will write in it */
929
  if (writable)
930
    ptr->dirty = TRUE;
931
  /* Return address of proper part of the buffer */
932
  return ptr->mem_buffer + (start_row - ptr->cur_start_row);
933
}
934

935

936
/*
937
 * Release all objects belonging to a specified pool.
938
 */
939

940
METHODDEF(void)
941
free_pool (j_common_ptr cinfo, int pool_id)
942
{
943
  my_mem_ptr mem = (my_mem_ptr) cinfo->mem;
944
  small_pool_ptr shdr_ptr;
945
  large_pool_ptr lhdr_ptr;
946
  size_t space_freed;
947

948
  if (pool_id < 0 || pool_id >= JPOOL_NUMPOOLS)
949
    ERREXIT1(cinfo, JERR_BAD_POOL_ID, pool_id); /* safety check */
950

951
#ifdef MEM_STATS
952
  if (cinfo->err->trace_level > 1)
953
    print_mem_stats(cinfo, pool_id); /* print pool's memory usage statistics */
954
#endif
955

956
  /* If freeing IMAGE pool, close any virtual arrays first */
957
  if (pool_id == JPOOL_IMAGE) {
958
    jvirt_sarray_ptr sptr;
959
    jvirt_barray_ptr bptr;
960

961
    for (sptr = mem->virt_sarray_list; sptr != NULL; sptr = sptr->next) {
962
      if (sptr->b_s_open) {     /* there may be no backing store */
963
        sptr->b_s_open = FALSE; /* prevent recursive close if error */
964
        (*sptr->b_s_info.close_backing_store) (cinfo, & sptr->b_s_info);
965
      }
966
    }
967
    mem->virt_sarray_list = NULL;
968
    for (bptr = mem->virt_barray_list; bptr != NULL; bptr = bptr->next) {
969
      if (bptr->b_s_open) {     /* there may be no backing store */
970
        bptr->b_s_open = FALSE; /* prevent recursive close if error */
971
        (*bptr->b_s_info.close_backing_store) (cinfo, & bptr->b_s_info);
972
      }
973
    }
974
    mem->virt_barray_list = NULL;
975
  }
976

977
  /* Release large objects */
978
  lhdr_ptr = mem->large_list[pool_id];
979
  mem->large_list[pool_id] = NULL;
980

981
  while (lhdr_ptr != NULL) {
982
    large_pool_ptr next_lhdr_ptr = lhdr_ptr->hdr.next;
983
    space_freed = lhdr_ptr->hdr.bytes_used +
984
                  lhdr_ptr->hdr.bytes_left +
985
                  SIZEOF(large_pool_hdr);
986
    jpeg_free_large(cinfo, (void FAR *) lhdr_ptr, space_freed);
987
    mem->total_space_allocated -= space_freed;
988
    lhdr_ptr = next_lhdr_ptr;
989
  }
990

991
  /* Release small objects */
992
  shdr_ptr = mem->small_list[pool_id];
993
  mem->small_list[pool_id] = NULL;
994

995
  while (shdr_ptr != NULL) {
996
    small_pool_ptr next_shdr_ptr = shdr_ptr->hdr.next;
997
    space_freed = shdr_ptr->hdr.bytes_used +
998
                  shdr_ptr->hdr.bytes_left +
999
                  SIZEOF(small_pool_hdr);
1000
    jpeg_free_small(cinfo, (void *) shdr_ptr, space_freed);
1001
    mem->total_space_allocated -= space_freed;
1002
    shdr_ptr = next_shdr_ptr;
1003
  }
1004
}
1005

1006

1007
/*
1008
 * Close up shop entirely.
1009
 * Note that this cannot be called unless cinfo->mem is non-NULL.
1010
 */
1011

1012
METHODDEF(void)
1013
self_destruct (j_common_ptr cinfo)
1014
{
1015
  int pool;
1016

1017
  /* Close all backing store, release all memory.
1018
   * Releasing pools in reverse order might help avoid fragmentation
1019
   * with some (brain-damaged) malloc libraries.
1020
   */
1021
  for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1022
    free_pool(cinfo, pool);
1023
  }
1024

1025
  /* Release the memory manager control block too. */
1026
  jpeg_free_small(cinfo, (void *) cinfo->mem, SIZEOF(my_memory_mgr));
1027
  cinfo->mem = NULL;            /* ensures I will be called only once */
1028

1029
  jpeg_mem_term(cinfo);         /* system-dependent cleanup */
1030
}
1031

1032

1033
/*
1034
 * Memory manager initialization.
1035
 * When this is called, only the error manager pointer is valid in cinfo!
1036
 */
1037

1038
GLOBAL(void)
1039
jinit_memory_mgr (j_common_ptr cinfo)
1040
{
1041
  my_mem_ptr mem;
1042
  size_t max_to_use;
1043
  int pool;
1044
  size_t test_mac;
1045

1046
  cinfo->mem = NULL;            /* for safety if init fails */
1047

1048
  /* Check for configuration errors.
1049
   * SIZEOF(ALIGN_TYPE) should be a power of 2; otherwise, it probably
1050
   * doesn't reflect any real hardware alignment requirement.
1051
   * The test is a little tricky: for X>0, X and X-1 have no one-bits
1052
   * in common if and only if X is a power of 2, ie has only one one-bit.
1053
   * Some compilers may give an "unreachable code" warning here; ignore it.
1054
   */
1055
  if ((SIZEOF(ALIGN_TYPE) & (SIZEOF(ALIGN_TYPE)-1)) != 0)
1056
    ERREXIT(cinfo, JERR_BAD_ALIGN_TYPE);
1057
  /* MAX_ALLOC_CHUNK must be representable as type size_t, and must be
1058
   * a multiple of SIZEOF(ALIGN_TYPE).
1059
   * Again, an "unreachable code" warning may be ignored here.
1060
   * But a "constant too large" warning means you need to fix MAX_ALLOC_CHUNK.
1061
   */
1062
  test_mac = (size_t) MAX_ALLOC_CHUNK;
1063
  if ((long) test_mac != MAX_ALLOC_CHUNK ||
1064
      (MAX_ALLOC_CHUNK % SIZEOF(ALIGN_TYPE)) != 0)
1065
    ERREXIT(cinfo, JERR_BAD_ALLOC_CHUNK);
1066

1067
  max_to_use = jpeg_mem_init(cinfo); /* system-dependent initialization */
1068

1069
  /* Attempt to allocate memory manager's control block */
1070
  mem = (my_mem_ptr) jpeg_get_small(cinfo, SIZEOF(my_memory_mgr));
1071

1072
  if (mem == NULL) {
1073
    jpeg_mem_term(cinfo);       /* system-dependent cleanup */
1074
    ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 0);
1075
  }
1076

1077
  /* OK, fill in the method pointers */
1078
  mem->pub.alloc_small = alloc_small;
1079
  mem->pub.alloc_large = alloc_large;
1080
  mem->pub.alloc_sarray = alloc_sarray;
1081
  mem->pub.alloc_barray = alloc_barray;
1082
  mem->pub.request_virt_sarray = request_virt_sarray;
1083
  mem->pub.request_virt_barray = request_virt_barray;
1084
  mem->pub.realize_virt_arrays = realize_virt_arrays;
1085
  mem->pub.access_virt_sarray = access_virt_sarray;
1086
  mem->pub.access_virt_barray = access_virt_barray;
1087
  mem->pub.free_pool = free_pool;
1088
  mem->pub.self_destruct = self_destruct;
1089

1090
  /* Make MAX_ALLOC_CHUNK accessible to other modules */
1091
  mem->pub.max_alloc_chunk = MAX_ALLOC_CHUNK;
1092

1093
  /* Initialize working state */
1094
  mem->pub.max_memory_to_use = max_to_use;
1095

1096
  for (pool = JPOOL_NUMPOOLS-1; pool >= JPOOL_PERMANENT; pool--) {
1097
    mem->small_list[pool] = NULL;
1098
    mem->large_list[pool] = NULL;
1099
  }
1100
  mem->virt_sarray_list = NULL;
1101
  mem->virt_barray_list = NULL;
1102

1103
  mem->total_space_allocated = SIZEOF(my_memory_mgr);
1104

1105
  /* Declare ourselves open for business */
1106
  cinfo->mem = & mem->pub;
1107

1108
  /* Check for an environment variable JPEGMEM; if found, override the
1109
   * default max_memory setting from jpeg_mem_init.  Note that the
1110
   * surrounding application may again override this value.
1111
   * If your system doesn't support getenv(), define NO_GETENV to disable
1112
   * this feature.
1113
   */
1114
#ifndef NO_GETENV
1115
  { char * memenv;
1116

1117
    if ((memenv = getenv("JPEGMEM")) != NULL) {
1118
      char ch = 'x';
1119
      unsigned int mem_max = 0u;
1120

1121
      if (sscanf(memenv, "%u%c", &mem_max, &ch) > 0) {
1122
        max_to_use = (size_t)mem_max;
1123
        if (ch == 'm' || ch == 'M')
1124
          max_to_use *= 1000L;
1125
        mem->pub.max_memory_to_use = max_to_use * 1000L;
1126
      }
1127
    }
1128
  }
1129
#endif
1130

1131
}
1132