compiler/libjpeg/main/jcomapi.c

   1 /*
   2     $Id$
   3 */
   4
   5 /*
   6  * jcomapi.c
   7  *
   8  * Copyright (C) 1994-1997, Thomas G. Lane.
   9  * This file is part of the Independent JPEG Group's software.
  10  * For conditions of distribution and use, see the accompanying README file.
  11  *
  12  * This file contains application interface routines that are used for both
  13  * compression and decompression.
  14  */
  15
  16 #define JPEG_INTERNALS
  17 #include "jinclude.h"
  18 #include "jpeglib.h"
  19
  20
  21 /*
  22  * Abort processing of a JPEG compression or decompression operation,
  23  * but don't destroy the object itself.
  24  *
  25  * For this, we merely clean up all the nonpermanent memory pools.
  26  * Note that temp files (virtual arrays) are not allowed to belong to
  27  * the permanent pool, so we will be able to close all temp files here.
  28  * Closing a data source or destination, if necessary, is the application's
  29  * responsibility.
  30  */
  31
  32 JGLOBAL(void)
  33 jpeg_abort (j_common_ptr cinfo)
  34 {
  35   int pool;
  36
  37   /* Do nothing if called on a not-initialized or destroyed JPEG object. */
  38   if (cinfo->mem == NULL)
  39     return;
  40
  41   /* Releasing pools in reverse order might help avoid fragmentation
  42    * with some (brain-damaged) malloc libraries.
  43    */
  44   for (pool = JPOOL_NUMPOOLS-1; pool > JPOOL_PERMANENT; pool--) {
  45     (*cinfo->mem->free_pool) (cinfo, pool);
  46   }
  47
  48   /* Reset overall state for possible reuse of object */
  49   if (cinfo->is_decompressor) {
  50     cinfo->global_state = DSTATE_START;
  51     /* Try to keep application from accessing now-deleted marker list.
  52      * A bit kludgy to do it here, but this is the most central place.
  53      */
  54     ((j_decompress_ptr) cinfo)->marker_list = NULL;
  55   } else {
  56     cinfo->global_state = CSTATE_START;
  57   }
  58 }
  59
  60
  61 /*
  62  * Destruction of a JPEG object.
  63  *
  64  * Everything gets deallocated except the master jpeg_compress_struct itself
  65  * and the error manager struct.  Both of these are supplied by the application
  66  * and must be freed, if necessary, by the application.  (Often they are on
  67  * the stack and so don't need to be freed anyway.)
  68  * Closing a data source or destination, if necessary, is the application's
  69  * responsibility.
  70  */
  71
  72 JGLOBAL(void)
  73 jpeg_destroy (j_common_ptr cinfo)
  74 {
  75   /* We need only tell the memory manager to release everything. */
  76   /* NB: mem pointer is NULL if memory mgr failed to initialize. */
  77   if (cinfo->mem != NULL)
  78     (*cinfo->mem->self_destruct) (cinfo);
  79   cinfo->mem = NULL;            /* be safe if jpeg_destroy is called twice */
  80   cinfo->global_state = 0;      /* mark it destroyed */
  81 }
  82
  83
  84 /*
  85  * Convenience routines for allocating quantization and Huffman tables.
  86  * (Would jutils.c be a more reasonable place to put these?)
  87  */
  88
  89 JGLOBAL(JQUANT_TBL *)
  90 jpeg_alloc_quant_table (j_common_ptr cinfo)
  91 {
  92   JQUANT_TBL *tbl;
  93
  94   tbl = (JQUANT_TBL *)
  95     (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JQUANT_TBL));
  96   tbl->sent_table = FALSE;      /* make sure this is false in any new table */
  97   return tbl;
  98 }
  99
 100
 101 JGLOBAL(JHUFF_TBL *)
 102 jpeg_alloc_huff_table (j_common_ptr cinfo)
 103 {
 104   JHUFF_TBL *tbl;
 105
 106   tbl = (JHUFF_TBL *)
 107     (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JHUFF_TBL));
 108   tbl->sent_table = FALSE;      /* make sure this is false in any new table */
 109   return tbl;
 110 }