media/libjpeg/jcomapi.c

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