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