fpdfapi_jcomapi.c revision ac3d58cff7c80b0ef56bf55130d91da17cbaa3c4 
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
28GLOBAL(void)
29jpeg_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
68GLOBAL(void)
69jpeg_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
85GLOBAL(JQUANT_TBL *)
86jpeg_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
97GLOBAL(JHUFF_TBL *)
98jpeg_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