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)
jpeg_abort(j_common_ptr cinfo)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)
jpeg_destroy(j_common_ptr cinfo)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 *)
jpeg_alloc_quant_table(j_common_ptr cinfo)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 *)
jpeg_alloc_huff_table(j_common_ptr cinfo)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