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e1929140 RR |
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 | } |