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)
jpeg_abort(j_common_ptr cinfo)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)
jpeg_destroy(j_common_ptr cinfo)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 *)
jpeg_alloc_quant_table(j_common_ptr cinfo)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 *)
jpeg_alloc_huff_table(j_common_ptr cinfo)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 }
110