00001 /* 00002 * jcomapi.c 00003 * 00004 * Copyright (C) 1994-1997, Thomas G. Lane. 00005 * This file is part of the Independent JPEG Group's software. 00006 * For conditions of distribution and use, see the accompanying README file. 00007 * 00008 * This file contains application interface routines that are used for both 00009 * compression and decompression. 00010 */ 00011 00012 #define JPEG_INTERNALS 00013 #include "jinclude.h" 00014 #include "jpeglib.h" 00015 00016 00017 /* 00018 * Abort processing of a JPEG compression or decompression operation, 00019 * but don't destroy the object itself. 00020 * 00021 * For this, we merely clean up all the nonpermanent memory pools. 00022 * Note that temp files (virtual arrays) are not allowed to belong to 00023 * the permanent pool, so we will be able to close all temp files here. 00024 * Closing a data source or destination, if necessary, is the application's 00025 * responsibility. 00026 */ 00027 00028 GLOBAL(void) 00029 jpeg_abort (j_common_ptr cinfo) 00030 { 00031 int pool; 00032 00033 /* Do nothing if called on a not-initialized or destroyed JPEG object. */ 00034 if (cinfo->mem == NULL) 00035 return; 00036 00037 /* Releasing pools in reverse order might help avoid fragmentation 00038 * with some (brain-damaged) malloc libraries. 00039 */ 00040 for (pool = JPOOL_NUMPOOLS-1; pool > JPOOL_PERMANENT; pool--) { 00041 (*cinfo->mem->free_pool) (cinfo, pool); 00042 } 00043 00044 /* Reset overall state for possible reuse of object */ 00045 if (cinfo->is_decompressor) { 00046 cinfo->global_state = DSTATE_START; 00047 /* Try to keep application from accessing now-deleted marker list. 00048 * A bit kludgy to do it here, but this is the most central place. 00049 */ 00050 ((j_decompress_ptr) cinfo)->marker_list = NULL; 00051 } else { 00052 cinfo->global_state = CSTATE_START; 00053 } 00054 } 00055 00056 00057 /* 00058 * Destruction of a JPEG object. 00059 * 00060 * Everything gets deallocated except the master jpeg_compress_struct itself 00061 * and the error manager struct. Both of these are supplied by the application 00062 * and must be freed, if necessary, by the application. (Often they are on 00063 * the stack and so don't need to be freed anyway.) 00064 * Closing a data source or destination, if necessary, is the application's 00065 * responsibility. 00066 */ 00067 00068 GLOBAL(void) 00069 jpeg_destroy (j_common_ptr cinfo) 00070 { 00071 /* We need only tell the memory manager to release everything. */ 00072 /* NB: mem pointer is NULL if memory mgr failed to initialize. */ 00073 if (cinfo->mem != NULL) 00074 (*cinfo->mem->self_destruct) (cinfo); 00075 cinfo->mem = NULL; /* be safe if jpeg_destroy is called twice */ 00076 cinfo->global_state = 0; /* mark it destroyed */ 00077 } 00078 00079 00080 /* 00081 * Convenience routines for allocating quantization and Huffman tables. 00082 * (Would jutils.c be a more reasonable place to put these?) 00083 */ 00084 00085 GLOBAL(JQUANT_TBL *) 00086 jpeg_alloc_quant_table (j_common_ptr cinfo) 00087 { 00088 JQUANT_TBL *tbl; 00089 00090 tbl = (JQUANT_TBL *) 00091 (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JQUANT_TBL)); 00092 tbl->sent_table = FALSE; /* make sure this is false in any new table */ 00093 return tbl; 00094 } 00095 00096 00097 GLOBAL(JHUFF_TBL *) 00098 jpeg_alloc_huff_table (j_common_ptr cinfo) 00099 { 00100 JHUFF_TBL *tbl; 00101 00102 tbl = (JHUFF_TBL *) 00103 (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JHUFF_TBL)); 00104 tbl->sent_table = FALSE; /* make sure this is false in any new table */ 00105 return tbl; 00106 }