jcomapi.cpp (2838B)
1 /* 2 * jcomapi.c 3 * 4 * Copyright (C) 1994, 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 int pool; 31 32 /* Releasing pools in reverse order might help avoid fragmentation 33 * with some (brain-damaged) malloc libraries. 34 */ 35 for ( pool = JPOOL_NUMPOOLS - 1; pool > JPOOL_PERMANENT; pool-- ) { 36 ( *cinfo->mem->free_pool )( cinfo, pool ); 37 } 38 39 /* Reset overall state for possible reuse of object */ 40 cinfo->global_state = ( cinfo->is_decompressor ? DSTATE_START : CSTATE_START ); 41 } 42 43 44 /* 45 * Destruction of a JPEG object. 46 * 47 * Everything gets deallocated except the master jpeg_compress_struct itself 48 * and the error manager struct. Both of these are supplied by the application 49 * and must be freed, if necessary, by the application. (Often they are on 50 * the stack and so don't need to be freed anyway.) 51 * Closing a data source or destination, if necessary, is the application's 52 * responsibility. 53 */ 54 55 GLOBAL void 56 jpeg_destroy( j_common_ptr cinfo ) { 57 /* We need only tell the memory manager to release everything. */ 58 /* NB: mem pointer is NULL if memory mgr failed to initialize. */ 59 if ( cinfo->mem != NULL ) { 60 ( *cinfo->mem->self_destruct )( cinfo ); 61 } 62 cinfo->mem = NULL; /* be safe if jpeg_destroy is called twice */ 63 cinfo->global_state = 0;/* mark it destroyed */ 64 } 65 66 67 /* 68 * Convenience routines for allocating quantization and Huffman tables. 69 * (Would jutils.c be a more reasonable place to put these?) 70 */ 71 72 GLOBAL JQUANT_TBL * 73 jpeg_alloc_quant_table( j_common_ptr cinfo ) { 74 JQUANT_TBL * tbl; 75 76 tbl = (JQUANT_TBL *) 77 ( *cinfo->mem->alloc_small )( cinfo, JPOOL_PERMANENT, SIZEOF( JQUANT_TBL ) ); 78 tbl->sent_table = FALSE;/* make sure this is false in any new table */ 79 return tbl; 80 } 81 82 83 GLOBAL JHUFF_TBL * 84 jpeg_alloc_huff_table( j_common_ptr cinfo ) { 85 JHUFF_TBL * tbl; 86 87 tbl = (JHUFF_TBL *) 88 ( *cinfo->mem->alloc_small )( cinfo, JPOOL_PERMANENT, SIZEOF( JHUFF_TBL ) ); 89 tbl->sent_table = FALSE;/* make sure this is false in any new table */ 90 return tbl; 91 }