Home | History | Annotate | Download | only in libjpeg-turbo 
      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)
     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)
     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 *)
     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 *)
    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