/*

 * jcomapi.c

 *

 * Copyright (C) 1994-1997, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains application interface routines that are used for both

 * compression and decompression.

 */



#define JPEG_INTERNALS

#include "jinclude.h"

#include "jpeglib.h"





/*

 * Abort processing of a JPEG compression or decompression operation,

 * but don't destroy the object itself.

 *

 * For this, we merely clean up all the nonpermanent memory pools.

 * Note that temp files (virtual arrays) are not allowed to belong to

 * the permanent pool, so we will be able to close all temp files here.

 * Closing a data source or destination, if necessary, is the application's

 * responsibility.

 */



GLOBAL(void)

jpeg_abort (j_common_ptr cinfo)

{

  int pool;



  /* Do nothing if called on a not-initialized or destroyed JPEG object. */

  if (cinfo->mem == NULL)

    return;



  /* Releasing pools in reverse order might help avoid fragmentation

   * with some (brain-damaged) malloc libraries.

   */

  for (pool = JPOOL_NUMPOOLS-1; pool > JPOOL_PERMANENT; pool--) {

    (*cinfo->mem->free_pool) (cinfo, pool);

  }



  /* Reset overall state for possible reuse of object */

  if (cinfo->is_decompressor) {

    cinfo->global_state = DSTATE_START;

    /* Try to keep application from accessing now-deleted marker list.

     * A bit kludgy to do it here, but this is the most central place.

     */

    ((j_decompress_ptr) cinfo)->marker_list = NULL;

  } else {

    cinfo->global_state = CSTATE_START;

  }

}





/*

 * Destruction of a JPEG object.

 *

 * Everything gets deallocated except the master jpeg_compress_struct itself

 * and the error manager struct.  Both of these are supplied by the application

 * and must be freed, if necessary, by the application.  (Often they are on

 * the stack and so don't need to be freed anyway.)

 * Closing a data source or destination, if necessary, is the application's

 * responsibility.

 */



GLOBAL(void)

jpeg_destroy (j_common_ptr cinfo)

{

  /* We need only tell the memory manager to release everything. */

  /* NB: mem pointer is NULL if memory mgr failed to initialize. */

  if (cinfo->mem != NULL)

    (*cinfo->mem->self_destruct) (cinfo);

  cinfo->mem = NULL;		/* be safe if jpeg_destroy is called twice */

  cinfo->global_state = 0;	/* mark it destroyed */

}





/*

 * Convenience routines for allocating quantization and Huffman tables.

 * (Would jutils.c be a more reasonable place to put these?)

 */



GLOBAL(JQUANT_TBL *)

jpeg_alloc_quant_table (j_common_ptr cinfo)

{

  JQUANT_TBL *tbl;



  tbl = (JQUANT_TBL *)

    (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JQUANT_TBL));

  tbl->sent_table = FALSE;	/* make sure this is false in any new table */

  return tbl;

}





GLOBAL(JHUFF_TBL *)

jpeg_alloc_huff_table (j_common_ptr cinfo)

{

  JHUFF_TBL *tbl;



  tbl = (JHUFF_TBL *)

    (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, SIZEOF(JHUFF_TBL));

  tbl->sent_table = FALSE;	/* make sure this is false in any new table */

  return tbl;

}

