jcomapi.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "mrpt_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 == nullptr) 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 = nullptr;
        }
        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 nullptr if memory mgr failed to initialize. */
        if (cinfo->mem != nullptr) (*cinfo->mem->self_destruct)(cinfo);
        cinfo->mem = nullptr; /* 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;
}