/**
* Copyright (c) 2005 Hin-Tak Leung. All rights reserved.
*
**/
/*
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
**/
/*
* jdatadbf.c
*
* Copyright (C) 2001, Dorian Goldstein, Thomas G. Lane.
*
* This file contains compression data destination routines for the case of
* This file is identicle with IJG's built in destination file manager in
* every respect but 1... instead fo emmiting data to a file
* it facilitates definition of a callback function.
*/
/* this is not a core library module, so it doesn't define JPEG_INTERNALS */
#include <stdio.h>
#include "jinclude.h"
#include "jpeglib.h"
#include "jerror.h"
/* Expanded data destination object for stdio output */
typedef struct {
struct jpeg_destination_mgr pub; /* public fields */
JOCTET * outbuff; // target output buffer
JOCTET * buffer; // start of internal buffer
int * size_outbuff; // current size of target output buffer
} my_destination_mgr;
typedef my_destination_mgr * my_dest_ptr;
#define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite'able size */
/*
* Initialize destination --- called by jpeg_start_compress
* before any data is actually written.
*/
METHODDEF(void)
init_destination (j_compress_ptr cinfo)
{
my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
/* Allocate the output buffer --- it will be released when done with image */
dest->buffer = (JOCTET *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
OUTPUT_BUF_SIZE * SIZEOF(JOCTET));
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
}
/*
* Empty the output buffer --- called whenever buffer fills up.
*
* In typical applications, this should write the entire output buffer
* (ignoring the current state of next_output_byte & free_in_buffer),
* reset the pointer & count to the start of the buffer, and return TRUE
* indicating that the buffer has been dumped.
*
* In applications that need to be able to suspend compression due to output
* overrun, a FALSE return indicates that the buffer cannot be emptied now.
* In this situation, the compressor will return to its caller (possibly with
* an indication that it has not accepted all the supplied scanlines). The
* application should resume compression after it has made more room in the
* output buffer. Note that there are substantial restrictions on the use of
* suspension --- see the documentation.
*
* When suspending, the compressor will back up to a convenient restart point
* (typically the start of the current MCU). next_output_byte & free_in_buffer
* indicate where the restart point will be if the current call returns FALSE.
* Data beyond this point will be regenerated after resumption, so do not
* write it out when emptying the buffer externally.
*/
METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo)
{
my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
if (dest->outbuff) {
MEMCOPY(dest->outbuff + *(dest->size_outbuff), dest->buffer, OUTPUT_BUF_SIZE);
*(dest->size_outbuff) += OUTPUT_BUF_SIZE;
}
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;
return TRUE;
}
/*
* Terminate destination --- called by jpeg_finish_compress
* after all data has been written. Usually needs to flush buffer.
*
* NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
* application must deal with any cleanup that should happen even
* for error exit.
*/
METHODDEF(void)
term_destination (j_compress_ptr cinfo)
{
my_dest_ptr dest = (my_dest_ptr) cinfo->dest;
size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;
/* Write any data remaining in the buffer */
if (datacount > 0) {
if (dest->outbuff) {
MEMCOPY(dest->outbuff + *(dest->size_outbuff), dest->buffer, datacount);
*dest->size_outbuff += datacount;
}
}
}
/*
* Prepare for output to a stdio stream.
* The caller must have already opened the stream, and is responsible
* for closing it after finishing compression.
*/
GLOBAL(void)
jpeg_buffer_dest (j_compress_ptr cinfo, JOCTET* outbuff, int *current_size)
{
my_dest_ptr dest;
/* The destination object is made permanent so that multiple JPEG images
* can be written to the same file without re-executing jpeg_stdio_dest.
* This makes it dangerous to use this manager and a different destination
* manager serially with the same JPEG object, because their private object
* sizes may be different. Caveat programmer.
*/
if (cinfo->dest == NULL) { /* first time for this JPEG object? */
cinfo->dest = (struct jpeg_destination_mgr *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
SIZEOF(my_destination_mgr));
}
dest = (my_dest_ptr) cinfo->dest;
dest->pub.init_destination = init_destination;
dest->pub.empty_output_buffer = empty_output_buffer;
dest->pub.term_destination = term_destination;
dest->outbuff = outbuff;
dest->size_outbuff = current_size;
}