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/*
* jdlossls.c
*
* Copyright (C) 1998, 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 the control logic for the lossless JPEG decompressor.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jlossls.h"
#ifdef D_LOSSLESS_SUPPORTED
/*
* Compute output image dimensions and related values.
*/
METHODDEF(void)
calc_output_dimensions (j_decompress_ptr cinfo)
{
/* Hardwire it to "no scaling" */
cinfo->output_width = cinfo->image_width;
cinfo->output_height = cinfo->image_height;
/* jdinput.c has already initialized codec_data_unit to 1,
* and has computed unscaled downsampled_width and downsampled_height.
*/
}
/*
* Initialize for an input processing pass.
*/
METHODDEF(void)
start_input_pass (j_decompress_ptr cinfo)
{
j_lossless_d_ptr losslsd = (j_lossless_d_ptr) cinfo->codec;
(*losslsd->entropy_start_pass) (cinfo);
(*losslsd->predict_start_pass) (cinfo);
(*losslsd->scaler_start_pass) (cinfo);
(*losslsd->diff_start_input_pass) (cinfo);
}
/*
* Initialize the lossless decompression codec.
* This is called only once, during master selection.
*/
GLOBAL(void)
jinit_lossless_d_codec(j_decompress_ptr cinfo)
{
j_lossless_d_ptr losslsd;
boolean use_c_buffer;
/* Create subobject in permanent pool */
losslsd = (j_lossless_d_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
SIZEOF(jpeg_lossless_d_codec));
cinfo->codec = (struct jpeg_d_codec *) losslsd;
/* Initialize sub-modules */
/* Entropy decoding: either Huffman or arithmetic coding. */
if (cinfo->arith_code) {
#ifdef WITH_ARITHMETIC_PATCH
jinit_arith_decoder(cinfo);
#else
ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
#endif
} else {
jinit_lhuff_decoder(cinfo);
}
/* Undifferencer */
jinit_undifferencer(cinfo);
/* Scaler */
jinit_d_scaler(cinfo);
use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
jinit_d_diff_controller(cinfo, use_c_buffer);
/* Initialize method pointers.
*
* Note: consume_data, start_output_pass and decompress_data are
* assigned in jddiffct.c.
*/
losslsd->pub.calc_output_dimensions = calc_output_dimensions;
losslsd->pub.start_input_pass = start_input_pass;
}
#endif /* D_LOSSLESS_SUPPORTED */
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