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85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
/*
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* jcinit.c
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*
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* Copyright (C) 1991-1997, Thomas G. Lane.
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* Modified 2003-2013 by Guido Vollbeding.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains initialization logic for the JPEG compressor.
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* This routine is in charge of selecting the modules to be executed and
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* making an initialization call to each one.
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*
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* Logically, this code belongs in jcmaster.c. It's split out because
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* linking this routine implies linking the entire compression library.
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* For a transcoding-only application, we want to be able to use jcmaster.c
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* without linking in the whole library.
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*/
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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/*
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* Master selection of compression modules.
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* This is done once at the start of processing an image. We determine
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* which modules will be used and give them appropriate initialization calls.
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*/
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GLOBAL(void)
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jinit_compress_master (j_compress_ptr cinfo)
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{
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long samplesperrow;
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JDIMENSION jd_samplesperrow;
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/* For now, precision must match compiled-in value... */
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if (cinfo->data_precision != BITS_IN_JSAMPLE)
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ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
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/* Sanity check on image dimensions */
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if (cinfo->image_height <= 0 || cinfo->image_width <= 0 ||
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cinfo->input_components <= 0)
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ERREXIT(cinfo, JERR_EMPTY_IMAGE);
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/* Width of an input scanline must be representable as JDIMENSION. */
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samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
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jd_samplesperrow = (JDIMENSION) samplesperrow;
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if ((long) jd_samplesperrow != samplesperrow)
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ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
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/* Initialize master control (includes parameter checking/processing) */
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jinit_c_master_control(cinfo, FALSE /* full compression */);
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/* Preprocessing */
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if (! cinfo->raw_data_in) {
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jinit_color_converter(cinfo);
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jinit_downsampler(cinfo);
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jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
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}
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/* Forward DCT */
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jinit_forward_dct(cinfo);
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/* Entropy encoding: either Huffman or arithmetic coding. */
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if (cinfo->arith_code)
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jinit_arith_encoder(cinfo);
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else {
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jinit_huff_encoder(cinfo);
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}
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/* Need a full-image coefficient buffer in any multi-pass mode. */
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jinit_c_coef_controller(cinfo,
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(boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
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jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
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jinit_marker_writer(cinfo);
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/* We can now tell the memory manager to allocate virtual arrays. */
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(*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
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/* Write the datastream header (SOI) immediately.
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* Frame and scan headers are postponed till later.
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* This lets application insert special markers after the SOI.
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*/
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(*cinfo->marker->write_file_header) (cinfo);
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}
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