118 lines
3.2 KiB
C
118 lines
3.2 KiB
C
/*
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* Small jpeg decoder library
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*
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* Copyright (c) 2006, Luc Saillard <luc@saillard.org>
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* All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* - Neither the name of the author nor the names of its contributors may be
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* used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdint.h>
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#include "tinyjpeg.h"
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#include "tinyjpeg-internal.h"
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/**
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* YCrCb -> Grey (1x1, 1x2)
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* .---.
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* | 1 |
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* `---'
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*/
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static void YCrCB_to_Grey_1xN(struct jdec_private *priv, int sx, int sy)
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{
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const unsigned char *y;
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unsigned char *p;
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unsigned int i;
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int offset_to_next_row;
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p = priv->plane[0];
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y = priv->Y;
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offset_to_next_row = priv->bytes_per_row[0];
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for (i = sy; i > 0; i--) {
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memcpy(p, y, sx);
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y += 8;
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p += offset_to_next_row;
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}
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}
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/**
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* YCrCb -> Grey (2x1, 2x2)
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* .-------.
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* | 1 | 2 |
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* `-------'
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*/
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static void YCrCB_to_Grey_2xN(struct jdec_private *priv, int sx, int sy)
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{
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const unsigned char *y;
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unsigned char *p;
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unsigned int i;
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int offset_to_next_row;
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p = priv->plane[0];
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y = priv->Y;
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offset_to_next_row = priv->bytes_per_row[0];
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for (i = sy; i > 0; i--) {
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memcpy(p, y, sx);
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y += 16;
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p += offset_to_next_row;
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}
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}
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static int initialize_grey(struct jdec_private *priv,
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unsigned int *bytes_per_blocklines,
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unsigned int *bytes_per_mcu)
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{
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if (!priv->bytes_per_row[0])
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priv->bytes_per_row[0] = priv->width;
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if (!priv->components[0])
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priv->components[0] = malloc(priv->height * priv->bytes_per_row[0]);
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bytes_per_blocklines[0] = priv->bytes_per_row[0] << 3;
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bytes_per_mcu[0] = 8;
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return !priv->components[0];
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}
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static const struct tinyjpeg_colorspace format_grey =
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{
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{
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YCrCB_to_Grey_1xN,
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YCrCB_to_Grey_1xN,
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YCrCB_to_Grey_2xN,
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YCrCB_to_Grey_2xN,
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},
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tinyjpeg_decode_mcu_1comp_table,
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initialize_grey
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};
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const tinyjpeg_colorspace_t TINYJPEG_FMT_GREY = &format_grey;
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