130 lines
3.0 KiB
C
130 lines
3.0 KiB
C
/*
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* Copyright (c) 2002-2003, Antonin Descampe
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* All rights reserved.
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*
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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
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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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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#include "raw.h"
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unsigned char raw_c;
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unsigned int raw_ct, raw_lenmax, raw_len;
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unsigned char *raw_bp;
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unsigned char *raw_start;
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unsigned char *raw_end;
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/* <summary> */
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/* Return the number of bytes already encoded. */
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/* </summary> */
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int raw_numbytes()
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{
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return raw_bp - raw_start;
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}
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/* <summary> */
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/* Initialize raw-encoder. */
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/* </summary> */
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/* <param name="bp">Output buffer.</param> */
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void raw_init_enc(unsigned char *bp)
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{
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raw_bp = bp - 1;
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raw_c = 0;
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raw_ct = 7;
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raw_start = bp;
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}
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/* <summary> */
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/* Encode a symbol using the RAW-coder. */
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/* </summary> */
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/* <param name="d"> The symbol to be encoded (0 or 1).</param> */
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void raw_encode(int d)
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{
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/* raw_c+=d; */
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raw_ct--;
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raw_c += (d << raw_ct);
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if (raw_ct == 0) {
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raw_bp++;
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*raw_bp = raw_c;
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raw_ct = 7;
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if (raw_c == 0xff) {
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raw_ct = 6;
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}
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raw_c = 0;
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}
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/*else
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{
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raw_ct--;
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raw_c<<=1;
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} */
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}
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/* <summary> */
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/* Flush encoded data. */
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/* </summary> */
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void raw_flush()
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{
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char first = 1;
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int prev = 1;
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while (raw_ct != 7) {
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raw_encode(first ? 0 : !(prev));
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prev = first ? 0 : !(prev);
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first = 0;
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}
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}
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/* <summary> */
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/* Initialize raw-decoder. */
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/* </summary> */
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void raw_init_dec(unsigned char *bp, int len)
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{
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raw_start = bp;
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raw_lenmax = len;
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raw_len = 0;
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raw_c = 0;
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raw_ct = 0;
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}
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/* <summary> */
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/* Decode a symbol using raw-decoder. Cfr p.506 TAUBMAN */
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/* </summary> */
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int raw_decode()
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{
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int d;
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if (raw_ct == 0) {
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raw_ct = 8;
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if (raw_len == raw_lenmax)
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raw_c = 0xff;
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else {
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if (raw_c == 0xff)
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raw_ct = 7;
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raw_c = *(raw_start + raw_len);
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raw_len++;
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}
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}
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raw_ct--;
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d = (raw_c >> raw_ct) & 0x01;
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return d;
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}
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