459 lines
16 KiB
C
459 lines
16 KiB
C
/* ***** BEGIN LICENSE BLOCK *****
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* Version: RCSL 1.0/RPSL 1.0
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*
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* Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved.
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*
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* The contents of this file, and the files included with this file, are
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* subject to the current version of the RealNetworks Public Source License
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* Version 1.0 (the "RPSL") available at
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* http://www.helixcommunity.org/content/rpsl unless you have licensed
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* the file under the RealNetworks Community Source License Version 1.0
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* (the "RCSL") available at http://www.helixcommunity.org/content/rcsl,
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* in which case the RCSL will apply. You may also obtain the license terms
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* directly from RealNetworks. You may not use this file except in
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* compliance with the RPSL or, if you have a valid RCSL with RealNetworks
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* applicable to this file, the RCSL. Please see the applicable RPSL or
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* RCSL for the rights, obligations and limitations governing use of the
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* contents of the file.
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*
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* This file is part of the Helix DNA Technology. RealNetworks is the
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* developer of the Original Code and owns the copyrights in the portions
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* it created.
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*
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* This file, and the files included with this file, is distributed and made
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* available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
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*
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* Technology Compatibility Kit Test Suite(s) Location:
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* http://www.helixcommunity.org/content/tck
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*
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* Contributor(s):
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*
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* ***** END LICENSE BLOCK ***** */
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/**************************************************************************************
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* Fixed-point MP3 decoder
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* Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
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* July 2003
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*
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* huffman.c - Huffman decoding of transform coefficients
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**************************************************************************************/
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#include "coder.h"
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/* helper macros - see comments in hufftabs.c about the format of the huffman tables */
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#define GetMaxbits(x) ((int)( (((unsigned short)(x)) >> 0) & 0x000f))
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#define GetHLen(x) ((int)( (((unsigned short)(x)) >> 12) & 0x000f))
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#define GetCWY(x) ((int)( (((unsigned short)(x)) >> 8) & 0x000f))
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#define GetCWX(x) ((int)( (((unsigned short)(x)) >> 4) & 0x000f))
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#define GetSignBits(x) ((int)( (((unsigned short)(x)) >> 0) & 0x000f))
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#define GetHLenQ(x) ((int)( (((unsigned char)(x)) >> 4) & 0x0f))
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#define GetCWVQ(x) ((int)( (((unsigned char)(x)) >> 3) & 0x01))
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#define GetCWWQ(x) ((int)( (((unsigned char)(x)) >> 2) & 0x01))
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#define GetCWXQ(x) ((int)( (((unsigned char)(x)) >> 1) & 0x01))
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#define GetCWYQ(x) ((int)( (((unsigned char)(x)) >> 0) & 0x01))
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/* apply sign of s to the positive number x (save in MSB, will do two's complement in dequant) */
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#define ApplySign(x, s) { (x) |= ((s) & 0x80000000); }
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/**************************************************************************************
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* Function: DecodeHuffmanPairs
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*
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* Description: decode 2-way vector Huffman codes in the "bigValues" region of spectrum
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*
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* Inputs: valid BitStreamInfo struct, pointing to start of pair-wise codes
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* pointer to xy buffer to received decoded values
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* number of codewords to decode
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* index of Huffman table to use
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* number of bits remaining in bitstream
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*
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* Outputs: pairs of decoded coefficients in vwxy
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* updated BitStreamInfo struct
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*
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* Return: number of bits used, or -1 if out of bits
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*
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* Notes: assumes that nVals is an even number
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* si_huff.bit tests every Huffman codeword in every table (though not
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* necessarily all linBits outputs for x,y > 15)
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**************************************************************************************/
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static int DecodeHuffmanPairs(int *xy, int nVals, int tabIdx, int bitsLeft, unsigned char *buf, int bitOffset)
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{
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int i, x, y;
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int cachedBits, padBits, len, startBits, linBits, maxBits, minBits;
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HuffTabType tabType;
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unsigned short cw, *tBase, *tCurr;
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unsigned int cache;
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if(nVals <= 0)
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return 0;
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if (bitsLeft < 0)
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return -1;
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startBits = bitsLeft;
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tBase = (unsigned short *)(huffTable + huffTabOffset[tabIdx]);
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linBits = huffTabLookup[tabIdx].linBits;
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tabType = huffTabLookup[tabIdx].tabType;
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ASSERT(!(nVals & 0x01));
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ASSERT(tabIdx < HUFF_PAIRTABS);
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ASSERT(tabIdx >= 0);
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ASSERT(tabType != invalidTab);
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/* initially fill cache with any partial byte */
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cache = 0;
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cachedBits = (8 - bitOffset) & 0x07;
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if (cachedBits)
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cache = (unsigned int)(*buf++) << (32 - cachedBits);
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bitsLeft -= cachedBits;
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if (tabType == noBits) {
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/* table 0, no data, x = y = 0 */
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for (i = 0; i < nVals; i+=2) {
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xy[i+0] = 0;
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xy[i+1] = 0;
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}
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return 0;
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} else if (tabType == oneShot) {
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/* single lookup, no escapes */
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maxBits = GetMaxbits(tBase[0]);
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tBase++;
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padBits = 0;
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while (nVals > 0) {
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/* refill cache - assumes cachedBits <= 16 */
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if (bitsLeft >= 16) {
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/* load 2 new bytes into left-justified cache */
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cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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cache |= (unsigned int)(*buf++) << (16 - cachedBits);
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cachedBits += 16;
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bitsLeft -= 16;
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} else {
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/* last time through, pad cache with zeros and drain cache */
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if (cachedBits + bitsLeft <= 0) return -1;
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if (bitsLeft > 0) cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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if (bitsLeft > 8) cache |= (unsigned int)(*buf++) << (16 - cachedBits);
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cachedBits += bitsLeft;
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bitsLeft = 0;
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cache &= (signed int)0x80000000 >> (cachedBits - 1);
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padBits = 11;
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cachedBits += padBits; /* okay if this is > 32 (0's automatically shifted in from right) */
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}
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/* largest maxBits = 9, plus 2 for sign bits, so make sure cache has at least 11 bits */
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while (nVals > 0 && cachedBits >= 11 ) {
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cw = tBase[cache >> (32 - maxBits)];
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len = GetHLen(cw);
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cachedBits -= len;
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cache <<= len;
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x = GetCWX(cw); if (x) {ApplySign(x, cache); cache <<= 1; cachedBits--;}
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y = GetCWY(cw); if (y) {ApplySign(y, cache); cache <<= 1; cachedBits--;}
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/* ran out of bits - should never have consumed padBits */
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if (cachedBits < padBits)
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return -1;
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*xy++ = x;
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*xy++ = y;
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nVals -= 2;
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}
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}
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bitsLeft += (cachedBits - padBits);
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return (startBits - bitsLeft);
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} else if (tabType == loopLinbits || tabType == loopNoLinbits) {
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tCurr = tBase;
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padBits = 0;
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while (nVals > 0) {
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/* refill cache - assumes cachedBits <= 16 */
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if (bitsLeft >= 16) {
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/* load 2 new bytes into left-justified cache */
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cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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cache |= (unsigned int)(*buf++) << (16 - cachedBits);
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cachedBits += 16;
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bitsLeft -= 16;
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} else {
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/* last time through, pad cache with zeros and drain cache */
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if (cachedBits + bitsLeft <= 0) return -1;
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if (bitsLeft > 0) cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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if (bitsLeft > 8) cache |= (unsigned int)(*buf++) << (16 - cachedBits);
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cachedBits += bitsLeft;
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bitsLeft = 0;
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cache &= (signed int)0x80000000 >> (cachedBits - 1);
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padBits = 11;
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cachedBits += padBits; /* okay if this is > 32 (0's automatically shifted in from right) */
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}
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/* largest maxBits = 9, plus 2 for sign bits, so make sure cache has at least 11 bits */
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while (nVals > 0 && cachedBits >= 11 ) {
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maxBits = GetMaxbits(tCurr[0]);
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cw = tCurr[(cache >> (32 - maxBits)) + 1];
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len = GetHLen(cw);
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if (!len) {
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cachedBits -= maxBits;
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cache <<= maxBits;
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tCurr += cw;
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continue;
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}
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cachedBits -= len;
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cache <<= len;
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x = GetCWX(cw);
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y = GetCWY(cw);
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if (x == 15 && tabType == loopLinbits) {
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minBits = linBits + 1 + (y ? 1 : 0);
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if (cachedBits + bitsLeft < minBits)
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return -1;
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while (cachedBits < minBits) {
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cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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cachedBits += 8;
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bitsLeft -= 8;
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}
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if (bitsLeft < 0) {
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cachedBits += bitsLeft;
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bitsLeft = 0;
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cache &= (signed int)0x80000000 >> (cachedBits - 1);
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}
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x += (int)(cache >> (32 - linBits));
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cachedBits -= linBits;
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cache <<= linBits;
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}
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if (x) {ApplySign(x, cache); cache <<= 1; cachedBits--;}
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if (y == 15 && tabType == loopLinbits) {
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minBits = linBits + 1;
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if (cachedBits + bitsLeft < minBits)
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return -1;
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while (cachedBits < minBits) {
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cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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cachedBits += 8;
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bitsLeft -= 8;
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}
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if (bitsLeft < 0) {
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cachedBits += bitsLeft;
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bitsLeft = 0;
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cache &= (signed int)0x80000000 >> (cachedBits - 1);
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}
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y += (int)(cache >> (32 - linBits));
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cachedBits -= linBits;
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cache <<= linBits;
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}
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if (y) {ApplySign(y, cache); cache <<= 1; cachedBits--;}
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/* ran out of bits - should never have consumed padBits */
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if (cachedBits < padBits)
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return -1;
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*xy++ = x;
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*xy++ = y;
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nVals -= 2;
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tCurr = tBase;
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}
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}
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bitsLeft += (cachedBits - padBits);
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return (startBits - bitsLeft);
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}
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/* error in bitstream - trying to access unused Huffman table */
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return -1;
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}
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/**************************************************************************************
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* Function: DecodeHuffmanQuads
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*
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* Description: decode 4-way vector Huffman codes in the "count1" region of spectrum
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*
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* Inputs: valid BitStreamInfo struct, pointing to start of quadword codes
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* pointer to vwxy buffer to received decoded values
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* maximum number of codewords to decode
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* index of quadword table (0 = table A, 1 = table B)
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* number of bits remaining in bitstream
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*
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* Outputs: quadruples of decoded coefficients in vwxy
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* updated BitStreamInfo struct
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*
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* Return: index of the first "zero_part" value (index of the first sample
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* of the quad word after which all samples are 0)
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*
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* Notes: si_huff.bit tests every vwxy output in both quad tables
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**************************************************************************************/
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static int DecodeHuffmanQuads(int *vwxy, int nVals, int tabIdx, int bitsLeft, unsigned char *buf, int bitOffset)
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{
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int i, v, w, x, y;
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int len, maxBits, cachedBits, padBits;
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unsigned int cache;
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unsigned char cw, *tBase;
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if (bitsLeft <= 0)
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return 0;
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tBase = (unsigned char *)quadTable + quadTabOffset[tabIdx];
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maxBits = quadTabMaxBits[tabIdx];
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/* initially fill cache with any partial byte */
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cache = 0;
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cachedBits = (8 - bitOffset) & 0x07;
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if (cachedBits)
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cache = (unsigned int)(*buf++) << (32 - cachedBits);
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bitsLeft -= cachedBits;
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i = padBits = 0;
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while (i < (nVals - 3)) {
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/* refill cache - assumes cachedBits <= 16 */
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if (bitsLeft >= 16) {
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/* load 2 new bytes into left-justified cache */
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cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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cache |= (unsigned int)(*buf++) << (16 - cachedBits);
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cachedBits += 16;
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bitsLeft -= 16;
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} else {
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/* last time through, pad cache with zeros and drain cache */
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if (cachedBits + bitsLeft <= 0) return i;
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if (bitsLeft > 0) cache |= (unsigned int)(*buf++) << (24 - cachedBits);
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if (bitsLeft > 8) cache |= (unsigned int)(*buf++) << (16 - cachedBits);
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cachedBits += bitsLeft;
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bitsLeft = 0;
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cache &= (signed int)0x80000000 >> (cachedBits - 1);
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padBits = 10;
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cachedBits += padBits; /* okay if this is > 32 (0's automatically shifted in from right) */
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}
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/* largest maxBits = 6, plus 4 for sign bits, so make sure cache has at least 10 bits */
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while (i < (nVals - 3) && cachedBits >= 10 ) {
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cw = tBase[cache >> (32 - maxBits)];
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len = GetHLenQ(cw);
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cachedBits -= len;
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cache <<= len;
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v = GetCWVQ(cw); if(v) {ApplySign(v, cache); cache <<= 1; cachedBits--;}
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w = GetCWWQ(cw); if(w) {ApplySign(w, cache); cache <<= 1; cachedBits--;}
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x = GetCWXQ(cw); if(x) {ApplySign(x, cache); cache <<= 1; cachedBits--;}
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y = GetCWYQ(cw); if(y) {ApplySign(y, cache); cache <<= 1; cachedBits--;}
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/* ran out of bits - okay (means we're done) */
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if (cachedBits < padBits)
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return i;
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*vwxy++ = v;
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*vwxy++ = w;
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*vwxy++ = x;
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*vwxy++ = y;
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i += 4;
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}
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}
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/* decoded max number of quad values */
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return i;
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}
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/**************************************************************************************
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* Function: DecodeHuffman
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*
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* Description: decode one granule, one channel worth of Huffman codes
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*
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* Inputs: MP3DecInfo structure filled by UnpackFrameHeader(), UnpackSideInfo(),
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* and UnpackScaleFactors() (for this granule)
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* buffer pointing to start of Huffman data in MP3 frame
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* pointer to bit offset (0-7) indicating starting bit in buf[0]
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* number of bits in the Huffman data section of the frame
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* (could include padding bits)
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* index of current granule and channel
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*
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* Outputs: decoded coefficients in hi->huffDecBuf[ch] (hi pointer in mp3DecInfo)
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* updated bitOffset
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*
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* Return: length (in bytes) of Huffman codes
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* bitOffset also returned in parameter (0 = MSB, 7 = LSB of
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* byte located at buf + offset)
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* -1 if null input pointers, huffBlockBits < 0, or decoder runs
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* out of bits prematurely (invalid bitstream)
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**************************************************************************************/
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int DecodeHuffman(MP3DecInfo *mp3DecInfo, unsigned char *buf, int *bitOffset, int huffBlockBits, int gr, int ch)
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{
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int r1Start, r2Start, rEnd[4]; /* region boundaries */
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int i, w, bitsUsed, bitsLeft;
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unsigned char *startBuf = buf;
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FrameHeader *fh;
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SideInfo *si;
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SideInfoSub *sis;
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ScaleFactorInfo *sfi;
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HuffmanInfo *hi;
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/* validate pointers */
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if (!mp3DecInfo || !mp3DecInfo->FrameHeaderPS || !mp3DecInfo->SideInfoPS || !mp3DecInfo->ScaleFactorInfoPS || !mp3DecInfo->HuffmanInfoPS)
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return -1;
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fh = ((FrameHeader *)(mp3DecInfo->FrameHeaderPS));
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si = ((SideInfo *)(mp3DecInfo->SideInfoPS));
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sis = &si->sis[gr][ch];
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sfi = ((ScaleFactorInfo *)(mp3DecInfo->ScaleFactorInfoPS));
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hi = (HuffmanInfo*)(mp3DecInfo->HuffmanInfoPS);
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if (huffBlockBits < 0)
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return -1;
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/* figure out region boundaries (the first 2*bigVals coefficients divided into 3 regions) */
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if (sis->winSwitchFlag && sis->blockType == 2) {
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if (sis->mixedBlock == 0) {
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r1Start = fh->sfBand->s[(sis->region0Count + 1)/3] * 3;
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} else {
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if (fh->ver == MPEG1) {
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r1Start = fh->sfBand->l[sis->region0Count + 1];
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} else {
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/* see MPEG2 spec for explanation */
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w = fh->sfBand->s[4] - fh->sfBand->s[3];
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r1Start = fh->sfBand->l[6] + 2*w;
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}
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}
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r2Start = MAX_NSAMP; /* short blocks don't have region 2 */
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} else {
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r1Start = fh->sfBand->l[sis->region0Count + 1];
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r2Start = fh->sfBand->l[sis->region0Count + 1 + sis->region1Count + 1];
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}
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/* offset rEnd index by 1 so first region = rEnd[1] - rEnd[0], etc. */
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rEnd[3] = MIN(MAX_NSAMP, 2 * sis->nBigvals);
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rEnd[2] = MIN(r2Start, rEnd[3]);
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rEnd[1] = MIN(r1Start, rEnd[3]);
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rEnd[0] = 0;
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/* rounds up to first all-zero pair (we don't check last pair for (x,y) == (non-zero, zero)) */
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hi->nonZeroBound[ch] = rEnd[3];
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/* decode Huffman pairs (rEnd[i] are always even numbers) */
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bitsLeft = huffBlockBits;
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for (i = 0; i < 3; i++) {
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bitsUsed = DecodeHuffmanPairs(hi->huffDecBuf[ch] + rEnd[i], rEnd[i+1] - rEnd[i], sis->tableSelect[i], bitsLeft, buf, *bitOffset);
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if (bitsUsed < 0 || bitsUsed > bitsLeft) /* error - overran end of bitstream */
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return -1;
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/* update bitstream position */
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buf += (bitsUsed + *bitOffset) >> 3;
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*bitOffset = (bitsUsed + *bitOffset) & 0x07;
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bitsLeft -= bitsUsed;
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}
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/* decode Huffman quads (if any) */
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hi->nonZeroBound[ch] += DecodeHuffmanQuads(hi->huffDecBuf[ch] + rEnd[3], MAX_NSAMP - rEnd[3], sis->count1TableSelect, bitsLeft, buf, *bitOffset);
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ASSERT(hi->nonZeroBound[ch] <= MAX_NSAMP);
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for (i = hi->nonZeroBound[ch]; i < MAX_NSAMP; i++)
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hi->huffDecBuf[ch][i] = 0;
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/* If bits used for 576 samples < huffBlockBits, then the extras are considered
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* to be stuffing bits (throw away, but need to return correct bitstream position)
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*/
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buf += (bitsLeft + *bitOffset) >> 3;
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*bitOffset = (bitsLeft + *bitOffset) & 0x07;
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return (buf - startBuf);
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}
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