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