add circuitpython code

1 files changed, 462 insertions, 0 deletions

diff --git a/circuitpython/lib/mp3/src/huffman.c b/circuitpython/lib/mp3/src/huffman.c
new file mode 100644
index 0000000..df170fa
--- /dev/null
+++ b/circuitpython/lib/mp3/src/huffman.c
@@ -0,0 +1,462 @@
+/* ***** 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);
+}
+