1 files changed, 285 insertions, 0 deletions
diff --git a/src/ccitt-adpcm/g711.c b/src/ccitt-adpcm/g711.c
new file mode 100644
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+++ b/src/ccitt-adpcm/g711.c
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+/*
+ * This source code is a product of Sun Microsystems, Inc. and is provided
+ * for unrestricted use.  Users may copy or modify this source code without
+ * charge.
+ *
+ * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
+ * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+ *
+ * Sun source code is provided with no support and without any obligation on
+ * the part of Sun Microsystems, Inc. to assist in its use, correction,
+ * modification or enhancement.
+ *
+ * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+ * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
+ * OR ANY PART THEREOF.
+ *
+ * In no event will Sun Microsystems, Inc. be liable for any lost revenue
+ * or profits or other special, indirect and consequential damages, even if
+ * Sun has been advised of the possibility of such damages.
+ *
+ * Sun Microsystems, Inc.
+ * 2550 Garcia Avenue
+ * Mountain View, California  94043
+ */
+
+#include "g72x.h"
+
+/*
+ * g711.c
+ *
+ * u-law, A-law and linear PCM conversions.
+ */
+#define	SIGN_BIT	(0x80)		/* Sign bit for a A-law byte. */
+#define	QUANT_MASK	(0xf)		/* Quantization field mask. */
+#define	NSEGS		(8)		/* Number of A-law segments. */
+#define	SEG_SHIFT	(4)		/* Left shift for segment number. */
+#define	SEG_MASK	(0x70)		/* Segment field mask. */
+
+static short seg_end[8] = {0xFF, 0x1FF, 0x3FF, 0x7FF,
+			    0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
+
+/* copy from CCITT G.711 specifications */
+unsigned char _u2a[128] = {			/* u- to A-law conversions */
+	1,	1,	2,	2,	3,	3,	4,	4,
+	5,	5,	6,	6,	7,	7,	8,	8,
+	9,	10,	11,	12,	13,	14,	15,	16,
+	17,	18,	19,	20,	21,	22,	23,	24,
+	25,	27,	29,	31,	33,	34,	35,	36,
+	37,	38,	39,	40,	41,	42,	43,	44,
+	46,	48,	49,	50,	51,	52,	53,	54,
+	55,	56,	57,	58,	59,	60,	61,	62,
+	64,	65,	66,	67,	68,	69,	70,	71,
+	72,	73,	74,	75,	76,	77,	78,	79,
+	81,	82,	83,	84,	85,	86,	87,	88,
+	89,	90,	91,	92,	93,	94,	95,	96,
+	97,	98,	99,	100,	101,	102,	103,	104,
+	105,	106,	107,	108,	109,	110,	111,	112,
+	113,	114,	115,	116,	117,	118,	119,	120,
+	121,	122,	123,	124,	125,	126,	127,	128};
+
+unsigned char _a2u[128] = {			/* A- to u-law conversions */
+	1,	3,	5,	7,	9,	11,	13,	15,
+	16,	17,	18,	19,	20,	21,	22,	23,
+	24,	25,	26,	27,	28,	29,	30,	31,
+	32,	32,	33,	33,	34,	34,	35,	35,
+	36,	37,	38,	39,	40,	41,	42,	43,
+	44,	45,	46,	47,	48,	48,	49,	49,
+	50,	51,	52,	53,	54,	55,	56,	57,
+	58,	59,	60,	61,	62,	63,	64,	64,
+	65,	66,	67,	68,	69,	70,	71,	72,
+	73,	74,	75,	76,	77,	78,	79,	79,
+	80,	81,	82,	83,	84,	85,	86,	87,
+	88,	89,	90,	91,	92,	93,	94,	95,
+	96,	97,	98,	99,	100,	101,	102,	103,
+	104,	105,	106,	107,	108,	109,	110,	111,
+	112,	113,	114,	115,	116,	117,	118,	119,
+	120,	121,	122,	123,	124,	125,	126,	127};
+
+static int
+search(
+	int		val,
+	short		*table,
+	int		size)
+{
+	int		i;
+
+	for (i = 0; i < size; i++) {
+		if (val <= *table++)
+			return (i);
+	}
+	return (size);
+}
+
+/*
+ * linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
+ *
+ * linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
+ *
+ *		Linear Input Code	Compressed Code
+ *	------------------------	---------------
+ *	0000000wxyza			000wxyz
+ *	0000001wxyza			001wxyz
+ *	000001wxyzab			010wxyz
+ *	00001wxyzabc			011wxyz
+ *	0001wxyzabcd			100wxyz
+ *	001wxyzabcde			101wxyz
+ *	01wxyzabcdef			110wxyz
+ *	1wxyzabcdefg			111wxyz
+ *
+ * For further information see John C. Bellamy's Digital Telephony, 1982,
+ * John Wiley & Sons, pps 98-111 and 472-476.
+ */
+unsigned char
+linear2alaw(
+	int		pcm_val)	/* 2's complement (16-bit range) */
+{
+	int		mask;
+	int		seg;
+	unsigned char	aval;
+
+	if (pcm_val >= 0) {
+		mask = 0xD5;		/* sign (7th) bit = 1 */
+	} else {
+		mask = 0x55;		/* sign bit = 0 */
+		pcm_val = -pcm_val - 8;
+	}
+
+	/* Convert the scaled magnitude to segment number. */
+	seg = search(pcm_val, seg_end, 8);
+
+	/* Combine the sign, segment, and quantization bits. */
+
+	if (seg >= 8)		/* out of range, return maximum value. */
+		return (0x7F ^ mask);
+	else {
+		aval = seg << SEG_SHIFT;
+		if (seg < 2)
+			aval |= (pcm_val >> 4) & QUANT_MASK;
+		else
+			aval |= (pcm_val >> (seg + 3)) & QUANT_MASK;
+		return (aval ^ mask);
+	}
+}
+
+/*
+ * alaw2linear() - Convert an A-law value to 16-bit linear PCM
+ *
+ */
+int
+alaw2linear(
+	unsigned char	a_val)
+{
+	int		t;
+	int		seg;
+
+	a_val ^= 0x55;
+
+	t = (a_val & QUANT_MASK) << 4;
+	seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
+	switch (seg) {
+	case 0:
+		t += 8;
+		break;
+	case 1:
+		t += 0x108;
+		break;
+	default:
+		t += 0x108;
+		t <<= seg - 1;
+	}
+	return ((a_val & SIGN_BIT) ? t : -t);
+}
+
+#define	BIAS		(0x84)		/* Bias for linear code. */
+
+/*
+ * linear2ulaw() - Convert a linear PCM value to u-law
+ *
+ * In order to simplify the encoding process, the original linear magnitude
+ * is biased by adding 33 which shifts the encoding range from (0 - 8158) to
+ * (33 - 8191). The result can be seen in the following encoding table:
+ *
+ *	Biased Linear Input Code	Compressed Code
+ *	------------------------	---------------
+ *	00000001wxyza			000wxyz
+ *	0000001wxyzab			001wxyz
+ *	000001wxyzabc			010wxyz
+ *	00001wxyzabcd			011wxyz
+ *	0001wxyzabcde			100wxyz
+ *	001wxyzabcdef			101wxyz
+ *	01wxyzabcdefg			110wxyz
+ *	1wxyzabcdefgh			111wxyz
+ *
+ * Each biased linear code has a leading 1 which identifies the segment
+ * number. The value of the segment number is equal to 7 minus the number
+ * of leading 0's. The quantization interval is directly available as the
+ * four bits wxyz.  * The trailing bits (a - h) are ignored.
+ *
+ * Ordinarily the complement of the resulting code word is used for
+ * transmission, and so the code word is complemented before it is returned.
+ *
+ * For further information see John C. Bellamy's Digital Telephony, 1982,
+ * John Wiley & Sons, pps 98-111 and 472-476.
+ */
+unsigned char
+linear2ulaw(
+	int		pcm_val)	/* 2's complement (16-bit range) */
+{
+	int		mask;
+	int		seg;
+	unsigned char	uval;
+
+	/* Get the sign and the magnitude of the value. */
+	if (pcm_val < 0) {
+		pcm_val = BIAS - pcm_val;
+		mask = 0x7F;
+	} else {
+		pcm_val += BIAS;
+		mask = 0xFF;
+	}
+
+	/* Convert the scaled magnitude to segment number. */
+	seg = search(pcm_val, seg_end, 8);
+
+	/*
+	 * Combine the sign, segment, quantization bits;
+	 * and complement the code word.
+	 */
+	if (seg >= 8)		/* out of range, return maximum value. */
+		return (0x7F ^ mask);
+	else {
+		uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0xF);
+		return (uval ^ mask);
+	}
+
+}
+
+/*
+ * ulaw2linear() - Convert a u-law value to 16-bit linear PCM
+ *
+ * First, a biased linear code is derived from the code word. An unbiased
+ * output can then be obtained by subtracting 33 from the biased code.
+ *
+ * Note that this function expects to be passed the complement of the
+ * original code word. This is in keeping with ISDN conventions.
+ */
+int
+ulaw2linear(
+	unsigned char	u_val)
+{
+	int		t;
+
+	/* Complement to obtain normal u-law value. */
+	u_val = ~u_val;
+
+	/*
+	 * Extract and bias the quantization bits. Then
+	 * shift up by the segment number and subtract out the bias.
+	 */
+	t = ((u_val & QUANT_MASK) << 3) + BIAS;
+	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
+
+	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
+}
+
+/* A-law to u-law conversion */
+unsigned char
+alaw2ulaw(
+	unsigned char	aval)
+{
+	aval &= 0xff;
+	return ((aval & 0x80) ? (0xFF ^ _a2u[aval ^ 0xD5]) :
+	    (0x7F ^ _a2u[aval ^ 0x55]));
+}
+
+/* u-law to A-law conversion */
+unsigned char
+ulaw2alaw(
+	unsigned char	uval)
+{
+	uval &= 0xff;
+	return ((uval & 0x80) ? (0xD5 ^ (_u2a[0xFF ^ uval] - 1)) :
+	    (0x55 ^ (_u2a[0x7F ^ uval] - 1)));
+}