/* *  Copyright 2006 by Texas Instruments Incorporated. * *  All rights reserved. Property of Texas Instruments Incorporated. *  Restricted rights to use, duplicate or disclose this code are *  granted through contract. * *//* * 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 *//* * g711.c * * u-law, A-law and linear PCM conversions. *//* * December 30, 1994: * Functions linear2alaw, linear2ulaw have been updated to correctly * convert unquantized 16 bit values. * Tables for direct u- to A-law and A- to u-law conversions have been * corrected. * Borge Lindberg, Center for PersonKommunikation, Aalborg University. * bli@cpk.auc.dk * */ #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_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF,                            0x1FF, 0x3FF, 0x7FF, 0xFFF};static short seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF,                            0x3FF, 0x7FF, 0xFFF, 0x1FFF};/* copy from CCITT G.711 specifications */static 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,/* corrected:        81,     82,     83,     84,     85,     86,     87,     88,    should be: */        80,     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};static 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,/* corrected:        73,     74,     75,     76,     77,     78,     79,     79,   should be: */        73,     74,     75,     76,     77,     78,     79,     80,        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 shortsearch(        short           val,        short           *table,        short           size){        short           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 charG711_SUN_linear2alaw(        short           pcm_val)        /* 2's complement (16-bit range) */{        short           mask;        short           seg;        unsigned char   aval;        pcm_val = pcm_val >> 3;        if (pcm_val >= 0) {                mask = 0xD5;            /* sign (7th) bit = 1 */        } else {                mask = 0x55;            /* sign bit = 0 */                pcm_val = -pcm_val - 1;        }        /* Convert the scaled magnitude to segment number. */        seg = search(pcm_val, seg_aend, 8);        /* Combine the sign, segment, and quantization bits. */        if (seg >= 8)           /* out of range, return maximum value. */                return (unsigned char) (0x7F ^ mask);        else {                aval = (unsigned char) seg << SEG_SHIFT;                if (seg < 2)                        aval |= (pcm_val >> 1) & QUANT_MASK;                else                        aval |= (pcm_val >> seg) & QUANT_MASK;                return (aval ^ mask);        }}/* * G711_SUN_alaw2linear() - Convert an A-law value to 16-bit linear PCM * */shortG711_SUN_alaw2linear(        unsigned char   a_val){        short           t;        short           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. */#define CLIP            8159/* * G711_SUN_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 charG711_SUN_linear2ulaw(        short           pcm_val)        /* 2's complement (16-bit range) */{        short           mask;        short           seg;        unsigned char   uval;        /* Get the sign and the magnitude of the value. */        pcm_val = pcm_val >> 2;        if (pcm_val < 0) {                pcm_val = -pcm_val;                mask = 0x7F;        } else {                mask = 0xFF;        }        if ( pcm_val > CLIP ) pcm_val = CLIP;           /* clip the magnitude */        pcm_val += (BIAS >> 2);        /* Convert the scaled magnitude to segment number. */        seg = search(pcm_val, seg_uend, 8);        /*         * Combine the sign, segment, quantization bits;         * and complement the code word.         */        if (seg >= 8)           /* out of range, return maximum value. */                return (unsigned char) (0x7F ^ mask);        else {                uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF);                return (uval ^ mask);        }}/* * G711_SUN_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. */shortG711_SUN_ulaw2linear(        unsigned char   u_val){        short           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 charG711_SUN_alaw2ulaw(        unsigned char   aval){        aval &= 0xff;        return (unsigned char) ((aval & 0x80) ? (0xFF ^ _a2u[aval ^ 0xD5]) :            (0x7F ^ _a2u[aval ^ 0x55]));}/* u-law to A-law conversion */unsigned charG711_SUN_ulaw2alaw(        unsigned char   uval){        uval &= 0xff;        return (unsigned char) ((uval & 0x80) ? (0xD5 ^ (_u2a[0xFF ^ uval] - 1)) :            (unsigned char) (0x55 ^ (_u2a[0x7F ^ uval] - 1)));}/* *  @(#) ti.xdais.dm.examples.g711; 1,0,0,20; 10-18-2006 19:11:57; /db/wtree/library/trees/dais-g07x/src/ */