g711.c

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/*
 * SpanDSP - a series of DSP components for telephony
 *
 * g711.c - A-law and u-law transcoding routines
 *
 * Written by Steve Underwood <steveu@coppice.org>
 *
 * Copyright (C) 2006 Steve Underwood
 *
 *  Despite my general liking of the GPL, I place this code in the
 *  public domain for the benefit of all mankind - even the slimy
 *  ones who might try to proprietize my work and use it to my
 *  detriment.
 *
 * $Id: g711.c,v 1.1 2006/06/07 15:46:39 steveu Exp $
 */

/*! \file */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#ifndef _MSC_VER
#include <inttypes.h>
#ifdef HAVE_TGMATH_H
#include <tgmath.h>
#endif
#endif

#include "g711.h"

/* Copied from the CCITT G.711 specification */
static const uint8_t ulaw_to_alaw_table[256] = {
        42, 43, 40, 41, 46, 47, 44, 45, 34, 35, 32, 33, 38, 39, 36, 37,
        58, 59, 56, 57, 62, 63, 60, 61, 50, 51, 48, 49, 54, 55, 52, 53,
        10, 11, 8, 9, 14, 15, 12, 13, 2, 3, 0, 1, 6, 7, 4, 26,
        27, 24, 25, 30, 31, 28, 29, 18, 19, 16, 17, 22, 23, 20, 21, 106,
        104, 105, 110, 111, 108, 109, 98, 99, 96, 97, 102, 103, 100, 101, 122, 120,
        126, 127, 124, 125, 114, 115, 112, 113, 118, 119, 116, 117, 75, 73, 79, 77,
        66, 67, 64, 65, 70, 71, 68, 69, 90, 91, 88, 89, 94, 95, 92, 93,
        82, 82, 83, 83, 80, 80, 81, 81, 86, 86, 87, 87, 84, 84, 85, 85,
        170, 171, 168, 169, 174, 175, 172, 173, 162, 163, 160, 161, 166, 167, 164, 165,
        186, 187, 184, 185, 190, 191, 188, 189, 178, 179, 176, 177, 182, 183, 180, 181,
        138, 139, 136, 137, 142, 143, 140, 141, 130, 131, 128, 129, 134, 135, 132, 154,
        155, 152, 153, 158, 159, 156, 157, 146, 147, 144, 145, 150, 151, 148, 149, 234,
        232, 233, 238, 239, 236, 237, 226, 227, 224, 225, 230, 231, 228, 229, 250, 248,
        254, 255, 252, 253, 242, 243, 240, 241, 246, 247, 244, 245, 203, 201, 207, 205,
        194, 195, 192, 193, 198, 199, 196, 197, 218, 219, 216, 217, 222, 223, 220, 221,
        210, 210, 211, 211, 208, 208, 209, 209, 214, 214, 215, 215, 212, 212, 213, 213
};

/* These transcoding tables are copied from the CCITT G.711 specification. To achieve
   optimal results, do not change them. */

static const uint8_t alaw_to_ulaw_table[256] = {
        42, 43, 40, 41, 46, 47, 44, 45, 34, 35, 32, 33, 38, 39, 36, 37,
        57, 58, 55, 56, 61, 62, 59, 60, 49, 50, 47, 48, 53, 54, 51, 52,
        10, 11, 8, 9, 14, 15, 12, 13, 2, 3, 0, 1, 6, 7, 4, 5,
        26, 27, 24, 25, 30, 31, 28, 29, 18, 19, 16, 17, 22, 23, 20, 21,
        98, 99, 96, 97, 102, 103, 100, 101, 93, 93, 92, 92, 95, 95, 94, 94,
        116, 118, 112, 114, 124, 126, 120, 122, 106, 107, 104, 105, 110, 111, 108, 109,
        72, 73, 70, 71, 76, 77, 74, 75, 64, 65, 63, 63, 68, 69, 66, 67,
        86, 87, 84, 85, 90, 91, 88, 89, 79, 79, 78, 78, 82, 83, 80, 81,
        170, 171, 168, 169, 174, 175, 172, 173, 162, 163, 160, 161, 166, 167, 164, 165,
        185, 186, 183, 184, 189, 190, 187, 188, 177, 178, 175, 176, 181, 182, 179, 180,
        138, 139, 136, 137, 142, 143, 140, 141, 130, 131, 128, 129, 134, 135, 132, 133,
        154, 155, 152, 153, 158, 159, 156, 157, 146, 147, 144, 145, 150, 151, 148, 149,
        226, 227, 224, 225, 230, 231, 228, 229, 221, 221, 220, 220, 223, 223, 222, 222,
        244, 246, 240, 242, 252, 254, 248, 250, 234, 235, 232, 233, 238, 239, 236, 237,
        200, 201, 198, 199, 204, 205, 202, 203, 192, 193, 191, 191, 196, 197, 194, 195,
        214, 215, 212, 213, 218, 219, 216, 217, 207, 207, 206, 206, 210, 211, 208, 209
};

uint8_t alaw_to_ulaw(uint8_t alaw)
{
        return alaw_to_ulaw_table[alaw];
}

/*- End of function --------------------------------------------------------*/

uint8_t ulaw_to_alaw(uint8_t ulaw)
{
        return ulaw_to_alaw_table[ulaw];
}

/*- End of function --------------------------------------------------------*/
/*- End of file ------------------------------------------------------------*/

/* For Emacs:
 * Local Variables:
 * mode:c
 * indent-tabs-mode:t
 * tab-width:4
 * c-basic-offset:4
 * End:
 * For VIM:
 * vim:set softtabstop=4 shiftwidth=4 tabstop=4 noet:
 */