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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
+ */
+
+/*
+ * g72x.c
+ *
+ * Common routines for G.721 and G.723 conversions.
+ */
+
+#include <stdlib.h>
+#include "g72x.h"
+
+static short power2[15] = {1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80,
+ 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000};
+
+/*
+ * quan()
+ *
+ * quantizes the input val against the table of size short integers.
+ * It returns i if table[i - 1] <= val < table[i].
+ *
+ * Using linear search for simple coding.
+ */
+static int
+quan(
+ int val,
+ short *table,
+ int size)
+{
+ int i;
+
+ for (i = 0; i < size; i++)
+ if (val < *table++)
+ break;
+ return (i);
+}
+
+/*
+ * fmult()
+ *
+ * returns the integer product of the 14-bit integer "an" and
+ * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
+ */
+static int
+fmult(
+ int an,
+ int srn)
+{
+ short anmag, anexp, anmant;
+ short wanexp, wanmant;
+ short retval;
+
+ anmag = (an > 0) ? an : ((-an) & 0x1FFF);
+ anexp = quan(anmag, power2, 15) - 6;
+ anmant = (anmag == 0) ? 32 :
+ (anexp >= 0) ? anmag >> anexp : anmag << -anexp;
+ wanexp = anexp + ((srn >> 6) & 0xF) - 13;
+
+ wanmant = (anmant * (srn & 077) + 0x30) >> 4;
+ retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) :
+ (wanmant >> -wanexp);
+
+ return (((an ^ srn) < 0) ? -retval : retval);
+}
+
+/*
+ * g72x_init_state()
+ *
+ * This routine initializes and/or resets the g72x_state structure
+ * pointed to by 'state_ptr'.
+ * All the initial state values are specified in the CCITT G.721 document.
+ */
+void
+g72x_init_state(
+ struct g72x_state *state_ptr)
+{
+ int cnta;
+
+ state_ptr->yl = 34816;
+ state_ptr->yu = 544;
+ state_ptr->dms = 0;
+ state_ptr->dml = 0;
+ state_ptr->ap = 0;
+ for (cnta = 0; cnta < 2; cnta++) {
+ state_ptr->a[cnta] = 0;
+ state_ptr->pk[cnta] = 0;
+ state_ptr->sr[cnta] = 32;
+ }
+ for (cnta = 0; cnta < 6; cnta++) {
+ state_ptr->b[cnta] = 0;
+ state_ptr->dq[cnta] = 32;
+ }
+ state_ptr->td = 0;
+}
+
+/*
+ * predictor_zero()
+ *
+ * computes the estimated signal from 6-zero predictor.
+ *
+ */
+int
+predictor_zero(
+ struct g72x_state *state_ptr)
+{
+ int i;
+ int sezi;
+
+ sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]);
+ for (i = 1; i < 6; i++) /* ACCUM */
+ sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
+ return (sezi);
+}
+/*
+ * predictor_pole()
+ *
+ * computes the estimated signal from 2-pole predictor.
+ *
+ */
+int
+predictor_pole(
+ struct g72x_state *state_ptr)
+{
+ return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
+ fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
+}
+/*
+ * step_size()
+ *
+ * computes the quantization step size of the adaptive quantizer.
+ *
+ */
+int
+step_size(
+ struct g72x_state *state_ptr)
+{
+ int y;
+ int dif;
+ int al;
+
+ if (state_ptr->ap >= 256)
+ return (state_ptr->yu);
+ else {
+ y = state_ptr->yl >> 6;
+ dif = state_ptr->yu - y;
+ al = state_ptr->ap >> 2;
+ if (dif > 0)
+ y += (dif * al) >> 6;
+ else if (dif < 0)
+ y += (dif * al + 0x3F) >> 6;
+ return (y);
+ }
+}
+
+/*
+ * quantize()
+ *
+ * Given a raw sample, 'd', of the difference signal and a
+ * quantization step size scale factor, 'y', this routine returns the
+ * ADPCM codeword to which that sample gets quantized. The step
+ * size scale factor division operation is done in the log base 2 domain
+ * as a subtraction.
+ */
+int
+quantize(
+ int d, /* Raw difference signal sample */
+ int y, /* Step size multiplier */
+ short *table, /* quantization table */
+ int size) /* table size of short integers */
+{
+ short dqm; /* Magnitude of 'd' */
+ short exp; /* Integer part of base 2 log of 'd' */
+ short mant; /* Fractional part of base 2 log */
+ short dl; /* Log of magnitude of 'd' */
+ short dln; /* Step size scale factor normalized log */
+ int i;
+
+ /*
+ * LOG
+ *
+ * Compute base 2 log of 'd', and store in 'dl'.
+ */
+ dqm = abs(d);
+ exp = quan(dqm >> 1, power2, 15);
+ mant = ((dqm << 7) >> exp) & 0x7F; /* Fractional portion. */
+ dl = (exp << 7) + mant;
+
+ /*
+ * SUBTB
+ *
+ * "Divide" by step size multiplier.
+ */
+ dln = dl - (y >> 2);
+
+ /*
+ * QUAN
+ *
+ * Obtain codword i for 'd'.
+ */
+ i = quan(dln, table, size);
+ if (d < 0) /* take 1's complement of i */
+ return ((size << 1) + 1 - i);
+ else if (i == 0) /* take 1's complement of 0 */
+ return ((size << 1) + 1); /* new in 1988 */
+ else
+ return (i);
+}
+/*
+ * reconstruct()
+ *
+ * Returns reconstructed difference signal 'dq' obtained from
+ * codeword 'i' and quantization step size scale factor 'y'.
+ * Multiplication is performed in log base 2 domain as addition.
+ */
+int
+reconstruct(
+ int sign, /* 0 for non-negative value */
+ int dqln, /* G.72x codeword */
+ int y) /* Step size multiplier */
+{
+ short dql; /* Log of 'dq' magnitude */
+ short dex; /* Integer part of log */
+ short dqt;
+ short dq; /* Reconstructed difference signal sample */
+
+ dql = dqln + (y >> 2); /* ADDA */
+
+ if (dql < 0) {
+ return ((sign) ? -0x8000 : 0);
+ } else { /* ANTILOG */
+ dex = (dql >> 7) & 15;
+ dqt = 128 + (dql & 127);
+ dq = (dqt << 7) >> (14 - dex);
+ return ((sign) ? (dq - 0x8000) : dq);
+ }
+}
+
+
+/*
+ * update()
+ *
+ * updates the state variables for each output code
+ */
+void
+update(
+ int code_size, /* distinguish 723_40 with others */
+ int y, /* quantizer step size */
+ int wi, /* scale factor multiplier */
+ int fi, /* for long/short term energies */
+ int dq, /* quantized prediction difference */
+ int sr, /* reconstructed signal */
+ int dqsez, /* difference from 2-pole predictor */
+ struct g72x_state *state_ptr) /* coder state pointer */
+{
+ int cnt;
+ short mag, exp; /* Adaptive predictor, FLOAT A */
+ short a2p = 0; /* LIMC */
+ short a1ul; /* UPA1 */
+ short pks1; /* UPA2 */
+ short fa1;
+ char tr; /* tone/transition detector */
+ short ylint, thr2, dqthr;
+ short ylfrac, thr1;
+ short pk0;
+
+ pk0 = (dqsez < 0) ? 1 : 0; /* needed in updating predictor poles */
+
+ mag = dq & 0x7FFF; /* prediction difference magnitude */
+ /* TRANS */
+ ylint = state_ptr->yl >> 15; /* exponent part of yl */
+ ylfrac = (state_ptr->yl >> 10) & 0x1F; /* fractional part of yl */
+ thr1 = (32 + ylfrac) << ylint; /* threshold */
+ thr2 = (ylint > 9) ? 31 << 10 : thr1; /* limit thr2 to 31 << 10 */
+ dqthr = (thr2 + (thr2 >> 1)) >> 1; /* dqthr = 0.75 * thr2 */
+ if (state_ptr->td == 0) /* signal supposed voice */
+ tr = 0;
+ else if (mag <= dqthr) /* supposed data, but small mag */
+ tr = 0; /* treated as voice */
+ else /* signal is data (modem) */
+ tr = 1;
+
+ /*
+ * Quantizer scale factor adaptation.
+ */
+
+ /* FUNCTW & FILTD & DELAY */
+ /* update non-steady state step size multiplier */
+ state_ptr->yu = y + ((wi - y) >> 5);
+
+ /* LIMB */
+ if (state_ptr->yu < 544) /* 544 <= yu <= 5120 */
+ state_ptr->yu = 544;
+ else if (state_ptr->yu > 5120)
+ state_ptr->yu = 5120;
+
+ /* FILTE & DELAY */
+ /* update steady state step size multiplier */
+ state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6);
+
+ /*
+ * Adaptive predictor coefficients.
+ */
+ if (tr == 1) { /* reset a's and b's for modem signal */
+ state_ptr->a[0] = 0;
+ state_ptr->a[1] = 0;
+ state_ptr->b[0] = 0;
+ state_ptr->b[1] = 0;
+ state_ptr->b[2] = 0;
+ state_ptr->b[3] = 0;
+ state_ptr->b[4] = 0;
+ state_ptr->b[5] = 0;
+ } else { /* update a's and b's */
+ pks1 = pk0 ^ state_ptr->pk[0]; /* UPA2 */
+
+ /* update predictor pole a[1] */
+ a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7);
+ if (dqsez != 0) {
+ fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0];
+ if (fa1 < -8191) /* a2p = function of fa1 */
+ a2p -= 0x100;
+ else if (fa1 > 8191)
+ a2p += 0xFF;
+ else
+ a2p += fa1 >> 5;
+
+ if (pk0 ^ state_ptr->pk[1])
+ /* LIMC */
+ if (a2p <= -12160)
+ a2p = -12288;
+ else if (a2p >= 12416)
+ a2p = 12288;
+ else
+ a2p -= 0x80;
+ else if (a2p <= -12416)
+ a2p = -12288;
+ else if (a2p >= 12160)
+ a2p = 12288;
+ else
+ a2p += 0x80;
+ }
+
+ /* TRIGB & DELAY */
+ state_ptr->a[1] = a2p;
+
+ /* UPA1 */
+ /* update predictor pole a[0] */
+ state_ptr->a[0] -= state_ptr->a[0] >> 8;
+ if (dqsez != 0) {
+ if (pks1 == 0)
+ state_ptr->a[0] += 192;
+ else
+ state_ptr->a[0] -= 192;
+ }
+
+ /* LIMD */
+ a1ul = 15360 - a2p;
+ if (state_ptr->a[0] < -a1ul)
+ state_ptr->a[0] = -a1ul;
+ else if (state_ptr->a[0] > a1ul)
+ state_ptr->a[0] = a1ul;
+
+ /* UPB : update predictor zeros b[6] */
+ for (cnt = 0; cnt < 6; cnt++) {
+ if (code_size == 5) /* for 40Kbps G.723 */
+ state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9;
+ else /* for G.721 and 24Kbps G.723 */
+ state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8;
+ if (dq & 0x7FFF) { /* XOR */
+ if ((dq ^ state_ptr->dq[cnt]) >= 0)
+ state_ptr->b[cnt] += 128;
+ else
+ state_ptr->b[cnt] -= 128;
+ }
+ }
+ }
+
+ for (cnt = 5; cnt > 0; cnt--)
+ state_ptr->dq[cnt] = state_ptr->dq[cnt-1];
+ /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
+ if (mag == 0) {
+ state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20;
+ } else {
+ exp = quan(mag, power2, 15);
+ state_ptr->dq[0] = (dq >= 0) ?
+ (exp << 6) + ((mag << 6) >> exp) :
+ (exp << 6) + ((mag << 6) >> exp) - 0x400;
+ }
+
+ state_ptr->sr[1] = state_ptr->sr[0];
+ /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */
+ if (sr == 0) {
+ state_ptr->sr[0] = 0x20;
+ } else if (sr > 0) {
+ exp = quan(sr, power2, 15);
+ state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp);
+ } else if (sr > -32768) {
+ mag = -sr;
+ exp = quan(mag, power2, 15);
+ state_ptr->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400;
+ } else
+ state_ptr->sr[0] = 0xFC20;
+
+ /* DELAY A */
+ state_ptr->pk[1] = state_ptr->pk[0];
+ state_ptr->pk[0] = pk0;
+
+ /* TONE */
+ if (tr == 1) /* this sample has been treated as data */
+ state_ptr->td = 0; /* next one will be treated as voice */
+ else if (a2p < -11776) /* small sample-to-sample correlation */
+ state_ptr->td = 1; /* signal may be data */
+ else /* signal is voice */
+ state_ptr->td = 0;
+
+ /*
+ * Adaptation speed control.
+ */
+ state_ptr->dms += (fi - state_ptr->dms) >> 5; /* FILTA */
+ state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7); /* FILTB */
+
+ if (tr == 1)
+ state_ptr->ap = 256;
+ else if (y < 1536) /* SUBTC */
+ state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
+ else if (state_ptr->td == 1)
+ state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
+ else if (abs((state_ptr->dms << 2) - state_ptr->dml) >=
+ (state_ptr->dml >> 3))
+ state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
+ else
+ state_ptr->ap += (-state_ptr->ap) >> 4;
+}
+
+/*
+ * tandem_adjust(sr, se, y, i, sign)
+ *
+ * At the end of ADPCM decoding, it simulates an encoder which may be receiving
+ * the output of this decoder as a tandem process. If the output of the
+ * simulated encoder differs from the input to this decoder, the decoder output
+ * is adjusted by one level of A-law or u-law codes.
+ *
+ * Input:
+ * sr decoder output linear PCM sample,
+ * se predictor estimate sample,
+ * y quantizer step size,
+ * i decoder input code,
+ * sign sign bit of code i
+ *
+ * Return:
+ * adjusted A-law or u-law compressed sample.
+ */
+int
+tandem_adjust_alaw(
+ int sr, /* decoder output linear PCM sample */
+ int se, /* predictor estimate sample */
+ int y, /* quantizer step size */
+ int i, /* decoder input code */
+ int sign,
+ short *qtab)
+{
+ unsigned char sp; /* A-law compressed 8-bit code */
+ short dx; /* prediction error */
+ char id; /* quantized prediction error */
+ int sd; /* adjusted A-law decoded sample value */
+ int im; /* biased magnitude of i */
+ int imx; /* biased magnitude of id */
+
+ if (sr <= -32768)
+ sr = -1;
+ sp = linear2alaw((sr >> 1) << 3); /* short to A-law compression */
+ dx = (alaw2linear(sp) >> 2) - se; /* 16-bit prediction error */
+ id = quantize(dx, y, qtab, sign - 1);
+
+ if (id == i) { /* no adjustment on sp */
+ return (sp);
+ } else { /* sp adjustment needed */
+ /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
+ im = i ^ sign; /* 2's complement to biased unsigned */
+ imx = id ^ sign;
+
+ if (imx > im) { /* sp adjusted to next lower value */
+ if (sp & 0x80) {
+ sd = (sp == 0xD5) ? 0x55 :
+ ((sp ^ 0x55) - 1) ^ 0x55;
+ } else {
+ sd = (sp == 0x2A) ? 0x2A :
+ ((sp ^ 0x55) + 1) ^ 0x55;
+ }
+ } else { /* sp adjusted to next higher value */
+ if (sp & 0x80)
+ sd = (sp == 0xAA) ? 0xAA :
+ ((sp ^ 0x55) + 1) ^ 0x55;
+ else
+ sd = (sp == 0x55) ? 0xD5 :
+ ((sp ^ 0x55) - 1) ^ 0x55;
+ }
+ return (sd);
+ }
+}
+
+int
+tandem_adjust_ulaw(
+ int sr, /* decoder output linear PCM sample */
+ int se, /* predictor estimate sample */
+ int y, /* quantizer step size */
+ int i, /* decoder input code */
+ int sign,
+ short *qtab)
+{
+ unsigned char sp; /* u-law compressed 8-bit code */
+ short dx; /* prediction error */
+ char id; /* quantized prediction error */
+ int sd; /* adjusted u-law decoded sample value */
+ int im; /* biased magnitude of i */
+ int imx; /* biased magnitude of id */
+
+ if (sr <= -32768)
+ sr = 0;
+ sp = linear2ulaw(sr << 2); /* short to u-law compression */
+ dx = (ulaw2linear(sp) >> 2) - se; /* 16-bit prediction error */
+ id = quantize(dx, y, qtab, sign - 1);
+ if (id == i) {
+ return (sp);
+ } else {
+ /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
+ im = i ^ sign; /* 2's complement to biased unsigned */
+ imx = id ^ sign;
+ if (imx > im) { /* sp adjusted to next lower value */
+ if (sp & 0x80)
+ sd = (sp == 0xFF) ? 0x7E : sp + 1;
+ else
+ sd = (sp == 0) ? 0 : sp - 1;
+
+ } else { /* sp adjusted to next higher value */
+ if (sp & 0x80)
+ sd = (sp == 0x80) ? 0x80 : sp - 1;
+ else
+ sd = (sp == 0x7F) ? 0xFE : sp + 1;
+ }
+ return (sd);
+ }
+}