--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/gsm0610_short_term.c	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,360 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * gsm0610_short_term.c - GSM 06.10 full rate speech codec.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2006 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * This code is based on the widely used GSM 06.10 code available from
+ * http://kbs.cs.tu-berlin.de/~jutta/toast.html
+ *
+ * $Id: gsm0610_short_term.c,v 1.9 2006/11/30 15:41:47 steveu Exp $
+ */
+
+/*! \file */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <assert.h>
+#include <inttypes.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+#include <stdlib.h>
+
+#include "spandsp/telephony.h"
+#include "spandsp/dc_restore.h"
+#include "spandsp/gsm0610.h"
+
+#include "gsm0610_local.h"
+
+/* SHORT TERM ANALYSIS FILTERING SECTION */
+
+/* 4.2.8 */
+static void decode_log_area_ratios(int16_t LARc[8], int16_t *LARpp)
+{
+    int16_t temp1;
+
+    /* This procedure requires for efficient implementation
+       two tables.
+       INVA[1..8] = integer((32768*8)/real_A[1..8])
+       MIC[1..8]  = minimum value of the LARc[1..8]
+    */
+
+    /* Compute the LARpp[1..8] */
+
+#undef STEP
+#define STEP(B,MIC,INVA)                        \
+    temp1 = gsm_add(*LARc++, MIC) << 10;       \
+    temp1 = gsm_sub(temp1, B << 1);            \
+    temp1 = gsm_mult_r (INVA, temp1);           \
+    *LARpp++ = gsm_add(temp1, temp1);
+
+    STEP(    0,  -32,  13107);
+    STEP(    0,  -32,  13107);
+    STEP( 2048,  -16,  13107);
+    STEP(-2560,  -16,  13107);
+
+    STEP(   94,   -8,  19223);
+    STEP(-1792,   -8,  17476);
+    STEP( -341,   -4,  31454);
+    STEP(-1144,   -4,  29708);
+
+    /* NOTE: the addition of *MIC is used to restore the sign of *LARc. */
+}
+/*- End of function --------------------------------------------------------*/
+
+/* 4.2.9 */
+
+/* Computation of the quantized reflection coefficients */
+
+/* 4.2.9.1  Interpolation of the LARpp[1..8] to get the LARp[1..8] */
+
+/* Within each frame of 160 analyzed speech samples the short term
+   analysis and synthesis filters operate with four different sets of
+   coefficients, derived from the previous set of decoded LARs(LARpp(j - 1))
+   and the actual set of decoded LARs (LARpp(j))
+  
+   (Initial value: LARpp(j - 1)[1..8] = 0.)
+*/
+
+static void coefficients_0_12(int16_t *LARpp_j_1,
+                              int16_t *LARpp_j,
+                              int16_t *LARp)
+{
+    int i;
+
+    for (i = 1;  i <= 8;  i++, LARp++, LARpp_j_1++, LARpp_j++)
+    {
+        *LARp = gsm_add(*LARpp_j_1 >> 2, *LARpp_j >> 2);
+        *LARp = gsm_add(*LARp, *LARpp_j_1 >> 1);
+    }
+    /*endfor*/
+}
+/*- End of function --------------------------------------------------------*/
+
+static void coefficients_13_26(int16_t *LARpp_j_1,
+                               int16_t *LARpp_j,
+                               int16_t *LARp)
+{
+    int i;
+
+    for (i = 1;  i <= 8;  i++, LARpp_j_1++, LARpp_j++, LARp++)
+        *LARp = gsm_add(*LARpp_j_1 >> 1, *LARpp_j >> 1);
+    /*endfor*/
+}
+/*- End of function --------------------------------------------------------*/
+
+static void coefficients_27_39(int16_t *LARpp_j_1,
+                               int16_t *LARpp_j,
+                               int16_t *LARp)
+{
+    int i;
+
+    for (i = 1;  i <= 8;  i++, LARpp_j_1++, LARpp_j++, LARp++)
+    {
+        *LARp = gsm_add(*LARpp_j_1 >> 2, *LARpp_j >> 2);
+        *LARp = gsm_add(*LARp, *LARpp_j >> 1);
+    }
+    /*endfor*/
+}
+/*- End of function --------------------------------------------------------*/
+
+static void coefficients_40_159(int16_t *LARpp_j, int16_t *LARp)
+{
+    int i;
+
+    for (i = 1;  i <= 8;  i++)
+        *LARp++ = *LARpp_j++;
+    /*endfor*/
+}
+/*- End of function --------------------------------------------------------*/
+
+/* 4.2.9.2 */
+static void larp_to_rp(int16_t LARp[8])
+{
+    int i;
+    int16_t *LARpx;
+    int16_t temp;
+
+    /* The input to this procedure is the interpolated LARp[0..7] array.
+       The reflection coefficients, rp[i], are used in the analysis
+       filter and in the synthesis filter.
+    */
+
+    LARpx = LARp;
+    for (i = 1;  i <= 8;  i++, LARpx++)
+    {
+        temp = *LARpx;
+        if (temp < 0)
+        {
+            if (temp == INT16_MIN)
+                temp = INT16_MAX;
+            else
+                temp = -temp;
+            /*endif*/
+            if (temp < 11059)
+                temp <<= 1;
+            else if (temp < 20070)
+                temp += 11059;
+            else
+                temp = gsm_add(temp >> 2, 26112);
+            /*endif*/
+            *LARpx = -temp;
+        }
+        else
+        {
+            if (temp < 11059)
+                temp <<= 1;
+            else if (temp < 20070)
+                temp += 11059;
+            else
+                temp = gsm_add(temp >> 2, 26112);
+            /*endif*/
+            *LARpx = temp;
+        }
+        /*endif*/
+    }
+    /*endfor*/
+}
+/*- End of function --------------------------------------------------------*/
+
+/* 4.2.10 */
+static void short_term_analysis_filtering(gsm0610_state_t *s,
+                                          int16_t rp[8],
+                                          int k_n,          // k_end - k_start
+                                          int16_t amp[])    // [0..n-1]     IN/OUT
+{
+    /* This procedure computes the short term residual signal d[..] to be fed
+       to the RPE-LTP loop from the s[..] signal and from the local rp[..]
+       array (quantized reflection coefficients).  As the call of this
+       procedure can be done in many ways (see the interpolation of the LAR
+       coefficient), it is assumed that the computation begins with index
+       k_start (for arrays d[..] and s[..]) and stops with index k_end
+       (k_start and k_end are defined in 4.2.9.1).  This procedure also
+       needs to keep the array u[0..7] in memory for each call.
+    */
+    int16_t *u0;
+    int16_t *u_top;
+    int i;
+    int16_t *u;
+    int16_t *rpx;
+    int32_t di;
+    int32_t u_out;
+
+    u0 = s->u;
+    u_top = u0 + 8;
+
+    for (i = 0;  i < k_n;  i++)
+    {
+        di =
+        u_out = amp[i];
+        for (rpx = rp, u = u0;  u < u_top;  )
+        {
+            int32_t ui;
+            int32_t rpi;
+
+            ui = *u;
+            *u++ = (int16_t) u_out;
+            rpi = *rpx++;
+            u_out = ui + (((rpi*di) + 0x4000) >> 15);
+            di = di + (((rpi*ui) + 0x4000) >> 15);
+            u_out = saturate(u_out);
+            di = saturate(di);
+        }
+        /*endfor*/
+        amp[i] = (int16_t) di;
+    }
+    /*endfor*/
+}
+/*- End of function --------------------------------------------------------*/
+
+static void short_term_synthesis_filtering(gsm0610_state_t *s,
+                                           int16_t rrp[8],
+                                           int k,          // k_end - k_start
+                                           int16_t *wt,    // [0..k - 1]
+                                           int16_t *sr)    // [0..k - 1]
+{
+    int16_t *v;
+    int i;
+    int16_t sri;
+    int16_t tmp1;
+    int16_t tmp2;
+
+    v = s->v;
+    while (k--)
+    {
+        sri = *wt++;
+        for (i = 8;  i--;  )
+        {
+            tmp1 = rrp[i];
+            tmp2 = v[i];
+            tmp2 = ((tmp1 == INT16_MIN  &&  tmp2 == INT16_MIN)
+                   ?
+                   INT16_MAX
+                   :
+                   (int16_t) (((int32_t) tmp1*(int32_t) tmp2 + 16384) >> 15) & 0xFFFF);
+
+            sri = gsm_sub(sri, tmp2);
+
+            tmp1 = ((tmp1 == INT16_MIN  &&  sri == INT16_MIN)
+                    ?
+                    INT16_MAX
+                    :
+                    (int16_t) (((int32_t) tmp1*(int32_t) sri + 16384) >> 15) & 0xFFFF);
+
+            v[i + 1] = gsm_add(v[i], tmp1);
+        }
+        /*endfor*/
+        *sr++ =
+        v[0] = sri;
+    }
+    /*endwhile*/
+}
+/*- End of function --------------------------------------------------------*/
+
+void gsm0610_short_term_analysis_filter(gsm0610_state_t *s,
+                                        int16_t LARc[8],
+                                        int16_t amp[GSM0610_FRAME_LEN])
+{
+    int16_t *LARpp_j;
+    int16_t *LARpp_j_1;
+    int16_t LARp[8];
+
+    LARpp_j = s->LARpp[s->j];
+    LARpp_j_1 = s->LARpp[s->j ^= 1];
+
+    decode_log_area_ratios(LARc, LARpp_j);
+
+    coefficients_0_12(LARpp_j_1, LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_analysis_filtering(s, LARp, 13, amp);
+
+    coefficients_13_26(LARpp_j_1, LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_analysis_filtering(s, LARp, 14, amp + 13);
+
+    coefficients_27_39(LARpp_j_1, LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_analysis_filtering(s, LARp, 13, amp + 27);
+
+    coefficients_40_159(LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_analysis_filtering(s, LARp, 120, amp + 40);
+}
+/*- End of function --------------------------------------------------------*/
+
+void gsm0610_short_term_synthesis_filter(gsm0610_state_t *s,
+                                         int16_t LARcr[8],
+                                         int16_t wt[GSM0610_FRAME_LEN],
+                                         int16_t amp[GSM0610_FRAME_LEN])
+{
+    int16_t *LARpp_j;
+    int16_t *LARpp_j_1;
+    int16_t LARp[8];
+
+    LARpp_j = s->LARpp[s->j];
+    LARpp_j_1 = s->LARpp[s->j ^= 1];
+
+    decode_log_area_ratios(LARcr, LARpp_j);
+
+    coefficients_0_12(LARpp_j_1, LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_synthesis_filtering(s, LARp, 13, wt, amp);
+
+    coefficients_13_26(LARpp_j_1, LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_synthesis_filtering(s, LARp, 14, wt + 13, amp + 13);
+
+    coefficients_27_39(LARpp_j_1, LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_synthesis_filtering(s, LARp, 13, wt + 27, amp + 27);
+
+    coefficients_40_159(LARpp_j, LARp);
+    larp_to_rp(LARp);
+    short_term_synthesis_filtering(s, LARp, 120, wt + 40, amp + 40);
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/