swap to new ilbc library

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@12095 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/ilbc/src/gainquant.c

@@ -0,0 +1,111 @@
+/*
+ * iLBC - a library for the iLBC codec
+ *
+ * gainquant.c - The iLBC low bit rate speech codec.
+ *
+ * Adapted by Steve Underwood <steveu@coppice.org> from the reference
+ * iLBC code supplied in RFC3951.
+ *
+ * Original code Copyright (C) The Internet Society (2004).
+ * All changes to produce this version Copyright (C) 2008 by Steve Underwood
+ * All Rights Reserved.
+ *
+ * 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.
+ *
+ * $Id: gainquant.c,v 1.2 2008/03/06 12:27:38 steveu Exp $
+ */
+
+/*! \file */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <inttypes.h>
+#include <math.h>
+#include <string.h>
+
+#include "constants.h"
+#include "filter.h"
+#include "gainquant.h"
+
+/*----------------------------------------------------------------*
+ *  quantizer for the gain in the gain-shape coding of residual
+ *---------------------------------------------------------------*/
+
+float gainquant(                /* (o) quantized gain value */
+                float in,       /* (i) gain value */
+                float maxIn,    /* (i) maximum of gain value */
+                int cblen,      /* (i) number of quantization indices */
+                int *index)     /* (o) quantization index */
+{
+    int i;
+    int tindex;
+    float minmeasure;
+    float measure;
+    const float *cb;
+    float scale;
+
+    /* ensure a lower bound on the scaling factor */
+    scale = maxIn;
+
+    if (scale < 0.1f)
+        scale = 0.1f;
+
+    /* select the quantization table */
+    if (cblen == 8)
+        cb = gain_sq3Tbl;
+    else if (cblen == 16)
+        cb = gain_sq4Tbl;
+    else
+        cb = gain_sq5Tbl;
+
+    /* select the best index in the quantization table */
+    minmeasure = 10000000.0f;
+    tindex = 0;
+    for (i = 0;  i < cblen;  i++)
+    {
+        measure = (in-scale*cb[i])*(in-scale*cb[i]);
+
+        if (measure < minmeasure)
+        {
+            tindex = i;
+            minmeasure = measure;
+        }
+    }
+    *index = tindex;
+
+    /* return the quantized value */
+    return scale*cb[tindex];
+}
+
+/*----------------------------------------------------------------*
+ *  decoder for quantized gains in the gain-shape coding of
+ *  residual
+ *---------------------------------------------------------------*/
+
+float gaindequant(              /* (o) quantized gain value */
+                  int index,    /* (i) quantization index */
+                  float maxIn,  /* (i) maximum of unquantized gain */
+                  int cblen)    /* (i) number of quantization indices */
+{
+    float scale;
+
+    /* obtain correct scale factor */
+    scale = fabsf(maxIn);
+
+    if (scale < 0.1f)
+        scale = 0.1f;
+
+    /* select the quantization table and return the decoded value */
+    if (cblen == 8)
+        return scale*gain_sq3Tbl[index];
+    if (cblen == 16)
+        return scale*gain_sq4Tbl[index];
+    if (cblen == 32)
+        return scale*gain_sq5Tbl[index];
+
+    return 0.0;
+}