Include iLBC source code for distribution with Asterisk

This patch includes the iLBC source code for distribution with Asterisk.
Clarification regarding the iLBC source code was provided by Google, and
the appropriate licenses have been included in the codecs/ilbc folder.

Review: https://reviewboard.asterisk.org/r/1675
Review: https://reviewboard.asterisk.org/r/1649

(closes issue: ASTERISK-18943)
Reporter: Leif Madsen
Tested by: Matt Jordan
........

Merged revisions 351450 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 351451 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@351452 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 116 insertions, 0 deletions

diff --git a/codecs/ilbc/gainquant.c b/codecs/ilbc/gainquant.c
new file mode 100644
index 000000000..0e74ff827
--- /dev/null
+++ b/codecs/ilbc/gainquant.c
@@ -0,0 +1,116 @@
+
+   /******************************************************************
+
+       iLBC Speech Coder ANSI-C Source Code
+
+
+
+
+
+
+       gainquant.c
+
+       Copyright (C) The Internet Society (2004).
+       All Rights Reserved.
+
+   ******************************************************************/
+
+   #include <string.h>
+   #include <math.h>
+   #include "constants.h"
+   #include "filter.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, tindex;
+       float minmeasure,measure, *cb, scale;
+
+       /* ensure a lower bound on the scaling factor */
+
+       scale=maxIn;
+
+       if (scale<0.1) {
+           scale=(float)0.1;
+       }
+
+       /* 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=10000000.0;
+       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=(float)fabs(maxIn);
+
+       if (scale<0.1) {
+           scale=(float)0.1;
+       }
+
+       /* select the quantization table and return the decoded value */
+
+       if (cblen==8) {
+           return scale*gain_sq3Tbl[index];
+       } else if (cblen==16) {
+           return scale*gain_sq4Tbl[index];
+       }
+       else if (cblen==32) {
+           return scale*gain_sq5Tbl[index];
+       }
+
+       return 0.0;
+   }
+
+
+
+
+
+