Moving src/webrtc into src/.

In order to eliminate the WebRTC Subtree mirror in Chromium, 
WebRTC is moving the content of the src/webrtc directory up
to the src/ directory.

NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
TBR=tommi@webrtc.org

Bug: chromium:611808
Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38
Reviewed-on: https://webrtc-review.googlesource.com/1560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#19845}

modules/audio_coding/codecs/ilbc/poly_to_lsp.c

@@ -0,0 +1,158 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/******************************************************************
+
+ iLBC Speech Coder ANSI-C Source Code
+
+ WebRtcIlbcfix_Poly2Lsp.c
+
+******************************************************************/
+
+#include "defines.h"
+#include "constants.h"
+#include "chebyshev.h"
+
+/*----------------------------------------------------------------*
+ * conversion from lpc coefficients to lsp coefficients
+ * function is only for 10:th order LPC
+ *---------------------------------------------------------------*/
+
+void WebRtcIlbcfix_Poly2Lsp(
+    int16_t *a,  /* (o) A coefficients in Q12 */
+    int16_t *lsp, /* (i) LSP coefficients in Q15 */
+    int16_t *old_lsp /* (i) old LSP coefficients that are used if the new
+                              coefficients turn out to be unstable */
+                            ) {
+  int16_t f[2][6]; /* f[0][] represents f1 and f[1][] represents f2 */
+  int16_t *a_i_ptr, *a_10mi_ptr;
+  int16_t *f1ptr, *f2ptr;
+  int32_t tmpW32;
+  int16_t x, y, xlow, ylow, xmid, ymid, xhigh, yhigh, xint;
+  int16_t shifts, sign;
+  int i, j;
+  int foundFreqs;
+  int fi_select;
+
+  /*
+     Calculate the two polynomials f1(z) and f2(z)
+     (the sum and the diff polynomial)
+     f1[0] = f2[0] = 1.0;
+     f1[i+1] = a[i+1] + a[10-i] - f1[i];
+     f2[i+1] = a[i+1] - a[10-i] - f1[i];
+  */
+
+  a_i_ptr = a + 1;
+  a_10mi_ptr = a + 10;
+  f1ptr = f[0];
+  f2ptr = f[1];
+  (*f1ptr) = 1024; /* 1.0 in Q10 */
+  (*f2ptr) = 1024; /* 1.0 in Q10 */
+  for (i = 0; i < 5; i++) {
+    *(f1ptr + 1) =
+        (int16_t)((((int32_t)(*a_i_ptr) + *a_10mi_ptr) >> 2) - *f1ptr);
+    *(f2ptr + 1) =
+        (int16_t)((((int32_t)(*a_i_ptr) - *a_10mi_ptr) >> 2) + *f2ptr);
+    a_i_ptr++;
+    a_10mi_ptr--;
+    f1ptr++;
+    f2ptr++;
+  }
+
+  /*
+    find the LSPs using the Chebychev pol. evaluation
+  */
+
+  fi_select = 0; /* selector between f1 and f2, start with f1 */
+
+  foundFreqs = 0;
+
+  xlow = WebRtcIlbcfix_kCosGrid[0];
+  ylow = WebRtcIlbcfix_Chebyshev(xlow, f[fi_select]);
+
+  /*
+     Iterate until all the 10 LSP's have been found or
+     all the grid points have been tried. If the 10 LSP's can
+     not be found, set the LSP vector to previous LSP
+  */
+
+  for (j = 1; j < COS_GRID_POINTS && foundFreqs < 10; j++) {
+    xhigh = xlow;
+    yhigh = ylow;
+    xlow = WebRtcIlbcfix_kCosGrid[j];
+    ylow = WebRtcIlbcfix_Chebyshev(xlow, f[fi_select]);
+
+    if (ylow * yhigh <= 0) {
+      /* Run 4 times to reduce the interval */
+      for (i = 0; i < 4; i++) {
+        /* xmid =(xlow + xhigh)/2 */
+        xmid = (xlow >> 1) + (xhigh >> 1);
+        ymid = WebRtcIlbcfix_Chebyshev(xmid, f[fi_select]);
+
+        if (ylow * ymid <= 0) {
+          yhigh = ymid;
+          xhigh = xmid;
+        } else {
+          ylow = ymid;
+          xlow = xmid;
+        }
+      }
+
+      /*
+        Calculater xint by linear interpolation:
+        xint = xlow - ylow*(xhigh-xlow)/(yhigh-ylow);
+      */
+
+      x = xhigh - xlow;
+      y = yhigh - ylow;
+
+      if (y == 0) {
+        xint = xlow;
+      } else {
+        sign = y;
+        y = WEBRTC_SPL_ABS_W16(y);
+        shifts = (int16_t)WebRtcSpl_NormW32(y)-16;
+        y <<= shifts;
+        y = (int16_t)WebRtcSpl_DivW32W16(536838144, y); /* 1/(yhigh-ylow) */
+
+        tmpW32 = (x * y) >> (19 - shifts);
+
+        /* y=(xhigh-xlow)/(yhigh-ylow) */
+        y = (int16_t)(tmpW32&0xFFFF);
+
+        if (sign < 0) {
+          y = -y;
+        }
+        /* tmpW32 = ylow*(xhigh-xlow)/(yhigh-ylow) */
+        tmpW32 = (ylow * y) >> 10;
+        xint = xlow-(int16_t)(tmpW32&0xFFFF);
+      }
+
+      /* Store the calculated lsp */
+      lsp[foundFreqs] = (int16_t)xint;
+      foundFreqs++;
+
+      /* if needed, set xlow and ylow for next recursion */
+      if (foundFreqs<10) {
+        xlow = xint;
+        /* Swap between f1 and f2 (f[0][] and f[1][]) */
+        fi_select = ((fi_select+1)&0x1);
+
+        ylow = WebRtcIlbcfix_Chebyshev(xlow, f[fi_select]);
+      }
+    }
+  }
+
+  /* Check if M roots found, if not then use the old LSP */
+  if (foundFreqs < 10) {
+    WEBRTC_SPL_MEMCPY_W16(lsp, old_lsp, 10);
+  }
+  return;
+}