1 files changed, 93 insertions, 0 deletions
diff --git a/vorbis/lib/lookup.c b/vorbis/lib/lookup.c
new file mode 100644
index 0000000..1cc1f88
--- /dev/null
+++ b/vorbis/lib/lookup.c
@@ -0,0 +1,93 @@
+/********************************************************************
+ *                                                                  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
+ * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
+ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
+ * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
+ *                                                                  *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
+ * by the Xiph.Org Foundation http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************
+
+  function: lookup based functions
+
+ ********************************************************************/
+
+#include <math.h>
+#include "lookup.h"
+#include "lookup_data.h"
+#include "os.h"
+#include "misc.h"
+
+#ifdef FLOAT_LOOKUP
+
+/* interpolated lookup based cos function, domain 0 to PI only */
+float vorbis_coslook(float a){
+  double d=a*(.31830989*(float)COS_LOOKUP_SZ);
+  int i=vorbis_ftoi(d-.5);
+
+  return COS_LOOKUP[i]+ (d-i)*(COS_LOOKUP[i+1]-COS_LOOKUP[i]);
+}
+
+/* interpolated 1./sqrt(p) where .5 <= p < 1. */
+float vorbis_invsqlook(float a){
+  double d=a*(2.f*(float)INVSQ_LOOKUP_SZ)-(float)INVSQ_LOOKUP_SZ;
+  int i=vorbis_ftoi(d-.5f);
+  return INVSQ_LOOKUP[i]+ (d-i)*(INVSQ_LOOKUP[i+1]-INVSQ_LOOKUP[i]);
+}
+
+/* interpolated 1./sqrt(p) where .5 <= p < 1. */
+float vorbis_invsq2explook(int a){
+  return INVSQ2EXP_LOOKUP[a-INVSQ2EXP_LOOKUP_MIN];
+}
+
+#include <stdio.h>
+/* interpolated lookup based fromdB function, domain -140dB to 0dB only */
+float vorbis_fromdBlook(float a){
+  int i=vorbis_ftoi(a*((float)(-(1<<FROMdB2_SHIFT)))-.5f);
+  return (i<0)?1.f:
+    ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f:
+     FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]);
+}
+
+#endif
+
+#ifdef INT_LOOKUP
+/* interpolated 1./sqrt(p) where .5 <= a < 1. (.100000... to .111111...) in
+   16.16 format
+
+   returns in m.8 format */
+long vorbis_invsqlook_i(long a,long e){
+  long i=(a&0x7fff)>>(INVSQ_LOOKUP_I_SHIFT-1);
+  long d=(a&INVSQ_LOOKUP_I_MASK)<<(16-INVSQ_LOOKUP_I_SHIFT); /*  0.16 */
+  long val=INVSQ_LOOKUP_I[i]-                                /*  1.16 */
+    (((INVSQ_LOOKUP_I[i]-INVSQ_LOOKUP_I[i+1])*               /*  0.16 */
+      d)>>16);                                               /* result 1.16 */
+
+  e+=32;
+  if(e&1)val=(val*5792)>>13; /* multiply val by 1/sqrt(2) */
+  e=(e>>1)-8;
+
+  return(val>>e);
+}
+
+/* interpolated lookup based fromdB function, domain -140dB to 0dB only */
+/* a is in n.12 format */
+float vorbis_fromdBlook_i(long a){
+  int i=(-a)>>(12-FROMdB2_SHIFT);
+  return (i<0)?1.f:
+    ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f:
+     FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]);
+}
+
+/* interpolated lookup based cos function, domain 0 to PI only */
+/* a is in 0.16 format, where 0==0, 2^^16-1==PI, return 0.14 */
+long vorbis_coslook_i(long a){
+  int i=a>>COS_LOOKUP_I_SHIFT;
+  int d=a&COS_LOOKUP_I_MASK;
+  return COS_LOOKUP_I[i]- ((d*(COS_LOOKUP_I[i]-COS_LOOKUP_I[i+1]))>>
+                           COS_LOOKUP_I_SHIFT);
+}
+
+#endif