Pad ff_cos_tabs and ff_sin_tabs so that index n points to the table for n bits.

While this "wastes" up to 2x32 bytes it makes the code slightly simpler and
less confusing.

Originally committed as revision 20449 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/dsputil.h

@@ -767,7 +767,7 @@ extern COSTABLE(8192);
 extern COSTABLE(16384);
 extern COSTABLE(32768);
 extern COSTABLE(65536);
-extern COSTABLE_CONST FFTSample* const ff_cos_tabs[13];
+extern COSTABLE_CONST FFTSample* const ff_cos_tabs[17];
 
 extern SINTABLE(16);
 extern SINTABLE(32);

libavcodec/fft.c

@@ -45,6 +45,7 @@ COSTABLE(32768);
 COSTABLE(65536);
 #endif
 COSTABLE_CONST FFTSample * const ff_cos_tabs[] = {
+    NULL, NULL, NULL, NULL,
     ff_cos_16, ff_cos_32, ff_cos_64, ff_cos_128, ff_cos_256, ff_cos_512, ff_cos_1024,
     ff_cos_2048, ff_cos_4096, ff_cos_8192, ff_cos_16384, ff_cos_32768, ff_cos_65536,
 };
@@ -99,7 +100,7 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
         for(j=4; j<=nbits; j++) {
             int m = 1<<j;
             double freq = 2*M_PI/m;
-            FFTSample *tab = ff_cos_tabs[j-4];
+            FFTSample *tab = ff_cos_tabs[j];
             for(i=0; i<=m/4; i++)
                 tab[i] = cos(i*freq);
             for(i=1; i<m/4; i++)

libavcodec/rdft.c

@@ -43,6 +43,7 @@ SINTABLE(32768);
 SINTABLE(65536);
 #endif
 SINTABLE_CONST FFTSample * const ff_sin_tabs[] = {
+    NULL, NULL, NULL, NULL,
     ff_sin_16, ff_sin_32, ff_sin_64, ff_sin_128, ff_sin_256, ff_sin_512, ff_sin_1024,
     ff_sin_2048, ff_sin_4096, ff_sin_8192, ff_sin_16384, ff_sin_32768, ff_sin_65536,
 };
@@ -63,8 +64,8 @@ av_cold int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans)
     if (ff_fft_init(&s->fft, nbits-1, trans == IRDFT || trans == RIDFT) < 0)
         return -1;
 
-    s->tcos = ff_cos_tabs[nbits-4];
-    s->tsin = ff_sin_tabs[nbits-4]+(trans == RDFT || trans == IRIDFT)*(n>>2);
+    s->tcos = ff_cos_tabs[nbits];
+    s->tsin = ff_sin_tabs[nbits]+(trans == RDFT || trans == IRIDFT)*(n>>2);
 #if !CONFIG_HARDCODED_TABLES
     for (i = 0; i < (n>>2); i++) {
         s->tsin[i] = sin(i*theta);