Use hardcoded instead of runtime-calculated ff_cos_* tables if

--enable-hardcoded-tables was used.
Due to the size, the code for the tables is generated at compile time.

Originally committed as revision 20232 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/Makefile

@@ -27,7 +27,8 @@ OBJS = allcodecs.o                                                      \
 # parts needed for many different codecs
 OBJS-$(CONFIG_AANDCT)                  += aandcttab.o
 OBJS-$(CONFIG_ENCODERS)                += faandct.o jfdctfst.o jfdctint.o
-OBJS-$(CONFIG_FFT)                     += fft.o
+FFT-OBJS-$(CONFIG_HARDCODED_TABLES)    += cos_tables.o
+OBJS-$(CONFIG_FFT)                     += fft.o $(FFT-OBJS-yes)
 OBJS-$(CONFIG_GOLOMB)                  += golomb.o
 OBJS-$(CONFIG_MDCT)                    += mdct.o
 OBJS-$(CONFIG_RDFT)                    += rdft.o
@@ -571,6 +572,14 @@ TESTPROGS-$(HAVE_MMX) += motion
 
 DIRS = alpha arm bfin mlib ppc ps2 sh4 sparc x86
 
+CLEANFILES = cos_tables.c costablegen$(HOSTEXESUF)
+
 include $(SUBDIR)../subdir.mak
 
 $(SUBDIR)dct-test$(EXESUF): $(SUBDIR)dctref.o
+
+$(SUBDIR)costablegen$(HOSTEXESUF): $(SUBDIR)costablegen.c
+	$(HOSTCC) $(HOSTCFLAGS) $(HOSTLDFLAGS) -o $@ $< $(HOSTLIBS)
+
+$(SUBDIR)cos_tables.c: $(SUBDIR)costablegen$(HOSTEXESUF)
+	./$< > $@

libavcodec/costablegen.c

+/*
+ * Generate a header file for hardcoded ff_cos_* tables
+ *
+ * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdio.h>
+#include <math.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+#define BITS 16
+#define FLOATFMT "%.18e"
+
+int main(void)
+{
+    int i, j;
+    printf("/* This file was generated by libavcodec/costablegen */\n");
+    printf("#include \"dsputil.h\"\n");
+    for (i = 4; i <= BITS; i++) {
+        int m = 1 << i;
+        double freq = 2*M_PI/m;
+        printf("const DECLARE_ALIGNED_16(FFTSample, ff_cos_%i[]) = {\n   ", m);
+        for (j = 0; j < m/2 - 1; j++) {
+            int idx = j > m/4 ? m/2 - j : j;
+            printf(" "FLOATFMT",", cos(idx*freq));
+            if ((j & 3) == 3)
+                printf("\n   ");
+        }
+        printf(" "FLOATFMT"\n};\n", cos(freq));
+    }
+    return 0;
+}

libavcodec/dsputil.h

@@ -742,7 +742,11 @@ typedef struct FFTContext {
 #define FF_MDCT_PERM_INTERLEAVE 1
 } FFTContext;
 
+#if CONFIG_HARDCODED_TABLES
+extern const FFTSample* const ff_cos_tabs[13];
+#else
 extern FFTSample* const ff_cos_tabs[13];
+#endif
 
 /**
  * Sets up a complex FFT.

libavcodec/fft.c

@@ -28,20 +28,31 @@
 
 #include "dsputil.h"
 
+#if CONFIG_HARDCODED_TABLES
+#define COSTABLE(size) \
+    extern const DECLARE_ALIGNED_16(FFTSample, ff_cos_##size[size/2]);
+#else
+#define COSTABLE(size) \
+    DECLARE_ALIGNED_16(FFTSample, ff_cos_##size[size/2]);
+#endif
+
 /* cos(2*pi*x/n) for 0<=x<=n/4, followed by its reverse */
-DECLARE_ALIGNED_16(FFTSample, ff_cos_16[8]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_32[16]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_64[32]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_128[64]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_256[128]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_512[256]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_1024[512]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_2048[1024]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_4096[2048]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_8192[4096]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_16384[8192]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_32768[16384]);
-DECLARE_ALIGNED_16(FFTSample, ff_cos_65536[32768]);
+COSTABLE(16)
+COSTABLE(32)
+COSTABLE(64)
+COSTABLE(128)
+COSTABLE(256)
+COSTABLE(512)
+COSTABLE(1024)
+COSTABLE(2048)
+COSTABLE(4096)
+COSTABLE(8192)
+COSTABLE(16384)
+COSTABLE(32768)
+COSTABLE(65536)
+#if CONFIG_HARDCODED_TABLES
+const
+#endif
 FFTSample * const ff_cos_tabs[] = {
     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,
@@ -93,6 +104,7 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
     if (HAVE_MMX)     ff_fft_init_mmx(s);
 
     if (s->split_radix) {
+#if !CONFIG_HARDCODED_TABLES
         for(j=4; j<=nbits; j++) {
             int m = 1<<j;
             double freq = 2*M_PI/m;
@@ -102,6 +114,7 @@ av_cold int ff_fft_init(FFTContext *s, int nbits, int inverse)
             for(i=1; i<m/4; i++)
                 tab[m/2-i] = tab[i];
         }
+#endif
         for(i=0; i<n; i++)
             s->revtab[-split_radix_permutation(i, n, s->inverse) & (n-1)] = i;
         s->tmp_buf = av_malloc(n * sizeof(FFTComplex));