internal checkpoint

split kiss_fft.c into multiple files.  It seems the best approach, all things considered.

CHANGELOG

@@ -1,3 +1,9 @@
+1.0
+    changed kiss_fft function from using a single buffer, to two buffers.
+    If the same buffer pointer is supplied for both in and out, kiss will
+    manage the buffer copies.
+
+
 
 
 0.4 : optimized for radix 2,3,4,5

TIPS

@@ -0,0 +1,16 @@
+Speed:
+    * experiment with compiler flags
+        Special thanks to Oscar Lesta. He suggested some compiler flags 
+        for gcc that make a big difference. They shave 10-15% off
+        execution time on some systems.  Try some combination of:
+                -march=pentiumpro
+                -ffast-math
+                -fomit-frame-pointer
+
+Reducing code size:
+    * remove some of the butterflies. There are currently butterflies optimized for radices
+        2,3,4,5.  It is worth mentioning that you can still use FFT sizes that contain 
+        these factors, they just won't be quite as fast.  You can decide for yourself 
+        whether to keep radix 2 or 4.  If you do some work in this area, let me 
+        know what you find.
+

_kiss_fft_guts.h

@@ -0,0 +1,83 @@
+/*
+Copyright (c) 2003, Mark Borgerding
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+    * Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* kiss_fft.h
+   defines kiss_fft_scalar as either short or a float type
+   and defines
+   typedef struct { kiss_fft_scalar r; kiss_fft_scalar i; }kiss_fft_cpx; */
+#include "kiss_fft.h"
+
+typedef struct {
+    int nfft;
+    int inverse;
+    int *factors;
+    kiss_fft_cpx * twiddles;
+    kiss_fft_cpx * tmpbuf;
+    kiss_fft_cpx * scratch;
+}kiss_fft_state;
+
+/*
+  Explanation of macros dealing with complex math:
+
+   C_MUL(m,a,b)         : m = a*b
+   C_FIXDIV( c , div )  : if a fixed point impl., c /= div. noop otherwise
+   C_SUB( res, a,b)     : res = a - b
+   C_SUBFROM( res , a)  : res -= a
+   C_ADDTO( res , a)    : res += a
+ * */
+#ifdef FIXED_POINT
+#   define S_MUL(a,b) ( ( (a)*(b) + (1<<14) )>>15 )
+#   define C_MUL(m,a,b) \
+      do{ (m).r = ( ( (a).r*(b).r - (a).i*(b).i)  + (1<<14) ) >> 15;\
+          (m).i = ( ( (a).r*(b).i + (a).i*(b).r)  + (1<<14) ) >> 15;\
+      }while(0)
+#   define C_FIXDIV(c,div) \
+    do{ (c).r /= div; (c).i /=div; }while(0)
+
+#   define C_MULBYSCALAR( c, s ) \
+    do{ (c).r = ( ( (c).r*(s) ) + (1<<14) ) >> 15;\
+        (c).i = ( ( (c).i*(s) ) + (1<<14) ) >> 15; }while(0)
+
+#else  /* not FIXED_POINT*/
+
+#   define S_MUL(a,b) ( (a)*(b) )
+#define C_MUL(m,a,b) \
+    do{ (m).r = (a).r*(b).r - (a).i*(b).i;\
+        (m).i = (a).r*(b).i + (a).i*(b).r; }while(0)
+#   define C_FIXDIV(c,div) /* NOOP */
+#   define C_MULBYSCALAR( c, s ) \
+    do{ (c).r *= (s);\
+        (c).i *= (s); }while(0)
+#endif
+
+#define  C_ADD( res, a,b)\
+    do {    (res).r=(a).r+(b).r;  (res).i=(a).i+(b).i;  }while(0)
+#define  C_SUB( res, a,b)\
+    do {    (res).r=(a).r-(b).r;  (res).i=(a).i-(b).i;  }while(0)
+#define C_ADDTO( res , a)\
+    do {    (res).r += (a).r;  (res).i += (a).i;  }while(0)
+#define C_SUBFROM( res , a)\
+    do {    (res).r -= (a).r;  (res).i -= (a).i;  }while(0)
+
+kiss_fft_cpx kf_cexp(double phase);
+int kf_allocsize(int nfft);
+void kf_init_state(kiss_fft_state * st,int nfft,int inverse_fft);
+void kf_work(
+        kiss_fft_cpx * Fout,
+        const kiss_fft_cpx * f,
+        int fstride,
+        int * factors,
+        const kiss_fft_state * st
+        );
+