1 files changed, 126 insertions, 0 deletions
diff --git a/src/kiss_fft.h b/src/kiss_fft.h
new file mode 100644
index 0000000..ea1349e
--- /dev/null
+++ b/src/kiss_fft.h
@@ -0,0 +1,126 @@
+#ifndef KISS_FFT_H
+#define KISS_FFT_H
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ ATTENTION!
+ If you would like a :
+ -- a utility that will handle the caching of fft objects
+ -- real-only (no imaginary time component ) FFT
+ -- a multi-dimensional FFT
+ -- a command-line utility to perform ffts
+ -- a command-line utility to perform fast-convolution filtering
+
+ Then see kfc.h kiss_fftr.h kiss_fftnd.h fftutil.c kiss_fastfir.c
+  in the tools/ directory.
+*/
+
+#ifdef USE_SIMD
+#include <xmmintrin.h>
+#define kiss_fft_scalar __m128
+#define KISS_FFT_MALLOC(nbytes) _mm_malloc(nbytes, 16)
+#define KISS_FFT_FREE _mm_free
+#else
+#define KISS_FFT_MALLOC malloc
+#define KISS_FFT_FREE free
+#endif
+
+#ifdef FIXED_POINT
+#include <sys/types.h>
+#if (FIXED_POINT == 32)
+#define kiss_fft_scalar int32_t
+#else
+#define kiss_fft_scalar int16_t
+#endif
+#else
+#ifndef kiss_fft_scalar
+/*  default is float */
+#define kiss_fft_scalar float
+#endif
+#endif
+
+typedef struct {
+  kiss_fft_scalar r;
+  kiss_fft_scalar i;
+} kiss_fft_cpx;
+
+typedef struct kiss_fft_state *kiss_fft_cfg;
+
+/*
+ *  kiss_fft_alloc
+ *
+ *  Initialize a FFT (or IFFT) algorithm's cfg/state buffer.
+ *
+ *  typical usage:      kiss_fft_cfg mycfg=kiss_fft_alloc(1024,0,NULL,NULL);
+ *
+ *  The return value from fft_alloc is a cfg buffer used internally
+ *  by the fft routine or NULL.
+ *
+ *  If lenmem is NULL, then kiss_fft_alloc will allocate a cfg buffer using
+ * malloc. The returned value should be free()d when done to avoid memory leaks.
+ *
+ *  The state can be placed in a user supplied buffer 'mem':
+ *  If lenmem is not NULL and mem is not NULL and *lenmem is large enough,
+ *      then the function places the cfg in mem and the size used in *lenmem
+ *      and returns mem.
+ *
+ *  If lenmem is not NULL and ( mem is NULL or *lenmem is not large enough),
+ *      then the function returns NULL and places the minimum cfg
+ *      buffer size in *lenmem.
+ * */
+
+kiss_fft_cfg kiss_fft_alloc(int nfft, int inverse_fft, void *mem,
+                            size_t *lenmem);
+
+/*
+ * kiss_fft(cfg,in_out_buf)
+ *
+ * Perform an FFT on a complex input buffer.
+ * for a forward FFT,
+ * fin should be  f[0] , f[1] , ... ,f[nfft-1]
+ * fout will be   F[0] , F[1] , ... ,F[nfft-1]
+ * Note that each element is complex and can be accessed like
+    f[k].r and f[k].i
+ * */
+void kiss_fft(kiss_fft_cfg cfg, const kiss_fft_cpx *fin, kiss_fft_cpx *fout);
+
+/*
+ A more generic version of the above function. It reads its input from every Nth
+ sample.
+ * */
+void kiss_fft_stride(kiss_fft_cfg cfg, const kiss_fft_cpx *fin,
+                     kiss_fft_cpx *fout, int fin_stride);
+
+/* If kiss_fft_alloc allocated a buffer, it is one contiguous
+   buffer and can be simply free()d when no longer needed*/
+#define kiss_fft_free free
+
+/*
+ Cleans up some memory that gets managed internally. Not necessary to call, but
+ it might clean up your compiler output to call this before you exit.
+*/
+void kiss_fft_cleanup(void);
+
+/*
+ * Returns the smallest integer k, such that k>=n and k has only "fast" factors
+ * (2,3,5)
+ */
+int kiss_fft_next_fast_size(int n);
+
+/* for real ffts, we need an even size */
+#define kiss_fftr_next_fast_size_real(n) \
+  (kiss_fft_next_fast_size(((n) + 1) >> 1) << 1)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif