New plugin: FFT, A frequency analyzer plugin

There is some more work needed:
- Keymaps are definitely not perfect, touchscreen targets are disabled due to no keymap
- There is no manual yet

Author: Delyan Kratunov 
Flyspray: FS#10065



git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24587 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 54 insertions, 0 deletions

diff --git a/apps/plugins/fft/kiss_fftr.h b/apps/plugins/fft/kiss_fftr.h
new file mode 100644
index 0000000000..19018a05c8
--- /dev/null
+++ b/apps/plugins/fft/kiss_fftr.h
@@ -0,0 +1,54 @@
+#ifndef KISS_FTR_H
+#define KISS_FTR_H
+
+#include "kiss_fft.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+    
+/* 
+ 
+ Real optimized version can save about 45% cpu time vs. complex fft of a real seq.
+
+ 
+ 
+ */
+
+struct kiss_fftr_state{
+    kiss_fft_cfg substate;
+    kiss_fft_cpx * tmpbuf;
+    kiss_fft_cpx * super_twiddles;
+#ifdef USE_SIMD    
+    long pad;
+#endif    
+};
+typedef struct kiss_fftr_state *kiss_fftr_cfg;
+
+
+kiss_fftr_cfg kiss_fftr_alloc(int nfft,int inverse_fft,void * mem, size_t * lenmem);
+/*
+ nfft must be even
+
+ If you don't care to allocate space, use mem = lenmem = NULL 
+*/
+
+
+void kiss_fftr(kiss_fftr_cfg cfg,const kiss_fft_scalar *timedata,kiss_fft_cpx *freqdata);
+/*
+ input timedata has nfft scalar points
+ output freqdata has nfft/2+1 complex points
+*/
+
+void kiss_fftri(kiss_fftr_cfg cfg,const kiss_fft_cpx *freqdata,kiss_fft_scalar *timedata);
+/*
+ input freqdata has  nfft/2+1 complex points
+ output timedata has nfft scalar points
+*/
+
+#define kiss_fftr_free free
+
+#ifdef __cplusplus
+}
+#endif
+#endif