From 3d5e9290ff75326709185a564096fc236857b756 Mon Sep 17 00:00:00 2001
From: "J.A. de Jong - Redu-Sone B.V., ASCEE V.O.F" <j.a.dejong@ascee.nl>
Date: Sun, 1 Mar 2020 15:04:51 +0100
Subject: [PATCH] Wrapped the functions of FFTW to load and store wisdom.

---
 lasp/c/lasp_fft.c | 20 ++++++++++++++++++++
 lasp/c/lasp_fft.h | 17 +++++++++++++++++
 lasp/wrappers.pyx | 23 +++++++++++++++++++++--
 3 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/lasp/c/lasp_fft.c b/lasp/c/lasp_fft.c
index 4a05be7..b1673fd 100644
--- a/lasp/c/lasp_fft.c
+++ b/lasp/c/lasp_fft.c
@@ -28,6 +28,26 @@ typedef struct Fft_s {
 
 #endif
 
+void load_fft_wisdom(const char* wisdom) {
+#ifdef LASP_FFT_BACKEND_FFTPACK
+#elif defined LASP_FFT_BACKEND_FFTW
+    if(wisdom) {
+        int rv= fftw_import_wisdom_from_string(wisdom);
+        if(rv != 1) {
+            fprintf(stderr, "Error loading FFTW wisdom");
+        }
+    }
+#endif
+}
+
+char* store_fft_wisdom() {
+#ifdef LASP_FFT_BACKEND_FFTPACK
+    return NULL;
+#elif defined LASP_FFT_BACKEND_FFTW
+    return fftw_export_wisdom_to_string();
+#endif
+}
+
 Fft* Fft_create(const us nfft) {
     fsTRACE(15);
     if(nfft == 0) {
diff --git a/lasp/c/lasp_fft.h b/lasp/c/lasp_fft.h
index 5da9e1d..701f658 100644
--- a/lasp/c/lasp_fft.h
+++ b/lasp/c/lasp_fft.h
@@ -11,6 +11,23 @@
 #include "lasp_types.h"
 #include "lasp_mat.h"
 
+/**
+ * Load wisdom data from a NULL-terminated character string. Note that at this
+ * point in time this is only used by the FFTW fft backend.
+ *
+ * @param[in] wisdom: Wisdom string
+ */
+void load_fft_wisdom(const char* wisdom);
+
+/**
+ * Creates a NULL-terminated string containing FFTW wisdom, or state knowledge
+ * from other libraries.
+ *
+ * @returns A NULL-terminated string. *Should be deallocated after being used*
+ */
+char* store_fft_wisdom(void);
+
+
 /**
  * Perform forward FFT's on real time data.
  * 
diff --git a/lasp/wrappers.pyx b/lasp/wrappers.pyx
index 5fb4920..bd6c53e 100644
--- a/lasp/wrappers.pyx
+++ b/lasp/wrappers.pyx
@@ -67,14 +67,15 @@ cdef extern from "lasp_python.h":
 
 __all__ = ['AvPowerSpectra', 'SosFilterBank', 'FilterBank', 'Siggen',
            'sweep_flag_forward', 'sweep_flag_backward', 'sweep_flag_linear',
-           'sweep_flag_exponential', 'sweep_flag_hyperbolic']
+           'sweep_flag_exponential', 'sweep_flag_hyperbolic',
+           'load_fft_wisdom', 'store_fft_wisdom']
+            
 
 setTracerLevel(15)
 cdef extern from "cblas.h":
     int openblas_get_num_threads()
     void openblas_set_num_threads(int)
 
-
 # If we touch this variable: we get segfaults when running from
 # Spyder!
 # openblas_set_num_threads(8)
@@ -86,6 +87,8 @@ def cls():
 # cls()
 
 cdef extern from "lasp_fft.h":
+    void c_load_fft_wisdom "load_fft_wisdom"  (const char* wisdom) 
+    char* c_store_fft_wisdom "store_fft_wisdom" ()
     ctypedef struct c_Fft "Fft"
     c_Fft* Fft_create(us nfft)
     void Fft_free(c_Fft*)
@@ -93,8 +96,24 @@ cdef extern from "lasp_fft.h":
     void Fft_ifft(c_Fft*,cmat * freqdata,dmat* timedata) nogil
     us Fft_nfft(c_Fft*)
 
+def load_fft_wisdom(const unsigned char[::1] wisdom):
+    c_load_fft_wisdom(<const char*> &wisdom[0])
 
+from cpython cimport PyBytes_FromString
+from libc.stdlib cimport free
 
+def store_fft_wisdom():
+    cdef char* wisdom = c_store_fft_wisdom()
+
+    if wisdom != NULL:
+        try:
+            bts = PyBytes_FromString(wisdom)
+        finally:
+            free(wisdom)
+        return bts
+    else:
+        return None
+    
 cdef class Fft:
     cdef:
         c_Fft* _fft