From 598b72be37afa160bf584942be0b6d278475b6ba Mon Sep 17 00:00:00 2001
From: dwarning <dwarning>
Date: Mon, 20 Aug 2018 16:41:43 +0200
Subject: [PATCH] prevent a huge memory leak by calling fftw3 in a loop

---
 src/frontend/com_fft.c | 51 ++++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/src/frontend/com_fft.c b/src/frontend/com_fft.c
index a1d86f7b0..e9bd460a1 100644
--- a/src/frontend/com_fft.c
+++ b/src/frontend/com_fft.c
@@ -160,15 +160,21 @@ com_fft(wordlist *wl)
     printf("FFT: Time span: %g s, input length: %d\n", span, length);
     printf("FFT: Frequency resolution: %g Hz, output length: %d\n", 1.0/span, fpts);
 
-    for (i = 0; i<ngood; i++) {
+    in = fftw_malloc(sizeof(double) * (unsigned int) length);
+    out = fftw_malloc(sizeof(fftw_complex) * (unsigned int) fpts);
 
-        in = fftw_malloc(sizeof(double) * (unsigned int) length);
-        out = fftw_malloc(sizeof(fftw_complex) * (unsigned int) fpts);
+    for (j = 0; j < length; j++)
+        in[j] = tdvec[0][j]*win[j];
 
-        for (j = 0; j < length; j++)
-            in[j] = tdvec[i][j]*win[j];
+    /* data have same type and length - so we need only one plan */
+    plan_forward = fftw_plan_dft_r2c_1d(length, in, out, FFTW_ESTIMATE); 
 
-        plan_forward = fftw_plan_dft_r2c_1d(length, in, out, FFTW_ESTIMATE);
+    for (i = 0; i<ngood; i++) {
+
+        if (i > 0) {
+            for (j = 0; j < length; j++)
+                in[j] = tdvec[i][j]*win[j];
+        }
 
         fftw_execute(plan_forward);
 
@@ -178,8 +184,12 @@ com_fft(wordlist *wl)
             fdvec[i][j].cx_imag = out[j][1]/scale;
         }
 
-        fftw_free(in);
-        fftw_free(out);
+    }
+
+    fftw_destroy_plan(plan_forward);
+
+    fftw_free(in);
+    fftw_free(out);
 
 #else /* Green's FFT */
 
@@ -213,14 +223,11 @@ com_fft(wordlist *wl)
 
         tfree(in);
 
-#endif
-
     }
 
-done:
-#ifdef HAVE_LIBFFTW3
-    fftw_destroy_plan(plan_forward);
 #endif
+
+done:
     tfree(tdvec);
     tfree(fdvec);
     tfree(win);
@@ -385,12 +392,18 @@ com_psd(wordlist *wl)
     in = fftw_malloc(sizeof(double) * (unsigned int) length);
     out = fftw_malloc(sizeof(fftw_complex) * (unsigned int) fpts);
 
-    for (i = 0; i<ngood; i++) {
+    for (j = 0; j < length; j++)
+        in[j] = tdvec[0][j]*win[j];
 
-        for (j = 0; j < length; j++)
-            in[j] = tdvec[i][j]*win[j];
+    /* data have same type and length - so we need only one plan */
+    plan_forward = fftw_plan_dft_r2c_1d(length, in, out, FFTW_ESTIMATE);
 
-        plan_forward = fftw_plan_dft_r2c_1d(length, in, out, FFTW_ESTIMATE);
+    for (i = 0; i<ngood; i++) {
+
+        if (i > 0) {
+            for (j = 0; j < length; j++)
+                in[j] = tdvec[i][j]*win[j];
+        }
 
         fftw_execute(plan_forward);
 
@@ -479,12 +492,12 @@ com_psd(wordlist *wl)
             fdvec[i][j].cx_real = reald[j] * (double)fpts / freq[fpts - 1];
     }
 
-done:
 #ifdef HAVE_LIBFFTW3
+    fftw_destroy_plan(plan_forward);
     fftw_free(in);
     fftw_free(out);
-    fftw_destroy_plan(plan_forward);
 #endif
+done:
     tfree(tdvec);
     tfree(fdvec);
     tfree(win);