From 10a54136f3a9a1d8b8ec899ae457a9a4d327e8cf Mon Sep 17 00:00:00 2001
From: Paul Brossier <piem@piem.org>
Date: Wed, 7 Oct 2009 18:26:59 +0200
Subject: [PATCH] src/mathutils.c: add aubio_is_power_of_two and
 aubio_next_power_of_two

---
 configure.ac     |  2 +-
 src/aubio_priv.h |  4 ++++
 src/mathutils.c  | 19 +++++++++++++++++++
 src/mathutils.h  |  6 ++++++
 wscript          |  1 +
 5 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 308d266f..7fb40c69 100644
--- a/configure.ac
+++ b/configure.ac
@@ -114,7 +114,7 @@ dnl Check for required libraries
 AC_CHECK_LIB(pthread, pthread_create)
 
 dnl Check for header files
-AC_CHECK_HEADERS([string.h stdlib.h stdio.h math.h errno.h stdarg.h unistd.h signal.h],,)
+AC_CHECK_HEADERS([string.h stdlib.h stdio.h math.h limits.h errno.h stdarg.h unistd.h signal.h],,)
 AC_CHECK_HEADERS(fftw3.h,,AC_MSG_ERROR([Ouch! missing fftw3.h header]))
 AC_ARG_ENABLE(complex,
   AC_HELP_STRING([--enable-complex],[compile with complex.h [[default=auto]]]),
diff --git a/src/aubio_priv.h b/src/aubio_priv.h
index 683056fc..ab950429 100644
--- a/src/aubio_priv.h
+++ b/src/aubio_priv.h
@@ -62,6 +62,10 @@
 #include <string.h>
 #endif
 
+#if HAVE_LIMITS_H
+#include <limits.h> // for CHAR_BIT, in C99 standard
+#endif
+
 #include "types.h"
 
 /****
diff --git a/src/mathutils.c b/src/mathutils.c
index 66dab58e..b99a96b4 100644
--- a/src/mathutils.c
+++ b/src/mathutils.c
@@ -409,6 +409,25 @@ aubio_miditobin (smpl_t midi, smpl_t samplerate, smpl_t fftsize)
   return aubio_freqtobin (freq, samplerate, fftsize);
 }
 
+uint_t
+aubio_is_power_of_two(uint_t a) {
+  if ((a & a-1) == 0) {
+    return 1;
+  } else {
+    return 0; 
+  }
+}
+
+uint_t
+aubio_next_power_of_two(uint_t a) {
+  uint_t i;
+  a--;
+  for (i = 0; i < sizeof(uint_t) * CHAR_BIT; i++ ) {
+    a = a | a >> 1;
+  }
+  return a+1;
+}
+
 smpl_t
 aubio_db_spl (fvec_t * o)
 {
diff --git a/src/mathutils.h b/src/mathutils.h
index d71cf77f..de970493 100644
--- a/src/mathutils.h
+++ b/src/mathutils.h
@@ -316,6 +316,12 @@ smpl_t aubio_freqtomidi (smpl_t freq);
 /** convert midi value (0-128) to frequency (Hz) */
 smpl_t aubio_miditofreq (smpl_t midi);
 
+/** return 1 if a is a power of 2, 0 otherwise */
+uint_t aubio_is_power_of_two(uint_t a);
+
+/** return the next power of power of 2 greater than a */
+uint_t aubio_next_power_of_two(uint_t a);
+
 /** compute sound pressure level (SPL) in dB
 
   This quantity is often wrongly called 'loudness'.
diff --git a/wscript b/wscript
index d8fe5a40..58bd1c9b 100644
--- a/wscript
+++ b/wscript
@@ -53,6 +53,7 @@ def configure(conf):
   conf.check(header_name='stdio.h')
   conf.check(header_name='math.h')
   conf.check(header_name='string.h')
+  conf.check(header_name='limits.h')
 
   # optionally use complex.h
   if (Options.options.disable_complex == False):
-- 
2.11.0