From 593a87ce2254a7966d33fa88e2efa9cbbdb4f7f0 Mon Sep 17 00:00:00 2001
From: eb
Date: Thu, 8 May 2008 06:17:55 +0000
Subject: better fix for ticket:243

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@8324 221aa14e-8319-0410-a670-987f0aec2ac5
---
 configure.ac                            |  1 +
 gnuradio-core/src/lib/viterbi/metrics.c | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/configure.ac b/configure.ac
index 05c2cc050..74dde0dd1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -152,6 +152,7 @@ AC_CHECK_LIB(m, sinf, [AC_DEFINE([HAVE_SINF],[1],[Define to 1 if your system has
 AC_CHECK_LIB(m, cosf, [AC_DEFINE([HAVE_COSF],[1],[Define to 1 if your system has `cosf'.])])
 AC_CHECK_LIB(m, trunc, [AC_DEFINE([HAVE_TRUNC],[1],[Define to 1 if your system has `trunc'.])])
 AC_CHECK_LIB(m, exp10, [AC_DEFINE([HAVE_EXP10],[1],[Define to 1 if your system has 'exp10'.])])
+AC_CHECK_LIB(m, log2, [AC_DEFINE([HAVE_LOG2],[1],[Define to 1 if your system has 'log2'.])])
 #AC_FUNC_MKTIME
 
 AH_BOTTOM([
diff --git a/gnuradio-core/src/lib/viterbi/metrics.c b/gnuradio-core/src/lib/viterbi/metrics.c
index 3351ff403..2dd4279aa 100644
--- a/gnuradio-core/src/lib/viterbi/metrics.c
+++ b/gnuradio-core/src/lib/viterbi/metrics.c
@@ -30,6 +30,10 @@
  *
  */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
 /* Symbols are offset-binary, with 128 corresponding to an erased (no
  * information) symbol
  */
@@ -41,6 +45,12 @@
 /* Normal function integrated from -Inf to x. Range: 0-1 */
 #define	normal(x)	(0.5 + 0.5*erf((x)/M_SQRT2))
 
+/* Logarithm base 2 */ 
+double log2(double);		/* declaration seems to be missing from some math.h's */
+#if !defined(HAVE_LOG2)
+#define log2(x) (log(x)*M_LOG2E)
+#endif
+
 /* Generate log-likelihood metrics for 8-bit soft quantized channel
  * assuming AWGN and BPSK
  */
-- 
cgit