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authorJohn Emmas <johne53@tiscali.co.uk>2015-01-10 11:56:24 +0000
committerJohn Emmas <johne53@tiscali.co.uk>2015-01-10 11:56:24 +0000
commitf59810596648ae107c7858ecc6add4b3b9ff1ac7 (patch)
treeea72dfb0668c617a34225bab3d01b918827690d7 /libs/pbd/msvc
parentca7965d7aa4b56bca74dd4137e03bdb581c738c8 (diff)
Add support for the C99 function 'log2()' which is newly needed by 'gtk2_ardour/tempo_lines.cc' (but isn't available from MSVC).
These changes are MSVC specific and shouldn't affect the other builds. (incidentally, libpbd already offers a function called 'fast_log2()'. Not sure if that could have been used instead...)
Diffstat (limited to 'libs/pbd/msvc')
-rw-r--r--libs/pbd/msvc/msvc_pbd.cc19
1 files changed, 19 insertions, 0 deletions
diff --git a/libs/pbd/msvc/msvc_pbd.cc b/libs/pbd/msvc/msvc_pbd.cc
index ddef968569..ab79d8f45d 100644
--- a/libs/pbd/msvc/msvc_pbd.cc
+++ b/libs/pbd/msvc/msvc_pbd.cc
@@ -262,6 +262,25 @@ trunc(double x)
return (floor(x));
}
+//***************************************************************
+//
+// log2()
+//
+// Emulates C99 log2() using log().
+//
+// Returns:
+//
+// On Success: The binary (base-2) logarithm of 'x'
+// (e.g. log2(1024) == 10).
+// On Failure: None, except that calling log(x) should generate
+// an appropriate error for us (such as ERANGE etc).
+//
+LIBPBD_API double PBD_APICALLTYPE
+log2(double x)
+{
+ return (log(x) / log((double)2.0));
+}
+
namespace PBD {
//***************************************************************