X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fstring.h;h=7c426ef3de3bd97e5056ef469f6db6cb528b1c61;hb=62a7b8edf965b89d3ca57da120dcedfcf36dfe02;hp=91a1c09e2f1df86bff864da0235ba5a9989b5a1b;hpb=f5436bfcf6797b979b308a9af782750f9d079686;p=lttng-tools.git

diff --git a/src/common/compat/string.h b/src/common/compat/string.h
index 91a1c09e2..7c426ef3d 100644
--- a/src/common/compat/string.h
+++ b/src/common/compat/string.h
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 Michael Jeanson <mjeanson@efficios.com>
+ *               2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -86,4 +87,41 @@ end:
 }
 #endif /* HAVE_STRNDUP */
 
+#ifdef HAVE_FLS
+static inline int lttng_fls(int val)
+{
+	return fls(val);
+}
+#else
+static inline int lttng_fls(int val)
+{
+	int r = 32;
+	unsigned int x = (unsigned int) val;
+
+	if (!x)
+		return 0;
+	if (!(x & 0xFFFF0000U)) {
+		x <<= 16;
+		r -= 16;
+	}
+	if (!(x & 0xFF000000U)) {
+		x <<= 8;
+		r -= 8;
+	}
+	if (!(x & 0xF0000000U)) {
+		x <<= 4;
+		r -= 4;
+	}
+	if (!(x & 0xC0000000U)) {
+		x <<= 2;
+		r -= 2;
+	}
+	if (!(x & 0x80000000U)) {
+		x <<= 1;
+		r -= 1;
+	}
+	return r;
+}
+#endif /* HAVE_FLS */
+
 #endif /* _COMPAT_STRING_H */