From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 10 Jul 2012 15:25:39 +0000 (+0300)
Subject: Add common_ancestor function
X-Git-Url: http://git.tdb.fi/?p=libs%2Fcore.git;a=commitdiff_plain;h=e4584bf621f6ef457a944c7604888b4132ad1706

Add common_ancestor function
---

diff --git a/source/fs/utils.cpp b/source/fs/utils.cpp
index a34dd4e..1da1859 100644
--- a/source/fs/utils.cpp
+++ b/source/fs/utils.cpp
@@ -154,6 +154,16 @@ Path relative(const Path &path, const Path &base)
 	return result;
 }
 
+Path common_ancestor(const Path &path1, const Path &path2)
+{
+	Path::Iterator i = path1.begin();
+	Path::Iterator j = path2.begin();
+	Path result;
+	for(; (i!=path1.end() && j!=path2.end() && *i==*j); ++i, ++j)
+		result /= *i;
+	return result;
+}
+
 int descendant_depth(const Path &path, const Path &parent)
 {
 	Path::Iterator i = path.begin();
diff --git a/source/fs/utils.h b/source/fs/utils.h
index df7bc76..a52e37d 100644
--- a/source/fs/utils.h
+++ b/source/fs/utils.h
@@ -38,6 +38,9 @@ void rename(const Path &from, const Path &to);
 /// Makes a path relative to some base path.  That is, base/result==path.
 Path relative(const Path &path, const Path &base);
 
+/// Returns the longest prefix shared by both paths.
+Path common_ancestor(const Path &, const Path &);
+
 /** Determines how many levels a path is below another.  Returns -1 if path is
 not a descendant of parent. */
 int descendant_depth(const Path &path, const Path &parent);