Add StringData::rfind(char) const method.

3 files changed, 29 insertions, 0 deletions

diff --git a/src/mongo/base/string_data-inl.h b/src/mongo/base/string_data-inl.h
index 9d6d024df9c..efad95154ea 100644
--- a/src/mongo/base/string_data-inl.h
+++ b/src/mongo/base/string_data-inl.h
@@ -90,6 +90,18 @@ namespace mongo {
 
     }
 
+    inline size_t StringData::rfind( char c, size_t fromPos ) const {
+        const size_t sz = size();
+        if ( fromPos > sz )
+            fromPos = sz;
+
+        for ( const char* cur = _data + fromPos; cur > _data; --cur ) {
+            if ( *(cur - 1) == c )
+                return (cur - _data) - 1;
+        }
+        return string::npos;
+    }
+
     inline StringData StringData::substr( size_t pos, size_t n ) const {
         if ( pos > size() )
             throw std::out_of_range( "out of range" );
diff --git a/src/mongo/base/string_data.h b/src/mongo/base/string_data.h
index dca41fa1e9a..f764549f700 100644
--- a/src/mongo/base/string_data.h
+++ b/src/mongo/base/string_data.h
@@ -98,6 +98,7 @@ namespace mongo {
 
         size_t find( char c , size_t fromPos = 0 ) const;
         size_t find( const StringData& needle ) const;
+        size_t rfind( char c, size_t fromPos = string::npos ) const;
 
         /**
          * Returns true if 'prefix' is a substring of this instance, anchored at position 0.
diff --git a/src/mongo/base/string_data_test.cpp b/src/mongo/base/string_data_test.cpp
index c8ca72ca76c..bbd40011002 100644
--- a/src/mongo/base/string_data_test.cpp
+++ b/src/mongo/base/string_data_test.cpp
@@ -123,6 +123,22 @@ namespace {
         ASSERT_EQUALS( string("foo").find( "" ), StringData("foo").find( "" ) );
     }
 
+    TEST(Rfind, Char1) {
+        ASSERT_EQUALS( string::npos, StringData( "foo" ).rfind( 'a' ) );
+
+        ASSERT_EQUALS( 0U, StringData( "foo" ).rfind( 'f' ) );
+        ASSERT_EQUALS( 0U, StringData( "foo" ).rfind( 'f', 3 ) );
+        ASSERT_EQUALS( 0U, StringData( "foo" ).rfind( 'f', 2 ) );
+        ASSERT_EQUALS( 0U, StringData( "foo" ).rfind( 'f', 1 ) );
+        ASSERT_EQUALS( string::npos, StringData( "foo", 0 ).rfind( 'f' ) );
+
+        ASSERT_EQUALS( 2U, StringData( "foo" ).rfind( 'o' ) );
+        ASSERT_EQUALS( 2U, StringData( "foo", 3 ).rfind( 'o' ) );
+        ASSERT_EQUALS( 1U, StringData( "foo", 2 ).rfind( 'o' ) );
+        ASSERT_EQUALS( string::npos, StringData( "foo", 1 ).rfind( 'o' ) );
+        ASSERT_EQUALS( string::npos, StringData( "foo", 0 ).rfind( 'o' ) );
+    }
+
     // this is to verify we match std::string
     void SUBSTR_TEST_HELP(StringData big, StringData small, size_t start, size_t len) {
         ASSERT_EQUALS(small.toString(), big.toString().substr(start, len));