2 files changed, 33 insertions, 1 deletions

diff --git a/common/str.cpp b/common/str.cpp
index cbfdc4f029..231272e82a 100644
--- a/common/str.cpp
+++ b/common/str.cpp
@@ -136,6 +136,35 @@ String &String::operator += (char c) {
 	return *this;
 }
 
+bool String::hasPrefix(const char *x) const {
+	assert(x != 0);
+	// Compare x with the start of _str.
+	const char *y = c_str();
+	while (*x && *x == *y) {
+		++x;
+		++y;
+	}
+	// It's a prefix, if and only if all letters in x are 'used up' before
+	// _str ends.
+	return *x == 0;
+}
+
+bool String::hasSuffix(const char *x) const {
+	assert(x != 0);
+	// Compare x with the end of _str.
+	const int x_len = strlen(x);
+	if (x_len > _len)
+		return false;
+	const char *y = c_str() + _len - x_len;
+	while (*x && *x == *y) {
+		++x;
+		++y;
+	}
+	// It's a suffix, if and only if all letters in x are 'used up' before
+	// _str ends.
+	return *x == 0;
+}
+
 void String::deleteLastChar() {
 	if (_len > 0) {
 		ensureCapacity(_len - 1, true);
diff --git a/common/str.h b/common/str.h
index 5a96f7939e..4ca744193d 100644
--- a/common/str.h
+++ b/common/str.h
@@ -60,6 +60,9 @@ public:
 	bool operator >(const String &x) const;
 	bool operator >=(const String &x) const;
 
+	bool hasSuffix(const char *x) const;
+	bool hasPrefix(const char *x) const;
+
 	const char *c_str() const		{ return _str ? _str : ""; }
 	uint size() const				{ return _len; }
 
@@ -75,7 +78,7 @@ public:
 		assert(_str && idx >= 0 && idx < _len);
 		return _str[idx];
 	}
-
+	
 	void deleteLastChar();
 	void deleteChar(int p);
 	void clear();