1 files changed, 44 insertions, 0 deletions
diff --git a/util/string_stream.hh b/util/string_stream.hh
new file mode 100644
index 000000000..730403d70
--- /dev/null
+++ b/util/string_stream.hh
@@ -0,0 +1,44 @@
+#ifndef UTIL_STRING_STREAM_H
+#define UTIL_STRING_STREAM_H
+
+#include "util/fake_ostream.hh"
+
+#include <cassert>
+#include <string>
+
+namespace util {
+
+class StringStream : public FakeOStream<StringStream> {
+  public:
+    // Semantics: appends to string.  Remember to clear first!
+    explicit StringStream(std::string &out)
+      : out_(out) {}
+
+    StringStream &flush() { return *this; }
+
+    StringStream &write(const void *data, std::size_t length) {
+      out_.append(static_cast<const char*>(data), length);
+      return *this;
+    }
+
+  protected:
+    friend class FakeOStream<StringStream>;
+    char *Ensure(std::size_t amount) {
+      std::size_t current = out_.size();
+      out_.resize(out_.size() + amount);
+      return &out_[current];
+    }
+
+    void AdvanceTo(char *to) {
+      assert(to <= &*out_.end());
+      assert(to >= &*out_.begin());
+      out_.resize(to - &*out_.begin());
+    }
+
+  private:
+    std::string &out_;
+};
+
+} // namespace
+
+#endif // UTIL_STRING_STREAM_H