1 files changed, 61 insertions, 0 deletions
diff --git a/libgo/go/strings/reader.go b/libgo/go/strings/reader.go
new file mode 100644
index 000000000..914faa003
--- /dev/null
+++ b/libgo/go/strings/reader.go
@@ -0,0 +1,61 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package strings
+
+import (
+	"os"
+	"utf8"
+)
+
+// A Reader satisfies calls to Read, ReadByte, and ReadRune by
+// reading from a string.
+type Reader string
+
+func (r *Reader) Read(b []byte) (n int, err os.Error) {
+	s := *r
+	if len(s) == 0 {
+		return 0, os.EOF
+	}
+	for n < len(s) && n < len(b) {
+		b[n] = s[n]
+		n++
+	}
+	*r = s[n:]
+	return
+}
+
+func (r *Reader) ReadByte() (b byte, err os.Error) {
+	s := *r
+	if len(s) == 0 {
+		return 0, os.EOF
+	}
+	b = s[0]
+	*r = s[1:]
+	return
+}
+
+// ReadRune reads and returns the next UTF-8-encoded
+// Unicode code point from the buffer.
+// If no bytes are available, the error returned is os.EOF.
+// If the bytes are an erroneous UTF-8 encoding, it
+// consumes one byte and returns U+FFFD, 1.
+func (r *Reader) ReadRune() (rune int, size int, err os.Error) {
+	s := *r
+	if len(s) == 0 {
+		return 0, 0, os.EOF
+	}
+	c := s[0]
+	if c < utf8.RuneSelf {
+		*r = s[1:]
+		return int(c), 1, nil
+	}
+	rune, size = utf8.DecodeRuneInString(string(s))
+	*r = s[size:]
+	return
+}
+
+// NewReader returns a new Reader reading from s.
+// It is similar to bytes.NewBufferString but more efficient and read-only.
+func NewReader(s string) *Reader { return (*Reader)(&s) }