Update and refactor to ack Go Authors

diff --git a/source/lazy_file_reader.go b/source/lazy_file_reader.go
index b11644befb611c8751ff5f94cdf422fdaf5395f8..6e75055ad7a0aff1c74467312ef6052e7e9fc786 100644 (file)
--- a/source/lazy_file_reader.go
+++ b/source/lazy_file_reader.go
@@ -1,4 +1,5 @@
 // Copyright 2015 The Hugo Authors. All rights reserved.
+// Portions Copyright 2009 The Go Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -129,15 +130,24 @@ func (l *LazyFileReader) WriteTo(w io.Writer) (n int64, err error) {
                return 0, nil
        }
 
-       // following code is taken from io.Copy in 'io/io.go'
-       buf := make([]byte, 32*1024)
+       return l.copyBuffer(w, f, nil)
+}
+
+// copyBuffer is the actual implementation of Copy and CopyBuffer.
+// If buf is nil, one is allocated.
+//
+// Most of this function is copied from the Go stdlib 'io/io.go'.
+func (l *LazyFileReader) copyBuffer(dst io.Writer, src io.Reader, buf []byte) (written int64, err error) {
+       if buf == nil {
+               buf = make([]byte, 32*1024)
+       }
        for {
-               nr, er := f.Read(buf)
+               nr, er := src.Read(buf)
                if nr > 0 {
-                       nw, ew := w.Write(buf[0:nr])
+                       nw, ew := dst.Write(buf[0:nr])
                        if nw > 0 {
                                l.pos += int64(nw)
-                               n += int64(nw)
+                               written += int64(nw)
                        }
                        if ew != nil {
                                err = ew
@@ -156,5 +166,5 @@ func (l *LazyFileReader) WriteTo(w io.Writer) (n int64, err error) {
                        break
                }
        }
-       return n, err
+       return written, err
 }