1 files changed, 146 insertions, 0 deletions
diff --git a/src/lib/io/io.go b/src/lib/io/io.go
new file mode 100644
index 000000000..9ae926441
--- /dev/null
+++ b/src/lib/io/io.go
@@ -0,0 +1,146 @@
+// 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 io
+
+import (
+	"os";
+	"syscall";
+)
+
+export var ErrEOF = os.NewError("EOF")
+
+export type Read interface {
+	Read(p *[]byte) (n int, err *os.Error);
+}
+
+export type Write interface {
+	Write(p *[]byte) (n int, err *os.Error);
+}
+
+export type ReadWrite interface {
+	Read(p *[]byte) (n int, err *os.Error);
+	Write(p *[]byte) (n int, err *os.Error);
+}
+
+export type ReadWriteClose interface {
+	Read(p *[]byte) (n int, err *os.Error);
+	Write(p *[]byte) (n int, err *os.Error);
+	Close() *os.Error;
+}
+
+export func WriteString(w Write, s string) (n int, err *os.Error) {
+	b := new([]byte, len(s)+1);
+	if !syscall.StringToBytes(b, s) {
+		return -1, os.EINVAL
+	}
+	// BUG return w.Write(b[0:len(s)])
+	r, e := w.Write(b[0:len(s)]);
+	return r, e
+}
+
+// Read until buffer is full, EOF, or error
+export func Readn(fd Read, buf *[]byte) (n int, err *os.Error) {
+	n = 0;
+	for n < len(buf) {
+		nn, e := fd.Read(buf[n:len(buf)]);
+		if nn > 0 {
+			n += nn
+		}
+		if e != nil {
+			return n, e
+		}
+		if nn <= 0 {
+			return n, ErrEOF	// no error but insufficient data
+		}
+	}
+	return n, nil
+}
+
+// Convert something that implements Read into something
+// whose Reads are always Readn
+type FullRead struct {
+	fd	Read;
+}
+
+func (fd *FullRead) Read(p *[]byte) (n int, err *os.Error) {
+	n, err = Readn(fd.fd, p);
+	return n, err
+}
+
+export func MakeFullReader(fd Read) Read {
+	if fr, ok := fd.(*FullRead); ok {
+		// already a FullRead
+		return fd
+	}
+	return &FullRead{fd}
+}
+
+// Copies n bytes (or until EOF is reached) from src to dst.
+// Returns the number of bytes copied and the error, if any.
+export func Copyn(src Read, dst Write, n int64) (written int64, err *os.Error) {
+	buf := new([]byte, 32*1024);
+	for written < n {
+		l := len(buf);
+		if d := n - written; d < int64(l) {
+			l = int(d);
+		}
+		nr, er := src.Read(buf[0 : l]);
+		if nr > 0 {
+			nw, ew := dst.Write(buf[0 : nr]);
+			if nw > 0 {
+				written += int64(nw);
+			}
+			if ew != nil {
+				err = ew;
+				break;
+			}
+			if nr != nw {
+				err = os.EIO;
+				break;
+			}
+		}
+		if er != nil {
+			err = er;
+			break;
+		}
+		if nr == 0 {
+			err = ErrEOF;
+			break;
+		}
+	}
+	return written, err
+}
+
+// Copies from src to dst until EOF is reached.
+// Returns the number of bytes copied and the error, if any.
+export func Copy(src Read, dst Write) (written int64, err *os.Error) {
+	buf := new([]byte, 32*1024);
+	for {
+		nr, er := src.Read(buf);
+		if nr > 0 {
+			nw, ew := dst.Write(buf[0:nr]);
+			if nw > 0 {
+				written += int64(nw);
+			}
+			if ew != nil {
+				err = ew;
+				break;
+			}
+			if nr != nw {
+				err = os.EIO;
+				break;
+			}
+		}
+		if er != nil {
+			err = er;
+			break;
+		}
+		if nr == 0 {
+			break;
+		}
+	}
+	return written, err
+}
+