make a (rudimentary) ByteBuffer and put it in package "io".

fix up protocol buffers to use it.

R=rsc
DELTA=1232  (612 added, 572 deleted, 48 changed)
OCL=19964
CL=19981

src/lib/Makefile

@@ -11,6 +11,7 @@ DIRS=\
 	fmt\
 	hash\
 	http\
+	io\
 	math\
 	net\
 	os\
@@ -25,7 +26,6 @@ FILES=\
 	bufio\
 	vector\
 	flag\
-	io\
 	once\
 	rand\
 	sort\
@@ -81,19 +81,19 @@ test: test.files
 # TODO: dependencies - should auto-generate
 
 bignum.6: fmt.dirinstall
-bufio.6: io.install os.dirinstall
+bufio.6: io.dirinstall os.dirinstall
 flag.6: fmt.dirinstall
-io.6: os.dirinstall syscall.dirinstall
 testing.6: flag.install fmt.dirinstall
 
-fmt.dirinstall: io.install reflect.dirinstall strconv.dirinstall
+fmt.dirinstall: io.dirinstall reflect.dirinstall strconv.dirinstall
 hash.dirinstall: os.dirinstall
-http.dirinstall: bufio.install io.install net.dirinstall os.dirinstall strings.install
+http.dirinstall: bufio.install io.dirinstall net.dirinstall os.dirinstall strings.install
+io.dirinstall: os.dirinstall syscall.dirinstall
 net.dirinstall: once.install os.dirinstall strconv.dirinstall
 os.dirinstall: syscall.dirinstall
 regexp.dirinstall: os.dirinstall
 reflect.dirinstall: strconv.dirinstall
 strconv.dirinstall: os.dirinstall utf8.install
-tabwriter.dirinstall: os.dirinstall io.install container/array.dirinstall
+tabwriter.dirinstall: os.dirinstall io.dirinstall container/array.dirinstall
 time.dirinstall: once.install os.dirinstall
 

src/lib/io/Makefile

+# 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.
+
+# DO NOT EDIT.  Automatically generated by gobuild.
+# gobuild -m >Makefile
+O=6
+GC=$(O)g
+CC=$(O)c -w
+AS=$(O)a
+AR=$(O)ar
+
+default: packages
+
+clean:
+	rm -f *.$O *.a $O.out
+
+test: packages
+	gotest
+
+coverage: packages
+	gotest
+	6cov -g `pwd` | grep -v '_test\.go:'
+
+%.$O: %.go
+	$(GC) $*.go
+
+%.$O: %.c
+	$(CC) $*.c
+
+%.$O: %.s
+	$(AS) $*.s
+
+O1=\
+	io.$O\
+	bytebuffer.$O\
+
+io.a: a1
+
+a1:	$(O1)
+	$(AR) grc io.a io.$O bytebuffer.$O
+	rm -f $(O1)
+
+newpkg: clean
+	$(AR) grc io.a
+
+$(O1): newpkg
+
+nuke: clean
+	rm -f $(GOROOT)/pkg/io.a
+
+packages: io.a
+
+install: packages
+	cp io.a $(GOROOT)/pkg/io.a
+

src/lib/io/bytebuffer.go

+// 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
+
+// Byte buffer for marshaling nested messages.
+
+import (
+	"io";
+	"os";
+)
+
+// A simple implementation of the io.Read and io.Write interfaces.
+// A newly allocated ByteBuffer is ready to use.
+
+// TODO(r): Do better memory management.
+
+func bytecopy(dst *[]byte, doff int, src *[]byte, soff int, count int) {
+	for i := 0; i < count; i++ {
+		dst[doff] = src[soff];
+		doff++;
+		soff++;
+	}
+}
+
+export type ByteBuffer struct {
+	buf	*[]byte;
+	off	int;	// Read from here
+	len	int;	// Write to here
+	cap	int;
+}
+
+func (b *ByteBuffer) Reset() {
+	b.off = 0;
+	b.len = 0;
+}
+
+func (b *ByteBuffer) Write(p *[]byte) (n int, err *os.Error) {
+	plen := len(p);
+	if b.buf == nil {
+		b.cap = plen + 1024;
+		b.buf = new([]byte, b.cap);
+		b.len = 0;
+	}
+	if b.len + len(p) > b.cap {
+		b.cap = 2*(b.cap + plen);
+		nb := new([]byte, b.cap);
+		bytecopy(nb, 0, b.buf, 0, b.len);
+		b.buf = nb;
+	}
+	bytecopy(b.buf, b.len, p, 0, plen);
+	b.len += plen;
+	return plen, nil;
+}
+
+func (b *ByteBuffer) Read(p *[]byte) (n int, err *os.Error) {
+	plen := len(p);
+	if b.buf == nil {
+		return 0, nil
+	}
+	if b.off == b.len {	// empty buffer
+		b.Reset();
+		return 0, nil
+	}
+	if plen > b.len - b.off {
+		plen = b.len - b.off
+	}
+	bytecopy(p, 0, b.buf, b.off, plen);
+	b.off += plen;
+	return plen, nil;
+}
+
+func (b *ByteBuffer) Len() int {
+	return b.len
+}
+
+func (b *ByteBuffer) Data() *[]byte {
+	return b.buf[b.off:b.len]
+}
+
+
+export func NewByteBufferFromArray(buf *[]byte) *ByteBuffer {
+	b := new(ByteBuffer);
+	b.buf = buf;
+	b.off = 0;
+	b.len = len(buf);
+	b.cap = len(buf);
+	return b;
+}