Simple memory testing for gae/wrapper

go/src/infra/gae/libs/wrapper/memory/binutils.go

Index: go/src/infra/gae/libs/wrapper/memory/binutils.go
diff --git a/go/src/infra/gae/libs/wrapper/memory/binutils.go b/go/src/infra/gae/libs/wrapper/memory/binutils.go
new file mode 100644
index 0000000000000000000000000000000000000000..45d141c43c5421ca9aed942d4e4837e982286248
--- /dev/null
+++ b/go/src/infra/gae/libs/wrapper/memory/binutils.go
@@ -0,0 +1,75 @@
+// Copyright 2015 The Chromium 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 memory
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"math"
+
+	"github.com/luci/luci-go/common/funnybase"
+)
+
+func writeString(buf *bytes.Buffer, s string) {

[M-A Ruel, 2015/05/27 20:14:47]

Why not a io.Writer? I'd be much more idiomatic.

[iannucci, 2015/05/27 21:36:22]

because io.Writer.Write returns an error... since I only use this with
bytes.Buffer (whose Write method is guaranteed to only return nil as the error),
I didn't want to deal with the extra error checks.

+	funnybase.WriteUint(buf, uint64(len(s)))
+	buf.WriteString(s)
+}
+
+func readString(buf *bytes.Buffer) (string, error) {
+	b, err := readBytes(buf)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+func writeBytes(buf *bytes.Buffer, b []byte) {
+	funnybase.WriteUint(buf, uint64(len(b)))
+	buf.Write(b)
+}
+
+func readBytes(buf *bytes.Buffer) ([]byte, error) {
+	val, err := funnybase.ReadUint(buf)
+	if err != nil {
+		return nil, err
+	}
+	if val > 2*1024*1024 { // 2MB
+		return nil, fmt.Errorf("readBytes: tried to read %d bytes (> 2MB)", val)
+	}
+	retBuf := make([]byte, val)
+	n, _ := buf.Read(retBuf) // err is either io.EOF or nil for bytes.Buffer
+	if uint64(n) != val {
+		return nil, fmt.Errorf("readBytes: expected %d bytes but read %d", val, n)
+	}
+	return retBuf, err
+}
+
+func writeFloat64(buf *bytes.Buffer, v float64) {
+	// byte-ordered floats http://stereopsis.com/radix.html
+	bits := math.Float64bits(v)
+	bits = bits ^ (-(bits >> 63) | (1 << 63))
+	data := make([]byte, 8)
+	binary.BigEndian.PutUint64(data, bits)
+	buf.Write(data)
+}
+
+func readFloat64(buf *bytes.Buffer) (float64, error) {
+	// byte-ordered floats http://stereopsis.com/radix.html
+	data := make([]byte, 8)
+	_, err := buf.Read(data)
+	if err != nil {
+		return 0, err
+	}
+	bits := binary.BigEndian.Uint64(data)
+	return math.Float64frombits(bits ^ (((bits >> 63) - 1) | (1 << 63))), nil
+}
+
+func btoi(b bool) byte {
+	if b {
+		return 1
+	}
+	return 0
+}