adding quickfix

quickfix/tag_value.go

@@ -0,0 +1,102 @@
+// Copyright (c) quickfixengine.org  All rights reserved.
+//
+// This file may be distributed under the terms of the quickfixengine.org
+// license as defined by quickfixengine.org and appearing in the file
+// LICENSE included in the packaging of this file.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING
+// THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A
+// PARTICULAR PURPOSE.
+//
+// See http://www.quickfixengine.org/LICENSE for licensing information.
+//
+// Contact ask@quickfixengine.org if any conditions of this licensing
+// are not clear to you.
+
+package quickfix
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+)
+
+// TagValue is a low-level FIX field abstraction.
+type TagValue struct {
+	tag   Tag
+	value []byte
+	bytes []byte
+}
+
+func (tv *TagValue) init(tag Tag, value []byte) {
+	tv.bytes = strconv.AppendInt(nil, int64(tag), 10)
+	tv.bytes = append(tv.bytes, []byte("=")...)
+	tv.bytes = append(tv.bytes, value...)
+	tv.bytes = append(tv.bytes, []byte("
")...)
+
+	tv.tag = tag
+	tv.value = value
+}
+
+func (tv *TagValue) parse(rawFieldBytes []byte) error {
+	var sepIndex int
+
+	// Most of the Fix tags are 4 or less characters long, so we can optimize
+	// for that by checking the 5 first characters without looping over the
+	// whole byte slice.
+	if len(rawFieldBytes) >= 5 {
+		if rawFieldBytes[1] == '=' {
+			sepIndex = 1
+			goto PARSE
+		} else if rawFieldBytes[2] == '=' {
+			sepIndex = 2
+			goto PARSE
+		} else if rawFieldBytes[3] == '=' {
+			sepIndex = 3
+			goto PARSE
+		} else if rawFieldBytes[4] == '=' {
+			sepIndex = 4
+			goto PARSE
+		}
+	}
+
+	sepIndex = bytes.IndexByte(rawFieldBytes, '=')
+	switch sepIndex {
+	case -1:
+		return fmt.Errorf("tagValue.Parse: No '=' in '%s'", rawFieldBytes)
+	case 0:
+		return fmt.Errorf("tagValue.Parse: No tag in '%s'", rawFieldBytes)
+	}
+
+PARSE:
+	parsedTag, err := atoi(rawFieldBytes[:sepIndex])
+	if err != nil {
+		return fmt.Errorf("tagValue.Parse: %s", err.Error())
+	}
+
+	tv.tag = Tag(parsedTag)
+	n := len(rawFieldBytes)
+	tv.value = rawFieldBytes[(sepIndex + 1):(n - 1):(n - 1)]
+	tv.bytes = rawFieldBytes[:n:n]
+
+	return nil
+}
+
+func (tv TagValue) String() string {
+	return string(tv.bytes)
+}
+
+func bytesTotal(bytes []byte) (total int) {
+	for _, b := range bytes {
+		total += int(b)
+	}
+	return
+}
+
+func (tv TagValue) total() int {
+	return bytesTotal(tv.bytes)
+}
+
+func (tv TagValue) length() int {
+	return len(tv.bytes)
+}