adding quickfix library

quickfix/fix_int.go

@@ -0,0 +1,78 @@
+// 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 (
+	"errors"
+	"strconv"
+)
+
+const (
+	// ASCII - char.
+	asciiMinus = 45
+
+	// ASCII numbers 0-9.
+	ascii0 = 48
+	ascii9 = 57
+)
+
+// atoi is similar to the function in strconv, but is tuned for ints appearing in FIX field types.
+func atoi(d []byte) (int, error) {
+	if d[0] == asciiMinus {
+		n, err := parseUInt(d[1:])
+		return (-1) * n, err
+	}
+
+	return parseUInt(d)
+}
+
+// parseUInt is similar to the function in strconv, but is tuned for ints appearing in FIX field types.
+func parseUInt(d []byte) (n int, err error) {
+	if len(d) == 0 {
+		err = errors.New("empty bytes")
+		return
+	}
+
+	for _, dec := range d {
+		if dec < ascii0 || dec > ascii9 {
+			err = errors.New("invalid format")
+			return
+		}
+
+		n = n*10 + (int(dec) - ascii0)
+	}
+
+	return
+}
+
+// FIXInt is a FIX Int Value, implements FieldValue.
+type FIXInt int
+
+// Int converts the FIXInt value to int.
+func (f FIXInt) Int() int { return int(f) }
+
+func (f *FIXInt) Read(bytes []byte) error {
+	i, err := atoi(bytes)
+	if err != nil {
+		return err
+	}
+	*f = FIXInt(i)
+	return nil
+}
+
+func (f FIXInt) Write() []byte {
+	return strconv.AppendInt(nil, int64(f), 10)
+}