add response parse module

session-dealer/mysql/resp.go

@@ -0,0 +1,75 @@
+package mysql
+
+import (
+	"fmt"
+)
+
+const (
+	PACKET_OK = 0
+	PACKET_EOF = 254
+	PACKET_ERR = 255
+)
+
+func lenencInt(bytesVal []byte) (val int64) {
+	if bytesVal == nil || len(bytesVal) < 1 {
+		val = -1
+		return
+	}
+
+	fb := bytesVal[0]
+	var offset int64
+	switch {
+	case fb < 251:
+		val = int64(fb)
+
+	case fb == 252:
+		numLen := int64(2)
+		offset = 1+numLen
+		val = int64(bytesToInt(bytesVal[1:offset]))
+
+	case fb == 253:
+		numLen := int64(3)
+		offset = 1+numLen
+		val = int64(bytesToInt(bytesVal[1:offset]))
+
+	case fb == 254:
+		numLen := int64(8)
+		offset = 1+numLen
+		val = int64(bytesToInt(bytesVal[1:offset]))
+
+	default:
+		val = -1
+	}
+	return
+}
+
+func parseResponseHeader(payload []byte) (ok, val int64, err error) {
+	if payload == nil || len(payload) < 1 {
+		err = fmt.Errorf("no bytes to parse")
+		return
+	}
+
+	fmt.Printf("%#v\n", payload)
+	defer func() {
+		fmt.Printf("%#v\n", ok)
+		fmt.Printf("%#v\n", val)
+	}()
+
+	switch {
+	case payload[0] == PACKET_OK && len(payload)>=7:
+	case payload[0] == PACKET_EOF && len(payload)<=9:
+		// set ok and mysql affected rows number
+		ok = 1
+		val = lenencInt(payload)
+
+	case payload[0] == PACKET_ERR && len(payload)>3:
+		// set not ok and mysql execute error-code
+		ok = 0
+		val = int64(bytesToIntSmallEndian(payload[1:3]))
+
+	default:
+		err = fmt.Errorf("invalid response packet")
+	}
+	return
+}
+