More pluggable value transcoding

value_transcoder.go

@@ -0,0 +1,94 @@
+package pgx
+
+import (
+	"fmt"
+	"strconv"
+)
+
+type valueTranscoder struct {
+	FromText func(*MessageReader, int32) interface{}
+	// FromBinary func(*MessageReader, int32) interface{}
+	// ToText func(interface{}) string
+	// ToBinary func(interface{}) []byte
+}
+
+var valueTranscoders map[oid]*valueTranscoder
+
+func init() {
+	valueTranscoders = make(map[oid]*valueTranscoder)
+
+	// bool
+	valueTranscoders[oid(16)] = &valueTranscoder{FromText: decodeBoolFromText}
+
+	// int8
+	valueTranscoders[oid(20)] = &valueTranscoder{FromText: decodeInt8FromText}
+
+	// int2
+	valueTranscoders[oid(21)] = &valueTranscoder{FromText: decodeInt2FromText}
+
+	// int4
+	valueTranscoders[oid(23)] = &valueTranscoder{FromText: decodeInt4FromText}
+
+	// float4
+	valueTranscoders[oid(700)] = &valueTranscoder{FromText: decodeFloat4FromText}
+
+	// float8
+	valueTranscoders[oid(701)] = &valueTranscoder{FromText: decodeFloat8FromText}
+}
+
+func decodeBoolFromText(mr *MessageReader, size int32) interface{} {
+	s := mr.ReadByteString(size)
+	switch s {
+	case "t":
+		return true
+	case "f":
+		return false
+	default:
+		panic(fmt.Sprintf("Received invalid bool: %v", s))
+	}
+}
+
+func decodeInt8FromText(mr *MessageReader, size int32) interface{} {
+	s := mr.ReadByteString(size)
+	n, err := strconv.ParseInt(s, 10, 64)
+	if err != nil {
+		panic(fmt.Sprintf("Received invalid int8: %v", s))
+	}
+	return n
+}
+
+func decodeInt2FromText(mr *MessageReader, size int32) interface{} {
+	s := mr.ReadByteString(size)
+	n, err := strconv.ParseInt(s, 10, 16)
+	if err != nil {
+		panic(fmt.Sprintf("Received invalid int2: %v", s))
+	}
+	return int16(n)
+}
+
+func decodeInt4FromText(mr *MessageReader, size int32) interface{} {
+	s := mr.ReadByteString(size)
+	n, err := strconv.ParseInt(s, 10, 32)
+	if err != nil {
+		panic(fmt.Sprintf("Received invalid int4: %v", s))
+	}
+	return int32(n)
+}
+
+func decodeFloat4FromText(mr *MessageReader, size int32) interface{} {
+	s := mr.ReadByteString(size)
+	n, err := strconv.ParseFloat(s, 32)
+	if err != nil {
+		panic(fmt.Sprintf("Received invalid float4: %v", s))
+	}
+	return float32(n)
+}
+
+func decodeFloat8FromText(mr *MessageReader, size int32) interface{} {
+	s := mr.ReadByteString(size)
+	v, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		panic(fmt.Sprintf("Received invalid float8: %v", s))
+	}
+	return v
+}