From dc71bedebfa0a5c8709811d88748c4c9e805a847 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Tue, 4 Apr 2017 20:30:04 -0500
Subject: [PATCH] Add pgtype.Polygon

---
 pgtype/pgtype.go       |   1 +
 pgtype/polygon.go      | 186 +++++++++++++++++++++++++++++++++++++++++
 pgtype/polygon_test.go |  21 +++++
 v3.md                  |   1 -
 4 files changed, 208 insertions(+), 1 deletion(-)
 create mode 100644 pgtype/polygon.go
 create mode 100644 pgtype/polygon_test.go

diff --git a/pgtype/pgtype.go b/pgtype/pgtype.go
index 5c8adb6e..cb0cec2c 100644
--- a/pgtype/pgtype.go
+++ b/pgtype/pgtype.go
@@ -250,6 +250,7 @@ func init() {
 		"oid":          &OidValue{},
 		"path":         &Path{},
 		"point":        &Point{},
+		"polygon":      &Polygon{},
 		"record":       &Record{},
 		"text":         &Text{},
 		"tid":          &Tid{},
diff --git a/pgtype/polygon.go b/pgtype/polygon.go
new file mode 100644
index 00000000..1e2df011
--- /dev/null
+++ b/pgtype/polygon.go
@@ -0,0 +1,186 @@
+package pgtype
+
+import (
+	"database/sql/driver"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+	"strings"
+
+	"github.com/jackc/pgx/pgio"
+)
+
+type Polygon struct {
+	P      []Vec2
+	Status Status
+}
+
+func (dst *Polygon) Set(src interface{}) error {
+	return fmt.Errorf("cannot convert %v to Polygon", src)
+}
+
+func (dst *Polygon) Get() interface{} {
+	switch dst.Status {
+	case Present:
+		return dst
+	case Null:
+		return nil
+	default:
+		return dst.Status
+	}
+}
+
+func (src *Polygon) AssignTo(dst interface{}) error {
+	return fmt.Errorf("cannot assign %v to %T", src, dst)
+}
+
+func (dst *Polygon) DecodeText(ci *ConnInfo, src []byte) error {
+	if src == nil {
+		*dst = Polygon{Status: Null}
+		return nil
+	}
+
+	if len(src) < 7 {
+		return fmt.Errorf("invalid length for Polygon: %v", len(src))
+	}
+
+	points := make([]Vec2, 0)
+
+	str := string(src[2:])
+
+	for {
+		end := strings.IndexByte(str, ',')
+		x, err := strconv.ParseFloat(str[:end], 64)
+		if err != nil {
+			return err
+		}
+
+		str = str[end+1:]
+		end = strings.IndexByte(str, ')')
+
+		y, err := strconv.ParseFloat(str[:end], 64)
+		if err != nil {
+			return err
+		}
+
+		points = append(points, Vec2{x, y})
+
+		if end+3 < len(str) {
+			str = str[end+3:]
+		} else {
+			break
+		}
+	}
+
+	*dst = Polygon{P: points, Status: Present}
+	return nil
+}
+
+func (dst *Polygon) DecodeBinary(ci *ConnInfo, src []byte) error {
+	if src == nil {
+		*dst = Polygon{Status: Null}
+		return nil
+	}
+
+	if len(src) < 5 {
+		return fmt.Errorf("invalid length for Polygon: %v", len(src))
+	}
+
+	pointCount := int(binary.BigEndian.Uint32(src))
+	rp := 4
+
+	if 4+pointCount*16 != len(src) {
+		return fmt.Errorf("invalid length for Polygon with %d points: %v", pointCount, len(src))
+	}
+
+	points := make([]Vec2, pointCount)
+	for i := 0; i < len(points); i++ {
+		x := binary.BigEndian.Uint64(src[rp:])
+		rp += 8
+		y := binary.BigEndian.Uint64(src[rp:])
+		rp += 8
+		points[i] = Vec2{math.Float64frombits(x), math.Float64frombits(y)}
+	}
+
+	*dst = Polygon{
+		P:      points,
+		Status: Present,
+	}
+	return nil
+}
+
+func (src *Polygon) EncodeText(ci *ConnInfo, w io.Writer) (bool, error) {
+	switch src.Status {
+	case Null:
+		return true, nil
+	case Undefined:
+		return false, errUndefined
+	}
+
+	if err := pgio.WriteByte(w, '('); err != nil {
+		return false, err
+	}
+
+	for i, p := range src.P {
+		if i > 0 {
+			if err := pgio.WriteByte(w, ','); err != nil {
+				return false, err
+			}
+		}
+		if _, err := io.WriteString(w, fmt.Sprintf(`(%f,%f)`, p.X, p.Y)); err != nil {
+			return false, err
+		}
+	}
+
+	err := pgio.WriteByte(w, ')')
+	return false, err
+}
+
+func (src *Polygon) EncodeBinary(ci *ConnInfo, w io.Writer) (bool, error) {
+	switch src.Status {
+	case Null:
+		return true, nil
+	case Undefined:
+		return false, errUndefined
+	}
+
+	if _, err := pgio.WriteInt32(w, int32(len(src.P))); err != nil {
+		return false, err
+	}
+
+	for _, p := range src.P {
+		if _, err := pgio.WriteUint64(w, math.Float64bits(p.X)); err != nil {
+			return false, err
+		}
+
+		if _, err := pgio.WriteUint64(w, math.Float64bits(p.Y)); err != nil {
+			return false, err
+		}
+	}
+
+	return false, nil
+}
+
+// Scan implements the database/sql Scanner interface.
+func (dst *Polygon) Scan(src interface{}) error {
+	if src == nil {
+		*dst = Polygon{Status: Null}
+		return nil
+	}
+
+	switch src := src.(type) {
+	case string:
+		return dst.DecodeText(nil, []byte(src))
+	case []byte:
+		return dst.DecodeText(nil, src)
+	}
+
+	return fmt.Errorf("cannot scan %T", src)
+}
+
+// Value implements the database/sql/driver Valuer interface.
+func (src *Polygon) Value() (driver.Value, error) {
+	return encodeValueText(src)
+}
diff --git a/pgtype/polygon_test.go b/pgtype/polygon_test.go
new file mode 100644
index 00000000..3a7e1431
--- /dev/null
+++ b/pgtype/polygon_test.go
@@ -0,0 +1,21 @@
+package pgtype_test
+
+import (
+	"testing"
+
+	"github.com/jackc/pgx/pgtype"
+)
+
+func TestPolygonTranscode(t *testing.T) {
+	testSuccessfulTranscode(t, "polygon", []interface{}{
+		&pgtype.Polygon{
+			P:      []pgtype.Vec2{{3.14, 1.678}, {7.1, 5.234}, {5.0, 3.234}},
+			Status: pgtype.Present,
+		},
+		&pgtype.Polygon{
+			P:      []pgtype.Vec2{{3.14, -1.678}, {7.1, -5.234}, {23.1, 9.34}},
+			Status: pgtype.Present,
+		},
+		&pgtype.Polygon{Status: pgtype.Null},
+	})
+}
diff --git a/v3.md b/v3.md
index 412d759d..a879e384 100644
--- a/v3.md
+++ b/v3.md
@@ -68,7 +68,6 @@ something like:
 select array[1,2,3], array[4,5,6,7]
 
 pgtype TODO:
-polygon
 circle
 macaddr
 varbit