multi_polygon.go

package ewkb

import (
	"database/sql/driver"
	"errors"
	"fmt"

	"github.com/kcasctiv/go-ewkb/geo"
)

// MultiPolygon presents MultiPolygon geometry object
type MultiPolygon struct {
	header
	mp geo.MultiPolygon
}

// NewMultiPolygon returns new MultiPolygon,
// created from geometry base and coords data
func NewMultiPolygon(b Base, mp geo.MultiPolygon) MultiPolygon {
	return MultiPolygon{
		header: header{
			byteOrder: b.ByteOrder(),
			wkbType: getFlags(
				b.HasZ(),
				b.HasM(),
				b.HasSRID(),
			) | MultiPolygonType,
			srid: b.SRID(),
		},
		mp: mp,
	}
}

// Polygon returns polygon with specified index
func (p *MultiPolygon) Polygon(idx int) geo.Polygon { return p.mp.Polygon(idx) }

// Len returns count of polygons
func (p *MultiPolygon) Len() int { return p.mp.Len() }

// String returns WKT/EWKT geometry representation
func (p *MultiPolygon) String() string {
	var s string
	if p.HasSRID() {
		s = fmt.Sprintf("SRID=%d;", p.srid)
	}
	s += "MULTIPOLYGON"
	if !p.HasZ() && p.HasM() {
		s += "M"
	}

	if p.Len() == 0 {
		s += " EMPTY"
		return s
	}

	s += "("
	if p.Len() > 0 {
		for idx := 0; idx < p.Len(); idx++ {
			s += printPolygon(p.Polygon(idx), p.HasZ(), p.HasM()) + ","
		}

		s = s[:len(s)-1]
	}

	return s + ")"
}

// Scan implements sql.Scanner interface
func (p *MultiPolygon) Scan(src interface{}) error {
	return scanGeometry(src, p)
}

// Value implements sql driver.Valuer interface
func (p *MultiPolygon) Value() (driver.Value, error) {
	return p.String(), nil
}

// UnmarshalBinary implements encoding.BinaryUnmarshaler interface
func (p *MultiPolygon) UnmarshalBinary(data []byte) error {
	h, byteOrder, offset := readHeader(data)
	if h.Type() != MultiPolygonType {
		return errors.New("not expected geometry type")
	}

	p.header = h

	var err error
	p.mp, _, err = readMultiPolygon(
		data[offset:],
		byteOrder,
		getReadPointFunc(h.wkbType),
	)
	return err
}

// MarshalBinary implements encoding.BinaryMarshaler interface
func (p *MultiPolygon) MarshalBinary() ([]byte, error) {
	size := headerSize(p.HasSRID()) + multiPolygonSize(p, p.HasZ(), p.HasM())
	b := make([]byte, size)

	byteOrder := getBinaryByteOrder(p.ByteOrder())
	offset := writeHeader(p, p.Type(), byteOrder, p.HasSRID(), b)
	writeMultiPolygon(p, byteOrder, p.HasZ(), p.HasM(), b[offset:])

	return b, nil
}