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line_string.go
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/
line_string.go
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package wkbcommon
import (
"errors"
"io"
"math"
"github.com/TucarApp/orb"
)
func unmarshalLineString(order byteOrder, data []byte) (orb.LineString, error) {
ps, err := unmarshalPoints(order, data)
if err != nil {
return nil, err
}
return orb.LineString(ps), nil
}
func readLineString(r io.Reader, order byteOrder, buf []byte) (orb.LineString, error) {
num, err := readUint32(r, order, buf[:4])
if err != nil {
return nil, err
}
alloc := num
if alloc > MaxPointsAlloc {
// invalid data can come in here and allocate tons of memory.
alloc = MaxPointsAlloc
}
result := make(orb.LineString, 0, alloc)
for i := 0; i < int(num); i++ {
p, err := readPoint(r, order, buf)
if err != nil {
return nil, err
}
result = append(result, p)
}
return result, nil
}
func (e *Encoder) writeLineString(ls orb.LineString, srid int) error {
err := e.writeTypePrefix(lineStringType, len(ls), srid)
if err != nil {
return err
}
for _, p := range ls {
e.order.PutUint64(e.buf, math.Float64bits(p[0]))
e.order.PutUint64(e.buf[8:], math.Float64bits(p[1]))
_, err = e.w.Write(e.buf)
if err != nil {
return err
}
}
return nil
}
func unmarshalMultiLineString(order byteOrder, data []byte) (orb.MultiLineString, error) {
if len(data) < 4 {
return nil, ErrNotWKB
}
num := unmarshalUint32(order, data)
data = data[4:]
alloc := num
if alloc > MaxMultiAlloc {
// invalid data can come in here and allocate tons of memory.
alloc = MaxMultiAlloc
}
result := make(orb.MultiLineString, 0, alloc)
for i := 0; i < int(num); i++ {
ls, _, err := ScanLineString(data)
if err != nil {
return nil, err
}
data = data[16*len(ls)+9:]
result = append(result, ls)
}
return result, nil
}
func readMultiLineString(r io.Reader, order byteOrder, buf []byte) (orb.MultiLineString, error) {
num, err := readUint32(r, order, buf[:4])
if err != nil {
return nil, err
}
alloc := num
if alloc > MaxMultiAlloc {
// invalid data can come in here and allocate tons of memory.
alloc = MaxMultiAlloc
}
result := make(orb.MultiLineString, 0, alloc)
for i := 0; i < int(num); i++ {
lOrder, typ, _, err := readByteOrderType(r, buf)
if err != nil {
return nil, err
}
if typ != lineStringType {
return nil, errors.New("expect multilines to contains lines, did not find a line")
}
ls, err := readLineString(r, lOrder, buf)
if err != nil {
return nil, err
}
result = append(result, ls)
}
return result, nil
}
func (e *Encoder) writeMultiLineString(mls orb.MultiLineString, srid int) error {
err := e.writeTypePrefix(multiLineStringType, len(mls), srid)
if err != nil {
return err
}
for _, ls := range mls {
err := e.Encode(ls, 0)
if err != nil {
return err
}
}
return nil
}