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package magic
import (
"bytes"
"encoding/binary"
)
// Shp matches a shape format file.
// https://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
func Shp(raw []byte, limit uint32) bool {
if len(raw) < 112 {
return false
}
if !(binary.BigEndian.Uint32(raw[0:4]) == 9994 &&
binary.BigEndian.Uint32(raw[4:8]) == 0 &&
binary.BigEndian.Uint32(raw[8:12]) == 0 &&
binary.BigEndian.Uint32(raw[12:16]) == 0 &&
binary.BigEndian.Uint32(raw[16:20]) == 0 &&
binary.BigEndian.Uint32(raw[20:24]) == 0 &&
binary.LittleEndian.Uint32(raw[28:32]) == 1000) {
return false
}
shapeTypes := []int{
0, // Null shape
1, // Point
3, // Polyline
5, // Polygon
8, // MultiPoint
11, // PointZ
13, // PolylineZ
15, // PolygonZ
18, // MultiPointZ
21, // PointM
23, // PolylineM
25, // PolygonM
28, // MultiPointM
31, // MultiPatch
}
for _, st := range shapeTypes {
if st == int(binary.LittleEndian.Uint32(raw[108:112])) {
return true
}
}
return false
}
// Shx matches a shape index format file.
// https://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
func Shx(raw []byte, limit uint32) bool {
return bytes.HasPrefix(raw, []byte{0x00, 0x00, 0x27, 0x0A})
}
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