--- /dev/null
+! Copyright (C) 2018 John Benediktsson
+! See http://factorcode.org/license.txt for BSD license
+
+USING: arrays combinators io io.binary.fast io.encodings.binary
+io.files kernel math sequences ;
+
+IN: shapefiles
+
+<PRIVATE
+
+: read-int ( -- n )
+ 4 read le> ;
+
+: read-double ( -- n )
+ 8 read le> bits>double ;
+
+: read-box ( -- box )
+ 4 [ read-double ] replicate ;
+
+: read-int-array ( n -- parts )
+ [ read-int ] replicate ;
+
+: read-range ( -- range )
+ read-double read-double 2array ;
+
+: read-double-array ( n -- array )
+ [ read-double ] replicate ;
+
+PRIVATE>
+
+TUPLE: header file-code file-length version shape-type x-min
+y-min x-max y-max z-min z-max m-min m-max ;
+
+: read-header ( -- header )
+ 4 read be> dup 9994 assert= ! file code
+ 20 read drop ! unused
+ 4 read be> ! file-length
+ read-int dup 1000 assert= ! version
+ read-int ! shape-type
+ read-double ! x-min
+ read-double ! y-min
+ read-double ! x-max
+ read-double ! y-max
+ read-double ! z-min
+ read-double ! z-max
+ read-double ! m-min
+ read-double ! m-max
+ header boa ;
+
+TUPLE: point x y ;
+
+: read-point ( -- point )
+ read-double read-double point boa ;
+
+: read-points ( n -- points )
+ [ read-point ] replicate ;
+
+TUPLE: multipoint box points ;
+
+: read-multipoint ( -- multipoint )
+ read-box read-int [ read-point ] replicate multipoint boa ;
+
+TUPLE: polyline box parts points ;
+
+: read-polyline ( -- polyline )
+ read-box read-int read-int
+ [ [ read-int ] replicate ]
+ [ [ read-point ] replicate ] bi*
+ polyline boa ;
+
+TUPLE: polygon box parts points ;
+
+: read-polygon ( -- polygon )
+ read-box read-int read-int
+ [ read-int-array ] [ read-points ] bi*
+ polygon boa ;
+
+TUPLE: point-m x y m ;
+
+: read-point-m ( -- point-m )
+ read-double read-double read-double point-m boa ;
+
+TUPLE: multipoint-m box points m-range m-array ;
+
+: read-multipoint-m ( -- multipoint-m )
+ read-box read-int
+ [ read-points read-range ] [ read-double-array ] bi
+ multipoint-m boa ;
+
+TUPLE: polyline-m box parts points m-range m-array ;
+
+: read-polyline-m ( -- polyline-m )
+ read-box read-int read-int [ read-int-array ] dip
+ [ read-points read-range ] [ read-double-array ] bi
+ polyline-m boa ;
+
+TUPLE: polygon-m box parts points m-range m-array ;
+
+: read-polygon-m ( -- polyline-m )
+ read-box read-int read-int [ read-int-array ] dip
+ [ read-points read-range ] [ read-double-array ] bi
+ polygon-m boa ;
+
+TUPLE: point-z x y z m ;
+
+: read-point-z ( -- point-z )
+ read-double read-double read-double read-double point-z boa ;
+
+TUPLE: multipoint-z box points z-range z-array m-range m-array ;
+
+: read-multipoint-z ( -- multipoint-z )
+ read-box read-int
+ [ read-points read-range ]
+ [ read-double-array read-range ]
+ [ read-double-array ] tri multipoint-z boa ;
+
+TUPLE: polyline-z box parts points z-range z-array m-range
+m-array ;
+
+: read-polyline-z ( -- polyline-z )
+ read-box read-int read-int [ read-int-array ] dip
+ [ read-points read-range ]
+ [ read-double-array read-range ]
+ [ read-double-array ] tri polyline-z boa ;
+
+TUPLE: polygon-z box parts points z-range z-array m-range
+m-array ;
+
+: read-polygon-z ( -- polyline-z )
+ read-box read-int read-int [ read-int-array ] dip
+ [ read-points read-range ]
+ [ read-double-array read-range ]
+ [ read-double-array ] tri polygon-z boa ;
+
+TUPLE: multipatch box parts points part-types z-range z-array
+m-range m-array ;
+
+: read-multipatch ( -- multipatch )
+ read-box read-int read-int
+ [ [ read-int-array ] [ read-int-array ] bi ] dip
+ [ read-points read-range ]
+ [ read-double-array read-range ]
+ [ read-double-array ] tri multipatch boa ;
+
+: read-shape ( -- shape )
+ 4 read le> {
+ { 0 [ null ] }
+ { 1 [ read-point ] }
+ { 3 [ read-polyline ] }
+ { 5 [ read-polygon ] }
+ { 8 [ read-multipoint ] }
+ { 11 [ read-point-z ] }
+ { 13 [ read-polyline-z ] }
+ { 15 [ read-polygon-z ] }
+ { 18 [ read-multipoint-z ] }
+ { 21 [ read-point-m ] }
+ { 23 [ read-polyline-m ] }
+ { 25 [ read-polygon-m ] }
+ { 28 [ read-multipoint-m ] }
+ { 31 [ read-multipatch ] }
+ } case ;
+
+TUPLE: record number content-length shape ;
+
+: read-record ( -- record/f )
+ 4 read [ be> 4 read be> read-shape record boa ] [ f ] if* ;
+
+: read-records ( -- records )
+ [ read-record dup ] [ ] produce nip ;
+
+: read-shp ( -- header shapes )
+ read-header read-records ;
+
+: file>shp ( path -- header shapes )
+ binary [ read-shp ] with-file-reader ;
+
+TUPLE: index offset content-length ;
+
+: read-index ( -- index/f )
+ 4 read [ be> 4 read be> index boa ] [ f ] if* ;
+
+: read-indices ( -- indices )
+ [ read-index dup ] [ ] produce nip ;
+
+: read-shx ( -- header indices )
+ read-header read-indices ;
+
+: file>shx ( path -- header indices )
+ binary [ read-shx ] with-file-reader ;