-
Notifications
You must be signed in to change notification settings - Fork 11
/
multipolygon.rs
91 lines (75 loc) · 2.75 KB
/
multipolygon.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
use crate::array::offset_builder::OffsetsBuilder;
use crate::array::{MultiPolygonArray, WKBArray};
use crate::error::Result;
use crate::geo_traits::MultiPolygonTrait;
use crate::io::wkb::reader::Endianness;
use crate::io::wkb::writer::polygon::{polygon_wkb_size, write_polygon_as_wkb};
use crate::trait_::GeometryArrayAccessor;
use crate::trait_::GeometryArrayTrait;
use arrow_array::{GenericBinaryArray, OffsetSizeTrait};
use byteorder::{LittleEndian, WriteBytesExt};
use std::io::{Cursor, Write};
/// The byte length of a WKBMultiPolygon
pub fn multi_polygon_wkb_size(geom: &impl MultiPolygonTrait) -> usize {
let mut sum = 1 + 4 + 4;
for polygon in geom.polygons() {
sum += polygon_wkb_size(&polygon);
}
sum
}
/// Write a MultiPolygon geometry to a Writer encoded as WKB
pub fn write_multi_polygon_as_wkb<W: Write>(
mut writer: W,
geom: &impl MultiPolygonTrait<T = f64>,
) -> Result<()> {
// Byte order
writer.write_u8(Endianness::LittleEndian.into()).unwrap();
// wkbType = 6
writer.write_u32::<LittleEndian>(6).unwrap();
// numPolygons
writer
.write_u32::<LittleEndian>(geom.num_polygons().try_into().unwrap())
.unwrap();
for polygon in geom.polygons() {
write_polygon_as_wkb(&mut writer, &polygon).unwrap();
}
Ok(())
}
impl<A: OffsetSizeTrait, B: OffsetSizeTrait> From<&MultiPolygonArray<A>> for WKBArray<B> {
fn from(value: &MultiPolygonArray<A>) -> Self {
let mut offsets: OffsetsBuilder<B> = OffsetsBuilder::with_capacity(value.len());
// First pass: calculate binary array offsets
for maybe_geom in value.iter() {
if let Some(geom) = maybe_geom {
offsets
.try_push_usize(multi_polygon_wkb_size(&geom))
.unwrap();
} else {
offsets.extend_constant(1);
}
}
let values = {
let values = Vec::with_capacity(offsets.last().to_usize().unwrap());
let mut writer = Cursor::new(values);
for geom in value.iter().flatten() {
write_multi_polygon_as_wkb(&mut writer, &geom).unwrap();
}
writer.into_inner()
};
let binary_arr =
GenericBinaryArray::new(offsets.into(), values.into(), value.nulls().cloned());
WKBArray::new(binary_arr, value.metadata())
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::test::multipolygon::{mp0, mp1};
#[test]
fn round_trip() {
let orig_arr: MultiPolygonArray<i32> = vec![Some(mp0()), Some(mp1()), None].into();
let wkb_arr: WKBArray<i32> = (&orig_arr).into();
let new_arr: MultiPolygonArray<i32> = wkb_arr.try_into().unwrap();
assert_eq!(orig_arr, new_arr);
}
}