point.rs

use crate::common::WKBDimension;
use crate::reader::coord::Coord;
use crate::Endianness;
use geo_traits::Dimensions;
use geo_traits::{CoordTrait, PointTrait};

/// A WKB Point.
///
/// This has been preprocessed, so access to any internal coordinate is `O(1)`.
///
/// See page 66 of <https://portal.ogc.org/files/?artifact_id=25355>.
#[derive(Debug, Clone, Copy)]
pub struct Point<'a> {
    /// The coordinate inside this Point
    coord: Coord<'a>,
    dim: WKBDimension,
    is_empty: bool,
}

impl<'a> Point<'a> {
    pub fn new(buf: &'a [u8], byte_order: Endianness, offset: u64, dim: WKBDimension) -> Self {
        // The space of the byte order + geometry type
        let offset = offset + 5;
        let coord = Coord::new(buf, byte_order, offset, dim);
        let is_empty = (0..coord.dim().size()).all(|coord_dim| {
            {
                // Safety:
                // We just checked the number of dimensions, and coord_dim is less than
                // coord.dim().size()
                unsafe { coord.nth_unchecked(coord_dim) }
            }
            .is_nan()
        });
        Self {
            coord,
            dim,
            is_empty,
        }
    }

    /// The number of bytes in this object, including any header
    ///
    /// Note that this is not the same as the length of the underlying buffer
    pub fn size(&self) -> u64 {
        // - 1: byteOrder
        // - 4: wkbType
        // - 4: numPoints
        // - dim size * 8: two f64s
        1 + 4 + (self.dim.size() as u64 * 8)
    }

    pub fn dimension(&self) -> WKBDimension {
        self.dim
    }
}

impl<'a> PointTrait for Point<'a> {
    type T = f64;
    type CoordType<'b>
        = Coord<'a>
    where
        Self: 'b;

    fn dim(&self) -> Dimensions {
        self.dim.into()
    }

    fn coord(&self) -> Option<Self::CoordType<'_>> {
        if self.is_empty {
            None
        } else {
            Some(self.coord)
        }
    }
}

impl<'a> PointTrait for &Point<'a> {
    type T = f64;
    type CoordType<'b>
        = Coord<'a>
    where
        Self: 'b;

    fn dim(&self) -> Dimensions {
        self.dim.into()
    }

    fn coord(&self) -> Option<Self::CoordType<'_>> {
        if self.is_empty {
            None
        } else {
            Some(self.coord)
        }
    }
}