mlt-core 0.12.7

MapLibre Tile library code
Documentation 
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
92
93

use crate::codecs::varint::parse_varint;
#[cfg(feature = "unstable-v2")]
use crate::decoder::root02::parse_layer02;
use crate::decoder::{Layer01, ParsedLayer01, Unknown};
use crate::utils::{parse_u8, take};
use crate::{
    DecodeState, Decoder, Layer, Lazy, MltError, MltRefResult, MltResult, ParsedLayer, Parser,
};

impl<'a, S: DecodeState> Layer<'a, S> {
    /// Returns the inner [`Layer01`] for any layer stored in the `Layer01`
    /// in-memory representation (both `Tag01` and `Tag02`), or `None` otherwise.
    #[must_use]
    pub fn as_layer01(&self) -> Option<&Layer01<'a, S>> {
        match self {
            Self::Tag01(l) => Some(l),
            #[cfg(feature = "unstable-v2")]
            Self::Tag02(l) => Some(l),
            Self::Unknown(_) => None,
        }
    }

    /// Consumes this layer and returns the inner [`Layer01`] for any layer stored
    /// in the `Layer01` in-memory representation, or `None` otherwise.
    #[must_use]
    pub fn into_layer01(self) -> Option<Layer01<'a, S>> {
        match self {
            Self::Tag01(l) => Some(l),
            #[cfg(feature = "unstable-v2")]
            Self::Tag02(l) => Some(l),
            Self::Unknown(_) => None,
        }
    }
}

impl<'a> Layer<'a> {
    /// Parse a single tuple that consists of `size (varint)`, `tag (varint)`, and `value (bytes)`.
    /// Reserves memory for decoded data against the parser's budget.
    pub(crate) fn from_bytes(input: &'a [u8], parser: &mut Parser) -> MltRefResult<'a, Self> {
        let (input, size) = parse_varint::<u32>(input)?;

        // tag is a varint, but we know fewer than 127 tags for now,
        // so we can use a faster u8 and fail if it is bigger than 127.
        let (input, tag) = parse_u8(input)?;
        // 1 byte must be parsed for the tag, so if size is 0, it's invalid
        let size = size.checked_sub(1).ok_or(MltError::ZeroLayerSize)?;
        let (input, value) = take(input, size)?;

        let layer = match tag {
            1 => Layer::Tag01(Layer01::from_bytes(value, parser)?),
            #[cfg(feature = "unstable-v2")]
            2 => Layer::Tag02(parse_layer02(value, parser)?),
            tag => Layer::Unknown(Unknown { tag, value }),
        };

        Ok((input, layer))
    }

    /// Decode all columns and return a fully-decoded [`ParsedLayer`].
    ///
    /// Consumes `self`.  For partial / incremental decoding, destructure with
    /// `Layer::Tag01(lazy)` and call the individual methods on [`Layer01`].
    pub fn decode_all(self, dec: &mut Decoder) -> MltResult<ParsedLayer<'a>> {
        match self {
            Layer::Tag01(v) => Ok(Layer::Tag01(v.decode_all(dec)?)),
            #[cfg(feature = "unstable-v2")]
            Layer::Tag02(v) => Ok(Layer::Tag02(v.decode_all(dec)?)),
            Layer::Unknown(u) => Ok(Layer::Unknown(u)),
        }
    }
}

impl<'a> Layer01<'a, Lazy> {
    /// Decode all columns and transition to [`Layer01<Parsed>`].
    ///
    /// Consumes `self` (a `Layer01<Lazy>`) and returns a `Layer01<Parsed>` where every
    /// column field holds its parsed value directly, enabling infallible readonly access.
    pub fn decode_all(self, dec: &mut Decoder) -> MltResult<ParsedLayer01<'a>> {
        Ok(Layer01 {
            name: self.name,
            extent: self.extent,
            id: self.id.map(|id| id.into_parsed(dec)).transpose()?,
            geometry: self.geometry.into_parsed(dec)?,
            properties: self
                .properties
                .into_iter()
                .map(|p| p.into_parsed(dec))
                .collect::<MltResult<Vec<_>>>()?,
            #[cfg(fuzzing)]
            layer_order: self.layer_order,
        })
    }
}