mlt_core/decoder/
into_tile.rs

1//! Conversion from the decoded columnar form into the row-oriented
2//! [`crate::tile`] model.
3//!
4//! [`ParsedLayer01::into_tile`] materializes one [`TileFeature`] per map
5//! feature, owning its geometry and property values outright. That is the form
6//! the optimizer, the sorting pipeline, and the converters work in.
7
8use crate::decoder::{Layer, Layer01, ParsedLayer, ParsedLayer01, ParsedProperty, PropValueRef};
9#[cfg(feature = "unstable-v2")]
10use crate::decoder::{Layer02, MValueSpans, ParsedLayer02, ParsedMValue, ParsedNested};
11use crate::errors::AsMltError as _;
12#[cfg(feature = "unstable-v2")]
13use crate::tile::{MValue, NestedKind, NestedValue};
14use crate::tile::{PropValue, TileFeature, TileLayer};
15use crate::{Decoder, Lazy, LendingIterator, MltResult};
16
17/// The parts of a [`TileLayer`] every wire version produces the same way.
18struct TileParts {
19    name: String,
20    extent: u32,
21    names: Vec<String>,
22    features: Vec<TileFeature>,
23}
24
25impl TileParts {
26    fn finish(self) -> MltResult<TileLayer> {
27        TileLayer::from_parts(self.name, self.extent, self.names, self.features)
28    }
29}
30
31impl ParsedLayer01<'_> {
32    /// Decode and convert into a row-oriented [`TileLayer`], charging every
33    /// heap allocation against `dec`.
34    pub fn into_tile(self, dec: &mut Decoder) -> MltResult<TileLayer> {
35        self.collect_parts(dec)?.finish()
36    }
37
38    /// One [`TileFeature`] per map feature, carrying only the columns every version
39    /// has. Borrows, so a version that adds its own can fill them in afterwards.
40    fn collect_parts(&self, dec: &mut Decoder) -> MltResult<TileParts> {
41        let name = self.name().to_string();
42        let extent = self.extent().get();
43        let names: Vec<String> = self.iterate_prop_names().map(|n| n.to_string()).collect();
44        let col_nulls = typed_nulls(&self.properties);
45        let mut features = dec.alloc::<TileFeature>(self.feature_count())?;
46        let mut feat_iter = self.iter_features();
47        while let Some(feat) = feat_iter.next() {
48            let feat = feat?;
49            let mut values = dec.alloc::<PropValue>(names.len())?;
50            for (col_idx, value) in feat.iter_all_properties().enumerate() {
51                values.push(match value {
52                    Some(v) => prop_value_from_ref(v),
53                    None => col_nulls[col_idx].clone(),
54                });
55            }
56
57            charge_str_props(dec, &values)?;
58
59            features.push(TileFeature {
60                id: feat.id(),
61                geometry: feat.geometry().clone(),
62                properties: values,
63                #[cfg(feature = "unstable-v2")]
64                m_values: Vec::new(),
65                #[cfg(feature = "unstable-v2")]
66                nested: Vec::new(),
67            });
68        }
69        Ok(TileParts {
70            name,
71            extent,
72            names,
73            features,
74        })
75    }
76}
77
78impl Layer01<'_> {
79    /// Decode and convert into a row-oriented [`TileLayer`]
80    pub fn into_tile(self, dec: &mut Decoder) -> MltResult<TileLayer> {
81        self.decode_all(dec)?.into_tile(dec)
82    }
83}
84
85#[cfg(feature = "unstable-v2")]
86impl ParsedLayer02<'_> {
87    /// Decode and convert into a row-oriented [`TileLayer`], adding the m-value
88    /// and nested columns only v2 carries.
89    pub fn into_tile(self, dec: &mut Decoder) -> MltResult<TileLayer> {
90        let m_names: Vec<String> = self.m_values.iter().map(|m| m.name().to_string()).collect();
91        let nested_names: Vec<String> = self.nested.iter().map(|n| n.name().to_string()).collect();
92        let nested_kinds: Vec<NestedKind> = self.nested.iter().map(ParsedNested::kind).collect();
93        // One walk per m-value column, stepped alongside the features. Cutting the
94        // columns up front instead would cost a span per feature per column, which is
95        // memory the tile declares rather than memory it carries.
96        let mut m_spans = dec.alloc::<MValueSpans>(self.m_values.len())?;
97        m_spans.extend(self.m_values.iter().map(|m| m.spans(&self.layer.geometry)));
98
99        let mut parts = self.layer.collect_parts(dec)?;
100        for (index, feature) in parts.features.iter_mut().enumerate() {
101            feature.m_values = m_values_of(&self.m_values, &mut m_spans, dec)?;
102            feature.nested = nested_of(&self.nested, index, dec)?;
103        }
104        parts
105            .finish()?
106            .with_m_value_names(m_names)?
107            .with_nested(nested_names, nested_kinds)
108    }
109}
110
111#[cfg(feature = "unstable-v2")]
112impl Layer02<'_> {
113    /// Decode and convert into a row-oriented [`TileLayer`]
114    pub fn into_tile(self, dec: &mut Decoder) -> MltResult<TileLayer> {
115        self.decode_all(dec)?.into_tile(dec)
116    }
117}
118
119impl ParsedLayer<'_> {
120    /// Convert into a row-oriented [`TileLayer`] whatever the tag, or `None` for a
121    /// tag this build does not know. Keeps every version's columns.
122    pub fn into_tile(self, dec: &mut Decoder) -> MltResult<Option<TileLayer>> {
123        match self {
124            Self::Tag01(l) => l.into_tile(dec).map(Some),
125            #[cfg(feature = "unstable-v2")]
126            Self::Tag02(l) => l.into_tile(dec).map(Some),
127            Self::Unknown(_) => Ok(None),
128        }
129    }
130}
131
132impl Layer<'_, Lazy> {
133    /// Decode every column, then convert into a row-oriented [`TileLayer`], or
134    /// `None` for a tag this build does not know.
135    pub fn into_tile(self, dec: &mut Decoder) -> MltResult<Option<TileLayer>> {
136        self.decode_all(dec)?.into_tile(dec)
137    }
138}
139
140/// The m-values of the next feature, one per column, charged against `dec`.
141///
142/// Every column's walk is stepped once per feature, which is what pairs a feature
143/// with its run.
144#[cfg(feature = "unstable-v2")]
145fn m_values_of(
146    columns: &[ParsedMValue<'_>],
147    spans: &mut [MValueSpans<'_>],
148    dec: &mut Decoder,
149) -> MltResult<Vec<MValue>> {
150    let mut values = dec.alloc::<MValue>(columns.len())?;
151    for (column, spans) in columns.iter().zip(spans) {
152        let span = spans.next().transpose()?.flatten();
153        if let Some(span) = &span {
154            dec.consume(u32::try_from(column.values().row_bytes(span)).or_overflow()?)?;
155        }
156        values.push(column.values().row(column.name(), span)?);
157    }
158    Ok(values)
159}
160
161/// The nested values of feature `index`, one per column, charged against `dec`.
162#[cfg(feature = "unstable-v2")]
163fn nested_of(
164    columns: &[ParsedNested<'_>],
165    index: usize,
166    dec: &mut Decoder,
167) -> MltResult<Vec<NestedValue>> {
168    let mut values = dec.alloc::<NestedValue>(columns.len())?;
169    for column in columns {
170        let value = column.row(index)?;
171        dec.consume(u32::try_from(value.heap_bytes()).or_overflow()?)?;
172        values.push(value);
173    }
174    Ok(values)
175}
176
177/// Convert a [`PropValueRef`] (as yielded by [`crate::FeatureRef::iter_all_properties`])
178/// into an owned [`PropValue`].
179fn prop_value_from_ref(value: PropValueRef<'_>) -> PropValue {
180    match value {
181        PropValueRef::Bool(v) => PropValue::Bool(Some(v)),
182        PropValueRef::I8(v) => PropValue::I8(Some(v)),
183        PropValueRef::U8(v) => PropValue::U8(Some(v)),
184        PropValueRef::I32(v) => PropValue::I32(Some(v)),
185        PropValueRef::U32(v) => PropValue::U32(Some(v)),
186        PropValueRef::I64(v) => PropValue::I64(Some(v)),
187        PropValueRef::U64(v) => PropValue::U64(Some(v)),
188        PropValueRef::F32(v) => PropValue::F32(Some(v)),
189        PropValueRef::F64(v) => PropValue::F64(Some(v)),
190        PropValueRef::Str(s) => PropValue::Str(Some(s.to_string())),
191    }
192}
193
194/// Build a flat list of typed null [`PropValue`]s, one per logical column position
195/// as yielded by [`crate::FeatureRef::iter_all_properties`].
196///
197/// Each scalar column contributes one entry with its specific null variant (e.g.
198/// `PropValue::Bool(None)`).  A `SharedDict` column expands to one `PropValue::Str(None)`
199/// entry per sub-item.
200fn typed_nulls(properties: &[ParsedProperty<'_>]) -> Vec<PropValue> {
201    use ParsedProperty as PP;
202    use PropValue as PV;
203    let mut nulls = Vec::new();
204    for prop in properties {
205        match prop {
206            PP::Bool(_) => nulls.push(PV::Bool(None)),
207            PP::I8(_) => nulls.push(PV::I8(None)),
208            PP::U8(_) => nulls.push(PV::U8(None)),
209            PP::I32(_) => nulls.push(PV::I32(None)),
210            PP::U32(_) => nulls.push(PV::U32(None)),
211            PP::I64(_) => nulls.push(PV::I64(None)),
212            PP::U64(_) => nulls.push(PV::U64(None)),
213            PP::F32(_) => nulls.push(PV::F32(None)),
214            PP::F64(_) => nulls.push(PV::F64(None)),
215            PP::Str(_) => nulls.push(PV::Str(None)),
216            PP::SharedDict(d) => {
217                for _ in &d.items {
218                    nulls.push(PV::Str(None));
219                }
220            }
221        }
222    }
223    nulls
224}
225
226/// Charge `dec` for the heap bytes of owned `String` values inside `PropValue::Str`.
227fn charge_str_props(dec: &mut Decoder, props: &[PropValue]) -> MltResult<()> {
228    let str_bytes = props
229        .iter()
230        .filter_map(|p| {
231            if let PropValue::Str(Some(s)) = p {
232                Some(s.len())
233            } else {
234                None
235            }
236        })
237        .try_fold(0u32, |acc, n| {
238            acc.checked_add(u32::try_from(n).or_overflow()?)
239                .or_overflow()
240        })?;
241    if str_bytes > 0 {
242        dec.consume(str_bytes)?;
243    }
244    Ok(())
245}
mlt_core/decoder/into_tile.rs

mlt_core/decoder/
into_tile.rs
