Extract Numerator and Denominator Constants to Byte Arrays

experimental/unitsconversion/Cargo.toml

@@ -25,9 +25,7 @@ displaydoc = { version = "0.2.3", default-features = false }
 icu_locid = { workspace = true }
 icu_provider = { workspace = true, features = ["macros"] }
 serde = { version = "1.0", default-features = false, features = ["derive", "alloc"], optional = true }
-tinystr = { workspace = true, features = ["zerovec"], default-features = false }
 zerovec = { workspace = true, features = ["yoke"] }
-
 icu_unitsconversion_data = { workspace = true, optional = true }
 
 [features]

experimental/unitsconversion/src/provider.rs

@@ -10,7 +10,7 @@
 //! Read more about data providers: [`icu_provider`]
 
 use icu_provider::prelude::*;
-use zerovec::ZeroMap;
+use zerovec::{ZeroMap, ZeroVec};
 
 #[cfg(feature = "compiled_data")]
 #[derive(Debug)]
@@ -36,15 +36,15 @@ const _: () = {
 /// The latest minimum set of keys required by this component.
 pub const KEYS: &[DataKey] = &[UnitsConstantsV1Marker::KEY];
 
-/// This type contains all of the constants data for units conversion.
+/// This type encapsulates all the constant data required for unit conversions.
 ///
 /// <div class="stab unstable">
 /// 🚧 This code is considered unstable; it may change at any time, in breaking or non-breaking ways,
 /// including in SemVer minor releases. While the serde representation of data structs is guaranteed
 /// to be stable, their Rust representation might not be. Use with caution.
 /// </div>
 #[icu_provider::data_struct(marker(UnitsConstantsV1Marker, "units/constants@1", singleton))]
-#[derive(Default, Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Debug)]
 #[cfg_attr(
     feature = "datagen",
     derive(serde::Serialize, databake::Bake),
@@ -57,5 +57,77 @@ pub struct UnitsConstantsV1<'data> {
     // Also, the constant types.
     /// Maps from constant name (e.g. ft_to_m) to the value of the constant (e.g. 0.3048).
     #[cfg_attr(feature = "serde", serde(borrow))]
-    pub constants_map: ZeroMap<'data, str, str>,
+    pub constants_map: ZeroMap<'data, str, ConstantValueULE>,
+}
+
+/// This enum is used to represent the type of a constant value.
+/// It can be either `ConstantType::Actual` or `ConstantType::Approximate`.
+/// If the constant type is `ConstantType::Approximate`, it indicates that the value is not numerically accurate.
+#[zerovec::make_ule(ConstantExactnessULE)]
+#[cfg_attr(
+    feature = "datagen",
+    derive(serde::Serialize, databake::Bake),
+    databake(path = icu_unitsconversion::provider),
+)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
+#[derive(Copy, Clone, Debug, PartialOrd, Ord, PartialEq, Eq, Default)]
+#[repr(u8)]
+pub enum ConstantExactness {
+    #[default]
+    Exact = 0,
+    Approximate = 1,
+}
+
+/// This enum is used to represent the sign of a constant value.
+#[zerovec::make_ule(SignULE)]
+#[cfg_attr(
+    feature = "datagen",
+    derive(serde::Serialize, databake::Bake),
+    databake(path = icu_unitsconversion::provider),
+)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
+#[derive(Copy, Clone, Debug, PartialOrd, Ord, PartialEq, Eq, Default)]
+#[repr(u8)]
+pub enum Sign {
+    #[default]
+    Positive = 0,
+    Negative = 1,
+}
+
+// TODO(#4098): Improve the ULE representation. Consider using a single byte for sign and type representation.
+/// This struct encapsulates a constant value, comprising a numerator, denominator, sign, and type.
+#[zerovec::make_varule(ConstantValueULE)]
+#[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq, Default)]
+#[cfg_attr(
+    feature = "datagen",
+    derive(databake::Bake),
+    databake(path = icu_unitsconversion::provider),
+)]
+#[cfg_attr(
+    feature = "datagen",
+    derive(serde::Serialize),
+    zerovec::derive(Serialize)
+)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Deserialize),
+    zerovec::derive(Deserialize)
+)]
+#[zerovec::derive(Debug)]
+pub struct ConstantValue<'data> {
+    // TODO(https://github.com/unicode-org/icu4x/issues/4092).
+    /// The numerator of the constant value in bytes starting with the least significant byte.
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    pub numerator: ZeroVec<'data, u8>,
+
+    // TODO(https://github.com/unicode-org/icu4x/issues/4092).
+    /// The denominator of the constant value in bytes starting with the least significant byte.
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    pub denominator: ZeroVec<'data, u8>,
+
+    /// Determines whether the constant value is positive or negative.
+    pub sign: Sign,
+
+    /// Determines whether the constant value is actual or approximate.
+    pub constant_exactness: ConstantExactness,
 }

provider/datagen/Cargo.toml

@@ -32,7 +32,6 @@ version.workspace = true
 all-features = true
 
 [dependencies]
-
 # ICU components
 icu_calendar = { workspace = true, features = ["datagen"] }
 icu_casemap = { workspace = true, features = ["datagen"] }
@@ -90,6 +89,10 @@ zip = { version = ">=0.5, <0.7", default-features = false, features = ["deflate"
 rayon = { version = "1.5", optional = true }
 ureq = { version = "2", optional = true }
 
+fraction = {version = "0.14.0", default-features = false }
+num-bigint = { version = "0.4.4", default-features = false }
+
+
 # Dependencies for "bin" feature
 clap = { version = "4", optional = true, features = ["derive"] }
 eyre = { version = "0.6", optional = true }