Add currency fractions provider (#7278)

Author: hansihe

components/experimental/src/dimension/provider/currency/fractions.rs

@@ -0,0 +1,70 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+// Provider structs must be stable
+#![allow(clippy::exhaustive_structs, clippy::exhaustive_enums)]
+
+//! Data provider struct definitions for currency fraction data.
+//!
+//! Read more about data providers: [`icu_provider`]
+
+use icu_provider::prelude::*;
+use tinystr::UnvalidatedTinyAsciiStr;
+use zerovec::ZeroMap;
+
+#[cfg(feature = "compiled_data")]
+/// Baked data
+///
+/// <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. In particular, the `DataProvider` implementations are only
+/// guaranteed to match with this version's `*_unstable` providers. Use with caution.
+/// </div>
+pub use crate::provider::Baked;
+
+icu_provider::data_marker!(
+    /// `CurrencyFractionsV1` provides currency fraction data for rounding and decimal digit rules.
+    CurrencyFractionsV1,
+    CurrencyFractions<'static>,
+    is_singleton = true
+);
+
+/// Currency fraction information for all currencies.
+///
+/// <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>
+#[derive(Clone, PartialEq, Debug, yoke::Yokeable, zerofrom::ZeroFrom)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
+#[cfg_attr(feature = "datagen", derive(serde::Serialize, databake::Bake))]
+#[cfg_attr(feature = "datagen", databake(path = icu_experimental::dimension::provider::currency::fractions))]
+#[yoke(prove_covariance_manually)]
+pub struct CurrencyFractions<'data> {
+    /// Map from 3-letter ISO code to fraction info (only currencies that differ from default)
+    #[cfg_attr(feature = "serde", serde(borrow))]
+    pub fractions: ZeroMap<'data, UnvalidatedTinyAsciiStr<3>, FractionInfo>,
+
+    /// Default fraction info (used when currency not in map)
+    pub default: FractionInfo,
+}
+
+icu_provider::data_struct!(CurrencyFractions<'_>, #[cfg(feature = "datagen")]);
+
+/// Fraction and rounding information for a currency.
+#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
+#[cfg_attr(feature = "datagen", derive(serde::Serialize, databake::Bake))]
+#[cfg_attr(feature = "datagen", databake(path = icu_experimental::dimension::provider::currency::fractions))]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Default)]
+pub struct FractionInfo {
+    /// Number of decimal digits for standard formatting
+    pub digits: u8,
+    /// Rounding increment (0 = no special rounding)
+    pub rounding: u8,
+    /// Number of decimal digits for cash transactions (if different)
+    pub cash_digits: Option<u8>,
+    /// Rounding increment for cash transactions (if different)
+    pub cash_rounding: Option<u8>,
+}

components/experimental/src/dimension/provider/currency/fractions_ule.rs

@@ -0,0 +1,80 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use super::fractions::FractionInfo;
+use zerovec::{
+    maps::ZeroMapKV,
+    ule::{AsULE, RawBytesULE},
+};
+
+/// Marker value indicating None for cash_digits and cash_rounding fields.
+const NONE_MARKER: u8 = 15;
+
+/// ULE type for FractionInfo - packed into 4 bytes.
+///
+/// Data layout:
+/// - Byte 0, bits 0-3: digits (lower nibble)
+/// - Byte 0, bits 4-7: rounding (upper nibble)
+/// - Byte 1, bits 0-3: cash_digits (lower nibble, 15 = None)
+/// - Byte 1, bits 4-7: cash_rounding (upper nibble, 15 = None)
+type FractionInfoULE = RawBytesULE<2>;
+
+impl AsULE for FractionInfo {
+    type ULE = FractionInfoULE;
+
+    #[inline]
+    fn to_unaligned(self) -> Self::ULE {
+        debug_assert!(self.digits < 16);
+        debug_assert!(self.rounding < 16);
+
+        let cash_digits = self.cash_digits.unwrap_or(NONE_MARKER);
+        debug_assert!(cash_digits < 16);
+
+        let cash_rounding = match self.cash_rounding {
+            None => 15,
+            Some(50) => 14,
+            Some(n) => {
+                debug_assert!(n < 14);
+                n
+            }
+        };
+
+        RawBytesULE([
+            (self.digits & 0x0f) | (self.rounding << 4),
+            (cash_digits & 0x0f) | (cash_rounding << 4),
+        ])
+    }
+
+    #[inline]
+    fn from_unaligned(unaligned: Self::ULE) -> Self {
+        let [b0, b1] = unaligned.0;
+
+        let digits = b0 & 0x0f;
+        let rounding = b0 >> 4;
+        let cash_digits = b1 & 0x0f;
+        let cash_rounding = b1 >> 4;
+
+        FractionInfo {
+            digits,
+            rounding,
+            cash_digits: if cash_digits == NONE_MARKER {
+                None
+            } else {
+                Some(cash_digits)
+            },
+            cash_rounding: match cash_rounding {
+                14 => Some(50),
+                15 => None,
+                n => Some(n),
+            },
+        }
+    }
+}
+
+impl<'a> ZeroMapKV<'a> for FractionInfo {
+    type Container = zerovec::ZeroVec<'a, FractionInfo>;
+    type Slice = zerovec::ZeroSlice<FractionInfo>;
+    type GetType = <FractionInfo as AsULE>::ULE;
+    type OwnedType = FractionInfo;
+}

components/experimental/src/dimension/provider/currency/mod.rs

@@ -7,5 +7,7 @@ pub mod compact_count_ule;
 pub mod displayname;
 pub mod essentials;
 pub mod extended;
+pub mod fractions;
+mod fractions_ule;
 pub mod patterns;
 pub mod ule;

components/experimental/src/lib.rs

@@ -52,6 +52,7 @@ pub mod provider {
         impl_currency_displayname_v1!(Baked);
         impl_currency_patterns_data_v1!(Baked);
         impl_currency_extended_data_v1!(Baked);
+        impl_currency_fractions_v1!(Baked);
         impl_units_display_names_v1!(Baked);
         impl_units_names_area_core_v1!(Baked);
         impl_units_names_area_extended_v1!(Baked);
@@ -121,6 +122,7 @@ pub mod provider {
         super::dimension::provider::currency::essentials::CurrencyEssentialsV1::INFO,
         super::dimension::provider::currency::patterns::CurrencyPatternsDataV1::INFO,
         super::dimension::provider::currency::extended::CurrencyExtendedDataV1::INFO,
+        super::dimension::provider::currency::fractions::CurrencyFractionsV1::INFO,
         super::dimension::provider::percent::PercentEssentialsV1::INFO,
         super::dimension::provider::units::essentials::UnitsEssentialsV1::INFO,
         super::dimension::provider::units::display_names::UnitsDisplayNamesV1::INFO,

provider/data/experimental/data/currency_fractions_v1.rs.data

@@ -63259,6 +63259,7 @@ currency/extended/data/v1, zu/ZAR, 45B, 22B, b41d10033141372c
 currency/extended/data/v1, zu/ZMK, 55B, 32B, 556373753497cd9f
 currency/extended/data/v1, zu/ZMW, 41B, 18B, 5df40b65221c99b7
 currency/extended/data/v1, zu/ZWG, -> en/ZWG
+currency/fractions/v1, <singleton>, 406B, 358B, e796b7e579009f83
 currency/patterns/data/v1, <lookup>, 95B, 14 identifiers
 currency/patterns/data/v1, <total>, 248B, 64B, 8 unique payloads
 currency/patterns/data/v1, blo, 28B, 5B, 62a8398982cad180