Iterate through canonical timezones and metazones

components/timezone/src/ids.rs

@@ -333,6 +333,19 @@ impl TimeZoneIdMapperBorrowed<'_> {
         Some(string)
     }
 
+    /// Iterates through all canonical time zones
+    pub fn iter_canonical(&self) -> impl Iterator<Item = TimeZoneBcp47Id> + '_ {
+        self.data.bcp47_ids.iter()
+    }
+
+    /// Iterates through all metazones
+    pub fn iter_metazones(&self) -> impl Iterator<Item = TimeZoneBcp47Id> + '_ {
+        self.data
+            .metazones
+            .iter()
+            .filter_map(|i| self.data.bcp47_ids.get(i as usize))
+    }
+
     /// Queries the data for `iana_id` without recording the normalized string.
     /// This is a fast, no-alloc lookup.
     fn iana_lookup_quick(&self, iana_id: impl AsRef<[u8]>) -> Option<IanaTrieValue> {

components/timezone/src/provider/names.rs

@@ -95,6 +95,8 @@ pub struct IanaToBcp47MapV3<'data> {
     // Note: this is 9739B as `ZeroVec<TimeZoneBcp47Id>` (`ZeroVec<TinyStr8>`)
     // and 9335B as `VarZeroVec<str>`
     pub bcp47_ids: ZeroVec<'data, TimeZoneBcp47Id>,
+    /// Metazones
+    pub metazones: ZeroVec<'data, u16>,
     /// An XxHash64 checksum of [`Self::bcp47_ids`].
     pub bcp47_ids_checksum: u64,
 }

ffi/capi/tests/missing_apis.txt

@@ -217,6 +217,8 @@ icu::timezone::CustomZonedDateTime::try_from_utf8#FnInStruct
 icu::timezone::CustomZonedDateTime::try_iso_from_str#FnInStruct
 icu::timezone::CustomZonedDateTime::try_iso_from_utf8#FnInStruct
 icu::timezone::ParseError#Enum
+icu::timezone::TimeZoneIdMapperBorrowed::iter_canonical#FnInStruct
+icu::timezone::TimeZoneIdMapperBorrowed::iter_metazones#FnInStruct
 icu::timezone::UnknownTimeZoneError#Struct
 icu::timezone::WindowsTimeZoneMapper#Struct
 icu::timezone::WindowsTimeZoneMapper::as_borrowed#FnInStruct

provider/data/timezone/fingerprints.csv

@@ -1,5 +1,5 @@
 time_zone/bcp47_to_iana@1, <singleton>, 7643B, 7623B, d999c8ca67868c35
-time_zone/iana_to_bcp47@3, <singleton>, 9579B, 9538B, 1bf6347ae2f6619d
+time_zone/iana_to_bcp47@3, <singleton>, 9921B, 9858B, 192398d2ca5e487
 time_zone/metazone_period@1, <singleton>, 11097B, 11009B, dcfa50fb39ebd549
 time_zone/offset_period@1, <singleton>, 13374B, 13286B, 397b18d3f2345411
 time_zone/windows_zones_to_bcp47@1, <singleton>, 8634B, 8591B, 90b7fe3f9cadf5bd

provider/source/src/cldr_serde/time_zones/meta_zones.rs

@@ -68,7 +68,7 @@ pub(crate) struct MapZone {
     #[serde(rename = "_type")]
     pub(crate) zone_type: String,
     #[serde(rename = "_territory")]
-    pub(crate) territory: String,
+    pub(crate) territory: icu::locale::subtags::Region,
 }
 
 #[derive(PartialEq, Debug, Clone, Deserialize)]
@@ -85,7 +85,7 @@ pub(crate) struct Metazones {
     #[serde(rename = "metazoneInfo")]
     pub(crate) meta_zone_info: MetazoneInfo,
     #[serde(rename = "metazones")]
-    pub(crate) _meta_zones_territory: MetazonesTerritory,
+    pub(crate) meta_zones_territory: MetazonesTerritory,
     #[serde(rename = "metazoneIds")]
     pub(crate) meta_zone_ids: MetazoneIds,
 }

provider/source/src/time_zones/mod.rs

@@ -7,9 +7,11 @@ use crate::IterableDataProviderCached;
 use crate::SourceDataProvider;
 use icu::datetime::provider::time_zones::*;
 use icu::timezone::provider::*;
+use icu_locale_core::subtags::region;
 use icu_locale_core::subtags::Region;
 use icu_provider::prelude::*;
 use std::collections::BTreeMap;
+use std::collections::BTreeSet;
 use std::collections::HashSet;
 use tinystr::tinystr;
 
@@ -104,6 +106,25 @@ impl SourceDataProvider {
         Ok(meta_zone_ids)
     }
 
+    fn compute_meta_zones_representatives(&self) -> Result<BTreeSet<String>, DataError> {
+        let metazones = &self
+            .cldr()?
+            .core()
+            .read_and_parse::<cldr_serde::time_zones::meta_zones::Resource>(
+                "supplemental/metaZones.json",
+            )?
+            .supplemental
+            .meta_zones;
+
+        Ok(metazones
+            .meta_zones_territory
+            .0
+            .iter()
+            .filter(|t| t.map_zone.territory == region!("001"))
+            .map(|t| t.map_zone.zone_type.clone())
+            .collect())
+    }
+
     fn compute_primary_zones(&self) -> Result<BTreeMap<TimeZoneBcp47Id, Region>, DataError> {
         let primary_zones = self
             .cldr()?

provider/source/src/time_zones/names.rs

@@ -72,6 +72,18 @@ impl DataProvider<IanaToBcp47MapV3Marker> for SourceDataProvider {
         // the canonical order of the IANA names.
         let bcp2iana = self.compute_canonical_tzids_btreemap()?;
 
+        let metazone_representatives = self.compute_meta_zones_representatives()?;
+
+        let metazones = bcp47_ids
+            .iter()
+            .enumerate()
+            .flat_map(|(i, bcp47)| {
+                metazone_representatives
+                    .contains(bcp2iana.get(&bcp47)?)
+                    .then_some(i as u16)
+            })
+            .collect();
+
         // Transform the map to use BCP indices:
         #[allow(clippy::unwrap_used)] // structures are derived from each other
         let map: BTreeMap<Vec<u8>, usize> = iana2bcp
@@ -105,6 +117,7 @@ impl DataProvider<IanaToBcp47MapV3Marker> for SourceDataProvider {
                 })?
                 .convert_store(),
             bcp47_ids,
+            metazones,
             bcp47_ids_checksum,
         };
         Ok(DataResponse {