Fix bits unit

fummicc1 · Nov 16, 2024 · 08bc1f8 · 08bc1f8
1 parent 0d25c22
commit 08bc1f8
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Showing 5 changed files with 52 additions and 52 deletions.
diff --git a/Sources/GeoHashFramework/GeoHash.swift b/Sources/GeoHashFramework/GeoHash.swift
@@ -4,7 +4,7 @@
 import Foundation
 
 public struct GeoHash: Sendable, Hashable {
-    public private(set) var precision: GeoHashPrecision
+    public private(set) var precision: GeoHashBitsPrecision
     public private(set) var binary: String
 
     /// Base32 characters used to hash
@@ -19,7 +19,7 @@ public struct GeoHash: Sendable, Hashable {
     /// - Parameter value: A string that contains only "0" or "1".
     public init(
         binary: String,
-        precision: GeoHashPrecision = .mid
+        precision: GeoHashBitsPrecision = .mid
     ) {
         precondition(
             binary.allSatisfy({
@@ -39,7 +39,7 @@ public struct GeoHash: Sendable, Hashable {
     public init(
         latitude: Double,
         longitude: Double,
-        precision: GeoHashPrecision = .mid
+        precision: GeoHashBitsPrecision = .mid
     ) {
         precondition(
             latitude >= -90 && latitude <= 90,
@@ -62,7 +62,7 @@ public struct GeoHash: Sendable, Hashable {
         )
     }
 
-    public init(geoHash: String, precision: GeoHashPrecision = .mid) {
+    public init(geoHash: String, precision: GeoHashBitsPrecision = .mid) {
         self.init(
             binary: Self.makeBinary(
                 from: geoHash,
@@ -77,7 +77,7 @@ public struct GeoHash: Sendable, Hashable {
 extension GeoHash {
     static func makeBinary(
         from geoHash: String,
-        precision: GeoHashPrecision
+        precision: GeoHashBitsPrecision
     ) -> String {
         var binary = ""
 
@@ -98,7 +98,7 @@ extension GeoHash {
         return binary
     }
 
-    static func makeBinary(from coordinate: GeoHashCoordinate2D, precision: GeoHashPrecision)
+    static func makeBinary(from coordinate: GeoHashCoordinate2D, precision: GeoHashBitsPrecision)
         -> String
     {
         let latitude = coordinate.latitude

diff --git a/Sources/GeoHashFramework/GeoHashBitsPrecision.swift b/Sources/GeoHashFramework/GeoHashBitsPrecision.swift
@@ -0,0 +1,33 @@
+/// A GeoHashPrecision enum represents the bits precision of the GeoHash in binary unit.
+///
+/// - low: 30 bits precision. This corresponds to 6 characters of GeoHash.
+/// - mid: 40 bits precision. This corresponds to 8 characters of GeoHash.
+/// - high: 50 bits precision. This corresponds to 10 characters of GeoHash.
+public enum GeoHashBitsPrecision: Sendable, Hashable {
+    /// 6 digits GeoHash
+    case low
+    /// 8 digits GeoHash
+    case mid
+    /// 10 digits GeoHash
+    case high
+
+    /// `digits` **bits** precision.
+    /// - Note: `digits` must be a multiple of 4 because each GeoHash character is 5 bits.
+    case exact(digits: Int)
+
+    public var rawValue: Int {
+        switch self {
+        case .low: return 6 * 5
+        case .mid: return 8 * 5
+        case .high: return 10 * 5
+        case .exact(let digits):
+            precondition(digits % 5 == 0)
+            return digits
+        }
+    }
+
+    var format: String {
+        let rawValue = self.rawValue
+        return "%0\(rawValue / 5)d"
+    }
+}
diff --git a/Sources/GeoHashFramework/GeoHashCluster.swift b/Sources/GeoHashFramework/GeoHashCluster.swift
@@ -9,17 +9,17 @@
 ///
 /// This data structure is used to store GeoHashes and their relations.
 public struct GeoHashCluster: Sendable, Hashable {
-    private var clusters: [GeoHashPrecision: [GeoHash]] = [:]
+    private var clusters: [GeoHashBitsPrecision: [GeoHash]] = [:]
 
     public init() {
         clusters = [:]
     }
 
-    public func isSame(geoHash1: GeoHash, geoHash2: GeoHash, precision: GeoHashPrecision) -> Bool {
+    public func isSame(geoHash1: GeoHash, geoHash2: GeoHash, precision: GeoHashBitsPrecision) -> Bool {
         fatalError("Not implemented")
     }
 
-    public func mergeIfPossible(geoHash1: GeoHash, geoHash2: GeoHash, precision: GeoHashPrecision) {
+    public func mergeIfPossible(geoHash1: GeoHash, geoHash2: GeoHash, precision: GeoHashBitsPrecision) {
         fatalError("Not implemented")
     }
 }
diff --git a/Sources/GeoHashFramework/GeoHashPrecision.swift b/Sources/GeoHashFramework/GeoHashPrecision.swift
diff --git a/Tests/GeoHashFrameworkTests/GeoHashTests.swift b/Tests/GeoHashFrameworkTests/GeoHashTests.swift
@@ -12,26 +12,26 @@ import Testing
 struct GeoHashTests {
     @Test
     func makeGeoHashFromBinary() async throws {
-        let input = "0110101001101010"
+        let input = "01101010011010100110"
         let geoHash = GeoHash(
             binary: input,
-            precision: .exact(digits: 16)
+            precision: .exact(digits: 20)
         )
-        #expect(geoHash.geoHash == "e9p0")
-        #expect(geoHash.geoHash.count == input.count / 4)
+        #expect(geoHash.geoHash == "e9p6")
+        #expect(geoHash.geoHash.count == input.count / 5)
     }
 
     @Test
     func makeFromBinary() async throws {
-        let input = "0110101001101010"
+        let input = "01101010011010100110"
 
-        let expectedLat = "10001000"
-        let expectedLng = "01110111"
+        let expectedLat = "1000100010"
+        let expectedLng = "0111011101"
 
         let geoHash = GeoHash(
             binary: input,
             precision: .exact(
-                digits: 16
+                digits: 20
             )
         )
         #expect(geoHash.latitudeBits == expectedLat)
@@ -45,10 +45,10 @@ struct GeoHashTests {
 
         let geoHash = GeoHash(latitude: lat, longitude: lng)
         #expect(
-            geoHash.binary == "11101101000011100110110101011111"
+            geoHash.binary == "1110110100001110011011010101111110001101"
         )
         #expect(
-            geoHash.geoHash == "xn76urs"
+            geoHash.geoHash == "xn76urwe"
         )
     }
 }