Start developing Decimal128

orlandos-nl · Jan 12, 2023 · 1e98bdf · 1e98bdf
1 parent d4582d8
commit 1e98bdf
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Showing 3 changed files with 30 additions and 8 deletions.
diff --git a/Sources/BSON/Document/Document+Cache.swift b/Sources/BSON/Document/Document+Cache.swift
@@ -172,11 +172,14 @@ extension Document {
         case .int32:
             return self.storage.getInteger(at: offset, endianness: .little, as: Int32.self)
         case .decimal128:
-            guard let slice = storage.getBytes(at: offset, length: 16) else {
+            guard
+                let low: UInt64 = storage.getInteger(at: offset),
+                let high: UInt64 = storage.getInteger(at: offset)
+            else {
                 return nil
             }
 
-            return Decimal128(slice)
+            return Decimal128(low: low, high: high)
         }
     }
 }
diff --git a/Sources/BSON/Document/Document+Dictionary.swift b/Sources/BSON/Document/Document+Dictionary.swift
@@ -198,7 +198,8 @@ extension Document: ExpressibleByDictionaryLiteral {
             storage.writeInteger(int, endianness: .little)
         case let decimal128 as Decimal128:
             writeKey(.decimal128)
-            storage.writeBytes(decimal128.storage)
+            storage.writeInteger(decimal128.low)
+            storage.writeInteger(decimal128.high)
         case is MaxKey: // 0x7F
             writeKey(.maxKey)
         case is MinKey: // 0xFF

diff --git a/Sources/BSON/Types/Decimal128.swift b/Sources/BSON/Types/Decimal128.swift
@@ -4,12 +4,30 @@ import NIOCore
 ///
 /// OpenKitten BSON currently does not support the handling of Decimal128 values. The type is a stub and provides no API. It serves as a point for future implementation.
 public struct Decimal128: Primitive, Hashable {
-    var storage: [UInt8]
+    private static let exponentBitCount: UInt64 = 14
+    private static let exponentBitMask: Int = 0b1111_1111_1111_11
+    private static let significandBitCount: UInt64 = 110
+    private static let nanBits = 0b11111
+    private static let infinityBits = 0b11110
 
-    internal init(_ storage: [UInt8]) {
-        Swift.assert(storage.count == 16)
-
-        self.storage = storage
+    public var isNegative: Bool {
+        high >> 58 == 1
+    }
+
+    public var isInfinity: Bool {
+        high >> 58 & 0b011111 == Self.infinityBits
+    }
+
+    public var isNaN: Bool {
+        high >> 58 & 0b011111 == Self.nanBits
+    }
+
+    let low: UInt64
+    let high: UInt64
+
+    internal init(low: UInt64, high: UInt64) {
+        self.low = low
+        self.high = high
     }
 
     public func encode(to encoder: Encoder) throws {