can now += and -= for HugeFloat, HugeDecimal, and `HugeRemain…

…der`
RandomHashTags · Apr 23, 2023 · 019355f · 019355f
1 parent 90b4369
commit 019355f
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Showing 3 changed files with 65 additions and 1 deletion.
diff --git a/Sources/huge-numbers/HugeDecimal.swift b/Sources/huge-numbers/HugeDecimal.swift
@@ -122,7 +122,7 @@ public extension HugeDecimal {
  Addition
  */
 public extension HugeDecimal {
-    static func + (left: HugeDecimal, right: HugeDecimal) -> (result: HugeDecimal, quotient: HugeInt?) {
+    static func + (left: HugeDecimal, right: HugeDecimal) -> (result: HugeDecimal, quotient: HugeInt?) { // TODO: support addition of repeating numbers
         let left_value:HugeInt = left.value, right_value:HugeInt = right.value
         let decimal_length:Int = max(left_value.length, right_value.length)
         var result:HugeInt = left_value + right_value, result_length:Int = result.length
@@ -136,6 +136,10 @@ public extension HugeDecimal {
         }
         return (HugeDecimal(value: result), quotient)
     }
+
+    static func += (left: inout HugeDecimal, right: HugeDecimal) { // TODO: support addition of repeating numbers
+        left.value += right.value
+    }
 }
 /*
  Subtraction
@@ -144,6 +148,10 @@ public extension HugeDecimal {
     static func - (left: HugeDecimal, right: HugeDecimal) -> (result: HugeDecimal, quotient: HugeInt?) {
         return left + -right
     }
+
+    static func -= (left: inout HugeDecimal, right: HugeDecimal) { // TODO: support subtraction of repeating numbers
+        left.value -= right.value
+    }
 }
 /*
  Multiplication

diff --git a/Sources/huge-numbers/HugeFloat.swift b/Sources/huge-numbers/HugeFloat.swift
@@ -251,6 +251,15 @@ public extension HugeFloat {
     static func + (left: HugeFloat, right: any BinaryInteger) -> HugeFloat {
         return left + HugeFloat(right)
     }
+
+    static func += (left: inout HugeFloat, right: HugeFloat) {
+        left.integer += right.integer
+        if left.decimal != nil {
+            left.decimal! += right.decimal ?? HugeDecimal.zero
+        } else if left.remainder != nil {
+            left.remainder! += right.remainder ?? HugeRemainder.zero
+        }
+    }
 }
 /*
  Subtraction
@@ -259,6 +268,15 @@ public extension HugeFloat {
     static func - (left: HugeFloat, right: HugeFloat) -> HugeFloat {
         return left + -right
     }
+
+    static func -= (left: inout HugeFloat, right: HugeFloat) {
+        left.integer -= right.integer
+        if left.decimal != nil {
+            left.decimal! -= right.decimal ?? HugeDecimal.zero
+        } else if left.remainder != nil {
+            left.remainder! -= right.remainder ?? HugeRemainder.zero
+        }
+    }
 }
 /*
  Multiplication

diff --git a/Sources/huge-numbers/HugeRemainder.swift b/Sources/huge-numbers/HugeRemainder.swift
@@ -210,6 +210,25 @@ public extension HugeRemainder {
     static func + (left: HugeRemainder, right: HugeInt) -> HugeRemainder {
         return left + HugeRemainder(dividend: right, divisor: HugeInt.one)
     }
+
+    static func += (left: inout HugeRemainder, right: HugeRemainder) {
+        if left == HugeRemainder.zero {
+            left.dividend = right.dividend
+            left.divisor = right.divisor
+        } else if right == HugeRemainder.zero {
+            return
+        } else {
+            let (common_denominator, are_equal, left_multiplier, right_multiplier):(HugeInt, Bool, HugeInt?, HugeInt?) = get_common_denominator(left: left, right: right)
+            if are_equal {
+                left.dividend += right.dividend
+            } else {
+                let left_dividend:HugeInt = left.dividend, right_dividend:HugeInt = right.dividend
+                let left_result:HugeInt = left_dividend * left_multiplier!, right_result:HugeInt = right_dividend * right_multiplier!
+                left.dividend = left_result + right_result
+                left.divisor = common_denominator
+            }
+        }
+    }
 }
 /*
  Subtraction
@@ -221,6 +240,25 @@ public extension HugeRemainder {
     static func - (left: HugeRemainder, right: HugeInt) -> HugeRemainder {
         return left - HugeRemainder(dividend: right, divisor: HugeInt.one)
     }
+
+    static func -= (left: inout HugeRemainder, right: HugeRemainder) {
+        if left == HugeRemainder.zero {
+            left.dividend = right.dividend
+            left.divisor = right.divisor
+        } else if right == HugeRemainder.zero {
+            return
+        } else {
+            let (common_denominator, are_equal, left_multiplier, right_multiplier):(HugeInt, Bool, HugeInt?, HugeInt?) = get_common_denominator(left: left, right: right)
+            if are_equal {
+                left.dividend -= right.dividend
+            } else {
+                let left_dividend:HugeInt = left.dividend, right_dividend:HugeInt = right.dividend
+                let left_result:HugeInt = left_dividend * left_multiplier!, right_result:HugeInt = right_dividend * right_multiplier!
+                left.dividend = left_result - right_result
+                left.divisor = common_denominator
+            }
+        }
+    }
 }
 /*
  Multiplication