no minLastIndex[...] methods (#136)

oscbyspro · Jun 15, 2023 · 554905a · 554905a
1 parent af28654
commit 554905a
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Showing 10 changed files with 52 additions and 484 deletions.
diff --git a/Sources/ANKCoreKit/Private/Namespace.swift b/Sources/ANKCoreKit/Private/Namespace.swift
@@ -35,4 +35,32 @@
 
     /// An unsafe pointer to a mutable collection of `UInt` machine words.
     public typealias UnsafeMutableWords = UnsafeMutableBufferPointer<UInt>
+
+    //=------------------------------------------------------------------------=
+    // MARK: Aliases x Tuples
+    //=------------------------------------------------------------------------=
+
+    /// A 128-bit pattern, split into `UInt64` words.
+    public typealias U128X64 = (UInt64, UInt64)
+
+    /// A 128-bit pattern, split into `UInt32` words.
+    public typealias U128X32 = (UInt32, UInt32, UInt32, UInt32)
+
+    /// A 192-bit pattern, split into `UInt64` words.
+    public typealias U192X64 = (UInt64, UInt64, UInt64)
+
+    /// A 192-bit pattern, split into `UInt32` words.
+    public typealias U192X32 = (UInt32, UInt32, UInt32, UInt32, UInt32, UInt32)
+
+    /// A 256-bit pattern, split into `UInt64` words.
+    public typealias U256X64 = (UInt64, UInt64, UInt64, UInt64)
+
+    /// A 256-bit pattern, split into `UInt32` words.
+    public typealias U256X32 = (UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32)
+
+    /// A 384-bit pattern, split into `UInt64` words.
+    public typealias U384X64 = (UInt64, UInt64, UInt64, UInt64, UInt64, UInt64)
+
+    /// A 384-bit pattern, split into `UInt32` words.
+    public typealias U384X32 = (UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32, UInt32)
 }
diff --git a/Sources/ANKCoreKit/Private/Tuples.swift b/Sources/ANKCoreKit/Private/Tuples.swift
diff --git a/Sources/ANKFullWidthKit/ANKFullWidth+Division.swift b/Sources/ANKFullWidthKit/ANKFullWidth+Division.swift
@@ -124,30 +124,29 @@ extension ANKFullWidth where High == High.Magnitude {
     @_specialize(where Self == UInt384)
     @_specialize(where Self == UInt512)
     @inlinable func quotientAndRemainderReportingOverflow(dividingBy other: Self) -> PVO<QR<Self, Self>> {
-        let other_ = other.minLastIndexReportingIsZeroOrMinusOne()
         //=--------------------------------------=
         // divisor is zero
         //=--------------------------------------=
-        if  other_.isZeroOrMinusOne {
+        guard let otherMinLastIndex: Int = other.lastIndex(where:{ !$0.isZero }) else {
             return PVO(QR(self, self), true)
         }
         //=--------------------------------------=
-        // divisor is greater than or equal
-        //=--------------------------------------=
-        if  self <= other {
-            return self == other ? PVO(QR(1, Self.zero), false) : PVO(QR(Self.zero, self), false)
-        }
-        //=--------------------------------------=
         // divisor is one word
         //=--------------------------------------=
-        if  other_.minLastIndex.isZero {
+        if  otherMinLastIndex.isZero {
             let qro: PVO<QR<Self, Digit>> = self.quotientAndRemainderReportingOverflow(dividingBy: other.first)
             return   PVO(QR(qro.partialValue.quotient, Self(digit: qro.partialValue.remainder)),  qro.overflow)
         }
         //=--------------------------------------=
-        let self_ = self.minLastIndexReportingIsZeroOrMinusOne()
-        let minLastIndexGapSize = self_.minLastIndex &- other_.minLastIndex as Int
-        let shift: Int = other[unchecked: other_.minLastIndex].leadingZeroBitCount
+        // divisor is greater than or equal
+        //=--------------------------------------=
+        if  self <= other {
+            return self == other ? PVO(QR(1, Self.zero), false) : PVO(QR(Self.zero, self), false)
+        }
+        //=--------------------------------------=
+        let thisMinLastIndex: Int = self.lastIndex(where:{ !$0.isZero })!
+        let minLastIndexGapSize = thisMinLastIndex &- otherMinLastIndex as Int
+        let shift = other[unchecked: otherMinLastIndex].leadingZeroBitCount as Int
         //=--------------------------------------=
         // shift to clamp approximation
         //=--------------------------------------=
@@ -158,7 +157,7 @@ extension ANKFullWidth where High == High.Magnitude {
         increment.low.bitshiftLeftUnchecked(words: minLastIndexGapSize, bits: shift)
         assert(increment.high.isZero)
 
-        let discriminant: UInt = increment.low[unchecked: self_.minLastIndex]
+        let discriminant: UInt = increment.low[unchecked: thisMinLastIndex]
         assert(discriminant.mostSignificantBit)
         //=--------------------------------------=
         // division
@@ -172,11 +171,11 @@ extension ANKFullWidth where High == High.Magnitude {
                 //=------------------------------=
                 // approximate quotient digit
                 //=------------------------------=
-                var digit: UInt = remainder.withUnsafeWords { remainder in
-                    let  remainderIndex  = other_.minLastIndex &+ quotientIndex
-                    let  remainderLast0  = remainder[unchecked: remainderIndex &+ 1]
-                    if   remainderLast0 >= discriminant { return UInt.max }
-                    let  remainderLast1  = remainder[unchecked: remainderIndex]
+                var digit: UInt = remainder.withUnsafeWords {  remainder in
+                    let remainderIndex  = otherMinLastIndex &+  quotientIndex
+                    let remainderLast0  = remainder[unchecked: remainderIndex &+ 1]
+                    if  remainderLast0 >= discriminant { return UInt.max }
+                    let remainderLast1  = remainder[unchecked: remainderIndex]
                     return discriminant.dividingFullWidth(HL(remainderLast0, remainderLast1)).quotient
                 }
                 //=------------------------------=
@@ -188,10 +187,14 @@ extension ANKFullWidth where High == High.Magnitude {
                     brrrrrrrrrrrrrrrrrrrrrrr: do { digit &-= 1; approximation &-= increment }
                     if approximation > remainder { digit &-= 1; approximation &-= increment }
                 }
-                //=------------------------------=
+
                 assert(approximation <= remainder)
+                //=------------------------------=
                 remainder &-= approximation
                 quotient[unchecked: quotientIndex] = digit
+                //=------------------------------=
+                guard !quotientIndex.isZero else { break }
+                assert(increment.low.first.isZero)
                 increment.low.bitshiftRightUnchecked(words: 1, bits: Int.zero)
             }
         }

diff --git a/Sources/ANKFullWidthKit/ANKFullWidth+Text+Radix.swift b/Sources/ANKFullWidthKit/ANKFullWidth+Text+Radix.swift
@@ -126,8 +126,8 @@ extension ANKFullWidth where High == High.Magnitude {
     }
 
     @inlinable func description(radix: PerfectRadixUIntRoot, alphabet: MaxRadixAlphabetEncoder, prefix: ANK.UnsafeUTF8) -> String {
-        let minLastIndex: Int = self.minLastIndexReportingIsZeroOrMinusOne().minLastIndex
-        let chunks: Words.SubSequence = self[...minLastIndex]
+        let index = self.lastIndex(where:{ !$0.isZero }) ?? self.startIndex
+        let chunks: Words.SubSequence = self[...index]
         return String.fromUTF8Unchecked(chunks: chunks, radix: radix, alphabet: alphabet, prefix: prefix)
     }
 

diff --git a/Sources/ANKFullWidthKit/ANKFullWidth+Words+Utilities.swift b/Sources/ANKFullWidthKit/ANKFullWidth+Words+Utilities.swift
diff --git a/Tests/ANKFullWidthKitBenchmarks/192+Words.swift b/Tests/ANKFullWidthKitBenchmarks/192+Words.swift