slice.go

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package sort
     6  
     7  import (
     8  	"internal/reflectlite"
     9  	"math/bits"
    10  )
    11  
    12  // Slice sorts the slice x given the provided less function.
    13  // It panics if x is not a slice.
    14  //
    15  // The sort is not guaranteed to be stable: equal elements
    16  // may be reversed from their original order.
    17  // For a stable sort, use [SliceStable].
    18  //
    19  // The less function must satisfy the same requirements as
    20  // the Interface type's Less method.
    21  //
    22  // Note: in many situations, the newer [slices.SortFunc] function is more
    23  // ergonomic and runs faster.
    24  func Slice(x any, less func(i, j int) bool) {
    25  	rv := reflectlite.ValueOf(x)
    26  	swap := reflectlite.Swapper(x)
    27  	length := rv.Len()
    28  	limit := bits.Len(uint(length))
    29  	pdqsort_func(lessSwap{less, swap}, 0, length, limit)
    30  }
    31  
    32  // SliceStable sorts the slice x using the provided less
    33  // function, keeping equal elements in their original order.
    34  // It panics if x is not a slice.
    35  //
    36  // The less function must satisfy the same requirements as
    37  // the Interface type's Less method.
    38  //
    39  // Note: in many situations, the newer [slices.SortStableFunc] function is more
    40  // ergonomic and runs faster.
    41  func SliceStable(x any, less func(i, j int) bool) {
    42  	rv := reflectlite.ValueOf(x)
    43  	swap := reflectlite.Swapper(x)
    44  	stable_func(lessSwap{less, swap}, rv.Len())
    45  }
    46  
    47  // SliceIsSorted reports whether the slice x is sorted according to the provided less function.
    48  // It panics if x is not a slice.
    49  //
    50  // Note: in many situations, the newer [slices.IsSortedFunc] function is more
    51  // ergonomic and runs faster.
    52  func SliceIsSorted(x any, less func(i, j int) bool) bool {
    53  	rv := reflectlite.ValueOf(x)
    54  	n := rv.Len()
    55  	for i := n - 1; i > 0; i-- {
    56  		if less(i, i-1) {
    57  			return false
    58  		}
    59  	}
    60  	return true
    61  }
    62
View as plain text