gonum.org/v1/gonum@v0.15.1-0.20240517103525-f853624cb1bb/graph/internal/set/same.go (about)

     1  // Copyright ©2014 The Gonum 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  //go:build !safe
     6  // +build !safe
     7  
     8  package set
     9  
    10  import "unsafe"
    11  
    12  // same determines whether two sets are backed by the same store. In the
    13  // current implementation using hash maps it makes use of the fact that
    14  // hash maps are passed as a pointer to a runtime Hmap struct. A map is
    15  // not seen by the runtime as a pointer though, so we use unsafe to get
    16  // the maps' pointer values to compare.
    17  func same(a, b Nodes) bool {
    18  	return *(*uintptr)(unsafe.Pointer(&a)) == *(*uintptr)(unsafe.Pointer(&b))
    19  }
    20  
    21  // intsSame determines whether two sets are backed by the same store. In the
    22  // current implementation using hash maps it makes use of the fact that
    23  // hash maps are passed as a pointer to a runtime Hmap struct. A map is
    24  // not seen by the runtime as a pointer though, so we use unsafe to get
    25  // the maps' pointer values to compare.
    26  func intsSame[T Int](a, b Ints[T]) bool {
    27  	return *(*uintptr)(unsafe.Pointer(&a)) == *(*uintptr)(unsafe.Pointer(&b))
    28  }