Imported Upstream version 60upstream/60

1 files changed, 59 insertions, 0 deletions

diff --git a/doc/progs/sort.go b/doc/progs/sort.go
new file mode 100644
index 000000000..894693f0d
--- /dev/null
+++ b/doc/progs/sort.go
@@ -0,0 +1,59 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sort
+
+type Interface interface {
+	Len() int
+	Less(i, j int) bool
+	Swap(i, j int)
+}
+
+func Sort(data Interface) {
+	for i := 1; i < data.Len(); i++ {
+		for j := i; j > 0 && data.Less(j, j-1); j-- {
+			data.Swap(j, j-1)
+		}
+	}
+}
+
+func IsSorted(data Interface) bool {
+	n := data.Len()
+	for i := n - 1; i > 0; i-- {
+		if data.Less(i, i-1) {
+			return false
+		}
+	}
+	return true
+}
+
+// Convenience types for common cases
+
+type IntSlice []int
+
+func (p IntSlice) Len() int           { return len(p) }
+func (p IntSlice) Less(i, j int) bool { return p[i] < p[j] }
+func (p IntSlice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+type Float64Slice []float64
+
+func (p Float64Slice) Len() int           { return len(p) }
+func (p Float64Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p Float64Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+type StringSlice []string
+
+func (p StringSlice) Len() int           { return len(p) }
+func (p StringSlice) Less(i, j int) bool { return p[i] < p[j] }
+func (p StringSlice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+// Convenience wrappers for common cases
+
+func SortInts(a []int)         { Sort(IntSlice(a)) }
+func SortFloat64s(a []float64) { Sort(Float64Slice(a)) }
+func SortStrings(a []string)   { Sort(StringSlice(a)) }
+
+func IntsAreSorted(a []int) bool         { return IsSorted(IntSlice(a)) }
+func Float64sAreSorted(a []float64) bool { return IsSorted(Float64Slice(a)) }
+func StringsAreSorted(a []string) bool   { return IsSorted(StringSlice(a)) }