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//go:build ignore
6
7// This program generates example_test.go.
8
9package main
10
11import (
12	"bytes"
13	"fmt"
14	"log"
15	"math/bits"
16	"os"
17)
18
19const header = `// Copyright 2017 The Go Authors. All rights reserved.
20// Use of this source code is governed by a BSD-style
21// license that can be found in the LICENSE file.
22
23// Code generated by go run make_examples.go. DO NOT EDIT.
24
25package bits_test
26
27import (
28	"fmt"
29	"math/bits"
30)
31`
32
33func main() {
34	w := bytes.NewBuffer([]byte(header))
35
36	for _, e := range []struct {
37		name string
38		in   int
39		out  [4]any
40		out2 [4]any
41	}{
42		{
43			name: "LeadingZeros",
44			in:   1,
45			out:  [4]any{bits.LeadingZeros8(1), bits.LeadingZeros16(1), bits.LeadingZeros32(1), bits.LeadingZeros64(1)},
46		},
47		{
48			name: "TrailingZeros",
49			in:   14,
50			out:  [4]any{bits.TrailingZeros8(14), bits.TrailingZeros16(14), bits.TrailingZeros32(14), bits.TrailingZeros64(14)},
51		},
52		{
53			name: "OnesCount",
54			in:   14,
55			out:  [4]any{bits.OnesCount8(14), bits.OnesCount16(14), bits.OnesCount32(14), bits.OnesCount64(14)},
56		},
57		{
58			name: "RotateLeft",
59			in:   15,
60			out:  [4]any{bits.RotateLeft8(15, 2), bits.RotateLeft16(15, 2), bits.RotateLeft32(15, 2), bits.RotateLeft64(15, 2)},
61			out2: [4]any{bits.RotateLeft8(15, -2), bits.RotateLeft16(15, -2), bits.RotateLeft32(15, -2), bits.RotateLeft64(15, -2)},
62		},
63		{
64			name: "Reverse",
65			in:   19,
66			out:  [4]any{bits.Reverse8(19), bits.Reverse16(19), bits.Reverse32(19), bits.Reverse64(19)},
67		},
68		{
69			name: "ReverseBytes",
70			in:   15,
71			out:  [4]any{nil, bits.ReverseBytes16(15), bits.ReverseBytes32(15), bits.ReverseBytes64(15)},
72		},
73		{
74			name: "Len",
75			in:   8,
76			out:  [4]any{bits.Len8(8), bits.Len16(8), bits.Len32(8), bits.Len64(8)},
77		},
78	} {
79		for i, size := range []int{8, 16, 32, 64} {
80			if e.out[i] == nil {
81				continue // function doesn't exist
82			}
83			f := fmt.Sprintf("%s%d", e.name, size)
84			fmt.Fprintf(w, "\nfunc Example%s() {\n", f)
85			switch e.name {
86			case "RotateLeft", "Reverse", "ReverseBytes":
87				fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", %d)\n", size, e.in)
88				if e.name == "RotateLeft" {
89					fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", bits.%s(%d, 2))\n", size, f, e.in)
90					fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", bits.%s(%d, -2))\n", size, f, e.in)
91				} else {
92					fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", bits.%s(%d))\n", size, f, e.in)
93				}
94				fmt.Fprintf(w, "\t// Output:\n")
95				fmt.Fprintf(w, "\t// %0*b\n", size, e.in)
96				fmt.Fprintf(w, "\t// %0*b\n", size, e.out[i])
97				if e.name == "RotateLeft" && e.out2[i] != nil {
98					fmt.Fprintf(w, "\t// %0*b\n", size, e.out2[i])
99				}
100			default:
101				fmt.Fprintf(w, "\tfmt.Printf(\"%s(%%0%db) = %%d\\n\", %d, bits.%s(%d))\n", f, size, e.in, f, e.in)
102				fmt.Fprintf(w, "\t// Output:\n")
103				fmt.Fprintf(w, "\t// %s(%0*b) = %d\n", f, size, e.in, e.out[i])
104			}
105			fmt.Fprintf(w, "}\n")
106		}
107	}
108
109	if err := os.WriteFile("example_test.go", w.Bytes(), 0666); err != nil {
110		log.Fatal(err)
111	}
112}
113