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// Copyright 2017 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.
//go:build ignore
// +build ignore
// This program generates example_test.go.
package main
import (
"bytes"
"fmt"
"log"
"math/bits"
"os"
)
const header = `// Copyright 2017 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.
// Code generated by go run make_examples.go. DO NOT EDIT.
package bits_test
import (
"fmt"
"math/bits"
)
`
func main() {
w := bytes.NewBuffer([]byte(header))
for _, e := range []struct {
name string
in int
out [4]any
out2 [4]any
}{
{
name: "LeadingZeros",
in: 1,
out: [4]any{bits.LeadingZeros8(1), bits.LeadingZeros16(1), bits.LeadingZeros32(1), bits.LeadingZeros64(1)},
},
{
name: "TrailingZeros",
in: 14,
out: [4]any{bits.TrailingZeros8(14), bits.TrailingZeros16(14), bits.TrailingZeros32(14), bits.TrailingZeros64(14)},
},
{
name: "OnesCount",
in: 14,
out: [4]any{bits.OnesCount8(14), bits.OnesCount16(14), bits.OnesCount32(14), bits.OnesCount64(14)},
},
{
name: "RotateLeft",
in: 15,
out: [4]any{bits.RotateLeft8(15, 2), bits.RotateLeft16(15, 2), bits.RotateLeft32(15, 2), bits.RotateLeft64(15, 2)},
out2: [4]any{bits.RotateLeft8(15, -2), bits.RotateLeft16(15, -2), bits.RotateLeft32(15, -2), bits.RotateLeft64(15, -2)},
},
{
name: "Reverse",
in: 19,
out: [4]any{bits.Reverse8(19), bits.Reverse16(19), bits.Reverse32(19), bits.Reverse64(19)},
},
{
name: "ReverseBytes",
in: 15,
out: [4]any{nil, bits.ReverseBytes16(15), bits.ReverseBytes32(15), bits.ReverseBytes64(15)},
},
{
name: "Len",
in: 8,
out: [4]any{bits.Len8(8), bits.Len16(8), bits.Len32(8), bits.Len64(8)},
},
} {
for i, size := range []int{8, 16, 32, 64} {
if e.out[i] == nil {
continue // function doesn't exist
}
f := fmt.Sprintf("%s%d", e.name, size)
fmt.Fprintf(w, "\nfunc Example%s() {\n", f)
switch e.name {
case "RotateLeft", "Reverse", "ReverseBytes":
fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", %d)\n", size, e.in)
if e.name == "RotateLeft" {
fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", bits.%s(%d, 2))\n", size, f, e.in)
fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", bits.%s(%d, -2))\n", size, f, e.in)
} else {
fmt.Fprintf(w, "\tfmt.Printf(\"%%0%db\\n\", bits.%s(%d))\n", size, f, e.in)
}
fmt.Fprintf(w, "\t// Output:\n")
fmt.Fprintf(w, "\t// %0*b\n", size, e.in)
fmt.Fprintf(w, "\t// %0*b\n", size, e.out[i])
if e.name == "RotateLeft" && e.out2[i] != nil {
fmt.Fprintf(w, "\t// %0*b\n", size, e.out2[i])
}
default:
fmt.Fprintf(w, "\tfmt.Printf(\"%s(%%0%db) = %%d\\n\", %d, bits.%s(%d))\n", f, size, e.in, f, e.in)
fmt.Fprintf(w, "\t// Output:\n")
fmt.Fprintf(w, "\t// %s(%0*b) = %d\n", f, size, e.in, e.out[i])
}
fmt.Fprintf(w, "}\n")
}
}
if err := os.WriteFile("example_test.go", w.Bytes(), 0666); err != nil {
log.Fatal(err)
}
}
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