make_examples.mx raw

   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  
   9  package main
  10  
  11  import (
  12  	"bytes"
  13  	"fmt"
  14  	"log"
  15  	"math/bits"
  16  	"os"
  17  )
  18  
  19  const 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  
  25  package bits_test
  26  
  27  import (
  28  	"fmt"
  29  	"math/bits"
  30  )
  31  `
  32  
  33  func main() {
  34  	w := bytes.NewBuffer([]byte(header))
  35  
  36  	for _, e := range []struct {
  37  		name []byte
  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