From 2ddd07138d08d12e5662b9480c1fb23d3feb6a5d Mon Sep 17 00:00:00 2001 From: griesemer Date: Wed, 4 Oct 2017 15:20:52 -0700 Subject: math/bits: complete examples MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Change-Id: Icbe6885ffd3aa4e77441ab03a2b9a04a9276d5eb Reviewed-on: https://go-review.googlesource.com/68311 Reviewed-by: Martin Möhrmann --- src/math/bits/make_examples.go | 174 +++++++++++++---------------------------- 1 file changed, 53 insertions(+), 121 deletions(-) (limited to 'src/math/bits/make_examples.go') diff --git a/src/math/bits/make_examples.go b/src/math/bits/make_examples.go index caef0b1b69..ac537d5778 100644 --- a/src/math/bits/make_examples.go +++ b/src/math/bits/make_examples.go @@ -11,16 +11,12 @@ package main import ( "bytes" "fmt" - "go/format" - "io" "io/ioutil" "log" "math/bits" - "sort" ) -var ( - header = []byte(`// Copyright 2017 The Go Authors. All rights reserved. +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. @@ -32,143 +28,79 @@ import ( "fmt" "math/bits" ) - -`) - - exampleRegF = ` -func Example%s() { - fmt.Printf("%s\n", %d, bits.%s(%d)) - // Output: - // %s -} ` - exampleRevF = ` -func Example%s() { - fmt.Printf("%s\n", %d) - fmt.Printf("%s\n", bits.%s(%d)) - // Output: - // %s - // %s -} -` -) func main() { - buf := bytes.NewBuffer(header) - - genReg(buf) - genRev(buf) - - out, err := format.Source(buf.Bytes()) - if err != nil { - log.Fatal(err) - } - - err = ioutil.WriteFile("example_test.go", out, 0666) - if err != nil { - log.Fatal(err) - } -} + w := bytes.NewBuffer([]byte(header)) -func genReg(w io.Writer) { - examples := []struct { + for _, e := range []struct { name string in int - out map[uint]interface{} + out [4]interface{} }{ { name: "LeadingZeros", in: 1, - out: map[uint]interface{}{ - 8: bits.LeadingZeros8(1), - 16: bits.LeadingZeros16(1), - 32: bits.LeadingZeros32(1), - 64: bits.LeadingZeros64(1), - }, - }, { + out: [4]interface{}{bits.LeadingZeros8(1), bits.LeadingZeros16(1), bits.LeadingZeros32(1), bits.LeadingZeros64(1)}, + }, + { name: "TrailingZeros", in: 14, - out: map[uint]interface{}{ - 8: bits.TrailingZeros8(14), - 16: bits.TrailingZeros16(14), - 32: bits.TrailingZeros32(14), - 64: bits.TrailingZeros64(14), - }, - }, { + out: [4]interface{}{bits.TrailingZeros8(14), bits.TrailingZeros16(14), bits.TrailingZeros32(14), bits.TrailingZeros64(14)}, + }, + { name: "OnesCount", in: 14, - out: map[uint]interface{}{ - 8: bits.OnesCount8(14), - 16: bits.OnesCount16(14), - 32: bits.OnesCount32(14), - 64: bits.OnesCount64(14), - }, - }, { - name: "Len", - in: 8, - out: map[uint]interface{}{ - 8: bits.Len8(8), - 16: bits.Len16(8), - 32: bits.Len32(8), - 64: bits.Len64(8), - }, + out: [4]interface{}{bits.OnesCount8(14), bits.OnesCount16(14), bits.OnesCount32(14), bits.OnesCount64(14)}, + }, + { + name: "RotateLeft", + in: 15, + out: [4]interface{}{bits.RotateLeft8(15, 2), bits.RotateLeft16(15, 2), bits.RotateLeft32(15, 2), bits.RotateLeft64(15, 2)}, }, - } - - for _, e := range examples { - sizes := sortedSizes(e.out) - - for _, size := range sizes { - fnName := fmt.Sprintf("%s%d", e.name, size) - outF := fmt.Sprintf("%s(%%0%db) = %%d", fnName, size) - out := fmt.Sprintf(outF, e.in, e.out[size]) - - fmt.Fprintf(w, exampleRegF, fnName, outF, e.in, fnName, e.in, out) - } - } -} - -func genRev(w io.Writer) { - examples := []struct { - name string - in int - out map[uint]interface{} - }{ { name: "Reverse", in: 19, - out: map[uint]interface{}{ - 8: bits.Reverse8(19), - 16: bits.Reverse16(19), - 32: bits.Reverse32(19), - 64: bits.Reverse64(19), - }, + out: [4]interface{}{bits.Reverse8(19), bits.Reverse16(19), bits.Reverse32(19), bits.Reverse64(19)}, }, - } - - for _, e := range examples { - sizes := sortedSizes(e.out) - - for _, size := range sizes { - fnName := fmt.Sprintf("%s%d", e.name, size) - outF := fmt.Sprintf("%%0%db", size) - out := fmt.Sprintf(outF, e.in) - secOut := fmt.Sprintf(outF, e.out[size]) - - fmt.Fprintf(w, exampleRevF, fnName, outF, e.in, outF, fnName, e.in, out, secOut) + { + name: "ReverseBytes", + in: 15, + out: [4]interface{}{nil, bits.ReverseBytes16(15), bits.ReverseBytes32(15), bits.ReverseBytes64(15)}, + }, + { + name: "Len", + in: 8, + out: [4]interface{}{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) + } 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]) + 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") } } -} -func sortedSizes(out map[uint]interface{}) []uint { - sizes := make([]uint, 0, len(out)) - for size := range out { - sizes = append(sizes, size) + if err := ioutil.WriteFile("example_test.go", w.Bytes(), 0666); err != nil { + log.Fatal(err) } - - sort.Slice(sizes, func(i, j int) bool { - return sizes[i] < sizes[j] - }) - - return sizes } -- cgit v1.3