152 lines
2.9 KiB
Go
152 lines
2.9 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package strconv_test
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"strconv"
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"strings"
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"testing"
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)
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func pow2(i int) float64 {
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switch {
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case i < 0:
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return 1 / pow2(-i)
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case i == 0:
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return 1
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case i == 1:
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return 2
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}
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return pow2(i/2) * pow2(i-i/2)
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}
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// Wrapper around strconv.ParseFloat(x, 64). Handles dddddp+ddd (binary exponent)
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// itself, passes the rest on to strconv.ParseFloat.
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func myatof64(s string) (f float64, ok bool) {
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a := strings.SplitN(s, "p", 2)
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if len(a) == 2 {
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n, err := strconv.ParseInt(a[0], 10, 64)
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if err != nil {
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return 0, false
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}
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e, err1 := strconv.Atoi(a[1])
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if err1 != nil {
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println("bad e", a[1])
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return 0, false
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}
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v := float64(n)
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// We expect that v*pow2(e) fits in a float64,
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// but pow2(e) by itself may not. Be careful.
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if e <= -1000 {
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v *= pow2(-1000)
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e += 1000
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for e < 0 {
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v /= 2
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e++
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}
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return v, true
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}
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if e >= 1000 {
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v *= pow2(1000)
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e -= 1000
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for e > 0 {
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v *= 2
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e--
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}
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return v, true
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}
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return v * pow2(e), true
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}
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f1, err := strconv.ParseFloat(s, 64)
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if err != nil {
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return 0, false
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}
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return f1, true
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}
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// Wrapper around strconv.ParseFloat(x, 32). Handles dddddp+ddd (binary exponent)
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// itself, passes the rest on to strconv.ParseFloat.
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func myatof32(s string) (f float32, ok bool) {
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a := strings.SplitN(s, "p", 2)
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if len(a) == 2 {
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n, err := strconv.Atoi(a[0])
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if err != nil {
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println("bad n", a[0])
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return 0, false
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}
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e, err1 := strconv.Atoi(a[1])
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if err1 != nil {
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println("bad p", a[1])
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return 0, false
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}
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return float32(float64(n) * pow2(e)), true
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}
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f64, err1 := strconv.ParseFloat(s, 32)
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f1 := float32(f64)
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if err1 != nil {
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return 0, false
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}
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return f1, true
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}
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func TestFp(t *testing.T) {
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f, err := os.Open("testfp.txt")
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if err != nil {
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t.Fatal("testfp: open testfp.txt:", err)
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}
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defer f.Close()
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b := bufio.NewReader(f)
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lineno := 0
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for {
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line, err2 := b.ReadString('\n')
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if err2 == io.EOF {
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break
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}
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if err2 != nil {
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t.Fatal("testfp: read testfp.txt: " + err2.Error())
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}
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line = line[0 : len(line)-1]
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lineno++
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if len(line) == 0 || line[0] == '#' {
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continue
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}
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a := strings.Split(line, " ")
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if len(a) != 4 {
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t.Error("testfp.txt:", lineno, ": wrong field count")
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continue
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}
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var s string
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var v float64
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switch a[0] {
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case "float64":
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var ok bool
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v, ok = myatof64(a[2])
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if !ok {
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t.Error("testfp.txt:", lineno, ": cannot atof64 ", a[2])
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continue
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}
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s = fmt.Sprintf(a[1], v)
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case "float32":
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v1, ok := myatof32(a[2])
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if !ok {
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t.Error("testfp.txt:", lineno, ": cannot atof32 ", a[2])
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continue
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}
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s = fmt.Sprintf(a[1], v1)
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v = float64(v1)
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}
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if s != a[3] {
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t.Error("testfp.txt:", lineno, ": ", a[0], " ", a[1], " ", a[2], " (", v, ") ",
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"want ", a[3], " got ", s)
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}
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}
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}
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