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encoding/json: streamline, unexport valid Number checking

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Followup to CL 12250.

For #10281.

Change-Id: If25d9cac92f10327bb355f2d11b00c625b464661
Reviewed-on: https://go-review.googlesource.com/17199
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Russ Cox 2015-11-25 11:34:41 -05:00
parent e8cc083ede
commit c4135dac63
3 changed files with 44 additions and 101 deletions
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120
src/encoding/json/decode.go
View File

@ -60,7 +60,7 @@ import (
// If the JSON array is smaller than the Go array,
// the additional Go array elements are set to zero values.
//
// To unmarshal a JSON object into a string-keyed map, Unmarshal first
// To unmarshal a JSON object into a string-keyed map, Unmarshal first
// establishes a map to use, If the map is nil, Unmarshal allocates a new map.
// Otherwise Unmarshal reuses the existing map, keeping existing entries.
// Unmarshal then stores key-value pairs from the JSON object into the map.
@ -184,122 +184,64 @@ func (n Number) Int64() (int64, error) {
return strconv.ParseInt(string(n), 10, 64)
}
// IsValid returns if the number is a valid JSON number literal.
func (n Number) IsValid() bool {
// isValidNumber reports whether s is a valid JSON number literal.
func isValidNumber(s string) bool {
// This function implements the JSON numbers grammar.
// See https://tools.ietf.org/html/rfc7159#section-6
// and http://json.org/number.gif
l := len(n)
if l == 0 {
if s == "" {
return false
}
i := 0
c := n[i]
i++
// Optional -
if c == '-' {
if i == l {
if s[0] == '-' {
s = s[1:]
if s == "" {
return false
}
c = n[i]
i++
}
// 1-9
if c >= '1' && c <= '9' {
// Eat digits.
for ; i < l; i++ {
c = n[i]
if c < '0' || c > '9' {
break
}
}
i++
} else if c != '0' {
// If it's not 0 or 1-9 it's invalid.
// Digits
switch {
default:
return false
} else {
if i == l {
// Just 0
return true
}
// Skip the 0
c = n[i]
i++
case s[0] == '0':
s = s[1:]
case '1' <= s[0] && s[0] <= '9':
s = s[1:]
for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
s = s[1:]
}
}
// . followed by 1 or more digits.
if c == '.' {
if i == l {
// Just 1. is invalid.
return false
if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
s = s[2:]
for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
s = s[1:]
}
// . needs to be followed by at least one digit.
c = n[i]
i++
if c < '0' || c > '9' {
return false
}
// Eat digits.
for ; i < l; i++ {
c = n[i]
if c < '0' || c > '9' {
break
}
}
i++
}
// e or E followed by an optional - or + and
// 1 or more digits.
if c == 'e' || c == 'E' {
if i == l {
// Just 1e is invalid.
return false
}
c = n[i]
i++
// Optional - or +
if c == '-' || c == '+' {
if i == l {
// Just 1e+ is invalid.
if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
s = s[1:]
if s[0] == '+' || s[0] == '-' {
s = s[1:]
if s == "" {
return false
}
c = n[i]
i++
}
// Need to have a digit.
if c < '0' || c > '9' {
return false
for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
s = s[1:]
}
// Eat digits.
for ; i < l; i++ {
c = n[i]
if c < '0' || c > '9' {
break
}
}
i++
}
// Make sure we are at the end.
if i <= l {
return false
}
return true
return s == ""
}
// decodeState represents the state while decoding a JSON value.
@ -909,7 +851,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
default:
if v.Kind() == reflect.String && v.Type() == numberType {
v.SetString(s)
if !Number(s).IsValid() {
if !isValidNumber(s) {
d.error(fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item))
}
break

5
src/encoding/json/encode.go
View File

@ -534,8 +534,9 @@ func stringEncoder(e *encodeState, v reflect.Value, quoted bool) {
// we keep compatibility so check validity after this.
if numStr == "" {
numStr = "0" // Number's zero-val
} else if !Number(numStr).IsValid() {
e.error(fmt.Errorf("json: invalid number literal, trying to marshal %s", v.String()))
}
if !isValidNumber(numStr) {
e.error(fmt.Errorf("json: invalid number literal %q", numStr))
}
e.WriteString(numStr)
return

20
src/encoding/json/number_test.go
View File

@ -63,17 +63,17 @@ func TestNumberIsValid(t *testing.T) {
}
for _, test := range validTests {
if !Number(test).IsValid() {
if !isValidNumber(test) {
t.Errorf("%s should be valid", test)
}
var f float64
if err := Unmarshal([]byte(test), &f); err != nil {
t.Errorf("%s should be invalid: %v", test, err)
t.Errorf("%s should be valid but Unmarshal failed: %v", test, err)
}
if !jsonNumberRegexp.MatchString(test) {
t.Errorf("%s should be invalid", test)
t.Errorf("%s should be valid but regexp does not match", test)
}
}
@ -102,32 +102,32 @@ func TestNumberIsValid(t *testing.T) {
}
for _, test := range invalidTests {
if Number(test).IsValid() {
if isValidNumber(test) {
t.Errorf("%s should be invalid", test)
}
var f float64
if err := Unmarshal([]byte(test), &f); err == nil {
t.Errorf("%s should be valid: %v", test, f)
t.Errorf("%s should be invalid but unmarshal wrote %v", test, f)
}
if jsonNumberRegexp.MatchString(test) {
t.Errorf("%s should be valid", test)
t.Errorf("%s should be invalid but matches regexp", test)
}
}
}
func BenchmarkNumberIsValid(b *testing.B) {
n := Number("-61657.61667E+61673")
s := "-61657.61667E+61673"
for i := 0; i < b.N; i++ {
n.IsValid()
isValidNumber(s)
}
}
func BenchmarkNumberIsValidRegexp(b *testing.B) {
var jsonNumberRegexp = regexp.MustCompile(`^-?(?:0|[1-9]\d*)(?:\.\d+)?(?:[eE][+-]?\d+)?$`)
n := "-61657.61667E+61673"
s := "-61657.61667E+61673"
for i := 0; i < b.N; i++ {
jsonNumberRegexp.MatchString(n)
jsonNumberRegexp.MatchString(s)
}
}