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// Parsing keys handling both bare and quoted keys.
package toml
import (
"bytes"
"errors"
"fmt"
"strconv"
"unicode"
)
var escapeSequenceMap = map[rune]rune{
'b': '\b',
't': '\t',
'n': '\n',
'f': '\f',
'r': '\r',
'"': '"',
'\\': '\\',
}
type parseKeyState int
const (
bare parseKeyState = iota
basic
literal
esc
unicode4
unicode8
)
func parseKey(key string) ([]string, error) {
groups := []string{}
var buffer bytes.Buffer
var hex bytes.Buffer
state := bare
wasInQuotes := false
ignoreSpace := true
expectDot := false
for _, char := range key {
if ignoreSpace {
if char == ' ' {
continue
}
ignoreSpace = false
}
if state == esc {
if char == 'u' {
state = unicode4
hex.Reset()
} else if char == 'U' {
state = unicode8
hex.Reset()
} else if newChar, ok := escapeSequenceMap[char]; ok {
buffer.WriteRune(newChar)
state = basic
} else {
return nil, fmt.Errorf(`invalid escape sequence \%c`, char)
}
continue
}
if state == unicode4 || state == unicode8 {
if isHexDigit(char) {
hex.WriteRune(char)
}
if (state == unicode4 && hex.Len() == 4) || (state == unicode8 && hex.Len() == 8) {
if value, err := strconv.ParseInt(hex.String(), 16, 32); err == nil {
buffer.WriteRune(rune(value))
} else {
return nil, err
}
state = basic
}
continue
}
switch char {
case '\\':
if state == basic {
state = esc
} else if state == literal {
buffer.WriteRune(char)
}
case '\'':
if state == bare {
state = literal
} else if state == literal {
groups = append(groups, buffer.String())
buffer.Reset()
wasInQuotes = true
state = bare
}
expectDot = false
case '"':
if state == bare {
state = basic
} else if state == basic {
groups = append(groups, buffer.String())
buffer.Reset()
state = bare
wasInQuotes = true
}
expectDot = false
case '.':
if state != bare {
buffer.WriteRune(char)
} else {
if !wasInQuotes {
if buffer.Len() == 0 {
return nil, errors.New("empty table key")
}
groups = append(groups, buffer.String())
buffer.Reset()
}
ignoreSpace = true
expectDot = false
wasInQuotes = false
}
case ' ':
if state == basic {
buffer.WriteRune(char)
} else {
expectDot = true
}
default:
if state == bare {
if !isValidBareChar(char) {
return nil, fmt.Errorf("invalid bare character: %c", char)
} else if expectDot {
return nil, errors.New("what?")
}
}
buffer.WriteRune(char)
expectDot = false
}
}
// state must be bare at the end
if state == esc {
return nil, errors.New("unfinished escape sequence")
} else if state != bare {
return nil, errors.New("mismatched quotes")
}
if buffer.Len() > 0 {
groups = append(groups, buffer.String())
}
if len(groups) == 0 {
return nil, errors.New("empty key")
}
return groups, nil
}
func isValidBareChar(r rune) bool {
return isAlphanumeric(r) || r == '-' || unicode.IsNumber(r)
}
|
