/
tag.go
145 lines (129 loc) · 2.72 KB
/
tag.go
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package screw
import (
"errors"
"strconv"
"strings"
"unicode/utf8"
)
var ErrNotPointerType = errors.New("Not pointer type")
var ErrUnsupportedType = errors.New("Unsupported type")
func contains(s string, b byte) bool {
return strings.IndexByte(s, b) != -1
}
func Unquote(s string) (string, error) {
n := len(s)
if n < 2 {
return "", strconv.ErrSyntax
}
quote := s[0]
if quote != s[n-1] {
return "", strconv.ErrSyntax
}
s = s[1 : n-1]
if quote == '`' {
if contains(s, '`') {
return "", strconv.ErrSyntax
}
if contains(s, '\r') {
// -1 because we know there is at least one \r to remove.
buf := make([]byte, 0, len(s)-1)
for i := 0; i < len(s); i++ {
if s[i] != '\r' {
buf = append(buf, s[i])
}
}
return string(buf), nil
}
return s, nil
}
if quote != '"' && quote != '\'' {
return "", strconv.ErrSyntax
}
/*
if contains(s, '\n') {
return "", strconv.ErrSyntax
}
*/
// Is it trivial? Avoid allocation.
if !contains(s, '\\') && !contains(s, quote) {
switch quote {
case '"':
if utf8.ValidString(s) {
return s, nil
}
case '\'':
r, size := utf8.DecodeRuneInString(s)
if size == len(s) && (r != utf8.RuneError || size != 1) {
return s, nil
}
}
}
var runeTmp [utf8.UTFMax]byte
buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
for len(s) > 0 {
c, multibyte, ss, err := strconv.UnquoteChar(s, quote)
if err != nil {
return "", err
}
s = ss
if c < utf8.RuneSelf || !multibyte {
buf = append(buf, byte(c))
} else {
n := utf8.EncodeRune(runeTmp[:], c)
buf = append(buf, runeTmp[:n]...)
}
if quote == '\'' && len(s) != 0 {
// single-quoted must be single character
return "", strconv.ErrSyntax
}
}
return string(buf), nil
}
type Tag string
func (tag Tag) Lookup(key string) (value string, ok bool) {
for tag != "" {
i := 0
for i < len(tag) && (tag[i] == ' ' || tag[i] == '\n' || tag[i] == '\t') {
i++
}
tag = tag[i:]
if tag == "" {
break
}
i = 0
for i < len(tag) && tag[i] > ' ' && tag[i] != ':' && tag[i] != '"' && tag[i] != 0x7f {
i++
}
if i == 0 || i+1 >= len(tag) || tag[i] != ':' || tag[i+1] != '"' {
break
}
name := string(tag[:i])
tag = tag[i+1:]
// Scan quoted string to find value.
i = 1
for i < len(tag) && tag[i] != '"' {
if tag[i] == '\\' {
i++
}
i++
}
if i >= len(tag) {
break
}
qvalue := string(tag[:i+1])
tag = tag[i+1:]
if key == name {
value, err := Unquote(qvalue)
//fmt.Printf("key(%s) name=(%s) tag(%s) qvalue(%s) err:%s\n", key, name, tag, qvalue, err)
if err != nil {
break
}
return value, true
}
}
return "", false
}
func (tag Tag) Get(key string) (value string) {
v, _ := tag.Lookup(key)
return v
}