解析C风格的字符串 Quote

unquote_cstyle_string.go

func UnquoteCStyleString(raw string) (string, error) {
	state := ""
	results := ""
	hexBuffer := ""

	scanner := bufio.NewScanner(bytes.NewBufferString(raw))
	scanner.Split(bufio.ScanBytes)

	index := 0
	for scanner.Scan() {
		index++
		//log.Infof("index: %d", index)

		b := scanner.Bytes()[0]
		if b == '\\' && state != "charStart" {
			state = "charStart"
			continue
		}

		switch state {
		case "hex":
			if len(hexBuffer) < 2 {
				//log.Infof("hex: %s", string(b))
				hexBuffer += string(b)
			}

			if len(hexBuffer) == 2 {
				_ret, err := hex.DecodeString(hexBuffer)
				if err != nil {
					return "", errors.Errorf("parse hex buffer[\\x%s] failed: %s", hexBuffer, err)
				}

				if len(_ret) != 1 {
					return "", errors.Errorf("BUG: \\x%s to %#v", hexBuffer, _ret)
				}

				results += string(_ret)
				state = ""
				hexBuffer = ""
			} else if len(hexBuffer) > 2 {
				return "", errors.Errorf("parse hex failed: \\x%s", hexBuffer)
			} else {
				state = "hex"
			}

		case "charStart":
			switch b {
			case '0':
				results += "\x00"
				break
			case 'a':
				results += "\a"
				break
			case 'b':
				results += "\n"
				break
			case 'f':
				results += "\f"
				break
			case 'n':
				results += "\n"
				break
			case 'r':
				results += "\r"
				break
			case 't':
				results += "\t"
				break
			case 'v':
				results += "\v"
				break
			case 'x':
				state = "hex"
				continue
			}
			state = ""
			continue
		default:
			results += string(b)
			continue
		}

	}
	return results, nil
}