package yaml import ( "encoding/base64" "math" "regexp" "strconv" "strings" "unicode/utf8" ) type resolveMapItem struct { value interface{} tag string } var resolveTable = make([]byte, 256) var resolveMap = make(map[string]resolveMapItem) func init() { t := resolveTable t[int('+')] = 'S' // Sign t[int('-')] = 'S' for _, c := range "0123456789" { t[int(c)] = 'D' // Digit } for _, c := range "yYnNtTfFoO~" { t[int(c)] = 'M' // In map } t[int('.')] = '.' // Float (potentially in map) var resolveMapList = []struct { v interface{} tag string l []string }{ {true, yaml_BOOL_TAG, []string{"y", "Y", "yes", "Yes", "YES"}}, {true, yaml_BOOL_TAG, []string{"true", "True", "TRUE"}}, {true, yaml_BOOL_TAG, []string{"on", "On", "ON"}}, {false, yaml_BOOL_TAG, []string{"n", "N", "no", "No", "NO"}}, {false, yaml_BOOL_TAG, []string{"false", "False", "FALSE"}}, {false, yaml_BOOL_TAG, []string{"off", "Off", "OFF"}}, {nil, yaml_NULL_TAG, []string{"", "~", "null", "Null", "NULL"}}, {math.NaN(), yaml_FLOAT_TAG, []string{".nan", ".NaN", ".NAN"}}, {math.Inf(+1), yaml_FLOAT_TAG, []string{".inf", ".Inf", ".INF"}}, {math.Inf(+1), yaml_FLOAT_TAG, []string{"+.inf", "+.Inf", "+.INF"}}, {math.Inf(-1), yaml_FLOAT_TAG, []string{"-.inf", "-.Inf", "-.INF"}}, {"<<", yaml_MERGE_TAG, []string{"<<"}}, } m := resolveMap for _, item := range resolveMapList { for _, s := range item.l { m[s] = resolveMapItem{item.v, item.tag} } } } const longTagPrefix = "tag:yaml.org,2002:" func shortTag(tag string) string { // TODO This can easily be made faster and produce less garbage. if strings.HasPrefix(tag, longTagPrefix) { return "!!" + tag[len(longTagPrefix):] } return tag } func longTag(tag string) string { if strings.HasPrefix(tag, "!!") { return longTagPrefix + tag[2:] } return tag } func resolvableTag(tag string) bool { switch tag { case "", yaml_STR_TAG, yaml_BOOL_TAG, yaml_INT_TAG, yaml_FLOAT_TAG, yaml_NULL_TAG: return true } return false } var yamlStyleFloat = regexp.MustCompile(`^[-+]?[0-9]*\.?[0-9]+([eE][-+][0-9]+)?$`) func resolve(tag string, in string) (rtag string, out interface{}) { if !resolvableTag(tag) { return tag, in } defer func() { switch tag { case "", rtag, yaml_STR_TAG, yaml_BINARY_TAG: return } failf("cannot decode %s `%s` as a %s", shortTag(rtag), in, shortTag(tag)) }() // Any data is accepted as a !!str or !!binary. // Otherwise, the prefix is enough of a hint about what it might be. hint := byte('N') if in != "" { hint = resolveTable[in[0]] } if hint != 0 && tag != yaml_STR_TAG && tag != yaml_BINARY_TAG { // Handle things we can lookup in a map. if item, ok := resolveMap[in]; ok { return item.tag, item.value } // Base 60 floats are a bad idea, were dropped in YAML 1.2, and // are purposefully unsupported here. They're still quoted on // the way out for compatibility with other parser, though. switch hint { case 'M': // We've already checked the map above. case '.': // Not in the map, so maybe a normal float. floatv, err := strconv.ParseFloat(in, 64) if err == nil { return yaml_FLOAT_TAG, floatv } case 'D', 'S': // Int, float, or timestamp. plain := strings.Replace(in, "_", "", -1) intv, err := strconv.ParseInt(plain, 0, 64) if err == nil { if intv == int64(int(intv)) { return yaml_INT_TAG, int(intv) } else { return yaml_INT_TAG, intv } } uintv, err := strconv.ParseUint(plain, 0, 64) if err == nil { return yaml_INT_TAG, uintv } if yamlStyleFloat.MatchString(plain) { floatv, err := strconv.ParseFloat(plain, 64) if err == nil { return yaml_FLOAT_TAG, floatv } } if strings.HasPrefix(plain, "0b") { intv, err := strconv.ParseInt(plain[2:], 2, 64) if err == nil { if intv == int64(int(intv)) { return yaml_INT_TAG, int(intv) } else { return yaml_INT_TAG, intv } } uintv, err := strconv.ParseUint(plain[2:], 2, 64) if err == nil { return yaml_INT_TAG, uintv } } else if strings.HasPrefix(plain, "-0b") { intv, err := strconv.ParseInt(plain[3:], 2, 64) if err == nil { if intv == int64(int(intv)) { return yaml_INT_TAG, -int(intv) } else { return yaml_INT_TAG, -intv } } } // XXX Handle timestamps here. default: panic("resolveTable item not yet handled: " + string(rune(hint)) + " (with " + in + ")") } } if tag == yaml_BINARY_TAG { return yaml_BINARY_TAG, in } if utf8.ValidString(in) { return yaml_STR_TAG, in } return yaml_BINARY_TAG, encodeBase64(in) } // encodeBase64 encodes s as base64 that is broken up into multiple lines // as appropriate for the resulting length. func encodeBase64(s string) string { const lineLen = 70 encLen := base64.StdEncoding.EncodedLen(len(s)) lines := encLen/lineLen + 1 buf := make([]byte, encLen*2+lines) in := buf[0:encLen] out := buf[encLen:] base64.StdEncoding.Encode(in, []byte(s)) k := 0 for i := 0; i < len(in); i += lineLen { j := i + lineLen if j > len(in) { j = len(in) } k += copy(out[k:], in[i:j]) if lines > 1 { out[k] = '\n' k++ } } return string(out[:k]) }