summaryrefslogtreecommitdiffstats
path: root/vendor/gopkg.in/yaml.v2/resolve.go
blob: 232313cc084556256505313a1c4eafae1fbd719b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
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])
}