summaryrefslogtreecommitdiff
path: root/vendor/golang.org/x/text/internal/number/number.go
blob: 2a21f07d032685abc7a42add86f8e06e651ec03b (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
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:generate go run gen.go gen_common.go

// Package number contains tools and data for formatting numbers.
package number

import (
	"unicode/utf8"

	"golang.org/x/text/internal"
	"golang.org/x/text/language"
)

// Info holds number formatting configuration data.
type Info struct {
	system   systemData // numbering system information
	symIndex symOffset  // index to symbols
}

// InfoFromLangID returns a Info for the given compact language identifier and
// numbering system identifier. If system is the empty string, the default
// numbering system will be taken for that language.
func InfoFromLangID(compactIndex int, numberSystem string) Info {
	p := langToDefaults[compactIndex]
	// Lookup the entry for the language.
	pSymIndex := symOffset(0) // Default: Latin, default symbols
	system, ok := systemMap[numberSystem]
	if !ok {
		// Take the value for the default numbering system. This is by far the
		// most common case as an alternative numbering system is hardly used.
		if p&hasNonLatnMask == 0 { // Latn digits.
			pSymIndex = p
		} else { // Non-Latn or multiple numbering systems.
			// Take the first entry from the alternatives list.
			data := langToAlt[p&^hasNonLatnMask]
			pSymIndex = data.symIndex
			system = data.system
		}
	} else {
		langIndex := compactIndex
		ns := system
	outerLoop:
		for ; ; p = langToDefaults[langIndex] {
			if p&hasNonLatnMask == 0 {
				if ns == 0 {
					// The index directly points to the symbol data.
					pSymIndex = p
					break
				}
				// Move to the parent and retry.
				langIndex = int(internal.Parent[langIndex])
			} else {
				// The index points to a list of symbol data indexes.
				for _, e := range langToAlt[p&^hasNonLatnMask:] {
					if int(e.compactTag) != langIndex {
						if langIndex == 0 {
							// The CLDR root defines full symbol information for
							// all numbering systems (even though mostly by
							// means of aliases). Fall back to the default entry
							// for Latn if there is no data for the numbering
							// system of this language.
							if ns == 0 {
								break
							}
							// Fall back to Latin and start from the original
							// language. See
							// http://unicode.org/reports/tr35/#Locale_Inheritance.
							ns = numLatn
							langIndex = compactIndex
							continue outerLoop
						}
						// Fall back to parent.
						langIndex = int(internal.Parent[langIndex])
					} else if e.system == ns {
						pSymIndex = e.symIndex
						break outerLoop
					}
				}
			}
		}
	}
	if int(system) >= len(numSysData) { // algorithmic
		// Will generate ASCII digits in case the user inadvertently calls
		// WriteDigit or Digit on it.
		d := numSysData[0]
		d.id = system
		return Info{
			system:   d,
			symIndex: pSymIndex,
		}
	}
	return Info{
		system:   numSysData[system],
		symIndex: pSymIndex,
	}
}

// InfoFromTag returns a Info for the given language tag.
func InfoFromTag(t language.Tag) Info {
	for {
		if index, ok := language.CompactIndex(t); ok {
			return InfoFromLangID(index, t.TypeForKey("nu"))
		}
		t = t.Parent()
	}
}

// IsDecimal reports if the numbering system can convert decimal to native
// symbols one-to-one.
func (n Info) IsDecimal() bool {
	return int(n.system.id) < len(numSysData)
}

// WriteDigit writes the UTF-8 sequence for n corresponding to the given ASCII
// digit to dst and reports the number of bytes written. dst must be large
// enough to hold the rune (can be up to utf8.UTFMax bytes).
func (n Info) WriteDigit(dst []byte, asciiDigit rune) int {
	copy(dst, n.system.zero[:n.system.digitSize])
	dst[n.system.digitSize-1] += byte(asciiDigit - '0')
	return int(n.system.digitSize)
}

// AppendDigit appends the UTF-8 sequence for n corresponding to the given digit
// to dst and reports the number of bytes written. dst must be large enough to
// hold the rune (can be up to utf8.UTFMax bytes).
func (n Info) AppendDigit(dst []byte, digit byte) []byte {
	dst = append(dst, n.system.zero[:n.system.digitSize]...)
	dst[len(dst)-1] += digit
	return dst
}

// Digit returns the digit for the numbering system for the corresponding ASCII
// value. For example, ni.Digit('3') could return '三'. Note that the argument
// is the rune constant '3', which equals 51, not the integer constant 3.
func (n Info) Digit(asciiDigit rune) rune {
	var x [utf8.UTFMax]byte
	n.WriteDigit(x[:], asciiDigit)
	r, _ := utf8.DecodeRune(x[:])
	return r
}

// Symbol returns the string for the given symbol type.
func (n Info) Symbol(t SymbolType) string {
	return symData.Elem(int(symIndex[n.symIndex][t]))
}

func formatForLang(t language.Tag, index []byte) *Pattern {
	for ; ; t = t.Parent() {
		if x, ok := language.CompactIndex(t); ok {
			return &formats[index[x]]
		}
	}
}