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Diffstat (limited to 'vendor/golang.org/x/text/feature/plural/plural.go')
| -rw-r--r-- | vendor/golang.org/x/text/feature/plural/plural.go | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/feature/plural/plural.go b/vendor/golang.org/x/text/feature/plural/plural.go new file mode 100644 index 000000000..2b4cfe321 --- /dev/null +++ b/vendor/golang.org/x/text/feature/plural/plural.go @@ -0,0 +1,234 @@ +// 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 plural provides utilities for handling linguistic plurals in text. +// +// The definitions in this package are based on the plural rule handling defined +// in CLDR. See +// http://unicode.org/reports/tr35/tr35-numbers.html#Language_Plural_Rules for +// details. +package plural + +import ( + "golang.org/x/text/language" +) + +// Rules defines the plural rules for all languages for a certain plural type. +// +// +// This package is UNDER CONSTRUCTION and its API may change. +type Rules struct { + rules []pluralCheck + index []byte + langToIndex []byte + inclusionMasks []uint64 +} + +var ( + // Cardinal defines the plural rules for numbers indicating quantities. + Cardinal *Rules = cardinal + + // Ordinal defines the plural rules for numbers indicating position + // (first, second, etc.). + Ordinal *Rules = ordinal + + ordinal = &Rules{ + ordinalRules, + ordinalIndex, + ordinalLangToIndex, + ordinalInclusionMasks[:], + } + + cardinal = &Rules{ + cardinalRules, + cardinalIndex, + cardinalLangToIndex, + cardinalInclusionMasks[:], + } +) + +// getIntApprox converts the digits in slice digits[start:end] to an integer +// according to the following rules: +// - Let i be asInt(digits[start:end]), where out-of-range digits are assumed +// to be zero. +// - Result n is big if i / 10^nMod > 1. +// - Otherwise the result is i % 10^nMod. +// +// For example, if digits is {1, 2, 3} and start:end is 0:5, then the result +// for various values of nMod is: +// - when nMod == 2, n == big +// - when nMod == 3, n == big +// - when nMod == 4, n == big +// - when nMod == 5, n == 12300 +// - when nMod == 6, n == 12300 +// - when nMod == 7, n == 12300 +func getIntApprox(digits []byte, start, end, nMod, big int) (n int) { + // Leading 0 digits just result in 0. + p := start + if p < 0 { + p = 0 + } + // Range only over the part for which we have digits. + mid := end + if mid >= len(digits) { + mid = len(digits) + } + // Check digits more significant that nMod. + if q := end - nMod; q > 0 { + if q > mid { + q = mid + } + for ; p < q; p++ { + if digits[p] != 0 { + return big + } + } + } + for ; p < mid; p++ { + n = 10*n + int(digits[p]) + } + // Multiply for trailing zeros. + for ; p < end; p++ { + n *= 10 + } + return n +} + +// MatchDigits computes the plural form for the given language and the given +// decimal floating point digits. The digits are stored in big-endian order and +// are of value byte(0) - byte(9). The floating point position is indicated by +// exp and the number of visible decimals is scale. All leading and trailing +// zeros may be omitted from digits. +// +// The following table contains examples of possible arguments to represent +// the given numbers. +// decimal digits exp scale +// 123 []byte{1, 2, 3} 3 0 +// 123.4 []byte{1, 2, 3, 4} 3 1 +// 123.40 []byte{1, 2, 3, 4} 3 2 +// 100000 []byte{1} 6......0 +// 100000.00 []byte{1} 6......3 +func (p *Rules) MatchDigits(t language.Tag, digits []byte, exp, scale int) Form { + index, _ := language.CompactIndex(t) + endN := len(digits) + exp + + // Differentiate up to including mod 1000000 for the integer part. + n := getIntApprox(digits, 0, endN, 6, 1000000) + + // Differentiate up to including mod 100 for the fractional part. + f := getIntApprox(digits, endN, endN+scale, 2, 100) + + return matchPlural(p, index, n, f, scale) +} + +func validForms(p *Rules, t language.Tag) (forms []Form) { + index, _ := language.CompactIndex(t) + offset := p.langToIndex[index] + rules := p.rules[p.index[offset]:p.index[offset+1]] + + forms = append(forms, Other) + last := Other + for _, r := range rules { + if cat := Form(r.cat & formMask); cat != andNext && last != cat { + forms = append(forms, cat) + last = cat + } + } + return forms +} + +func (p *Rules) matchComponents(t language.Tag, n, f, scale int) Form { + index, _ := language.CompactIndex(t) + return matchPlural(p, index, n, f, scale) +} + +func matchPlural(p *Rules, index int, n, f, v int) Form { + nMask := p.inclusionMasks[n%maxMod] + // Compute the fMask inline in the rules below, as it is relatively rare. + // fMask := p.inclusionMasks[f%maxMod] + vMask := p.inclusionMasks[v%maxMod] + + // Do the matching + offset := p.langToIndex[index] + rules := p.rules[p.index[offset]:p.index[offset+1]] + for i := 0; i < len(rules); i++ { + rule := rules[i] + setBit := uint64(1 << rule.setID) + var skip bool + switch op := opID(rule.cat >> opShift); op { + case opI: // i = x + skip = n >= numN || nMask&setBit == 0 + + case opI | opNotEqual: // i != x + skip = n < numN && nMask&setBit != 0 + + case opI | opMod: // i % m = x + skip = nMask&setBit == 0 + + case opI | opMod | opNotEqual: // i % m != x + skip = nMask&setBit != 0 + + case opN: // n = x + skip = f != 0 || n >= numN || nMask&setBit == 0 + + case opN | opNotEqual: // n != x + skip = f == 0 && n < numN && nMask&setBit != 0 + + case opN | opMod: // n % m = x + skip = f != 0 || nMask&setBit == 0 + + case opN | opMod | opNotEqual: // n % m != x + skip = f == 0 && nMask&setBit != 0 + + case opF: // f = x + skip = f >= numN || p.inclusionMasks[f%maxMod]&setBit == 0 + + case opF | opNotEqual: // f != x + skip = f < numN && p.inclusionMasks[f%maxMod]&setBit != 0 + + case opF | opMod: // f % m = x + skip = p.inclusionMasks[f%maxMod]&setBit == 0 + + case opF | opMod | opNotEqual: // f % m != x + skip = p.inclusionMasks[f%maxMod]&setBit != 0 + + case opV: // v = x + skip = v < numN && vMask&setBit == 0 + + case opV | opNotEqual: // v != x + skip = v < numN && vMask&setBit != 0 + + case opW: // w == 0 + skip = f != 0 + + case opW | opNotEqual: // w != 0 + skip = f == 0 + + // Hard-wired rules that cannot be handled by our algorithm. + + case opBretonM: + skip = f != 0 || n == 0 || n%1000000 != 0 + + case opAzerbaijan00s: + // 100,200,300,400,500,600,700,800,900 + skip = n == 0 || n >= 1000 || n%100 != 0 + + case opItalian800: + skip = (f != 0 || n >= numN || nMask&setBit == 0) && n != 800 + } + if skip { + // advance over AND entries. + for ; i < len(rules) && rules[i].cat&formMask == andNext; i++ { + } + continue + } + // return if we have a final entry. + if cat := rule.cat & formMask; cat != andNext { + return Form(cat) + } + } + return Other +} |