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1 files changed, 485 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/internal/number/pattern.go b/vendor/golang.org/x/text/internal/number/pattern.go
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+// Copyright 2015 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.
+
+package number
+
+import (
+ "errors"
+ "unicode/utf8"
+)
+
+// This file contains a parser for the CLDR number patterns as described in
+// http://unicode.org/reports/tr35/tr35-numbers.html#Number_Format_Patterns.
+//
+// The following BNF is derived from this standard.
+//
+// pattern := subpattern (';' subpattern)?
+// subpattern := affix? number exponent? affix?
+// number := decimal | sigDigits
+// decimal := '#'* '0'* ('.' fraction)? | '#' | '0'
+// fraction := '0'* '#'*
+// sigDigits := '#'* '@' '@'* '#'*
+// exponent := 'E' '+'? '0'* '0'
+// padSpec := '*' \L
+//
+// Notes:
+// - An affix pattern may contain any runes, but runes with special meaning
+// should be escaped.
+// - Sequences of digits, '#', and '@' in decimal and sigDigits may have
+// interstitial commas.
+
+// TODO: replace special characters in affixes (-, +, ¤) with control codes.
+
+// Pattern holds information for formatting numbers. It is designed to hold
+// information from CLDR number patterns.
+//
+// This pattern is precompiled for all patterns for all languages. Even though
+// the number of patterns is not very large, we want to keep this small.
+//
+// This type is only intended for internal use.
+type Pattern struct {
+ RoundingContext
+
+ Affix string // includes prefix and suffix. First byte is prefix length.
+ Offset uint16 // Offset into Affix for prefix and suffix
+ NegOffset uint16 // Offset into Affix for negative prefix and suffix or 0.
+ PadRune rune
+ FormatWidth uint16
+
+ GroupingSize [2]uint8
+ Flags PatternFlag
+}
+
+// A RoundingContext indicates how a number should be converted to digits.
+// It contains all information needed to determine the "visible digits" as
+// required by the pluralization rules.
+type RoundingContext struct {
+ // TODO: unify these two fields so that there is a more unambiguous meaning
+ // of how precision is handled.
+ MaxSignificantDigits int16 // -1 is unlimited
+ MaxFractionDigits int16 // -1 is unlimited
+
+ Increment uint32
+ IncrementScale uint8 // May differ from printed scale.
+
+ Mode RoundingMode
+
+ DigitShift uint8 // Number of decimals to shift. Used for % and ‰.
+
+ // Number of digits.
+ MinIntegerDigits uint8
+
+ MaxIntegerDigits uint8
+ MinFractionDigits uint8
+ MinSignificantDigits uint8
+
+ MinExponentDigits uint8
+}
+
+// RoundSignificantDigits returns the number of significant digits an
+// implementation of Convert may round to or n < 0 if there is no maximum or
+// a maximum is not recommended.
+func (r *RoundingContext) RoundSignificantDigits() (n int) {
+ if r.MaxFractionDigits == 0 && r.MaxSignificantDigits > 0 {
+ return int(r.MaxSignificantDigits)
+ } else if r.isScientific() && r.MaxIntegerDigits == 1 {
+ if r.MaxSignificantDigits == 0 ||
+ int(r.MaxFractionDigits+1) == int(r.MaxSignificantDigits) {
+ // Note: don't add DigitShift: it is only used for decimals.
+ return int(r.MaxFractionDigits) + 1
+ }
+ }
+ return -1
+}
+
+// RoundFractionDigits returns the number of fraction digits an implementation
+// of Convert may round to or n < 0 if there is no maximum or a maximum is not
+// recommended.
+func (r *RoundingContext) RoundFractionDigits() (n int) {
+ if r.MinExponentDigits == 0 &&
+ r.MaxSignificantDigits == 0 &&
+ r.MaxFractionDigits >= 0 {
+ return int(r.MaxFractionDigits) + int(r.DigitShift)
+ }
+ return -1
+}
+
+// SetScale fixes the RoundingContext to a fixed number of fraction digits.
+func (r *RoundingContext) SetScale(scale int) {
+ r.MinFractionDigits = uint8(scale)
+ r.MaxFractionDigits = int16(scale)
+}
+
+func (r *RoundingContext) SetPrecision(prec int) {
+ r.MaxSignificantDigits = int16(prec)
+}
+
+func (r *RoundingContext) isScientific() bool {
+ return r.MinExponentDigits > 0
+}
+
+func (f *Pattern) needsSep(pos int) bool {
+ p := pos - 1
+ size := int(f.GroupingSize[0])
+ if size == 0 || p == 0 {
+ return false
+ }
+ if p == size {
+ return true
+ }
+ if p -= size; p < 0 {
+ return false
+ }
+ // TODO: make second groupingsize the same as first if 0 so that we can
+ // avoid this check.
+ if x := int(f.GroupingSize[1]); x != 0 {
+ size = x
+ }
+ return p%size == 0
+}
+
+// A PatternFlag is a bit mask for the flag field of a Pattern.
+type PatternFlag uint8
+
+const (
+ AlwaysSign PatternFlag = 1 << iota
+ ElideSign // Use space instead of plus sign. AlwaysSign must be true.
+ AlwaysExpSign
+ AlwaysDecimalSeparator
+ ParenthesisForNegative // Common pattern. Saves space.
+
+ PadAfterNumber
+ PadAfterAffix
+
+ PadBeforePrefix = 0 // Default
+ PadAfterPrefix = PadAfterAffix
+ PadBeforeSuffix = PadAfterNumber
+ PadAfterSuffix = PadAfterNumber | PadAfterAffix
+ PadMask = PadAfterNumber | PadAfterAffix
+)
+
+type parser struct {
+ *Pattern
+
+ leadingSharps int
+
+ pos int
+ err error
+ doNotTerminate bool
+ groupingCount uint
+ hasGroup bool
+ buf []byte
+}
+
+func (p *parser) setError(err error) {
+ if p.err == nil {
+ p.err = err
+ }
+}
+
+func (p *parser) updateGrouping() {
+ if p.hasGroup &&
+ 0 < p.groupingCount && p.groupingCount < 255 {
+ p.GroupingSize[1] = p.GroupingSize[0]
+ p.GroupingSize[0] = uint8(p.groupingCount)
+ }
+ p.groupingCount = 0
+ p.hasGroup = true
+}
+
+var (
+ // TODO: more sensible and localizeable error messages.
+ errMultiplePadSpecifiers = errors.New("format: pattern has multiple pad specifiers")
+ errInvalidPadSpecifier = errors.New("format: invalid pad specifier")
+ errInvalidQuote = errors.New("format: invalid quote")
+ errAffixTooLarge = errors.New("format: prefix or suffix exceeds maximum UTF-8 length of 256 bytes")
+ errDuplicatePercentSign = errors.New("format: duplicate percent sign")
+ errDuplicatePermilleSign = errors.New("format: duplicate permille sign")
+ errUnexpectedEnd = errors.New("format: unexpected end of pattern")
+)
+
+// ParsePattern extracts formatting information from a CLDR number pattern.
+//
+// See http://unicode.org/reports/tr35/tr35-numbers.html#Number_Format_Patterns.
+func ParsePattern(s string) (f *Pattern, err error) {
+ p := parser{Pattern: &Pattern{}}
+
+ s = p.parseSubPattern(s)
+
+ if s != "" {
+ // Parse negative sub pattern.
+ if s[0] != ';' {
+ p.setError(errors.New("format: error parsing first sub pattern"))
+ return nil, p.err
+ }
+ neg := parser{Pattern: &Pattern{}} // just for extracting the affixes.
+ s = neg.parseSubPattern(s[len(";"):])
+ p.NegOffset = uint16(len(p.buf))
+ p.buf = append(p.buf, neg.buf...)
+ }
+ if s != "" {
+ p.setError(errors.New("format: spurious characters at end of pattern"))
+ }
+ if p.err != nil {
+ return nil, p.err
+ }
+ if affix := string(p.buf); affix == "\x00\x00" || affix == "\x00\x00\x00\x00" {
+ // No prefix or suffixes.
+ p.NegOffset = 0
+ } else {
+ p.Affix = affix
+ }
+ if p.Increment == 0 {
+ p.IncrementScale = 0
+ }
+ return p.Pattern, nil
+}
+
+func (p *parser) parseSubPattern(s string) string {
+ s = p.parsePad(s, PadBeforePrefix)
+ s = p.parseAffix(s)
+ s = p.parsePad(s, PadAfterPrefix)
+
+ s = p.parse(p.number, s)
+ p.updateGrouping()
+
+ s = p.parsePad(s, PadBeforeSuffix)
+ s = p.parseAffix(s)
+ s = p.parsePad(s, PadAfterSuffix)
+ return s
+}
+
+func (p *parser) parsePad(s string, f PatternFlag) (tail string) {
+ if len(s) >= 2 && s[0] == '*' {
+ r, sz := utf8.DecodeRuneInString(s[1:])
+ if p.PadRune != 0 {
+ p.err = errMultiplePadSpecifiers
+ } else {
+ p.Flags |= f
+ p.PadRune = r
+ }
+ return s[1+sz:]
+ }
+ return s
+}
+
+func (p *parser) parseAffix(s string) string {
+ x := len(p.buf)
+ p.buf = append(p.buf, 0) // placeholder for affix length
+
+ s = p.parse(p.affix, s)
+
+ n := len(p.buf) - x - 1
+ if n > 0xFF {
+ p.setError(errAffixTooLarge)
+ }
+ p.buf[x] = uint8(n)
+ return s
+}
+
+// state implements a state transition. It returns the new state. A state
+// function may set an error on the parser or may simply return on an incorrect
+// token and let the next phase fail.
+type state func(r rune) state
+
+// parse repeatedly applies a state function on the given string until a
+// termination condition is reached.
+func (p *parser) parse(fn state, s string) (tail string) {
+ for i, r := range s {
+ p.doNotTerminate = false
+ if fn = fn(r); fn == nil || p.err != nil {
+ return s[i:]
+ }
+ p.FormatWidth++
+ }
+ if p.doNotTerminate {
+ p.setError(errUnexpectedEnd)
+ }
+ return ""
+}
+
+func (p *parser) affix(r rune) state {
+ switch r {
+ case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+ '#', '@', '.', '*', ',', ';':
+ return nil
+ case '\'':
+ p.FormatWidth--
+ return p.escapeFirst
+ case '%':
+ if p.DigitShift != 0 {
+ p.setError(errDuplicatePercentSign)
+ }
+ p.DigitShift = 2
+ case '\u2030': // ‰ Per mille
+ if p.DigitShift != 0 {
+ p.setError(errDuplicatePermilleSign)
+ }
+ p.DigitShift = 3
+ // TODO: handle currency somehow: ¤, ¤¤, ¤¤¤, ¤¤¤¤
+ }
+ p.buf = append(p.buf, string(r)...)
+ return p.affix
+}
+
+func (p *parser) escapeFirst(r rune) state {
+ switch r {
+ case '\'':
+ p.buf = append(p.buf, "\\'"...)
+ return p.affix
+ default:
+ p.buf = append(p.buf, '\'')
+ p.buf = append(p.buf, string(r)...)
+ }
+ return p.escape
+}
+
+func (p *parser) escape(r rune) state {
+ switch r {
+ case '\'':
+ p.FormatWidth--
+ p.buf = append(p.buf, '\'')
+ return p.affix
+ default:
+ p.buf = append(p.buf, string(r)...)
+ }
+ return p.escape
+}
+
+// number parses a number. The BNF says the integer part should always have
+// a '0', but that does not appear to be the case according to the rest of the
+// documentation. We will allow having only '#' numbers.
+func (p *parser) number(r rune) state {
+ switch r {
+ case '#':
+ p.groupingCount++
+ p.leadingSharps++
+ case '@':
+ p.groupingCount++
+ p.leadingSharps = 0
+ p.MaxFractionDigits = -1
+ return p.sigDigits(r)
+ case ',':
+ if p.leadingSharps == 0 { // no leading commas
+ return nil
+ }
+ p.updateGrouping()
+ case 'E':
+ p.MaxIntegerDigits = uint8(p.leadingSharps)
+ return p.exponent
+ case '.': // allow ".##" etc.
+ p.updateGrouping()
+ return p.fraction
+ case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+ return p.integer(r)
+ default:
+ return nil
+ }
+ return p.number
+}
+
+func (p *parser) integer(r rune) state {
+ if !('0' <= r && r <= '9') {
+ var next state
+ switch r {
+ case 'E':
+ if p.leadingSharps > 0 {
+ p.MaxIntegerDigits = uint8(p.leadingSharps) + p.MinIntegerDigits
+ }
+ next = p.exponent
+ case '.':
+ next = p.fraction
+ case ',':
+ next = p.integer
+ }
+ p.updateGrouping()
+ return next
+ }
+ p.Increment = p.Increment*10 + uint32(r-'0')
+ p.groupingCount++
+ p.MinIntegerDigits++
+ return p.integer
+}
+
+func (p *parser) sigDigits(r rune) state {
+ switch r {
+ case '@':
+ p.groupingCount++
+ p.MaxSignificantDigits++
+ p.MinSignificantDigits++
+ case '#':
+ return p.sigDigitsFinal(r)
+ case 'E':
+ p.updateGrouping()
+ return p.normalizeSigDigitsWithExponent()
+ default:
+ p.updateGrouping()
+ return nil
+ }
+ return p.sigDigits
+}
+
+func (p *parser) sigDigitsFinal(r rune) state {
+ switch r {
+ case '#':
+ p.groupingCount++
+ p.MaxSignificantDigits++
+ case 'E':
+ p.updateGrouping()
+ return p.normalizeSigDigitsWithExponent()
+ default:
+ p.updateGrouping()
+ return nil
+ }
+ return p.sigDigitsFinal
+}
+
+func (p *parser) normalizeSigDigitsWithExponent() state {
+ p.MinIntegerDigits, p.MaxIntegerDigits = 1, 1
+ p.MinFractionDigits = p.MinSignificantDigits - 1
+ p.MaxFractionDigits = p.MaxSignificantDigits - 1
+ p.MinSignificantDigits, p.MaxSignificantDigits = 0, 0
+ return p.exponent
+}
+
+func (p *parser) fraction(r rune) state {
+ switch r {
+ case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+ p.Increment = p.Increment*10 + uint32(r-'0')
+ p.IncrementScale++
+ p.MinFractionDigits++
+ p.MaxFractionDigits++
+ case '#':
+ p.MaxFractionDigits++
+ case 'E':
+ if p.leadingSharps > 0 {
+ p.MaxIntegerDigits = uint8(p.leadingSharps) + p.MinIntegerDigits
+ }
+ return p.exponent
+ default:
+ return nil
+ }
+ return p.fraction
+}
+
+func (p *parser) exponent(r rune) state {
+ switch r {
+ case '+':
+ // Set mode and check it wasn't already set.
+ if p.Flags&AlwaysExpSign != 0 || p.MinExponentDigits > 0 {
+ break
+ }
+ p.Flags |= AlwaysExpSign
+ p.doNotTerminate = true
+ return p.exponent
+ case '0':
+ p.MinExponentDigits++
+ return p.exponent
+ }
+ // termination condition
+ if p.MinExponentDigits == 0 {
+ p.setError(errors.New("format: need at least one digit"))
+ }
+ return nil
+}