VictoriaMetrics/vendor/github.com/rivo/uniseg/wordrules.go
2024-02-01 17:10:39 +02:00

282 lines
8.2 KiB
Go

package uniseg
import "unicode/utf8"
// The states of the word break parser.
const (
wbAny = iota
wbCR
wbLF
wbNewline
wbWSegSpace
wbHebrewLetter
wbALetter
wbWB7
wbWB7c
wbNumeric
wbWB11
wbKatakana
wbExtendNumLet
wbOddRI
wbEvenRI
wbZWJBit = 16 // This bit is set for any states followed by at least one zero-width joiner (see WB4 and WB3c).
)
// wbTransitions implements the word break parser's state transitions. It's
// anologous to [grTransitions], see comments there for details.
//
// Unicode version 15.0.0.
func wbTransitions(state, prop int) (newState int, wordBreak bool, rule int) {
switch uint64(state) | uint64(prop)<<32 {
// WB3b.
case wbAny | prNewline<<32:
return wbNewline, true, 32
case wbAny | prCR<<32:
return wbCR, true, 32
case wbAny | prLF<<32:
return wbLF, true, 32
// WB3a.
case wbNewline | prAny<<32:
return wbAny, true, 31
case wbCR | prAny<<32:
return wbAny, true, 31
case wbLF | prAny<<32:
return wbAny, true, 31
// WB3.
case wbCR | prLF<<32:
return wbLF, false, 30
// WB3d.
case wbAny | prWSegSpace<<32:
return wbWSegSpace, true, 9990
case wbWSegSpace | prWSegSpace<<32:
return wbWSegSpace, false, 34
// WB5.
case wbAny | prALetter<<32:
return wbALetter, true, 9990
case wbAny | prHebrewLetter<<32:
return wbHebrewLetter, true, 9990
case wbALetter | prALetter<<32:
return wbALetter, false, 50
case wbALetter | prHebrewLetter<<32:
return wbHebrewLetter, false, 50
case wbHebrewLetter | prALetter<<32:
return wbALetter, false, 50
case wbHebrewLetter | prHebrewLetter<<32:
return wbHebrewLetter, false, 50
// WB7. Transitions to wbWB7 handled by transitionWordBreakState().
case wbWB7 | prALetter<<32:
return wbALetter, false, 70
case wbWB7 | prHebrewLetter<<32:
return wbHebrewLetter, false, 70
// WB7a.
case wbHebrewLetter | prSingleQuote<<32:
return wbAny, false, 71
// WB7c. Transitions to wbWB7c handled by transitionWordBreakState().
case wbWB7c | prHebrewLetter<<32:
return wbHebrewLetter, false, 73
// WB8.
case wbAny | prNumeric<<32:
return wbNumeric, true, 9990
case wbNumeric | prNumeric<<32:
return wbNumeric, false, 80
// WB9.
case wbALetter | prNumeric<<32:
return wbNumeric, false, 90
case wbHebrewLetter | prNumeric<<32:
return wbNumeric, false, 90
// WB10.
case wbNumeric | prALetter<<32:
return wbALetter, false, 100
case wbNumeric | prHebrewLetter<<32:
return wbHebrewLetter, false, 100
// WB11. Transitions to wbWB11 handled by transitionWordBreakState().
case wbWB11 | prNumeric<<32:
return wbNumeric, false, 110
// WB13.
case wbAny | prKatakana<<32:
return wbKatakana, true, 9990
case wbKatakana | prKatakana<<32:
return wbKatakana, false, 130
// WB13a.
case wbAny | prExtendNumLet<<32:
return wbExtendNumLet, true, 9990
case wbALetter | prExtendNumLet<<32:
return wbExtendNumLet, false, 131
case wbHebrewLetter | prExtendNumLet<<32:
return wbExtendNumLet, false, 131
case wbNumeric | prExtendNumLet<<32:
return wbExtendNumLet, false, 131
case wbKatakana | prExtendNumLet<<32:
return wbExtendNumLet, false, 131
case wbExtendNumLet | prExtendNumLet<<32:
return wbExtendNumLet, false, 131
// WB13b.
case wbExtendNumLet | prALetter<<32:
return wbALetter, false, 132
case wbExtendNumLet | prHebrewLetter<<32:
return wbHebrewLetter, false, 132
case wbExtendNumLet | prNumeric<<32:
return wbNumeric, false, 132
case wbExtendNumLet | prKatakana<<32:
return wbKatakana, false, 132
default:
return -1, false, -1
}
}
// transitionWordBreakState determines the new state of the word break parser
// given the current state and the next code point. It also returns whether a
// word boundary was detected. If more than one code point is needed to
// determine the new state, the byte slice or the string starting after rune "r"
// can be used (whichever is not nil or empty) for further lookups.
func transitionWordBreakState(state int, r rune, b []byte, str string) (newState int, wordBreak bool) {
// Determine the property of the next character.
nextProperty := property(workBreakCodePoints, r)
// "Replacing Ignore Rules".
if nextProperty == prZWJ {
// WB4 (for zero-width joiners).
if state == wbNewline || state == wbCR || state == wbLF {
return wbAny | wbZWJBit, true // Make sure we don't apply WB4 to WB3a.
}
if state < 0 {
return wbAny | wbZWJBit, false
}
return state | wbZWJBit, false
} else if nextProperty == prExtend || nextProperty == prFormat {
// WB4 (for Extend and Format).
if state == wbNewline || state == wbCR || state == wbLF {
return wbAny, true // Make sure we don't apply WB4 to WB3a.
}
if state == wbWSegSpace || state == wbAny|wbZWJBit {
return wbAny, false // We don't break but this is also not WB3d or WB3c.
}
if state < 0 {
return wbAny, false
}
return state, false
} else if nextProperty == prExtendedPictographic && state >= 0 && state&wbZWJBit != 0 {
// WB3c.
return wbAny, false
}
if state >= 0 {
state = state &^ wbZWJBit
}
// Find the applicable transition in the table.
var rule int
newState, wordBreak, rule = wbTransitions(state, nextProperty)
if newState < 0 {
// No specific transition found. Try the less specific ones.
anyPropState, anyPropWordBreak, anyPropRule := wbTransitions(state, prAny)
anyStateState, anyStateWordBreak, anyStateRule := wbTransitions(wbAny, nextProperty)
if anyPropState >= 0 && anyStateState >= 0 {
// Both apply. We'll use a mix (see comments for grTransitions).
newState, wordBreak, rule = anyStateState, anyStateWordBreak, anyStateRule
if anyPropRule < anyStateRule {
wordBreak, rule = anyPropWordBreak, anyPropRule
}
} else if anyPropState >= 0 {
// We only have a specific state.
newState, wordBreak, rule = anyPropState, anyPropWordBreak, anyPropRule
// This branch will probably never be reached because okAnyState will
// always be true given the current transition map. But we keep it here
// for future modifications to the transition map where this may not be
// true anymore.
} else if anyStateState >= 0 {
// We only have a specific property.
newState, wordBreak, rule = anyStateState, anyStateWordBreak, anyStateRule
} else {
// No known transition. WB999: Any ÷ Any.
newState, wordBreak, rule = wbAny, true, 9990
}
}
// For those rules that need to look up runes further in the string, we
// determine the property after nextProperty, skipping over Format, Extend,
// and ZWJ (according to WB4). It's -1 if not needed, if such a rune cannot
// be determined (because the text ends or the rune is faulty).
farProperty := -1
if rule > 60 &&
(state == wbALetter || state == wbHebrewLetter || state == wbNumeric) &&
(nextProperty == prMidLetter || nextProperty == prMidNumLet || nextProperty == prSingleQuote || // WB6.
nextProperty == prDoubleQuote || // WB7b.
nextProperty == prMidNum) { // WB12.
for {
var (
r rune
length int
)
if b != nil { // Byte slice version.
r, length = utf8.DecodeRune(b)
b = b[length:]
} else { // String version.
r, length = utf8.DecodeRuneInString(str)
str = str[length:]
}
if r == utf8.RuneError {
break
}
prop := property(workBreakCodePoints, r)
if prop == prExtend || prop == prFormat || prop == prZWJ {
continue
}
farProperty = prop
break
}
}
// WB6.
if rule > 60 &&
(state == wbALetter || state == wbHebrewLetter) &&
(nextProperty == prMidLetter || nextProperty == prMidNumLet || nextProperty == prSingleQuote) &&
(farProperty == prALetter || farProperty == prHebrewLetter) {
return wbWB7, false
}
// WB7b.
if rule > 72 &&
state == wbHebrewLetter &&
nextProperty == prDoubleQuote &&
farProperty == prHebrewLetter {
return wbWB7c, false
}
// WB12.
if rule > 120 &&
state == wbNumeric &&
(nextProperty == prMidNum || nextProperty == prMidNumLet || nextProperty == prSingleQuote) &&
farProperty == prNumeric {
return wbWB11, false
}
// WB15 and WB16.
if newState == wbAny && nextProperty == prRegionalIndicator {
if state != wbOddRI && state != wbEvenRI { // Includes state == -1.
// Transition into the first RI.
return wbOddRI, true
}
if state == wbOddRI {
// Don't break pairs of Regional Indicators.
return wbEvenRI, false
}
return wbOddRI, true // We can break after a pair.
}
return
}