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Diffstat (limited to 'src/pkg/unicode/letter.go')
-rw-r--r-- | src/pkg/unicode/letter.go | 326 |
1 files changed, 0 insertions, 326 deletions
diff --git a/src/pkg/unicode/letter.go b/src/pkg/unicode/letter.go deleted file mode 100644 index dbd8638ea..000000000 --- a/src/pkg/unicode/letter.go +++ /dev/null @@ -1,326 +0,0 @@ -// Copyright 2009 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 unicode provides data and functions to test some properties of -// Unicode code points. -package unicode - -const ( - MaxRune = 0x10FFFF // Maximum valid Unicode code point. - ReplacementChar = 0xFFFD // Represents invalid code points. - MaxASCII = 0x7F // maximum ASCII value. - MaxLatin1 = 0xFF // maximum Latin-1 value. -) - -// RangeTable defines a set of Unicode code points by listing the ranges of -// code points within the set. The ranges are listed in two slices -// to save space: a slice of 16-bit ranges and a slice of 32-bit ranges. -// The two slices must be in sorted order and non-overlapping. -// Also, R32 should contain only values >= 0x10000 (1<<16). -type RangeTable struct { - R16 []Range16 - R32 []Range32 -} - -// Range16 represents of a range of 16-bit Unicode code points. The range runs from Lo to Hi -// inclusive and has the specified stride. -type Range16 struct { - Lo uint16 - Hi uint16 - Stride uint16 -} - -// Range32 represents of a range of Unicode code points and is used when one or -// more of the values will not fit in 16 bits. The range runs from Lo to Hi -// inclusive and has the specified stride. Lo and Hi must always be >= 1<<16. -type Range32 struct { - Lo uint32 - Hi uint32 - Stride uint32 -} - -// CaseRange represents a range of Unicode code points for simple (one -// code point to one code point) case conversion. -// The range runs from Lo to Hi inclusive, with a fixed stride of 1. Deltas -// are the number to add to the code point to reach the code point for a -// different case for that character. They may be negative. If zero, it -// means the character is in the corresponding case. There is a special -// case representing sequences of alternating corresponding Upper and Lower -// pairs. It appears with a fixed Delta of -// {UpperLower, UpperLower, UpperLower} -// The constant UpperLower has an otherwise impossible delta value. -type CaseRange struct { - Lo uint32 - Hi uint32 - Delta d -} - -// SpecialCase represents language-specific case mappings such as Turkish. -// Methods of SpecialCase customize (by overriding) the standard mappings. -type SpecialCase []CaseRange - -//BUG(r): Provide a mechanism for full case folding (those that involve -// multiple runes in the input or output). - -// Indices into the Delta arrays inside CaseRanges for case mapping. -const ( - UpperCase = iota - LowerCase - TitleCase - MaxCase -) - -type d [MaxCase]int32 // to make the CaseRanges text shorter - -// If the Delta field of a CaseRange is UpperLower or LowerUpper, it means -// this CaseRange represents a sequence of the form (say) -// Upper Lower Upper Lower. -const ( - UpperLower = MaxRune + 1 // (Cannot be a valid delta.) -) - -// is16 uses binary search to test whether rune is in the specified slice of 16-bit ranges. -func is16(ranges []Range16, rune uint16) bool { - // binary search over ranges - lo := 0 - hi := len(ranges) - for lo < hi { - m := lo + (hi-lo)/2 - r := ranges[m] - if r.Lo <= rune && rune <= r.Hi { - return (rune-r.Lo)%r.Stride == 0 - } - if rune < r.Lo { - hi = m - } else { - lo = m + 1 - } - } - return false -} - -// is32 uses binary search to test whether rune is in the specified slice of 32-bit ranges. -func is32(ranges []Range32, rune uint32) bool { - // binary search over ranges - lo := 0 - hi := len(ranges) - for lo < hi { - m := lo + (hi-lo)/2 - r := ranges[m] - if r.Lo <= rune && rune <= r.Hi { - return (rune-r.Lo)%r.Stride == 0 - } - if rune < r.Lo { - hi = m - } else { - lo = m + 1 - } - } - return false -} - -// Is tests whether rune is in the specified table of ranges. -func Is(rangeTab *RangeTable, rune int) bool { - // common case: rune is ASCII or Latin-1. - if uint32(rune) <= MaxLatin1 { - // Only need to check R16, since R32 is always >= 1<<16. - r16 := uint16(rune) - for _, r := range rangeTab.R16 { - if r16 > r.Hi { - continue - } - if r16 < r.Lo { - return false - } - return (r16-r.Lo)%r.Stride == 0 - } - return false - } - r16 := rangeTab.R16 - if len(r16) > 0 && rune <= int(r16[len(r16)-1].Hi) { - return is16(r16, uint16(rune)) - } - r32 := rangeTab.R32 - if len(r32) > 0 && rune >= int(r32[0].Lo) { - return is32(r32, uint32(rune)) - } - return false -} - -// IsUpper reports whether the rune is an upper case letter. -func IsUpper(rune int) bool { - // See comment in IsGraphic. - if uint32(rune) <= MaxLatin1 { - return properties[uint8(rune)]&pLu != 0 - } - return Is(Upper, rune) -} - -// IsLower reports whether the rune is a lower case letter. -func IsLower(rune int) bool { - // See comment in IsGraphic. - if uint32(rune) <= MaxLatin1 { - return properties[uint8(rune)]&pLl != 0 - } - return Is(Lower, rune) -} - -// IsTitle reports whether the rune is a title case letter. -func IsTitle(rune int) bool { - if rune <= MaxLatin1 { - return false - } - return Is(Title, rune) -} - -// to maps the rune using the specified case mapping. -func to(_case int, rune int, caseRange []CaseRange) int { - if _case < 0 || MaxCase <= _case { - return ReplacementChar // as reasonable an error as any - } - // binary search over ranges - lo := 0 - hi := len(caseRange) - for lo < hi { - m := lo + (hi-lo)/2 - r := caseRange[m] - if int(r.Lo) <= rune && rune <= int(r.Hi) { - delta := int(r.Delta[_case]) - if delta > MaxRune { - // In an Upper-Lower sequence, which always starts with - // an UpperCase letter, the real deltas always look like: - // {0, 1, 0} UpperCase (Lower is next) - // {-1, 0, -1} LowerCase (Upper, Title are previous) - // The characters at even offsets from the beginning of the - // sequence are upper case; the ones at odd offsets are lower. - // The correct mapping can be done by clearing or setting the low - // bit in the sequence offset. - // The constants UpperCase and TitleCase are even while LowerCase - // is odd so we take the low bit from _case. - return int(r.Lo) + ((rune-int(r.Lo))&^1 | _case&1) - } - return rune + delta - } - if rune < int(r.Lo) { - hi = m - } else { - lo = m + 1 - } - } - return rune -} - -// To maps the rune to the specified case: UpperCase, LowerCase, or TitleCase. -func To(_case int, rune int) int { - return to(_case, rune, CaseRanges) -} - -// ToUpper maps the rune to upper case. -func ToUpper(rune int) int { - if rune <= MaxASCII { - if 'a' <= rune && rune <= 'z' { - rune -= 'a' - 'A' - } - return rune - } - return To(UpperCase, rune) -} - -// ToLower maps the rune to lower case. -func ToLower(rune int) int { - if rune <= MaxASCII { - if 'A' <= rune && rune <= 'Z' { - rune += 'a' - 'A' - } - return rune - } - return To(LowerCase, rune) -} - -// ToTitle maps the rune to title case. -func ToTitle(rune int) int { - if rune <= MaxASCII { - if 'a' <= rune && rune <= 'z' { // title case is upper case for ASCII - rune -= 'a' - 'A' - } - return rune - } - return To(TitleCase, rune) -} - -// ToUpper maps the rune to upper case giving priority to the special mapping. -func (special SpecialCase) ToUpper(rune int) int { - r := to(UpperCase, rune, []CaseRange(special)) - if r == rune { - r = ToUpper(rune) - } - return r -} - -// ToTitle maps the rune to title case giving priority to the special mapping. -func (special SpecialCase) ToTitle(rune int) int { - r := to(TitleCase, rune, []CaseRange(special)) - if r == rune { - r = ToTitle(rune) - } - return r -} - -// ToLower maps the rune to lower case giving priority to the special mapping. -func (special SpecialCase) ToLower(rune int) int { - r := to(LowerCase, rune, []CaseRange(special)) - if r == rune { - r = ToLower(rune) - } - return r -} - -// caseOrbit is defined in tables.go as []foldPair. Right now all the -// entries fit in uint16, so use uint16. If that changes, compilation -// will fail (the constants in the composite literal will not fit in uint16) -// and the types here can change to uint32. -type foldPair struct { - From uint16 - To uint16 -} - -// SimpleFold iterates over Unicode code points equivalent under -// the Unicode-defined simple case folding. Among the code points -// equivalent to rune (including rune itself), SimpleFold returns the -// smallest r >= rune if one exists, or else the smallest r >= 0. -// -// For example: -// SimpleFold('A') = 'a' -// SimpleFold('a') = 'A' -// -// SimpleFold('K') = 'k' -// SimpleFold('k') = '\u212A' (Kelvin symbol, K) -// SimpleFold('\u212A') = 'K' -// -// SimpleFold('1') = '1' -// -func SimpleFold(rune int) int { - // Consult caseOrbit table for special cases. - lo := 0 - hi := len(caseOrbit) - for lo < hi { - m := lo + (hi-lo)/2 - if int(caseOrbit[m].From) < rune { - lo = m + 1 - } else { - hi = m - } - } - if lo < len(caseOrbit) && int(caseOrbit[lo].From) == rune { - return int(caseOrbit[lo].To) - } - - // No folding specified. This is a one- or two-element - // equivalence class containing rune and ToLower(rune) - // and ToUpper(rune) if they are different from rune. - if l := ToLower(rune); l != rune { - return l - } - return ToUpper(rune) -} |