libgo/go/unicode/graphic.go

   1 // Copyright 2011 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package unicode
   6
   7 // Bit masks for each code point under U+0100, for fast lookup.
   8 const (
   9         pC     = 1 << iota // a control character.
  10         pP                 // a punctuation character.
  11         pN                 // a numeral.
  12         pS                 // a symbolic character.
  13         pZ                 // a spacing character.
  14         pLu                // an upper-case letter.
  15         pLl                // a lower-case letter.
  16         pp                 // a printable character according to Go's definition.
  17         pg     = pp | pZ   // a graphical character according to the Unicode definition.
  18         pLo    = pLl | pLu // a letter that is neither upper nor lower case.
  19         pLmask = pLo
  20 )
  21
  22 // GraphicRanges defines the set of graphic characters according to Unicode.
  23 var GraphicRanges = []*RangeTable{
  24         L, M, N, P, S, Zs,
  25 }
  26
  27 // PrintRanges defines the set of printable characters according to Go.
  28 // ASCII space, U+0020, is handled separately.
  29 var PrintRanges = []*RangeTable{
  30         L, M, N, P, S,
  31 }
  32
  33 // IsGraphic reports whether the rune is defined as a Graphic by Unicode.
  34 // Such characters include letters, marks, numbers, punctuation, symbols, and
  35 // spaces, from categories L, M, N, P, S, Zs.
  36 func IsGraphic(r rune) bool {
  37         // We convert to uint32 to avoid the extra test for negative,
  38         // and in the index we convert to uint8 to avoid the range check.
  39         if uint32(r) <= MaxLatin1 {
  40                 return properties[uint8(r)]&pg != 0
  41         }
  42         return In(r, GraphicRanges...)
  43 }
  44
  45 // IsPrint reports whether the rune is defined as printable by Go. Such
  46 // characters include letters, marks, numbers, punctuation, symbols, and the
  47 // ASCII space character, from categories L, M, N, P, S and the ASCII space
  48 // character. This categorization is the same as IsGraphic except that the
  49 // only spacing character is ASCII space, U+0020.
  50 func IsPrint(r rune) bool {
  51         if uint32(r) <= MaxLatin1 {
  52                 return properties[uint8(r)]&pp != 0
  53         }
  54         return In(r, PrintRanges...)
  55 }
  56
  57 // IsOneOf reports whether the rune is a member of one of the ranges.
  58 // The function "In" provides a nicer signature and should be used in preference to IsOneOf.
  59 func IsOneOf(ranges []*RangeTable, r rune) bool {
  60         for _, inside := range ranges {
  61                 if Is(inside, r) {
  62                         return true
  63                 }
  64         }
  65         return false
  66 }
  67
  68 // In reports whether the rune is a member of one of the ranges.
  69 func In(r rune, ranges ...*RangeTable) bool {
  70         for _, inside := range ranges {
  71                 if Is(inside, r) {
  72                         return true
  73                 }
  74         }
  75         return false
  76 }
  77
  78 // IsControl reports whether the rune is a control character.
  79 // The C (Other) Unicode category includes more code points
  80 // such as surrogates; use Is(C, r) to test for them.
  81 func IsControl(r rune) bool {
  82         if uint32(r) <= MaxLatin1 {
  83                 return properties[uint8(r)]&pC != 0
  84         }
  85         // All control characters are < MaxLatin1.
  86         return false
  87 }
  88
  89 // IsLetter reports whether the rune is a letter (category L).
  90 func IsLetter(r rune) bool {
  91         if uint32(r) <= MaxLatin1 {
  92                 return properties[uint8(r)]&(pLmask) != 0
  93         }
  94         return isExcludingLatin(Letter, r)
  95 }
  96
  97 // IsMark reports whether the rune is a mark character (category M).
  98 func IsMark(r rune) bool {
  99         // There are no mark characters in Latin-1.
 100         return isExcludingLatin(Mark, r)
 101 }
 102
 103 // IsNumber reports whether the rune is a number (category N).
 104 func IsNumber(r rune) bool {
 105         if uint32(r) <= MaxLatin1 {
 106                 return properties[uint8(r)]&pN != 0
 107         }
 108         return isExcludingLatin(Number, r)
 109 }
 110
 111 // IsPunct reports whether the rune is a Unicode punctuation character
 112 // (category P).
 113 func IsPunct(r rune) bool {
 114         if uint32(r) <= MaxLatin1 {
 115                 return properties[uint8(r)]&pP != 0
 116         }
 117         return Is(Punct, r)
 118 }
 119
 120 // IsSpace reports whether the rune is a space character as defined
 121 // by Unicode's White Space property; in the Latin-1 space
 122 // this is
 123 //      '\t', '\n', '\v', '\f', '\r', ' ', U+0085 (NEL), U+00A0 (NBSP).
 124 // Other definitions of spacing characters are set by category
 125 // Z and property Pattern_White_Space.
 126 func IsSpace(r rune) bool {
 127         // This property isn't the same as Z; special-case it.
 128         if uint32(r) <= MaxLatin1 {
 129                 switch r {
 130                 case '\t', '\n', '\v', '\f', '\r', ' ', 0x85, 0xA0:
 131                         return true
 132                 }
 133                 return false
 134         }
 135         return isExcludingLatin(White_Space, r)
 136 }
 137
 138 // IsSymbol reports whether the rune is a symbolic character.
 139 func IsSymbol(r rune) bool {
 140         if uint32(r) <= MaxLatin1 {
 141                 return properties[uint8(r)]&pS != 0
 142         }
 143         return isExcludingLatin(Symbol, r)
 144 }