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| 1 | +package scala.internal |
| 2 | + |
| 3 | +import scala.annotation.switch |
| 4 | +import java.lang.{Character => JCharacter} |
| 5 | +import java.lang.Character.LETTER_NUMBER |
| 6 | +import java.lang.Character.LOWERCASE_LETTER |
| 7 | +import java.lang.Character.OTHER_LETTER |
| 8 | +import java.lang.Character.TITLECASE_LETTER |
| 9 | +import java.lang.Character.UPPERCASE_LETTER |
| 10 | + |
| 11 | +/** Contains constants and classifier methods for characters */ |
| 12 | +object Chars { |
| 13 | + |
| 14 | + final val LF = '\u000A' |
| 15 | + final val FF = '\u000C' |
| 16 | + final val CR = '\u000D' |
| 17 | + final val SU = '\u001A' |
| 18 | + |
| 19 | + /** Convert a character digit to an Int according to given base, |
| 20 | + * -1 if no success |
| 21 | + */ |
| 22 | + def digit2int(ch: Char, base: Int): Int = { |
| 23 | + val num = ( |
| 24 | + if (ch <= '9') ch - '0' |
| 25 | + else if ('a' <= ch && ch <= 'z') ch - 'a' + 10 |
| 26 | + else if ('A' <= ch && ch <= 'Z') ch - 'A' + 10 |
| 27 | + else -1 |
| 28 | + ) |
| 29 | + if (0 <= num && num < base) num else -1 |
| 30 | + } |
| 31 | + /** Buffer for creating '\ u XXXX' strings. */ |
| 32 | + private[this] val char2uescapeArray = Array[Char]('\\', 'u', 0, 0, 0, 0) |
| 33 | + |
| 34 | + /** Convert a character to a backslash-u escape */ |
| 35 | + def char2uescape(c: Char): String = { |
| 36 | + @forceInline def hexChar(ch: Int): Char = |
| 37 | + (( if (ch < 10) '0' else 'A' - 10 ) + ch).toChar |
| 38 | + |
| 39 | + char2uescapeArray(2) = hexChar((c >> 12) ) |
| 40 | + char2uescapeArray(3) = hexChar((c >> 8) % 16) |
| 41 | + char2uescapeArray(4) = hexChar((c >> 4) % 16) |
| 42 | + char2uescapeArray(5) = hexChar((c ) % 16) |
| 43 | + |
| 44 | + new String(char2uescapeArray) |
| 45 | + } |
| 46 | + |
| 47 | + /** Is character a line break? */ |
| 48 | + def isLineBreakChar(c: Char): Boolean = (c: @switch) match { |
| 49 | + case LF|FF|CR|SU => true |
| 50 | + case _ => false |
| 51 | + } |
| 52 | + |
| 53 | + /** Is character a whitespace character (but not a new line)? */ |
| 54 | + def isWhitespace(c: Char): Boolean = |
| 55 | + c == ' ' || c == '\t' || c == CR |
| 56 | + |
| 57 | + /** Can character form part of a doc comment variable $xxx? */ |
| 58 | + def isVarPart(c: Char): Boolean = |
| 59 | + '0' <= c && c <= '9' || 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z' |
| 60 | + |
| 61 | + /** Can character start an alphanumeric Scala identifier? */ |
| 62 | + def isIdentifierStart(c: Char): Boolean = |
| 63 | + (c == '_') || (c == '$') || JCharacter.isUnicodeIdentifierStart(c) |
| 64 | + |
| 65 | + /** Can character form part of an alphanumeric Scala identifier? */ |
| 66 | + def isIdentifierPart(c: Char): Boolean = |
| 67 | + (c == '$') || JCharacter.isUnicodeIdentifierPart(c) |
| 68 | + |
| 69 | + /** Is character a math or other symbol in Unicode? */ |
| 70 | + def isSpecial(c: Char): Boolean = { |
| 71 | + val chtp = JCharacter.getType(c) |
| 72 | + chtp == JCharacter.MATH_SYMBOL.toInt || chtp == JCharacter.OTHER_SYMBOL.toInt |
| 73 | + } |
| 74 | + |
| 75 | + def isValidJVMChar(c: Char): Boolean = |
| 76 | + !(c == '.' || c == ';' || c =='[' || c == '/') |
| 77 | + |
| 78 | + def isValidJVMMethodChar(c: Char): Boolean = |
| 79 | + !(c == '.' || c == ';' || c =='[' || c == '/' || c == '<' || c == '>') |
| 80 | + |
| 81 | + private final val otherLetters = Set[Char]('\u0024', '\u005F') // '$' and '_' |
| 82 | + private final val letterGroups = { |
| 83 | + import JCharacter._ |
| 84 | + Set[Byte](LOWERCASE_LETTER, UPPERCASE_LETTER, OTHER_LETTER, TITLECASE_LETTER, LETTER_NUMBER) |
| 85 | + } |
| 86 | + def isScalaLetter(ch: Char): Boolean = letterGroups(JCharacter.getType(ch).toByte) || otherLetters(ch) |
| 87 | + |
| 88 | + /** Can character form part of a Scala operator name? */ |
| 89 | + def isOperatorPart(c : Char) : Boolean = (c: @switch) match { |
| 90 | + case '~' | '!' | '@' | '#' | '%' | |
| 91 | + '^' | '*' | '+' | '-' | '<' | |
| 92 | + '>' | '?' | ':' | '=' | '&' | |
| 93 | + '|' | '/' | '\\' => true |
| 94 | + case c => isSpecial(c) |
| 95 | + } |
| 96 | +} |
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