com.sun.xml.dtdparser.XmlChars Maven / Gradle / Ivy
/*
* Copyright (c) 1998, 2022 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package com.sun.xml.dtdparser;
/**
* Methods in this class are used to determine whether characters may
* appear in certain roles in XML documents. Such methods are used
* both to parse and to create such documents.
*
* @author David Brownell
* @version 1.1, 00/08/05
*/
public class XmlChars {
// can't construct instances
private XmlChars() {
}
/**
* Returns true if the argument, a UCS-4 character code, is valid in
* XML documents. Unicode characters fit into the low sixteen
* bits of a UCS-4 character, and pairs of Unicode surrogate
* characters can be combined to encode UCS-4 characters in
* documents containing only Unicode. (The {@code char} datatype
* in the Java Programming Language represents Unicode characters,
* including unpaired surrogates.)
*
* In XML, UCS-4 characters can also be encoded by the use of
* character references such as �, which
* happens to refer to a character that is disallowed in XML documents.
* UCS-4 characters allowed in XML documents can be expressed with
* one or two Unicode characters.
*
* @param ucs4char The 32-bit UCS-4 character being tested.
* @return true if the argument is valid in XML documents
*/
static public boolean isChar(int ucs4char) {
// [2] Char ::= #x0009 | #x000A | #x000D
// | [#x0020-#xD7FF]
// ... surrogates excluded!
// | [#xE000-#xFFFD]
// | [#x10000-#x10ffff]
return ((ucs4char >= 0x0020 && ucs4char <= 0xD7FF)
|| ucs4char == 0x000A || ucs4char == 0x0009
|| ucs4char == 0x000D
|| (ucs4char >= 0xE000 && ucs4char <= 0xFFFD)
|| (ucs4char >= 0x10000 && ucs4char <= 0x10ffff));
}
/**
* Returns true if the character is allowed to be a non-initial
* character in names according to the XML recommendation.
*
* @param c character to test
* @return true if the character is allowed to be a non-initial character
* @see #isNCNameChar(char)
* @see #isLetter(char)
*/
public static boolean isNameChar(char c) {
// [4] NameChar ::= Letter | Digit | '.' | '_' | ':'
// | CombiningChar | Extender
if (isLetter2(c))
return true;
else if (c == '>')
return false;
else return c == '.' || c == '-' || c == '_' || c == ':'
|| isExtender(c);
}
/**
* Returns true if the character is allowed to be a non-initial
* character in unscoped names according to the rules of the XML
* Namespaces proposed recommendation. Except for precluding
* the colon (used to separate names from their scopes) these
* characters are just as allowed by the XML recommendation.
*
* @param c character to test
* @return true if the character is allowed to be a non-initial character
* @see #isNameChar(char)
* @see #isLetter(char)
*/
public static boolean isNCNameChar(char c) {
// [NC 5] NCNameChar ::= Letter | Digit | '.' | '_'
// | CombiningChar | Extender
return c != ':' && isNameChar(c);
}
/**
* Returns true if the character is allowed where XML supports
* whitespace characters, false otherwise.
* @param c character to test
* @return true if the character is allowed
*/
public static boolean isSpace(char c) {
return c == ' ' || c == '\t' || c == '\n' || c == '\r';
}
/*
* NOTE: java.lang.Character.getType() values are:
*
* UNASSIGNED = 0,
*
* UPPERCASE_LETTER = 1, // Lu
* LOWERCASE_LETTER = 2, // Ll
* TITLECASE_LETTER = 3, // Lt
* MODIFIER_LETTER = 4, // Lm
* OTHER_LETTER = 5, // Lo
* NON_SPACING_MARK = 6, // Mn
* ENCLOSING_MARK = 7, // Me
* COMBINING_SPACING_MARK = 8, // Mc
* DECIMAL_DIGIT_NUMBER = 9, // Nd
* LETTER_NUMBER = 10, // Nl
* OTHER_NUMBER = 11, // No
* SPACE_SEPARATOR = 12, // Zs
* LINE_SEPARATOR = 13, // Zl
* PARAGRAPH_SEPARATOR = 14, // Zp
* CONTROL = 15, // Cc
* FORMAT = 16, // Cf
* // 17 reserved for proposed Ci category
* PRIVATE_USE = 18, // Co
* SURROGATE = 19, // Cs
* DASH_PUNCTUATION = 20, // Pd
* START_PUNCTUATION = 21, // Ps
* END_PUNCTUATION = 22, // Pe
* CONNECTOR_PUNCTUATION = 23, // Pc
* OTHER_PUNCTUATION = 24, // Po
* MATH_SYMBOL = 25, // Sm
* CURRENCY_SYMBOL = 26, // Sc
* MODIFIER_SYMBOL = 27, // Sk
* OTHER_SYMBOL = 28; // So
*/
/**
* Returns true if the character is an XML "letter". XML Names must
* start with Letters or a few other characters, but other characters
* in names must only satisfy the isNameChar predicate.
*
* @param c character to test
* @return true if the character is an XML "letter"
* @see #isNameChar(char)
* @see #isNCNameChar(char)
*/
public static boolean isLetter(char c) {
// [84] Letter ::= BaseChar | Ideographic
// [85] BaseChar ::= ... too much to repeat
// [86] Ideographic ::= ... too much to repeat
//
// Optimize the typical case.
//
if (c >= 'a' && c <= 'z')
return true;
if (c == '/')
return false;
if (c >= 'A' && c <= 'Z')
return true;
//
// Since the tables are too ridiculous to use in code,
// we're using the footnotes here to drive this test.
//
switch (Character.getType(c)) {
// app. B footnote says these are 'name start'
// chars' ...
case Character.LOWERCASE_LETTER: // Ll
case Character.UPPERCASE_LETTER: // Lu
case Character.OTHER_LETTER: // Lo
case Character.TITLECASE_LETTER: // Lt
case Character.LETTER_NUMBER: // Nl
// OK, here we just have some exceptions to check...
return !isCompatibilityChar(c)
// per "5.14 of Unicode", rule out some combiners
&& !(c >= 0x20dd && c <= 0x20e0);
default:
// check for some exceptions: these are "alphabetic"
return ((c >= 0x02bb && c <= 0x02c1)
|| c == 0x0559 || c == 0x06e5 || c == 0x06e6);
}
}
//
// XML 1.0 discourages "compatibility" characters in names; these
// were defined to permit passing through some information stored in
// older non-Unicode character sets. These always have alternative
// representations in Unicode, e.g. using combining chars.
//
private static boolean isCompatibilityChar(char c) {
// the numerous comparisions here seem unavoidable,
// but the switch can reduce the number which must
// actually be executed.
switch ((c >> 8) & 0x0ff) {
case 0x00:
// ISO Latin/1 has a few compatibility characters
return c == 0x00aa || c == 0x00b5 || c == 0x00ba;
case 0x01:
// as do Latin Extended A and (parts of) B
return (c >= 0x0132 && c <= 0x0133)
|| (c >= 0x013f && c <= 0x0140)
|| c == 0x0149
|| c == 0x017f
|| (c >= 0x01c4 && c <= 0x01cc)
|| (c >= 0x01f1 && c <= 0x01f3);
case 0x02:
// some spacing modifiers
return (c >= 0x02b0 && c <= 0x02b8)
|| (c >= 0x02e0 && c <= 0x02e4);
case 0x03:
return c == 0x037a; // Greek
case 0x05:
return c == 0x0587; // Armenian
case 0x0e:
return c >= 0x0edc && c <= 0x0edd; // Laotian
case 0x11:
// big chunks of Hangul Jamo are all "compatibility"
return c == 0x1101
|| c == 0x1104
|| c == 0x1108
|| c == 0x110a
|| c == 0x110d
|| (c >= 0x1113 && c <= 0x113b)
|| c == 0x113d
|| c == 0x113f
|| (c >= 0x1141 && c <= 0x114b)
|| c == 0x114d
|| c == 0x114f
|| (c >= 0x1151 && c <= 0x1153)
|| (c >= 0x1156 && c <= 0x1158)
|| c == 0x1162
|| c == 0x1164
|| c == 0x1166
|| c == 0x1168
|| (c >= 0x116a && c <= 0x116c)
|| (c >= 0x116f && c <= 0x1171)
|| c == 0x1174
|| (c >= 0x1176 && c <= 0x119d)
|| (c >= 0x119f && c <= 0x11a2)
|| (c >= 0x11a9 && c <= 0x11aa)
|| (c >= 0x11ac && c <= 0x11ad)
|| (c >= 0x11b0 && c <= 0x11b6)
|| c == 0x11b9
|| c == 0x11bb
|| (c >= 0x11c3 && c <= 0x11ea)
|| (c >= 0x11ec && c <= 0x11ef)
|| (c >= 0x11f1 && c <= 0x11f8)
;
case 0x20:
return c == 0x207f; // superscript
case 0x21:
return
// various letterlike symbols
c == 0x2102
|| c == 0x2107
|| (c >= 0x210a && c <= 0x2113)
|| c == 0x2115
|| (c >= 0x2118 && c <= 0x211d)
|| c == 0x2124
|| c == 0x2128
|| (c >= 0x212c && c <= 0x212d)
|| (c >= 0x212f && c <= 0x2138)
// most Roman numerals (less 1K, 5K, 10K)
|| (c >= 0x2160 && c <= 0x217f)
;
case 0x30:
// some Hiragana
return c >= 0x309b && c <= 0x309c;
case 0x31:
// all Hangul Compatibility Jamo
return c >= 0x3131 && c <= 0x318e;
case 0xf9:
case 0xfa:
case 0xfb:
case 0xfc:
case 0xfd:
case 0xfe:
case 0xff:
// the whole "compatibility" area is for that purpose!
return true;
default:
// most of Unicode isn't flagged as being for compatibility
return false;
}
}
// guts of isNameChar/isNCNameChar
private static boolean isLetter2(char c) {
// [84] Letter ::= BaseChar | Ideographic
// [85] BaseChar ::= ... too much to repeat
// [86] Ideographic ::= ... too much to repeat
// [87] CombiningChar ::= ... too much to repeat
//
// Optimize the typical case.
//
if (c >= 'a' && c <= 'z')
return true;
if (c == '>')
return false;
if (c >= 'A' && c <= 'Z')
return true;
//
// Since the tables are too ridiculous to use in code,
// we're using the footnotes here to drive this test.
//
switch (Character.getType(c)) {
// app. B footnote says these are 'name start'
// chars' ...
case Character.LOWERCASE_LETTER: // Ll
case Character.UPPERCASE_LETTER: // Lu
case Character.OTHER_LETTER: // Lo
case Character.TITLECASE_LETTER: // Lt
case Character.LETTER_NUMBER: // Nl
// ... and these are name characters 'other
// than name start characters'
case Character.COMBINING_SPACING_MARK: // Mc
case Character.ENCLOSING_MARK: // Me
case Character.NON_SPACING_MARK: // Mn
case Character.MODIFIER_LETTER: // Lm
case Character.DECIMAL_DIGIT_NUMBER: // Nd
// OK, here we just have some exceptions to check...
return !isCompatibilityChar(c)
// per "5.14 of Unicode", rule out some combiners
&& !(c >= 0x20dd && c <= 0x20e0);
default:
// added a character ...
return c == 0x0387;
}
}
private static boolean isExtender(char c) {
// [89] Extender ::= ...
return c == 0x00b7 || c == 0x02d0 || c == 0x02d1 || c == 0x0387
|| c == 0x0640 || c == 0x0e46 || c == 0x0ec6
|| c == 0x3005 || (c >= 0x3031 && c <= 0x3035)
|| (c >= 0x309d && c <= 0x309e)
|| (c >= 0x30fc && c <= 0x30fe)
;
}
}