/*
* Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
*******************************************************************************
* Copyright (C) 1996-2011, International Business Machines Corporation and *
* others. All Rights Reserved. *
*******************************************************************************
*/
package sun.text.normalizer;
import java.io.IOException;
import java.util.Locale;
final class Utility {
Convert characters outside the range U+0020 to U+007F to
Unicode escapes, and convert backslash to a double backslash.
/**
* Convert characters outside the range U+0020 to U+007F to
* Unicode escapes, and convert backslash to a double backslash.
*/
public static final String escape(String s) {
StringBuilder buf = new StringBuilder();
for (int i=0; i<s.length(); ) {
int c = Character.codePointAt(s, i);
i += UTF16.getCharCount(c);
if (c >= ' ' && c <= 0x007F) {
if (c == '\\') {
buf.append("\\\\"); // That is, "\\"
} else {
buf.append((char)c);
}
} else {
boolean four = c <= 0xFFFF;
buf.append(four ? "\\u" : "\\U");
buf.append(hex(c, four ? 4 : 8));
}
}
return buf.toString();
}
/* This map must be in ASCENDING ORDER OF THE ESCAPE CODE */
private static final char[] UNESCAPE_MAP = {
/*" 0x22, 0x22 */
/*' 0x27, 0x27 */
/*? 0x3F, 0x3F */
/*\ 0x5C, 0x5C */
/*a*/ 0x61, 0x07,
/*b*/ 0x62, 0x08,
/*e*/ 0x65, 0x1b,
/*f*/ 0x66, 0x0c,
/*n*/ 0x6E, 0x0a,
/*r*/ 0x72, 0x0d,
/*t*/ 0x74, 0x09,
/*v*/ 0x76, 0x0b
};
Convert an escape to a 32-bit code point value. We attempt
to parallel the icu4c unescapeAt() function.
Params: - offset16 – an array containing offset to the character
after the backslash. Upon return offset16[0] will
be updated to point after the escape sequence.
Returns: character value from 0 to 10FFFF, or -1 on error.
/**
* Convert an escape to a 32-bit code point value. We attempt
* to parallel the icu4c unescapeAt() function.
* @param offset16 an array containing offset to the character
* <em>after</em> the backslash. Upon return offset16[0] will
* be updated to point after the escape sequence.
* @return character value from 0 to 10FFFF, or -1 on error.
*/
public static int unescapeAt(String s, int[] offset16) {
int c;
int result = 0;
int n = 0;
int minDig = 0;
int maxDig = 0;
int bitsPerDigit = 4;
int dig;
int i;
boolean braces = false;
/* Check that offset is in range */
int offset = offset16[0];
int length = s.length();
if (offset < 0 || offset >= length) {
return -1;
}
/* Fetch first UChar after '\\' */
c = Character.codePointAt(s, offset);
offset += UTF16.getCharCount(c);
/* Convert hexadecimal and octal escapes */
switch (c) {
case 'u':
minDig = maxDig = 4;
break;
case 'U':
minDig = maxDig = 8;
break;
case 'x':
minDig = 1;
if (offset < length && UTF16.charAt(s, offset) == 0x7B /*{*/) {
++offset;
braces = true;
maxDig = 8;
} else {
maxDig = 2;
}
break;
default:
dig = UCharacter.digit(c, 8);
if (dig >= 0) {
minDig = 1;
maxDig = 3;
n = 1; /* Already have first octal digit */
bitsPerDigit = 3;
result = dig;
}
break;
}
if (minDig != 0) {
while (offset < length && n < maxDig) {
c = UTF16.charAt(s, offset);
dig = UCharacter.digit(c, (bitsPerDigit == 3) ? 8 : 16);
if (dig < 0) {
break;
}
result = (result << bitsPerDigit) | dig;
offset += UTF16.getCharCount(c);
++n;
}
if (n < minDig) {
return -1;
}
if (braces) {
if (c != 0x7D /*}*/) {
return -1;
}
++offset;
}
if (result < 0 || result >= 0x110000) {
return -1;
}
// If an escape sequence specifies a lead surrogate, see
// if there is a trail surrogate after it, either as an
// escape or as a literal. If so, join them up into a
// supplementary.
if (offset < length &&
UTF16.isLeadSurrogate((char) result)) {
int ahead = offset+1;
c = s.charAt(offset); // [sic] get 16-bit code unit
if (c == '\\' && ahead < length) {
int o[] = new int[] { ahead };
c = unescapeAt(s, o);
ahead = o[0];
}
if (UTF16.isTrailSurrogate((char) c)) {
offset = ahead;
result = UCharacterProperty.getRawSupplementary(
(char) result, (char) c);
}
}
offset16[0] = offset;
return result;
}
/* Convert C-style escapes in table */
for (i=0; i<UNESCAPE_MAP.length; i+=2) {
if (c == UNESCAPE_MAP[i]) {
offset16[0] = offset;
return UNESCAPE_MAP[i+1];
} else if (c < UNESCAPE_MAP[i]) {
break;
}
}
/* Map \cX to control-X: X & 0x1F */
if (c == 'c' && offset < length) {
c = UTF16.charAt(s, offset);
offset16[0] = offset + UTF16.getCharCount(c);
return 0x1F & c;
}
/* If no special forms are recognized, then consider
* the backslash to generically escape the next character. */
offset16[0] = offset;
return c;
}
Supplies a zero-padded hex representation of an integer (without 0x)
/**
* Supplies a zero-padded hex representation of an integer (without 0x)
*/
public static String hex(long i, int places) {
if (i == Long.MIN_VALUE) return "-8000000000000000";
boolean negative = i < 0;
if (negative) {
i = -i;
}
String result = Long.toString(i, 16).toUpperCase(Locale.ENGLISH);
if (result.length() < places) {
result = "0000000000000000".substring(result.length(),places) + result;
}
if (negative) {
return '-' + result;
}
return result;
}
static final char DIGITS[] = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z'
};
Return true if the character is NOT printable ASCII. The tab,
newline and linefeed characters are considered unprintable.
/**
* Return true if the character is NOT printable ASCII. The tab,
* newline and linefeed characters are considered unprintable.
*/
public static boolean isUnprintable(int c) {
//0x20 = 32 and 0x7E = 126
return !(c >= 0x20 && c <= 0x7E);
}
Escape unprintable characters using uxxxx notation
for U+0000 to U+FFFF and Uxxxxxxxx for U+10000 and
above. If the character is printable ASCII, then do nothing
and return FALSE. Otherwise, append the escaped notation and
return TRUE.
/**
* Escape unprintable characters using <backslash>uxxxx notation
* for U+0000 to U+FFFF and <backslash>Uxxxxxxxx for U+10000 and
* above. If the character is printable ASCII, then do nothing
* and return FALSE. Otherwise, append the escaped notation and
* return TRUE.
*/
public static <T extends Appendable> boolean escapeUnprintable(T result, int c) {
try {
if (isUnprintable(c)) {
result.append('\\');
if ((c & ~0xFFFF) != 0) {
result.append('U');
result.append(DIGITS[0xF&(c>>28)]);
result.append(DIGITS[0xF&(c>>24)]);
result.append(DIGITS[0xF&(c>>20)]);
result.append(DIGITS[0xF&(c>>16)]);
} else {
result.append('u');
}
result.append(DIGITS[0xF&(c>>12)]);
result.append(DIGITS[0xF&(c>>8)]);
result.append(DIGITS[0xF&(c>>4)]);
result.append(DIGITS[0xF&c]);
return true;
}
return false;
} catch (IOException e) {
throw new IllegalArgumentException(e);
}
}
}