/*
* Copyright 2008-2009 Sun Microsystems, Inc. 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.
*
* 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package org.visage.tools.antlr;
import com.sun.tools.mjavac.util.Log;
import org.visage.tools.util.MsgSym;
/**
* Convert escapes in string literals
*
* @author Robert Field
*
* Stolen liberally from the javac Scanner
*/
public class StringLiteralProcessor {
private final int basepos;
/** A character buffer for literals.
*/
private char[] sbuf;
private int sp;
/** The input buffer, index of next chacter to be read,
* index of one past last character in buffer.
*/
private final char[] buf;
private int bp;
private final int buflen;
/** The current character.
*/
private char ch;
/** The buffer index of the last converted unicode character
*/
private int unicodeConversionBp = -1;
/** The log to be used for error reporting.
*/
private final Log log;
public static String convert(Log log, int pos, String str) {
StringLiteralProcessor slp = new StringLiteralProcessor(log, pos, str);
return slp.convert();
}
private StringLiteralProcessor(Log log, int pos, String str) {
this.log = log;
this.basepos = pos;
this.buf = str.toCharArray();
this.buflen = buf.length - 1; // skip trailing quote
this.bp = 0; // scanChar pre-increments so we skip the leading quote
this.sbuf = new char[buflen];
this.sp = 0;
}
private String convert() {
scanChar();
while (bp < buflen) {
scanLitChar();
}
return new String(sbuf, 0, sp);
}
/** Report an error at the given position using the provided arguments.
*/
private void lexError(String key, Object... args) {
log.error(basepos+bp-1-buflen, key, args);
}
/** Convert an ASCII digit from its base (8, 10, or 16)
* to its value.
*/
private int digit(int base) {
char c = ch;
int result = Character.digit(c, base);
if (result >= 0 && c > 0x7f) {
lexError(MsgSym.MESSAGE_ILLEGAL_NONASCII_DIGIT);
ch = "0123456789abcdef".charAt(result);
}
return result;
}
/** Append a character to sbuf.
*/
private void putChar(char ch) {
if (sp == sbuf.length) {
char[] newsbuf = new char[sbuf.length * 2];
System.arraycopy(sbuf, 0, newsbuf, 0, sbuf.length);
sbuf = newsbuf;
}
sbuf[sp++] = ch;
}
/** Convert unicode escape; bp points to initial '\' character
* (Spec 3.3).
*/
private void convertUnicode() {
if (ch == '\\' && unicodeConversionBp != bp) {
bp++; ch = buf[bp];
if (ch == 'u') {
do {
bp++; ch = buf[bp];
} while (ch == 'u');
int limit = bp + 3;
if (limit < buflen) {
int d = digit(16);
int code = d;
while (bp < limit && d >= 0) {
bp++; ch = buf[bp];
d = digit(16);
code = (code << 4) + d;
}
if (d >= 0) {
ch = (char)code;
unicodeConversionBp = bp;
return;
}
}
lexError(MsgSym.MESSAGE_ILLEGAL_UNICODE_ESC);
} else {
bp--;
ch = '\\';
}
}
}
/** Read next character.
*/
private void scanChar() {
ch = buf[++bp];
if (ch == '\\') {
convertUnicode();
}
}
/** Read next character in character or string literal and copy into sbuf.
*/
private void scanLitChar() {
if (ch == '\\') {
if (buf[bp+1] == '\\' && unicodeConversionBp != bp) {
bp++;
putChar('\\');
scanChar();
} else {
scanChar();
switch (ch) {
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
char leadch = ch;
int oct = digit(8);
scanChar();
if ('0' <= ch && ch <= '7') {
oct = oct * 8 + digit(8);
scanChar();
if (leadch <= '3' && '0' <= ch && ch <= '7') {
oct = oct * 8 + digit(8);
scanChar();
}
}
putChar((char)oct);
break;
case 'b':
putChar('\b'); scanChar(); break;
case 't':
putChar('\t'); scanChar(); break;
case 'n':
putChar('\n'); scanChar(); break;
case 'f':
putChar('\f'); scanChar(); break;
case 'r':
putChar('\r'); scanChar(); break;
case '\'':
putChar('\''); scanChar(); break;
case '\"':
putChar('\"'); scanChar(); break;
case '{':
putChar('{'); scanChar(); break;
case '}':
putChar('}'); scanChar(); break;
case '\\':
putChar('\\'); scanChar(); break;
default:
lexError(MsgSym.MESSAGE_ILLEGAL_ESC_CHAR);
}
}
} else if (bp != buflen) {
putChar(ch); scanChar();
}
}
}