/jEdit/tags/jedit-4-2-pre4/gnu/regexp/CharIndexedInputStream.java
Java | 131 lines | 87 code | 18 blank | 26 comment | 32 complexity | 3f8476adc37a8bdbf2999fc0114fee3b MD5 | raw file
Possible License(s): BSD-3-Clause, AGPL-1.0, Apache-2.0, LGPL-2.0, LGPL-3.0, GPL-2.0, CC-BY-SA-3.0, LGPL-2.1, GPL-3.0, MPL-2.0-no-copyleft-exception, IPL-1.0
- /*
- * gnu/regexp/CharIndexedReader.java
- * Copyright (C) 1998-2001 Wes Biggs
- *
- * This library is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published
- * by the Free Software Foundation; either version 2.1 of the License, or
- * (at your option) any later version.
- *
- * This library 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 Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
- package gnu.regexp;
- import java.io.InputStream;
- import java.io.BufferedInputStream;
- import java.io.IOException;
- // TODO: move(x) shouldn't rely on calling next() x times
- class CharIndexedInputStream implements CharIndexed {
- private static final int BUFFER_INCREMENT = 1024;
- private static final int UNKNOWN = Integer.MAX_VALUE; // value for end
-
- private BufferedInputStream br;
- // so that we don't try to reset() right away
- private int index = -1;
- private int bufsize = BUFFER_INCREMENT;
- private int end = UNKNOWN;
- private char cached = OUT_OF_BOUNDS;
- // Big enough for a \r\n pair
- // lookBehind[0] = most recent
- // lookBehind[1] = second most recent
- private char[] lookBehind = new char[] { OUT_OF_BOUNDS, OUT_OF_BOUNDS };
-
- CharIndexedInputStream(InputStream str, int index) {
- if (str instanceof BufferedInputStream) br = (BufferedInputStream) str;
- else br = new BufferedInputStream(str,BUFFER_INCREMENT);
- next();
- if (index > 0) move(index);
- }
-
- private boolean next() {
- if (end == 1) return false;
- end--; // closer to end
- try {
- if (index != -1) {
- br.reset();
- }
- int i = br.read();
- br.mark(bufsize);
- if (i == -1) {
- end = 1;
- cached = OUT_OF_BOUNDS;
- return false;
- }
- cached = (char) i;
- index = 1;
- } catch (IOException e) {
- e.printStackTrace();
- cached = OUT_OF_BOUNDS;
- return false;
- }
- return true;
- }
-
- public char charAt(int index) {
- if (index == 0) {
- return cached;
- } else if (index >= end) {
- return OUT_OF_BOUNDS;
- } else if (index == -1) {
- return lookBehind[0];
- } else if (index == -2) {
- return lookBehind[1];
- } else if (index < -2) {
- return OUT_OF_BOUNDS;
- } else if (index >= bufsize) {
- // Allocate more space in the buffer.
- try {
- while (bufsize <= index) bufsize += BUFFER_INCREMENT;
- br.reset();
- br.mark(bufsize);
- br.skip(index-1);
- } catch (IOException e) { }
- } else if (this.index != index) {
- try {
- br.reset();
- br.skip(index-1);
- } catch (IOException e) { }
- }
- char ch = OUT_OF_BOUNDS;
-
- try {
- int i = br.read();
- this.index = index+1; // this.index is index of next pos relative to charAt(0)
- if (i == -1) {
- // set flag that next should fail next time?
- end = index;
- return ch;
- }
- ch = (char) i;
- } catch (IOException ie) { }
-
- return ch;
- }
-
- public boolean move(int index) {
- // move read position [index] clicks from 'charAt(0)'
- boolean retval = true;
- while (retval && (index-- > 0)) retval = next();
- return retval;
- }
-
- public boolean isValid() {
- return (cached != OUT_OF_BOUNDS);
- }
- }