| /* gnu/regexp/CharIndexedInputStream.java |
| Copyright (C) 1998-2001, 2004, 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.java.util.regex; |
| import java.io.BufferedInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| // 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); |
| } |
| |
| public CharIndexed lookBehind(int index, int length) { |
| throw new UnsupportedOperationException( |
| "difficult to look behind for an input stream"); |
| } |
| |
| public int length() { |
| throw new UnsupportedOperationException( |
| "difficult to tell the length for an input stream"); |
| } |
| |
| public void setLastMatch(REMatch match) { |
| throw new UnsupportedOperationException( |
| "difficult to support setLastMatch for an input stream"); |
| } |
| |
| public REMatch getLastMatch() { |
| throw new UnsupportedOperationException( |
| "difficult to support getLastMatch for an input stream"); |
| } |
| |
| public int getAnchor() { |
| throw new UnsupportedOperationException( |
| "difficult to support getAnchor for an input stream"); |
| } |
| |
| public void setAnchor(int anchor) { |
| throw new UnsupportedOperationException( |
| "difficult to support setAnchor for an input stream"); |
| } |
| |
| |
| } |
| |