/*
* Copyright (c) 1999, 2006, 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
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*/
package com.sun.tools.javac.util;
import java.util.BitSet;
import static com.sun.tools.javac.util.LayoutCharacters.*;
/** A class that defines source code positions as simple character
* offsets from the beginning of the file. The first character
* is at position 0.
*
* Support is also provided for (line,column) coordinates, but tab
* expansion is optional and no Unicode excape translation is considered.
* The first character is at location (1,1).
*
* <p><b>This is NOT part of any supported API.
* If you write code that depends on this, you do so at your own risk.
* This code and its internal interfaces are subject to change or
* deletion without notice.</b>
*/
public class Position {
public static final int NOPOS = -1;
public static final int FIRSTPOS = 0;
public static final int FIRSTLINE = 1;
public static final int FIRSTCOLUMN = 1;
public static final int LINESHIFT = 10;
public static final int MAXCOLUMN = (1<<LINESHIFT) - 1;
public static final int MAXLINE = (1<<(Integer.SIZE-LINESHIFT)) - 1;
public static final int MAXPOS = Integer.MAX_VALUE;
/**
* This is class is not supposed to be instantiated.
*/
private Position() {}
/** A two-way map between line/column numbers and positions,
* derived from a scan done at creation time. Tab expansion is
* optionally supported via a character map. Text content
* is not retained.
*<p>
* Notes: The first character position FIRSTPOS is at
* (FIRSTLINE,FIRSTCOLUMN). No account is taken of Unicode escapes.
*
* @param src Source characters
* @param max Number of characters to read
* @param expandTabs If true, expand tabs when calculating columns
*/
public static LineMap makeLineMap(char[] src, int max, boolean expandTabs) {
LineMapImpl lineMap = expandTabs ?
new LineTabMapImpl(max) : new LineMapImpl();
lineMap.build(src, max);
return lineMap;
}
/** Encode line and column numbers in an integer as:
* line-number << LINESHIFT + column-number
* {@link Position.NOPOS represents an undefined position.
*
* @param line number of line (first is 1)
* @param col number of character on line (first is 1)
* @return an encoded position or {@link Position.NOPOS
* if the line or column number is too big to
* represent in the encoded format
* @throws IllegalArgumentException if line or col is less than 1
*/
public static int encodePosition(int line, int col) {
if (line < 1)
throw new IllegalArgumentException("line must be greater than 0");
if (col < 1)
throw new IllegalArgumentException("column must be greater than 0");
if (line > MAXLINE || col > MAXCOLUMN) {
return NOPOS;
}
return (line << LINESHIFT) + col;
}
public static interface LineMap extends com.sun.source.tree.LineMap {
/** Find the start position of a line.
*
* @param line number of line (first is 1)
* @return position of first character in line
* @throws ArrayIndexOutOfBoundsException
* if <tt>lineNumber < 1</tt>
* if <tt>lineNumber > no. of lines</tt>
*/
int getStartPosition(int line);
/** Find the position corresponding to a (line,column).
*
* @param line number of line (first is 1)
* @param column number of character on line (first is 1)
*
* @return position of character
* @throws ArrayIndexOutOfBoundsException
* if <tt>line < 1</tt>
* if <tt>line > no. of lines</tt>
*/
int getPosition(int line, int column);
/** Find the line containing a position; a line termination
* character is on the line it terminates.
*
* @param pos character offset of the position
* @return the line number on which pos occurs (first line is 1)
*/
int getLineNumber(int pos);
/** Find the column for a character position.
* Note: this method does not handle tab expansion.
* If tab expansion is needed, use a LineTabMap instead.
*
* @param pos character offset of the position
* @return the column number at which pos occurs
*/
int getColumnNumber(int pos);
}
static class LineMapImpl implements LineMap {
protected int[] startPosition; // start position of each line
protected LineMapImpl() {}
protected void build(char[] src, int max) {
int c = 0;
int i = 0;
int[] linebuf = new int[max];
while (i < max) {
linebuf[c++] = i;
do {
char ch = src[i];
if (ch == '\r' || ch == '\n') {
if (ch == '\r' && (i+1) < max && src[i+1] == '\n')
i += 2;
else
++i;
break;
}
else if (ch == '\t')
setTabPosition(i);
} while (++i < max);
}
this.startPosition = new int[c];
System.arraycopy(linebuf, 0, startPosition, 0, c);
}
public int getStartPosition(int line) {
return startPosition[line - FIRSTLINE];
}
public long getStartPosition(long line) {
return getStartPosition(longToInt(line));
}
public int getPosition(int line, int column) {
return startPosition[line - FIRSTLINE] + column - FIRSTCOLUMN;
}
public long getPosition(long line, long column) {
return getPosition(longToInt(line), longToInt(column));
}
// Cache of last line number lookup
private int lastPosition = Position.FIRSTPOS;
private int lastLine = Position.FIRSTLINE;
public int getLineNumber(int pos) {
if (pos == lastPosition) {
return lastLine;
}
lastPosition = pos;
int low = 0;
int high = startPosition.length-1;
while (low <= high) {
int mid = (low + high) >> 1;
int midVal = startPosition[mid];
if (midVal < pos)
low = mid + 1;
else if (midVal > pos)
high = mid - 1;
else {
lastLine = mid + 1; // pos is at beginning of this line
return lastLine;
}
}
lastLine = low;
return lastLine; // pos is on this line
}
public long getLineNumber(long pos) {
return getLineNumber(longToInt(pos));
}
public int getColumnNumber(int pos) {
return pos - startPosition[getLineNumber(pos) - FIRSTLINE] + FIRSTCOLUMN;
}
public long getColumnNumber(long pos) {
return getColumnNumber(longToInt(pos));
}
private static int longToInt(long longValue) {
int intValue = (int)longValue;
if (intValue != longValue)
throw new IndexOutOfBoundsException();
return intValue;
}
protected void setTabPosition(int offset) {}
}
/**
* A LineMap that handles tab expansion correctly. The cost is
* an additional bit per character in the source array.
*/
public static class LineTabMapImpl extends LineMapImpl {
private BitSet tabMap; // bits set for tab positions.
public LineTabMapImpl(int max) {
super();
tabMap = new BitSet(max);
}
protected void setTabPosition(int offset) {
tabMap.set(offset);
}
public int getColumnNumber(int pos) {
int lineStart = startPosition[getLineNumber(pos) - FIRSTLINE];
int column = 0;
for (int bp = lineStart; bp < pos; bp++) {
if (tabMap.get(bp))
column = (column / TabInc * TabInc) + TabInc;
else
column++;
}
return column + FIRSTCOLUMN;
}
public int getPosition(int line, int column) {
int pos = startPosition[line - FIRSTLINE];
column -= FIRSTCOLUMN;
int col = 0;
while (col < column) {
pos++;
if (tabMap.get(pos))
col = (col / TabInc * TabInc) + TabInc;
else
col++;
}
return pos;
}
}
}