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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package ch.epfl.lamp.util;
public class Position {
//########################################################################
// Public Constants
/** Number of bits used to encode the file */
public static final int FILE_BITS = 6;
/** Number of bits used to encode the line number */
public static final int LINE_BITS = 16;
/** Number of bits used to encode the column number */
public static final int COLUMN_BITS = 32 - LINE_BITS - FILE_BITS;
/** Mask to decode the file */
public static final int FILE_MASK = (1 << FILE_BITS) - 1;
/** Mask to decode the line number */
public static final int LINE_MASK = (1 << LINE_BITS) - 1;
/** Mask to decode the column number */
public static final int COLUMN_MASK = (1 << COLUMN_BITS) - 1;
/** The undefined position */
public static final int NOPOS = 0;
/** The first position in a source file */
public static final int FIRSTPOS = encode(null, 1, 1);
//########################################################################
// Public Functions
/** Encodes a position into a single int. */
public static int encode(SourceFile file, int line, int column) {
int fileId = file == null ? 0 : file.id() & FILE_MASK;
if (fileId < 0 || FILE_MASK < fileId) fileId = 0;
if (line < 0 || LINE_MASK < line) line = 0;
if (column < 0 || COLUMN_MASK < column) column = 0;
return (((fileId << LINE_BITS) | line) << COLUMN_BITS) | column;
}
/** Returns the file of the encoded position. */
public static SourceFile file(int position) {
int fileId = (position >> (COLUMN_BITS + LINE_BITS)) & FILE_MASK;
return SourceFile.fromId(fileId);
}
/** Returns the line number of the encoded position. */
public static int line(int position) {
return (position >> COLUMN_BITS) & LINE_MASK;
}
/** Returns the column number of the encoded position. */
public static int column(int position) {
return position & COLUMN_MASK;
}
//########################################################################
// Private Fields
/** The position's file */
private final SourceFile file;
/** The position's line number */
private final int line;
/** The position's column number */
private final int column;
//########################################################################
// Public Constructors
/** Initializes a new instance. */
public Position(int position) {
this(file(position), line(position), column(position));
}
/** Initializes a new instance. */
public Position(String source) {
this(new SourceFile(source, new byte[0]));
}
/** Initializes a new instance. */
public Position(SourceFile file) {
this(file, 0, 0);
}
/** Initializes a new instance. */
public Position(SourceFile file, int line, int column) {
this.file = file;
this.line = line;
this.column = column;
}
//########################################################################
// Public Methods
/** Returns an int encoding this position. */
public int encode() {
return encode(file, line, column);
}
/** Returns the file of this position. */
public SourceFile file() {
return file;
}
/** Returns the line number of this position. */
public int line() {
return line;
}
/** Returns the column number of this position. */
public int column() {
return column;
}
/** Returns a string representation of this position. */
public String toString() {
return file.name() + ":" + line + ":" + column;
}
/** Returns the hash code of this position. */
public int hashCode() {
return encode();
}
/** Returns true iff the given object represents the same position. */
public boolean equals(Object object) {
if (!(object instanceof Position)) return false;
Position that = (Position)object;
return file == that.file && line == that.line && column == that.column;
}
//########################################################################
}
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