suplib/src/FileID.m3


 Copyright 1997-2003 John D. Polstra.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgment:
 *      This product includes software developed by John D. Polstra.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 

MODULE FileID;

IMPORT
  DevT, FileAttr, FileAttrRep, Utypes, Word;

REVEAL
  T = BRANDED REF RECORD
    device: Utypes.dev_t;
    inode: Utypes.ino_t;
  END;

PROCEDURE FromAttr(fa: FileAttr.T): T =
  BEGIN
    IF NOT FileAttr.AttrType.Dev IN fa.mask
    OR NOT FileAttr.AttrType.Inode IN fa.mask THEN
      RETURN NIL;
    END;
    RETURN NEW(T, device := fa.stat.st_dev, inode := fa.stat.st_ino);
  END FromAttr;

PROCEDURE Equal(a, b: T): BOOLEAN =
  BEGIN
    RETURN a.inode = b.inode AND DevT.Equal(a.device, b.device);
  END Equal;

PROCEDURE Hash(fid: T): Word.T =
  BEGIN
    RETURN Word.Xor(DevT.Hash(fid.device), DevT.Hash(fid.inode));
  END Hash;

BEGIN
END FileID.

interface Utypes is in: