systems.h

这是一个mp3的源代码

/* systems.h - Most of the system dependant code and defines are here. */

/*  This file is part of GDBM, the GNU data base manager, by Philip A. Nelson.
    Copyright (C) 1990, 1991, 1993  Free Software Foundation, Inc.

    GDBM 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.

    GDBM 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 GDBM; see the file COPYING.  If not, write to
    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

    You may contact the author by:
       e-mail:  [e-mail]
      us-mail:  Philip A. Nelson
                Computer Science Department
                Western Washington University
                Bellingham, WA 98226
       
*************************************************************************/


/* Include all system headers first. */
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#include <stdio.h>
#if HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#include <sys/stat.h>
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif

#if WIN32
#include <windows.h>
#endif

#ifndef SEEK_SET
#define SEEK_SET        0
#endif

#ifndef L_SET
#define L_SET SEEK_SET
#endif

/* Do we have flock?  (BSD...) */

#if HAVE_FLOCK

#ifndef LOCK_SH
#define LOCK_SH	1
#endif

#ifndef LOCK_EX
#define LOCK_EX	2
#endif

#ifndef LOCK_NB
#define LOCK_NB 4
#endif

#ifndef LOCK_UN
#define LOCK_UN 8
#endif

#define UNLOCK_FILE(dbf) flock (dbf->desc, LOCK_UN)
#define READLOCK_FILE(dbf) lock_val = flock (dbf->desc, LOCK_SH + LOCK_NB)
#define WRITELOCK_FILE(dbf) lock_val = flock (dbf->desc, LOCK_EX + LOCK_NB)

#else
#ifndef WIN32

/* Assume it is done like System V. */

#define UNLOCK_FILE(dbf) \
	{					\
	  struct flock flock;			\
	  flock.l_type = F_UNLCK;		\
	  flock.l_whence = SEEK_SET;		\
	  flock.l_start = flock.l_len = 0L;	\
	  fcntl (dbf->desc, F_SETLK, &flock);	\
	}
#define READLOCK_FILE(dbf) \
	{					\
	  struct flock flock;			\
	  flock.l_type = F_RDLCK;		\
	  flock.l_whence = SEEK_SET;			\
	  flock.l_start = flock.l_len = 0L;	\
	  lock_val = fcntl (dbf->desc, F_SETLK, &flock);	\
	}
#define WRITELOCK_FILE(dbf) \
	{					\
	  struct flock flock;			\
	  flock.l_type = F_WRLCK;		\
	  flock.l_whence = SEEK_SET;			\
	  flock.l_start = flock.l_len = 0L;	\
	  lock_val = fcntl (dbf->desc, F_SETLK, &flock);	\
	}
#endif
#endif

/* Do we have memory.h? */
#if HAVE_MEMORY_H
#include <memory.h>
#endif

/* Do we have fsync? */
#if !HAVE_FSYNC
#define fsync(f) {sync(); sync();}
#endif

/* Default block size.  Some systems do not have blocksize in their
   stat record. This code uses the BSD blocksize from stat. */

#if HAVE_ST_BLKSIZE
#define STATBLKSIZE file_stat.st_blksize
#else
#define STATBLKSIZE 1024
#endif

/* Do we have ftruncate? */
#if HAVE_FTRUNCATE
#define TRUNCATE(dbf) ftruncate (dbf->desc, 0)
#else
#define TRUNCATE(dbf) close( open (dbf->name, O_RDWR|O_TRUNC, mode));
#endif

#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif

       //      Added by "Dave Roth" [e-mail] 970829
       //      Modifications made by "Sergei Romanenko" <[e-mail]> 980602
#ifdef WIN32
#include <io.h>
int    lock_val;
#undef UNLOCK_FILE
#define        UNLOCK_FILE(dbf) lock_val = !UnlockFile((HANDLE) _get_osfhandle((int) dbf->desc ), 0, 0, 0xffffffff, 0xffffffff);
#undef WRITELOCK_FILE
#define        WRITELOCK_FILE(dbf)      lock_val = !LockFile((HANDLE) _get_osfhandle((int) dbf->desc ), 0, 0, 0xffffffff, 0xffffffff);
#undef READLOCK_FILE
#define        READLOCK_FILE(dbf)      lock_val = !LockFile((HANDLE) _get_osfhandle((int) dbf->desc ), 0, 0, 0xffffffff, 0xffffffff);

#undef fsync
#define fsync(dbf)  _commit(dbf)

       //      Redefine open() so files are opened in binary mode
#define        open(x, y, z)   open(x, y | O_BINARY, z)

#endif //      WIN32