xa.c

linux下的MPEG1

/*
    $Id: xa.c,v 1.3 2005/01/01 02:43:57 rockyb Exp $

    Copyright (C) 2000 Herbert Valerio Riedel <[e-mail]>
    Copyright (C) 2003 Rocky Bernstein <[e-mail]>

    This program 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 of the License, or
    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/


#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

/* Public headers */
#include <cdio/iso9660.h>
#include <cdio/util.h>
#include <cdio/bytesex.h>

/* Private headers */
#include "cdio_assert.h"

#define BUF_COUNT 16
#define BUF_SIZE 80

/* Return a pointer to a internal free buffer */
static char *
_getbuf (void)
{
  static char _buf[BUF_COUNT][BUF_SIZE];
  static int _num = -1;
  
  _num++;
  _num %= BUF_COUNT;

  memset (_buf[_num], 0, BUF_SIZE);

  return _buf[_num];
}

/*!
  Returns a string which interpreting the extended attribute xa_attr. 
  For example:
  \verbatim
  d---1xrxrxr
  ---2--r-r-r
  -a--1xrxrxr
  \endverbatim

  A description of the characters in the string follows
  The 1st character is either "d" if the entry is a directory, or "-" if not.
  The 2nd character is either "a" if the entry is CDDA (audio), or "-" if not.
  The 3rd character is either "i" if the entry is interleaved, or "-" if not.
  The 4th character is either "2" if the entry is mode2 form2 or "-" if not.
  The 5th character is either "1" if the entry is mode2 form1 or "-" if not.
   Note that an entry will either be in mode2 form1 or mode form2. That
   is you will either see "2-" or "-1" in the 4th & 5th positions.

  The 6th and 7th characters refer to permissions for a user while the
  the 8th and 9th characters refer to permissions for a group while, and 
  the 10th and 11th characters refer to permissions for a others. 
 
  In each of these pairs the first character (6, 8, 10) is "x" if the 
  entry is executable. For a directory this means the directory is
  allowed to be listed or "searched".
  The second character of a pair (7, 9, 11) is "r" if the entry is allowed
  to be read. 
*/

const char *
iso9660_get_xa_attr_str (uint16_t xa_attr)
{
  char *result = _getbuf();

  xa_attr = uint16_from_be (xa_attr);

  result[ 0] = (xa_attr & XA_ATTR_DIRECTORY) ? 'd' : '-';
  result[ 1] = (xa_attr & XA_ATTR_CDDA) ? 'a' : '-';
  result[ 2] = (xa_attr & XA_ATTR_INTERLEAVED) ? 'i' : '-';
  result[ 3] = (xa_attr & XA_ATTR_MODE2FORM2) ? '2' : '-';
  result[ 4] = (xa_attr & XA_ATTR_MODE2FORM1) ? '1' : '-';

  result[ 5] = (xa_attr & XA_PERM_XUSR) ? 'x' : '-';
  result[ 6] = (xa_attr & XA_PERM_RUSR) ? 'r' : '-';

  result[ 7] = (xa_attr & XA_PERM_XGRP) ? 'x' : '-';
  result[ 8] = (xa_attr & XA_PERM_RGRP) ? 'r' : '-';

  /* Hack alert: wonder if this should be ROTH and XOTH? */
  result[ 9] = (xa_attr & XA_PERM_XSYS) ? 'x' : '-';
  result[10] = (xa_attr & XA_PERM_RSYS) ? 'r' : '-';

  result[11] = '\0';

  return result;
}

iso9660_xa_t *
iso9660_xa_init (iso9660_xa_t *_xa, uint16_t uid, uint16_t gid, uint16_t attr, 
	      uint8_t filenum)
{
  cdio_assert (_xa != NULL);
  
  _xa->user_id = uint16_to_be (uid);
  _xa->group_id = uint16_to_be (gid);
  _xa->attributes = uint16_to_be (attr);

  _xa->signature[0] = 'X';
  _xa->signature[1] = 'A';

  _xa->filenum = filenum;

  _xa->reserved[0] 
    = _xa->reserved[1] 
    = _xa->reserved[2] 
    = _xa->reserved[3] 
    = _xa->reserved[4] = 0x00;

  return _xa;
}