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ar-pdp11.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 2002-2007 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                                                                      *
***********************************************************************/
#pragma prototyped
/*
 * pdp11 archive format method
 */

#include <ardirlib.h>
#include <swap.h>
#include <tm.h>

#define MAGIC           0177545
#define MAGIC_SIZE      2

typedef struct Header_s
{
      char        ar_name[14];
      uint32_t    ar_date;          /* native representation*/
      char        ar_uid;                 /*    "           */
      char        ar_gid;                 /*    "           */
      uint16_t    ar_mode;          /*    "           */
      uint32_t    ar_size;          /*    "           */
} Header_t;

typedef struct State_s              /* method state               */
{
      off_t       current;    /* current dirent offset      */
      off_t       offset;           /* next dirent offset         */
      int         swap;       /* swapget() op if necessary  */
      Header_t    header;           /* current header       */
      char        name[15];   /* ar_name with trailing '\0' */
} State_t;

/*
 * closef
 */

static int
pdpclose(Ardir_t* ar)
{
      State_t*    state;

      if (ar && (state = (State_t*)ar->data))
            free(state);
      return 0;
}

/*
 * openf
 */

static int
pdpopen(Ardir_t* ar, char* buf, size_t n)
{
      int         swap;
      State_t*    state;

      if (n <= MAGIC_SIZE)
            return -1;
      if (swapget(0, buf, MAGIC_SIZE) == MAGIC)
            swap = 0;
      else if (swapget(1, buf, MAGIC_SIZE) == MAGIC)
            swap = 3;
      else
            return -1;
      if (!(state = newof(0, State_t, 1, 0)))
            return -1;
      ar->data = (void*)state;
      state->swap = swap;
      state->offset = MAGIC_SIZE;
      ar->truncate = 14;
      return 0;
}

/*
 * nextf
 */

static Ardirent_t*
pdpnext(Ardir_t* ar)
{
      State_t*    state = (State_t*)ar->data;
      ssize_t           z;

      state->current = state->offset;
      if (lseek(ar->fd, state->offset, SEEK_SET) != state->offset)
      {
            ar->error = errno;
            return 0;
      }
      if (read(ar->fd, (char*)&state->header, sizeof(state->header)) != sizeof(state->header))
      {
            if ((z = read(ar->fd, (char*)&state->header, 1)) < 0)
                  ar->error = errno;
            else if (z > 0)
                  ar->error = EINVAL;
            return 0;
            
      }
      strncpy(ar->dirent.name = state->name, state->header.ar_name, sizeof(state->header.ar_name));
      ar->dirent.mtime = swapget(state->swap, (char*)&state->header.ar_date, sizeof(state->header.ar_date));
      ar->dirent.uid = swapget(state->swap, (char*)&state->header.ar_uid, sizeof(state->header.ar_uid));
      ar->dirent.gid = swapget(state->swap, (char*)&state->header.ar_gid, sizeof(state->header.ar_gid));
      ar->dirent.mode = swapget(state->swap, (char*)&state->header.ar_mode, sizeof(state->header.ar_mode));
      ar->dirent.offset = state->offset += sizeof(state->header);
      ar->dirent.size = swapget(state->swap, (char*)&state->header.ar_size, sizeof(state->header.ar_size));
      state->offset += ar->dirent.size + (ar->dirent.size & 01);
      return &ar->dirent;
}

/*
 * changef
 */

static int
pdpchange(Ardir_t* ar, Ardirent_t* ent)
{
      State_t*    state = (State_t*)ar->data;
      off_t       o;

      o = state->current + offsetof(Header_t, ar_date);
      if (lseek(ar->fd, o, SEEK_SET) != o)
      {
            ar->error = errno;
            return -1;
      }
      swapput(state->swap, (char*)&state->header.ar_date, sizeof(state->header.ar_date), (intmax_t)ent->mtime);
      if (write(ar->fd, &state->header.ar_date, sizeof(state->header.ar_date)) != sizeof(state->header.ar_date))
      {
            ar->error = errno;
            return -1;
      }
      return 0;
}

Ardirmeth_t ar_pdp11 =
{
      "pdp11",
      "pdp11 archive",
      pdpopen,
      pdpnext,
      pdpchange,
      0,
      0,
      pdpclose,
      ar_pdp11_next
};

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