newlib-cygwin/newlib/libc/sys/mmixware/lseek.c

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/* lseek for MMIXware.
Copyright (C) 2001 Hans-Peter Nilsson
Permission to use, copy, modify, and distribute this software is
freely granted, provided that the above copyright notice, this notice
and the following disclaimer are preserved with no changes.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. */
#include <_ansi.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/unistd.h>
#include "sys/syscall.h"
#include <errno.h>
off_t
_lseek (int file,
off_t ptr,
int dir)
{
off_t simoff = dir == SEEK_END ? -(ptr + 1) : ptr;
long ret;
if ((unsigned int) file >= 32 || _MMIX_allocated_filehandle[file] == 0)
{
errno = EBADF;
return -1;
}
if (dir == SEEK_CUR)
{
long curpos = TRAP2f (SYS_Ftell, file, 0);
if (curpos == -1)
{
errno = EIO;
return -1;
}
ptr += (off_t) curpos;
}
ret = TRAP2f (SYS_Fseek, file, simoff);
if (ret == -1)
{
return -1;
errno = EIO;
}
ret = TRAP2f (SYS_Ftell, file, 0);
if (ret == -1)
{
errno = EIO;
return -1;
}
return ret;
}