Function archive_seek

libctru/source/archive_dev.c:724–776

! Update an open file's current offset * * @param[in,out] r newlib reentrancy struct * @param[in,out] fd Pointer to archive_file_t * @param[in] pos Offset to seek to * @param[in] whence Where to seek from * * @returns new offset for success * @returns -1 for error */

 *  @returns -1 for error
 */
static off_t
archive_seek(struct _reent *r,
             void          *fd,
             off_t         pos,
             int           whence)
{
  Result      rc;
  u64         offset;

  /* get pointer to our data */
  archive_file_t *file = (archive_file_t*)fd;

  /* find the offset to see from */
  switch(whence)
  {
    /* set absolute position; start offset is 0 */
    case SEEK_SET:
      offset = 0;
      break;

    /* set position relative to the current position */
    case SEEK_CUR:
      offset = file->offset;
      break;

    /* set position relative to the end of the file */
    case SEEK_END:
      rc = FSFILE_GetSize(file->fd, &offset);
      if(R_FAILED(rc))
      {
        r->_errno = archive_translate_error(rc);
        return -1;
      }
      break;

    /* an invalid option was provided */
    default:
      r->_errno = EINVAL;
      return -1;
  }

  /* TODO: A better check that prevents overflow. */
  if(pos < 0 && (s64)offset < -(s64)pos)
  {
    /* don't allow seek to before the beginning of the file */
    r->_errno = EINVAL;
    return -1;
  }

  /* update the current offset */
  file->offset = offset + pos;
  return file->offset;
}

/*! Get file stats from an open file
 *