Method: StringIO#seek

Defined in:
ext/stringio/stringio.c

#seek(offset, whence = SEEK_SET) ⇒ 0

Sets the current position to the given integer offset (in bytes), with respect to a given constant whence; see Position.

Returns:

  • (0) 


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# File 'ext/stringio/stringio.c', line 785

static VALUE
strio_seek(int argc, VALUE *argv, VALUE self)
{
    VALUE whence;
    struct StringIO *ptr = StringIO(self);
    long amount, offset;

    rb_scan_args(argc, argv, "11", NULL, &whence);
    amount = NUM2LONG(argv[0]);
    if (CLOSED(self)) {
  rb_raise(rb_eIOError, "closed stream");
    }
    switch (NIL_P(whence) ? 0 : NUM2LONG(whence)) {
      case 0:
  offset = 0;
  break;
      case 1:
  offset = ptr->pos;
  break;
      case 2:
  offset = RSTRING_LEN(ptr->string);
  break;
      default:
  error_inval("invalid whence");
    }
    if (amount > LONG_MAX - offset || amount + offset < 0) {
  error_inval(0);
    }
    ptr->pos = amount + offset;
    return INT2FIX(0);
}