/*
DESCRIPTION
  cavlc.go provides utilities for context-adaptive variable-length coding
  for the parsing of H.264 syntax structure fields.

AUTHORS
  Saxon A. Nelson-Milton <saxon@ausocean.org>

LICENSE
  Copyright (C) 2019 the Australian Ocean Lab (AusOcean).

  It is free software: you can redistribute it and/or modify them
  under the terms of the GNU General Public License as published by the
  Free Software Foundation, either version 3 of the License, or (at your
  option) any later version.

  It 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
  in gpl.txt.  If not, see http://www.gnu.org/licenses.
*/

package h264dec

import (
	"fmt"

	"bitbucket.org/ausocean/av/codec/h264/h264dec/bits"
)

// parseLevelPrefix parses the level_prefix variable as specified by the process
// outlined in section 9.2.2.1 in the specifications.
func parseLevelPrefix(br *bits.BitReader) (int, error) {
	zeros := -1
	for b := 0; b != 1; zeros++ {
		_b, err := br.ReadBits(1)
		if err != nil {
			return -1, fmt.Errorf("could not read bit, failed with error: %v", err)
		}
		b = int(_b)
	}
	return zeros, nil
}