/*
NAME
  RtpToTsConverter.go - provides utilities for the conversion of Rtp packets
  to equivalent MpegTs packets.

DESCRIPTION
  See Readme.md

AUTHOR
  Saxon Nelson-Milton <saxon.milton@gmail.com>

LICENSE
  RtpToTsConverter.go is Copyright (C) 2017 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
  along with revid in gpl.txt.  If not, see [GNU licenses](http://www.gnu.org/licenses).
*/

package h264

import (
  "bitbucket.org/ausocean/av/itut"
  "reflect"
)

type H264Parser struct {
  inputBuffer []byte
  isParsing bool
  OutputChan chan<- []byte
}

func (p* H264Parser)SendInputData(someData []byte){
  p.inputBuffer = append(p.inputBuffer, someData...)
}

func (p* H264Parser)Stop(){
  p.isParsing = false
}

func (p* H264Parser)Parse() {
  p.isParsing = true
  buffer := p.inputBuffer
  for p.isParsing {
    for i := 0; len(buffer) > 10; i++{
  		var start bool
  		i, start = func() (int,bool) {
  			switch{
  			case reflect.DeepEqual(buffer[i:i+3],itut.StartCode1()):
  				return i+3, true
  			case reflect.DeepEqual(buffer[i:i+4],itut.StartCode2()):
  				return i+4, true
  			}
  				return i, false
  		}()
  		if nalType := buffer[i] & 0x1F; start && ( nalType == 1 || nalType == 5) {
  			for ; i < len(buffer) && !(i+3 < len(buffer) && ( reflect.DeepEqual(buffer[i:i+3],itut.StartCode1()) ||
  				reflect.DeepEqual(buffer[i:i+4],itut.StartCode2()))); i++ {}
  			p.OutputChan<-append(append(itut.StartCode1(),itut.AUD()...),buffer[:i]...)
  			buffer = buffer[i:]
  			i=0
  		}
  		if i >= len(buffer) {
			buffer = []byte{}
			break
		}
  	}
  }
}