/// \file flv_tag.cpp
/// Holds all code for the FLV namespace.

#include "adts.h"
#include "defines.h"
#include "flv_tag.h"
#include "mp4_generic.h"
#include "rtmpchunks.h"
#include "timing.h"
#include "util.h"
#include <fcntl.h> //for Tag::FileLoader
#include <sstream>
#include <stdio.h>  //for Tag::FileLoader
#include <stdlib.h> //malloc
#include <string.h> //memcpy
#include <unistd.h> //for Tag::FileLoader

#include "h264.h" //Needed for init data parsing in case of invalid values from FLV init

/// Holds the last FLV header parsed.
/// Defaults to a audio+video header on FLV version 0x01 if no header received yet.
char FLV::Header[13] ={'F', 'L', 'V', 0x01, 0x05, 0, 0, 0, 0x09, 0, 0, 0, 0};

bool FLV::Parse_Error = false; ///< This variable is set to true if a problem is encountered while parsing the FLV.
std::string FLV::Error_Str = "";

/// Checks a FLV Header for validness. Returns true if the header is valid, false
/// if the header is not. Not valid can mean:
/// - Not starting with the string "FLV".
/// - The DataOffset is not 9 bytes.
/// - The PreviousTagSize is not 0 bytes.
///
/// Note that we see PreviousTagSize as part of the FLV header, not part of the tag header!
bool FLV::check_header(char *header){
  if (header[0] != 'F') return false;
  if (header[1] != 'L') return false;
  if (header[2] != 'V') return false;
  if (header[5] != 0) return false;
  if (header[6] != 0) return false;
  if (header[7] != 0) return false;
  if (header[8] != 0x09) return false;
  if (header[9] != 0) return false;
  if (header[10] != 0) return false;
  if (header[11] != 0) return false;
  if (header[12] != 0) return false;
  return true;
}// FLV::check_header

/// Checks the first 3 bytes for the string "FLV". Implementing a basic FLV header check,
/// returning true if it is, false if not.
bool FLV::is_header(char *header){
  if (header[0] != 'F') return false;
  if (header[1] != 'L') return false;
  if (header[2] != 'V') return false;
  return true;
}// FLV::is_header

/// Helper function that can quickly skip through a file looking for a particular tag type
bool FLV::seekToTagType(FILE *f, uint8_t t){
  long long startPos = Util::ftell(f);
  DONTEVEN_MSG("Starting seek at %lld", startPos);
  char buf[4];
  if (fread(buf, 4, 1, f) != 1){return false;}
  while (!feof(f) && !ferror(f)){
    switch (buf[0]){
    case 0x09:
    case 0x08:
    case 0x12:{
      if (t == buf[0]){
        if (fseek(f, -4, SEEK_CUR)){WARN_MSG("Could not seek back in FLV stream!");}
        INSANE_MSG("Found tag of type %u at %" PRIu64, t, Util::ftell(f));
        return true;
      }
      long len = (buf[1] << 16) | (buf[2] << 8) | buf[3];
      if (fseek(f, len + 11, SEEK_CUR)){
        WARN_MSG("Could not seek forward in FLV stream!");
      }else{
        DONTEVEN_MSG("Seeking %ld+4 bytes forward, now at %" PRIu64, len + 11, Util::ftell(f));
      }
      if (fread(buf, 4, 1, f) != 1){return false;}
    }break;
    default:
      WARN_MSG("Invalid FLV tag detected! Aborting search.");
      if (fseek(f, -4, SEEK_CUR)){WARN_MSG("Could not seek back in FLV stream!");}
      return false;
    }
  }
  return false;
}

/// True if this media type requires init data.
/// Will always return false if the tag type is not 0x08 or 0x09.
/// Returns true for H263, AVC (H264), AAC.
/// \todo Check if MP3 does or does not require init data...
bool FLV::Tag::needsInitData(){
  switch (data[0]){
  case 0x09:
    switch (data[11] & 0x0F){
    case 2: return true; break;   // H263 requires init data
    case 7: return true; break;   // AVC requires init data
    default: return false; break; // other formats do not
    }
    break;
  case 0x08:
    switch (data[11] & 0xF0){
    case 0x20: return false; break; // MP3 does not...? Unsure.
    case 0xA0: return true; break;  // AAC requires init data
    case 0xE0: return false; break; // MP38kHz does not...?
    default: return false; break;   // other formats do not
    }
    break;
  }
  return false; // only audio/video can require init data
}

/// True if current tag is init data for this media type.
bool FLV::Tag::isInitData(){
  switch (data[0]){
  case 0x09:
    switch (data[11] & 0xF0){
    case 0x50: return true; break;
    }
    if ((data[11] & 0x0F) == 7){
      switch (data[12]){
      case 0: return true; break;
      }
    }
    break;
  case 0x08:
    if ((data[12] == 0) && ((data[11] & 0xF0) == 0xA0)){return true;}
    break;
  }
  return false;
}

const char *FLV::Tag::getVideoCodec(){
  switch (data[11] & 0x0F){
  case 1: return "JPEG";
  case 2: return "H263";
  case 3: return "ScreenVideo1";
  case 4: return "VP6";
  case 5: return "VP6Alpha";
  case 6: return "ScreenVideo2";
  case 7: return "H264";
  default: return "unknown";
  }
}

const char *FLV::Tag::getAudioCodec(){
  switch (data[11] & 0xF0){
  case 0x00:
    if (data[11] & 0x02){
      return "PCMPE"; // unknown endianness
    }else{
      return "PCM"; // 8 bit is always regular PCM
    }
  case 0x10: return "ADPCM";
  case 0x20: return "MP3";
  case 0x30: return "PCM";
  case 0x40:
  case 0x50:
  case 0x60: return "Nellymoser";
  case 0x70: return "ALAW";
  case 0x80: return "ULAW";
  case 0x90: return "reserved";
  case 0xA0: return "AAC";
  case 0xB0: return "Speex";
  case 0xE0: return "MP3";
  case 0xF0: return "DeviceSpecific";
  default: return "unknown";
  }
}

/// Returns a std::string describing the tag in detail.
/// The string includes information about whether the tag is
/// audio, video or metadata, what encoding is used, and the details
/// of the encoding itself.
std::string FLV::Tag::tagType(){
  std::stringstream R;
  R << len << " bytes of ";
  switch (data[0]){
  case 0x09:
    R << getVideoCodec() << " video ";
    switch (data[11] & 0xF0){
    case 0x10: R << "keyframe"; break;
    case 0x20: R << "iframe"; break;
    case 0x30: R << "disposableiframe"; break;
    case 0x40: R << "generatedkeyframe"; break;
    case 0x50: R << "videoinfo"; break;
    }
    if ((data[11] & 0x0F) == 7){
      switch (data[12]){
      case 0: R << " header"; break;
      case 1: R << " NALU"; break;
      case 2: R << " endofsequence"; break;
      }
    }
    break;
  case 0x08:
    R << getAudioCodec();
    switch (data[11] & 0x0C){
    case 0x0: R << " 5.5kHz"; break;
    case 0x4: R << " 11kHz"; break;
    case 0x8: R << " 22kHz"; break;
    case 0xC: R << " 44kHz"; break;
    }
    switch (data[11] & 0x02){
    case 0: R << " 8bit"; break;
    case 2: R << " 16bit"; break;
    }
    switch (data[11] & 0x01){
    case 0: R << " mono"; break;
    case 1: R << " stereo"; break;
    }
    R << " audio";
    if ((data[12] == 0) && ((data[11] & 0xF0) == 0xA0)){R << " initdata";}
    break;
  case 0x12:{
    R << "(meta)data: ";
    AMF::Object metadata = AMF::parse((unsigned char *)data + 11, len - 15);
    R << metadata.Print();
    break;
  }
  default: R << "unknown"; break;
  }
  return R.str();
}// FLV::Tag::tagtype

/// Returns the 24-bit offset of this tag.
/// Returns 0 if the tag isn't H264
int64_t FLV::Tag::offset(){
  if ((data[11] & 0x0F) != 7){return 0;}
  return (((data[13] << 16) + (data[14] << 8) + data[15]) << 8) >> 8;
}// offset getter

/// Sets the 24-bit offset of this tag.
/// Ignored if the tag isn't H264
void FLV::Tag::offset(int64_t o){
  data[13] = (o >> 16) & 0xFF;
  data[14] = (o >> 8) & 0XFF;
  data[15] = o & 0xFF;
}// offset setter

/// Returns the 32-bit timestamp of this tag.
uint64_t FLV::Tag::tagTime(){
  return ((uint64_t)data[4] << 16) + ((uint64_t)data[5] << 8) + data[6] + ((uint64_t)data[7] << 24);
}// tagTime getter

/// Sets the 32-bit timestamp of this tag.
void FLV::Tag::tagTime(uint64_t T){
  data[4] = ((T >> 16) & 0xFF);
  data[5] = ((T >> 8) & 0xFF);
  data[6] = (T & 0xFF);
  data[7] = ((T >> 24) & 0xFF);
}// tagTime setter

/// Constructor for a new, empty, tag.
/// The buffer length is initialized to 0, and later automatically
/// increased if neccesary.
FLV::Tag::Tag(){
  len = 0;
  buf = 0;
  data = 0;
  isKeyframe = false;
  done = true;
  sofar = 0;
}// empty constructor

/// Copy constructor, copies the contents of an existing tag.
/// The buffer length is initialized to the actual size of the tag
/// that is being copied, and later automaticallt increased if
/// neccesary.
FLV::Tag::Tag(const Tag &O){
  done = true;
  sofar = 0;
  len = O.len;
  data = 0;
  if (len > 0){
    if (checkBufferSize()){memcpy(data, O.data, len);}
  }
  isKeyframe = O.isKeyframe;
}// copy constructor

/// Copy constructor from a RTMP chunk.
/// Copies the contents of a RTMP chunk into a valid FLV tag.
/// Exactly the same as making a chunk by through the default (empty) constructor
/// and then calling FLV::Tag::ChunkLoader with the chunk as argument.
FLV::Tag::Tag(const RTMPStream::Chunk &O){
  len = 0;
  buf = 0;
  data = 0;
  isKeyframe = false;
  done = true;
  sofar = 0;
  ChunkLoader(O);
}

/// Generic destructor that frees the allocated memory in the internal data variable, if any.
FLV::Tag::~Tag(){
  if (data){
    free(data);
    data = 0;
    buf = 0;
    len = 0;
  }
}

/// Assignment operator - works exactly like the copy constructor.
/// This operator checks for self-assignment.
FLV::Tag &FLV::Tag::operator=(const FLV::Tag &O){
  if (this != &O){// no self-assignment
    done = true;
    sofar = 0;
    len = O.len;
    if (len > 0){
      if (checkBufferSize()){
        memcpy(data, O.data, len);
      }else{
        len = buf;
      }
    }
    isKeyframe = O.isKeyframe;
  }
  return *this;
}// assignment operator

bool FLV::Tag::DTSCLoader(DTSC::Packet &packData, const DTSC::Meta &M, size_t idx){
  std::string meta_str;
  len = 0;
  if (idx == INVALID_TRACK_ID){
    WARN_MSG("packet with invalid track id found!");
    return false;
  }
  std::string type = M.getType(idx);
  std::string codec = M.getCodec(idx);
  if (type == "video"){
    char *tmpData = 0;
    size_t tmpLen = 0;
    packData.getString("data", tmpData, tmpLen);
    len = tmpLen + 16;
    if (codec == "H264"){len += 4;}
    if (!checkBufferSize()){return false;}
    if (codec == "H264"){
      memcpy(data + 16, tmpData, len - 20);
      data[12] = 1;
      offset(packData.getInt("offset"));
    }else{
      memcpy(data + 12, tmpData, len - 16);
    }
    data[11] = 0;
    if (codec == "H264"){data[11] |= 7;}
    if (codec == "ScreenVideo2"){data[11] |= 6;}
    if (codec == "VP6Alpha"){data[11] |= 5;}
    if (codec == "VP6"){data[11] |= 4;}
    if (codec == "ScreenVideo1"){data[11] |= 3;}
    if (codec == "H263"){data[11] |= 2;}
    if (codec == "JPEG"){data[11] |= 1;}
    if (packData.getFlag("keyframe")){
      data[11] |= 0x10;
    }else{
      data[11] |= 0x20;
    }
    if (packData.getFlag("disposableframe")){data[11] |= 0x30;}
  }
  if (type == "audio"){
    char *tmpData = 0;
    size_t tmpLen = 0;
    packData.getString("data", tmpData, tmpLen);
    len = tmpLen + 16;
    if (codec == "AAC"){len++;}
    if (!checkBufferSize()){return false;}
    if (codec == "AAC"){
      memcpy(data + 13, tmpData, len - 17);
      data[12] = 1; // raw AAC data, not sequence header
    }else{
      memcpy(data + 12, tmpData, len - 16);
    }
    unsigned int datarate = M.getRate(idx);
    data[11] = 0;
    if (codec == "AAC"){data[11] |= 0xA0;}
    if (codec == "MP3"){
      if (datarate == 8000){
        data[11] |= 0xE0;
      }else{
        data[11] |= 0x20;
      }
    }
    if (codec == "ADPCM"){data[11] |= 0x10;}
    if (codec == "PCM"){data[11] |= 0x30;}
    if (codec == "Nellymoser"){
      if (datarate == 8000){
        data[11] |= 0x50;
      }else if (datarate == 16000){
        data[11] |= 0x40;
      }else{
        data[11] |= 0x60;
      }
    }
    if (codec == "ALAW"){data[11] |= 0x70;}
    if (codec == "ULAW"){data[11] |= 0x80;}
    if (codec == "Speex"){data[11] |= 0xB0;}
    if (datarate >= 44100){
      data[11] |= 0x0C;
    }else if (datarate >= 22050){
      data[11] |= 0x08;
    }else if (datarate >= 11025){
      data[11] |= 0x04;
    }
    if (M.getSize(idx) != 8){data[11] |= 0x02;}
    if (M.getChannels(idx) > 1){data[11] |= 0x01;}
  }
  if (!len){return false;}
  setLen();
  if (type == "video"){data[0] = 0x09;}
  if (type == "audio"){data[0] = 0x08;}
  if (type == "meta"){data[0] = 0x12;}
  data[1] = ((len - 15) >> 16) & 0xFF;
  data[2] = ((len - 15) >> 8) & 0xFF;
  data[3] = (len - 15) & 0xFF;
  data[8] = 0;
  data[9] = 0;
  data[10] = 0;
  tagTime(packData.getTime());
  return true;
}

/// Helper function that properly sets the tag length from the internal len variable.
void FLV::Tag::setLen(){
  int len4 = len - 4;
  int i = len;
  data[--i] = (len4)&0xFF;
  len4 >>= 8;
  data[--i] = (len4)&0xFF;
  len4 >>= 8;
  data[--i] = (len4)&0xFF;
  len4 >>= 8;
  data[--i] = (len4)&0xFF;
}

/// FLV Video init data loader function from metadata.
bool FLV::Tag::DTSCVideoInit(DTSC::Meta &meta, uint32_t vTrack){
  // Unknown? Assume H264.
  len = 0;
  if (meta.getCodec(vTrack) == "?"){meta.setCodec(vTrack, "H264");}
  std::string initData = meta.getInit(vTrack);
  if (meta.getCodec(vTrack) == "H264"){len = initData.size() + 20;}
  if (len <= 0 || !checkBufferSize()){return false;}
  memcpy(data + 16, initData.c_str(), len - 20);
  data[12] = 0; // H264 sequence header
  data[13] = 0;
  data[14] = 0;
  data[15] = 0;
  data[11] = 0x17; // H264 keyframe (0x07 & 0x10)
  setLen();
  data[0] = 0x09;
  data[1] = ((len - 15) >> 16) & 0xFF;
  data[2] = ((len - 15) >> 8) & 0xFF;
  data[3] = (len - 15) & 0xFF;
  data[8] = 0;
  data[9] = 0;
  data[10] = 0;
  tagTime(0);
  return true;
}

/// FLV Audio init data loader function from metadata.
bool FLV::Tag::DTSCAudioInit(DTSC::Meta &meta, uint32_t aTrack){
  len = 0;
  // Unknown? Assume AAC.
  if (meta.getCodec(aTrack) == "?"){meta.setCodec(aTrack, "AAC");}
  std::string initData = meta.getInit(aTrack);
  if (meta.getCodec(aTrack) == "AAC"){len = initData.size() + 17;}
  if (len <= 0 || !checkBufferSize()){return false;}
  memcpy(data + 13, initData.c_str(), len - 17);
  data[12] = 0; // AAC sequence header
  data[11] = 0;
  if (meta.getCodec(aTrack) == "AAC"){data[11] += 0xA0;}
  if (meta.getCodec(aTrack) == "MP3"){data[11] += 0x20;}
  unsigned int datarate = meta.getRate(aTrack);
  if (datarate >= 44100){
    data[11] += 0x0C;
  }else if (datarate >= 22050){
    data[11] += 0x08;
  }else if (datarate >= 11025){
    data[11] += 0x04;
  }
  if (meta.getSize(aTrack) != 8){data[11] += 0x02;}
  if (meta.getChannels(aTrack) > 1){data[11] += 0x01;}
  setLen();
  data[0] = 0x08;
  data[1] = ((len - 15) >> 16) & 0xFF;
  data[2] = ((len - 15) >> 8) & 0xFF;
  data[3] = (len - 15) & 0xFF;
  data[8] = 0;
  data[9] = 0;
  data[10] = 0;
  tagTime(0);
  return true;
}

bool FLV::Tag::DTSCMetaInit(const DTSC::Meta &M, std::set<long unsigned int> &selTracks){
  AMF::Object amfdata("root", AMF::AMF0_DDV_CONTAINER);
  amfdata.addContent(AMF::Object("", "onMetaData"));
  amfdata.addContent(AMF::Object("", AMF::AMF0_ECMA_ARRAY));
  AMF::Object trinfo = AMF::Object("trackinfo", AMF::AMF0_STRICT_ARRAY);
  int i = 0;
  uint64_t mediaLen = 0;
  for (std::set<long unsigned int>::iterator it = selTracks.begin(); it != selTracks.end(); it++){
    if (M.getLastms(*it) - M.getFirstms(*it) > mediaLen){
      mediaLen = M.getLastms(*it) - M.getFirstms(*it);
    }
    if (M.getType(*it) == "video"){
      trinfo.addContent(AMF::Object("", AMF::AMF0_OBJECT));
      trinfo.getContentP(i)->addContent(AMF::Object(
          "length", ((double)M.getLastms(*it) / 1000) * ((double)M.getFpks(*it) / 1000.0), AMF::AMF0_NUMBER));
      trinfo.getContentP(i)->addContent(AMF::Object("timescale", ((double)M.getFpks(*it) / 1000), AMF::AMF0_NUMBER));
      trinfo.getContentP(i)->addContent(AMF::Object("sampledescription", AMF::AMF0_STRICT_ARRAY));
      amfdata.getContentP(1)->addContent(AMF::Object("hasVideo", 1, AMF::AMF0_BOOL));
      std::string codec = M.getCodec(*it);
      if (codec == "H264"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 7, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "avc1"));
      }
      if (codec == "ScreenVideo2"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 6, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "sv2"));
      }
      if (codec == "VP6Alpha"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 5, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "vp6a"));
      }
      if (codec == "VP6"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 4, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "vp6"));
      }
      if (codec == "ScreenVideo1"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 3, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "sv1"));
      }
      if (codec == "H263"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 2, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "h263"));
      }
      if (codec == "JPEG"){
        amfdata.getContentP(1)->addContent(AMF::Object("videocodecid", 1, AMF::AMF0_NUMBER));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "jpeg"));
      }
      amfdata.getContentP(1)->addContent(AMF::Object("width", M.getWidth(*it), AMF::AMF0_NUMBER));
      amfdata.getContentP(1)->addContent(AMF::Object("height", M.getHeight(*it), AMF::AMF0_NUMBER));
      amfdata.getContentP(1)->addContent(
          AMF::Object("videoframerate", (double)M.getFpks(*it) / 1000.0, AMF::AMF0_NUMBER));
      amfdata.getContentP(1)->addContent(
          AMF::Object("videodatarate", (double)M.getBps(*it) / 128.0, AMF::AMF0_NUMBER));
      ++i;
    }
    if (M.getType(*it) == "audio"){
      trinfo.addContent(AMF::Object("", AMF::AMF0_OBJECT));
      trinfo.getContentP(i)->addContent(
          AMF::Object("length", (double)(M.getLastms(*it) * M.getRate(*it)), AMF::AMF0_NUMBER));
      trinfo.getContentP(i)->addContent(AMF::Object("timescale", M.getRate(*it), AMF::AMF0_NUMBER));
      trinfo.getContentP(i)->addContent(AMF::Object("sampledescription", AMF::AMF0_STRICT_ARRAY));
      amfdata.getContentP(1)->addContent(AMF::Object("hasAudio", 1, AMF::AMF0_BOOL));
      amfdata.getContentP(1)->addContent(AMF::Object("audiodelay", 0.0, AMF::AMF0_NUMBER));
      std::string codec = M.getCodec(*it);
      if (codec == "AAC"){
        amfdata.getContentP(1)->addContent(AMF::Object("audiocodecid", "mp4a"));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "mp4a"));
      }
      if (codec == "MP3"){
        amfdata.getContentP(1)->addContent(AMF::Object("audiocodecid", "mp3"));
        trinfo.getContentP(i)->getContentP(2)->addContent(AMF::Object("sampletype", "mp3"));
      }
      amfdata.getContentP(1)->addContent(AMF::Object("audiochannels", M.getChannels(*it), AMF::AMF0_NUMBER));
      amfdata.getContentP(1)->addContent(AMF::Object("audiosamplerate", M.getRate(*it), AMF::AMF0_NUMBER));
      amfdata.getContentP(1)->addContent(AMF::Object("audiosamplesize", M.getSize(*it), AMF::AMF0_NUMBER));
      amfdata.getContentP(1)->addContent(
          AMF::Object("audiodatarate", (double)M.getBps(*it) / 128.0, AMF::AMF0_NUMBER));
      ++i;
    }
  }
  if (M.getVod()){
    amfdata.getContentP(1)->addContent(AMF::Object("duration", mediaLen / 1000, AMF::AMF0_NUMBER));
  }
  amfdata.getContentP(1)->addContent(trinfo);

  std::string tmp = amfdata.Pack();
  len = tmp.length() + 15;
  if (len <= 0 || !checkBufferSize()){return false;}
  memcpy(data + 11, tmp.data(), len - 15);
  setLen();
  data[0] = 0x12;
  data[1] = ((len - 15) >> 16) & 0xFF;
  data[2] = ((len - 15) >> 8) & 0xFF;
  data[3] = (len - 15) & 0xFF;
  data[8] = 0;
  data[9] = 0;
  data[10] = 0;
  tagTime(0);
  return true;
}

/// FLV loader function from chunk.
/// Copies the contents and wraps it in a FLV header.
bool FLV::Tag::ChunkLoader(const RTMPStream::Chunk &O){
  len = O.len + 15;
  if (len > 0){
    if (!checkBufferSize()){return false;}
    memcpy(data + 11, &(O.data[0]), O.len);
  }
  setLen();
  data[0] = O.msg_type_id;
  data[3] = O.len & 0xFF;
  data[2] = (O.len >> 8) & 0xFF;
  data[1] = (O.len >> 16) & 0xFF;
  tagTime(O.timestamp);
  isKeyframe = ((data[0] == 0x09) && (((data[11] & 0xf0) >> 4) == 1));
  return true;
}

/// Helper function for FLV::MemLoader.
/// This function will try to read count bytes from data buffer D into buffer.
/// This function should be called repeatedly until true.
/// P and sofar are not the same value, because D may not start with the current tag.
/// \param buffer The target buffer.
/// \param count Amount of bytes to read.
/// \param sofar Current amount read.
/// \param D The location of the data buffer.
/// \param S The size of the data buffer.
/// \param P The current position in the data buffer. Will be updated to reflect new position.
/// \return True if count bytes are read succesfully, false otherwise.
bool FLV::Tag::MemReadUntil(char *buffer, unsigned int count, unsigned int &sofar, char *D,
                            unsigned int S, unsigned int &P){
  if (sofar >= count){return true;}
  int r = 0;
  if (P + (count - sofar) > S){
    r = S - P;
  }else{
    r = count - sofar;
  }
  memcpy(buffer + sofar, D + P, r);
  P += r;
  sofar += r;
  if (sofar >= count){return true;}
  return false;
}// Tag::MemReadUntil

/// Try to load a tag from a data buffer in memory.
/// This is a stateful function - if fed incorrect data, it will most likely never return true
/// again! While this function returns false, the Tag might not contain valid data. \param D The
/// location of the data buffer. \param S The size of the data buffer. \param P The current position
/// in the data buffer. Will be updated to reflect new position. \return True if a whole tag is
/// succesfully read, false otherwise.
bool FLV::Tag::MemLoader(char *D, unsigned int S, unsigned int &P){
  if (len < 15){len = 15;}
  if (!checkBufferSize()){return false;}
  if (done){
    // read a header
    if (MemReadUntil(data, 11, sofar, D, S, P)){
      // if its a correct FLV header, throw away and read tag header
      if (FLV::is_header(data)){
        if (MemReadUntil(data, 13, sofar, D, S, P)){
          if (FLV::check_header(data)){
            sofar = 0;
            memcpy(FLV::Header, data, 13);
          }else{
            FLV::Parse_Error = true;
            Error_Str = "Invalid header received.";
            return false;
          }
        }
      }else{
        // if a tag header, calculate length and read tag body
        len = data[3] + 15;
        len += (data[2] << 8);
        len += (data[1] << 16);
        if (!checkBufferSize()){return false;}
        if (data[0] > 0x12){
          data[0] += 32;
          FLV::Parse_Error = true;
          Error_Str = "Invalid Tag received (";
          Error_Str += data[0];
          Error_Str += ").";
          return false;
        }
        done = false;
      }
    }
  }else{
    // read tag body
    if (MemReadUntil(data, len, sofar, D, S, P)){
      // calculate keyframeness, next time read header again, return true
      isKeyframe = ((data[0] == 0x09) && (((data[11] & 0xf0) >> 4) == 1));
      done = true;
      sofar = 0;
      return true;
    }
  }
  return false;
}// Tag::MemLoader

/// Helper function for FLV::FileLoader.
/// This function will try to read count bytes from file f into buffer.
/// This function should be called repeatedly until true.
/// \param buffer The target buffer.
/// \param count Amount of bytes to read.
/// \param sofar Current amount read.
/// \param f File to read from.
/// \return True if count bytes are read succesfully, false otherwise.
bool FLV::Tag::FileReadUntil(char *buffer, unsigned int count, unsigned int &sofar, FILE *f){
  if (sofar >= count){return true;}
  int r = 0;
  r = fread(buffer + sofar, 1, count - sofar, f);
  if (r < 0){
    FLV::Parse_Error = true;
    Error_Str = "File reading error.";
    return false;
  }
  sofar += r;
  if (sofar >= count){return true;}
  return false;
}

/// Try to load a tag from a file.
/// This is a stateful function - if fed incorrect data, it will most likely never return true
/// again! While this function returns false, the Tag might not contain valid data. \param f The
/// file to read from. \return True if a whole tag is succesfully read, false otherwise.
bool FLV::Tag::FileLoader(FILE *f){
  int preflags = fcntl(fileno(f), F_GETFL, 0);
  int postflags = preflags | O_NONBLOCK;
  fcntl(fileno(f), F_SETFL, postflags);

  if (len < 15){len = 15;}
  if (!checkBufferSize()){return false;}

  if (done){
    // read a header
    if (FileReadUntil(data, 11, sofar, f)){
      // if its a correct FLV header, throw away and read tag header
      if (FLV::is_header(data)){
        if (FileReadUntil(data, 13, sofar, f)){
          if (FLV::check_header(data)){
            sofar = 0;
            memcpy(FLV::Header, data, 13);
          }else{
            FLV::Parse_Error = true;
            Error_Str = "Invalid header received.";
            return false;
          }
        }else{
          Util::sleep(100); // sleep 100ms
        }
      }else{
        // if a tag header, calculate length and read tag body
        len = data[3] + 15;
        len += (((unsigned int)data[2]) << 8);
        len += (((unsigned int)data[1]) << 16);
        if (!checkBufferSize()){return false;}
        if (data[0] > 0x12){
          data[0] += 32;
          FLV::Parse_Error = true;
          Error_Str = "Invalid Tag received (";
          Error_Str += data[0];
          Error_Str += ").";
          return false;
        }
        done = false;
      }
    }else{
      Util::sleep(100); // sleep 100ms
    }
  }else{
    // read tag body
    if (FileReadUntil(data, len, sofar, f)){
      // calculate keyframeness, next time read header again, return true
      isKeyframe = ((data[0] == 0x09) && (((data[11] & 0xf0) >> 4) == 1));
      done = true;
      sofar = 0;
      fcntl(fileno(f), F_SETFL, preflags);
      return true;
    }else{
      Util::sleep(100); // sleep 100ms
    }
  }
  fcntl(fileno(f), F_SETFL, preflags);
  return false;
}// FLV_GetPacket

/// Returns 1 for video, 2 for audio, 3 for meta, 0 otherwise.
unsigned int FLV::Tag::getTrackID(){
  switch (data[0]){
  case 0x08: return 2; // audio track
  case 0x09: return 1; // video track
  case 0x12: return 3; // meta track
  default: return INVALID_TRACK_ID;
  }
}

/// Returns a pointer to the raw media data for this packet.
char *FLV::Tag::getData(){
  if (data[0] == 0x08 && (data[11] & 0xF0) == 0xA0){return data + 13;}
  if (data[0] == 0x09 && (data[11] & 0x0F) == 7){return data + 16;}
  return data + 12;
}

/// Returns the length of the raw media data for this packet.
unsigned int FLV::Tag::getDataLen(){
  if (data[0] == 0x08 && (data[11] & 0xF0) == 0xA0){
    if (len < 17){return 0;}
    return len - 17;
  }
  if (data[0] == 0x09 && (data[11] & 0x0F) == 7){
    if (len < 20){return 0;}
    return len - 20;
  }
  if (len < 16){return 0;}
  return len - 16;
}

void FLV::Tag::toMeta(DTSC::Meta &meta, AMF::Object &amf_storage){
  size_t reTrack = INVALID_TRACK_ID;
  std::map<std::string, std::string> targetParams;
  toMeta(meta, amf_storage, reTrack, targetParams);
}
void FLV::Tag::toMeta(DTSC::Meta &meta, AMF::Object &amf_storage, size_t &reTrack, const std::map<std::string, std::string> &targetParams){
  std::string trackType;
  switch (data[0]){
  case 0x09: trackType = "video"; break; // video
  case 0x08: trackType = "audio"; break; // audio
  case 0x12: trackType = "meta"; break;  // meta
  }

  if (data[0] == 0x12){
    AMF::Object meta_in = AMF::parse((unsigned char *)data + 11, len - 15);
    AMF::Object *tmp = 0;
    if (meta_in.getContentP(1) && meta_in.getContentP(0) && (meta_in.getContentP(0)->StrValue() == "onMetaData")){
      tmp = meta_in.getContentP(1);
    }else{
      if (meta_in.getContentP(2) && meta_in.getContentP(1) && (meta_in.getContentP(1)->StrValue() == "onMetaData")){
        tmp = meta_in.getContentP(2);
      }
    }
    if (tmp){amf_storage = *tmp;}
    return;
  }

  if (meta.getVod() && reTrack == INVALID_TRACK_ID){
    reTrack = meta.trackIDToIndex(getTrackID(), getpid());
  }

  if (reTrack == INVALID_TRACK_ID){
    reTrack = meta.addTrack();
    meta.setID(reTrack, getTrackID());
    if (targetParams.count("lang")){
      meta.setLang(reTrack, targetParams.at("lang"));
    }
  }

  std::string codec = meta.getCodec(reTrack);
  if (data[0] == 0x08 && (codec == "" || codec != getAudioCodec() || (needsInitData() && isInitData()))){
    char audiodata = data[11];
    meta.setType(reTrack, "audio");
    meta.setCodec(reTrack, getAudioCodec());

    switch (audiodata & 0x0C){
    case 0x0: meta.setRate(reTrack, 5512); break;
    case 0x4: meta.setRate(reTrack, 11025); break;
    case 0x8: meta.setRate(reTrack, 22050); break;
    case 0xC: meta.setRate(reTrack, 44100); break;
    }
    if (amf_storage.getContentP("audiosamplerate")){
      meta.setRate(reTrack, amf_storage.getContentP("audiosamplerate")->NumValue());
    }
    meta.setSize(reTrack, audiodata & 0x02 ? 16 : 8);
    if (amf_storage.getContentP("audiosamplesize")){
      meta.setSize(reTrack, amf_storage.getContentP("audiosamplesize")->NumValue());
    }
    meta.setChannels(reTrack, audiodata & 0x01 ? 2 : 1);
    if (amf_storage.getContentP("stereo")){
      meta.setChannels(reTrack, amf_storage.getContentP("stereo")->NumValue() == 1 ? 2 : 1);
    }
    if (needsInitData() && isInitData()){
      if ((audiodata & 0xF0) == 0xA0){
        meta.setInit(reTrack, data + 13, len - 17);
      }else{
        meta.setInit(reTrack, data + 12, len - 16);
      }
      if (metadata.tracks[reTrack].codec == "AAC"){
        metadata.tracks[reTrack].rate = aac::AudSpecConf::rate(metadata.tracks[reTrack].init);
        metadata.tracks[reTrack].channels = aac::AudSpecConf::channels(metadata.tracks[reTrack].init);
      }
    }
  }

  if (data[0] == 0x09 && ((needsInitData() && isInitData()) || !codec.size())){
    char videodata = data[11];
    meta.setCodec(reTrack, getVideoCodec());
    meta.setType(reTrack, "video");
    if (amf_storage.getContentP("width")){
      meta.setWidth(reTrack, amf_storage.getContentP("width")->NumValue());
    }
    if (amf_storage.getContentP("height")){
      meta.setHeight(reTrack, amf_storage.getContentP("height")->NumValue());
    }
    if (!meta.getFpks(reTrack) && amf_storage.getContentP("videoframerate")){
      if (amf_storage.getContentP("videoframerate")->NumValue()){
        meta.setFpks(reTrack, amf_storage.getContentP("videoframerate")->NumValue() * 1000.0);
      }else{
        meta.setFpks(reTrack, atoi(amf_storage.getContentP("videoframerate")->StrValue().c_str()) * 1000.0);
      }
    }
    if (needsInitData() && isInitData()){
      if ((videodata & 0x0F) == 7){
        if (len < 21){return;}
        MP4::AVCC avccBox;
        avccBox.setPayload(data + 16, len - 20);
        avccBox.sanitize();
        meta.setInit(reTrack, avccBox.payload(), avccBox.payloadSize());
      }else{
        if (len < 17){return;}
        MP4::AVCC avccBox;
        avccBox.setPayload(data + 12, len - 16);
        avccBox.sanitize();
        meta.setInit(reTrack, avccBox.payload(), avccBox.payloadSize());
      }
      /// this is a hacky way around invalid FLV data (since it gets ignored nearly everywhere, but
      /// we do need correct data...
      if (!meta.getWidth(reTrack) || !meta.getHeight(reTrack) || !meta.getFpks(reTrack)){
        std::string init = meta.getInit(reTrack);
        h264::sequenceParameterSet sps;
        sps.fromDTSCInit(init);
        h264::SPSMeta spsChar = sps.getCharacteristics();
        meta.setWidth(reTrack, spsChar.width);
        meta.setHeight(reTrack, spsChar.height);
        meta.setFpks(reTrack, spsChar.fps * 1000);
      }
    }
  }
}

/// Checks if buf is large enough to contain len.
/// Attempts to resize data buffer if not/
/// \returns True if buffer is large enough, false otherwise.
bool FLV::Tag::checkBufferSize(){
  if (buf < len || !data){
    char *newdata = (char *)realloc(data, len);
    // on realloc fail, retain the old data
    if (newdata != 0){
      data = newdata;
      buf = len;
    }else{
      len = buf;
      return false;
    }
  }
  return true;
}