C++ AP4_DataBuffer类代码示例

/*----------------------------------------------------------------------
|   AP4_OmaDcfCtrSampleEncrypter::EncryptSampleData
+---------------------------------------------------------------------*/
AP4_Result
AP4_OmaDcfCtrSampleEncrypter::EncryptSampleData(AP4_DataBuffer& data_in,
        AP4_DataBuffer& data_out,
        AP4_UI64        counter,
        bool            /*skip_encryption*/)
{
    // setup the buffers
    const unsigned char* in = data_in.GetData();
    AP4_CHECK(data_out.SetDataSize(data_in.GetDataSize()+AP4_CIPHER_BLOCK_SIZE+1));
    unsigned char* out = data_out.UseData();

    // selective encryption flag
    *out++ = 0x80;

    // IV on 16 bytes: [SSSSSSSSXXXXXXXX]
    // where SSSSSSSS is the 64-bit salt and
    // XXXXXXXX is the 64-bit base counter
    AP4_CopyMemory(out, m_Salt, 8);
    AP4_BytesFromUInt64BE(&out[8], counter);

    // encrypt the payload
    AP4_Size data_size = data_in.GetDataSize();
    m_Cipher->SetIV(out);
    m_Cipher->ProcessBuffer(in, data_size, out+AP4_CIPHER_BLOCK_SIZE);

    return AP4_SUCCESS;
}

/*----------------------------------------------------------------------
|   AP4_SgpdAtom::InspectFields
+---------------------------------------------------------------------*/
AP4_Result
AP4_SgpdAtom::InspectFields(AP4_AtomInspector& inspector)
{
    char fourcc[5];
    AP4_FormatFourChars(fourcc, m_GroupingType);
    inspector.AddField("grouping_type", fourcc);
    if (m_Version >= 1) {
        inspector.AddField("default_length", m_DefaultLength);
    }
    inspector.AddField("entry_count", m_Entries.ItemCount());
    
    // inspect entries
    char header[32];
    unsigned int i=0;
    for (AP4_List<AP4_DataBuffer>::Item* item = m_Entries.FirstItem();
                                         item;
                                         item = item->GetNext()) {
        AP4_DataBuffer* entry = item->GetData();
        AP4_FormatString(header, sizeof(header), "entry %02d", i);
        ++i;
        inspector.AddField(header, entry->GetData(), entry->GetDataSize());
    }

    return AP4_SUCCESS;
}

/*----------------------------------------------------------------------
|   AP4_SgpdAtom::WriteFields
+---------------------------------------------------------------------*/
AP4_Result
AP4_SgpdAtom::WriteFields(AP4_ByteStream& stream)
{
    AP4_Result result;
    result = stream.WriteUI32(m_GroupingType);
    if (AP4_FAILED(result)) return result;

    if (m_Version >= 1) {
        result = stream.WriteUI32(m_DefaultLength);
        if (AP4_FAILED(result)) return result;
    }
    
    // write the children
    result = stream.WriteUI32(m_Entries.ItemCount());
    if (AP4_FAILED(result)) return result;
    
    for (AP4_List<AP4_DataBuffer>::Item* item = m_Entries.FirstItem();
                                         item;
                                         item = item->GetNext()) {
        AP4_DataBuffer* entry = item->GetData();
        if (m_Version >= 1) {
            if (m_DefaultLength == 0) {
                stream.WriteUI32((AP4_UI32)entry->GetDataSize());
            }
        }
        result = stream.Write(entry->GetData(), entry->GetDataSize());
        if (AP4_FAILED(result)) {
            return result;
        }
    }
    
    return AP4_SUCCESS;
}

/*----------------------------------------------------------------------
|       AP4_DecoderSpecificInfoDescriptor::AP4_DecoderSpecificInfoDescriptor
+---------------------------------------------------------------------*/
AP4_DecoderSpecificInfoDescriptor::AP4_DecoderSpecificInfoDescriptor(
    const AP4_DataBuffer& data) :
    AP4_Descriptor(AP4_DESCRIPTOR_TAG_DECODER_SPECIFIC_INFO, 
                   MinHeaderSize(data.GetDataSize()), 
                   data.GetDataSize()),
    m_Info(data)
{
}

/*----------------------------------------------------------------------
|   AP4_DefaultFragmentHandler::ProcessSample
+---------------------------------------------------------------------*/
AP4_Result 
AP4_DefaultFragmentHandler::ProcessSample(AP4_DataBuffer& data_in, AP4_DataBuffer& data_out)
{
    if (m_TrackHandler == NULL) {
        data_out.SetData(data_in.GetData(), data_in.GetDataSize());
        return AP4_SUCCESS;
    }
    return m_TrackHandler->ProcessSample(data_in, data_out);
}

/*----------------------------------------------------------------------
|       AP4_IsmaCipher::DecryptSample
+---------------------------------------------------------------------*/
AP4_Result 
AP4_IsmaCipher::DecryptSample(AP4_DataBuffer& data_in,
                              AP4_DataBuffer& data_out)
{
    bool                 is_encrypted = true;
    const unsigned char* in = data_in.GetData();
    if (m_SelectiveEncryption) {
        is_encrypted = ((in[0]&1)==1);
        in++;
    }

    // get the IV (this implementation only supports un to 32 bits of IV)
    // so we skip anything beyond the last 4 bytes
    unsigned int to_read = m_IvLength;
    if (to_read > 16 || to_read == 0) return AP4_ERROR_INVALID_FORMAT;
    while (to_read > 4) {
        to_read--;
        in++;
    }
    AP4_UI32 iv = 0;
    while (to_read--) {
        iv = (iv<<8) | *in++; 
    }

    // get the key indicator (we only support up to 32 bits as well)
    to_read = m_KeyIndicatorLength;
    if (to_read > 4 ) return AP4_ERROR_INVALID_FORMAT;
    while (to_read > 4) {
        to_read--;
        in++;
    }
    AP4_UI32 key_indicator = 0;
    while (to_read--) {
        key_indicator = (key_indicator<<8) | *in++; 
    }
    // we only support key indicator = 0 for now... (TODO)
    if (key_indicator != 0) {
        return AP4_FAILURE;
    }

    // process the sample data
    unsigned int header_size = in-data_in.GetData();
    unsigned int payload_size = data_in.GetDataSize()-header_size;
    data_out.SetDataSize(payload_size);
    unsigned char* out = data_out.UseData();
    if (is_encrypted) {
        m_Cipher->SetStreamOffset(iv);
        m_Cipher->ProcessBuffer(in, out, payload_size);
    } else {
        memcpy(out, in, payload_size);
    }

    return AP4_SUCCESS;
}

  virtual void UpdatePPSId(AP4_DataBuffer const &buffer) override
  {
    //Search the Slice header NALU
    const AP4_UI08 *data(buffer.GetData());
    unsigned int data_size(buffer.GetDataSize());
    for (; data_size;)
    {
      // sanity check
      if (data_size < naluLengthSize)
        break;

      // get the next NAL unit
      AP4_UI32 nalu_size;
      switch (naluLengthSize) {
      case 1:nalu_size = *data++; data_size--; break;
      case 2:nalu_size = AP4_BytesToInt16BE(data); data += 2; data_size -= 2; break;
      case 4:nalu_size = AP4_BytesToInt32BE(data); data += 4; data_size -= 4; break;
      default: data_size = 0; nalu_size = 1; break;
      }
      if (nalu_size > data_size)
        break;

      // Stop further NALU processing
      if (countPictureSetIds < 2)
        naluLengthSize = 0;

      unsigned int nal_unit_type = *data & 0x1F;

      if (
        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_OF_NON_IDR_PICTURE ||
        nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_OF_IDR_PICTURE //||
        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_DATA_PARTITION_A ||
        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_DATA_PARTITION_B ||
        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_DATA_PARTITION_C
      ) {

        AP4_DataBuffer unescaped(data, data_size);
        AP4_NalParser::Unescape(unescaped);
        AP4_BitReader bits(unescaped.GetData(), unescaped.GetDataSize());

        bits.SkipBits(8); // NAL Unit Type

        AP4_AvcFrameParser::ReadGolomb(bits); // first_mb_in_slice
        AP4_AvcFrameParser::ReadGolomb(bits); // slice_type
        pictureId = AP4_AvcFrameParser::ReadGolomb(bits); //picture_set_id
      }
      // move to the next NAL unit
      data += nalu_size;
      data_size -= nalu_size;
    }
  }

/*----------------------------------------------------------------------
|   AP4_UnknownSampleEntry::AP4_UnknownSampleEntry
+---------------------------------------------------------------------*/
AP4_UnknownSampleEntry::AP4_UnknownSampleEntry(AP4_Atom::Type  type, 
                                               AP4_DataBuffer& payload) :
    AP4_SampleEntry(type),
    m_Payload(payload)
{
    m_Size32 += payload.GetDataSize();
}

/*----------------------------------------------------------------------
|       AP4_IsmaTrackEncrypter::ProcessSample
+---------------------------------------------------------------------*/
AP4_Result 
AP4_IsmaTrackEncrypter::ProcessSample(AP4_DataBuffer& data_in,
                                      AP4_DataBuffer& data_out)
{
    AP4_Result result = m_Cipher->EncryptSample(data_in, data_out, m_ByteOffset, false);
    if (AP4_FAILED(result)) return result;

    m_ByteOffset += data_in.GetDataSize();
    return AP4_SUCCESS;
}

/*----------------------------------------------------------------------
|   AP4_HintTrackReader::BuildRtpPacket
+---------------------------------------------------------------------*/
AP4_Result
AP4_HintTrackReader::BuildRtpPacket(AP4_RtpPacket*  packet, 
                                    AP4_DataBuffer& packet_data)
{
    // set the data size
    AP4_Result result = packet_data.SetDataSize(packet->GetConstructedDataSize());
    if (AP4_FAILED(result)) return result;

    // now write
    AP4_ByteStream* stream = new AP4_MemoryByteStream(packet_data); 

    // header + ssrc
    stream->WriteUI08(0x80 | (packet->GetPBit() << 5) | (packet->GetXBit() << 4));
    stream->WriteUI08((packet->GetMBit() << 7) | packet->GetPayloadType());
    stream->WriteUI16(m_RtpSequenceStart + packet->GetSequenceSeed());
    stream->WriteUI32(m_RtpTimeStampStart + (AP4_UI32)m_CurrentHintSample.GetCts() + packet->GetTimeStampOffset());
    stream->WriteUI32(m_Ssrc);

    AP4_List<AP4_RtpConstructor>::Item* constructors_it 
        = packet->GetConstructors().FirstItem();
    while (constructors_it != NULL) {
        AP4_RtpConstructor* constructor = constructors_it->GetData();

        // add data to the packet according to the constructor
        switch (constructor->GetType()) {
            case AP4_RTP_CONSTRUCTOR_TYPE_NOOP:
                // nothing to do here
                break;
            case AP4_RTP_CONSTRUCTOR_TYPE_IMMEDIATE:
                result = WriteImmediateRtpData(
                    static_cast<AP4_ImmediateRtpConstructor*>(constructor), stream);
                if (AP4_FAILED(result)) return result;
                break;
            case AP4_RTP_CONSTRUCTOR_TYPE_SAMPLE:
                result = WriteSampleRtpData(
                    static_cast<AP4_SampleRtpConstructor*>(constructor), stream);
                if (AP4_FAILED(result)) return result;
                break;
            case AP4_RTP_CONSTRUCTOR_TYPE_SAMPLE_DESC:
                return AP4_ERROR_NOT_SUPPORTED;
            default:
                // unknown constructor type
                return AP4_FAILURE;
        }

        // iterate
        constructors_it = constructors_it->GetNext();
    }

    // release the stream
    stream->Release();

    return result;
}

/*----------------------------------------------------------------------
|   AP4_SgpdAtom::AP4_SgpdAtom
+---------------------------------------------------------------------*/
AP4_SgpdAtom::AP4_SgpdAtom(AP4_UI32         size,
                           AP4_UI08         version,
                           AP4_UI32         flags,
                           AP4_ByteStream&  stream) :
    AP4_Atom(AP4_ATOM_TYPE_SGPD, size, version, flags),
    m_GroupingType(0),
    m_DefaultLength(0)
{
    AP4_Size bytes_available = size-AP4_FULL_ATOM_HEADER_SIZE;
    stream.ReadUI32(m_GroupingType);
    bytes_available -= 4;
    if (version >= 1) {
        stream.ReadUI32(m_DefaultLength);
        bytes_available -= 4;
    }

    // read the number of entries
    AP4_UI32 entry_count = 0;
    AP4_Result result = stream.ReadUI32(entry_count);
    if (AP4_FAILED(result)) return;
    bytes_available -= 4;

    // read all entries
    for (unsigned int i=0; i<entry_count; i++) {
        AP4_UI32 description_length = m_DefaultLength;
        if (m_Version == 0) {
            // entry size unknown, read the whole thing
            description_length = bytes_available;
        } else {
            if (m_DefaultLength == 0) {
                description_length = stream.ReadUI32(description_length);
            }
        }
        if (description_length <= bytes_available) {
            AP4_DataBuffer* payload = new AP4_DataBuffer(description_length);
            payload->SetDataSize(description_length);
            stream.Read(payload->UseData(), description_length);
            m_Entries.Add(payload);
        }
    }
}

/*----------------------------------------------------------------------
|   AP4_MarlinIpmpTrackDecrypter:ProcessSample
+---------------------------------------------------------------------*/
AP4_Result 
AP4_MarlinIpmpTrackDecrypter::ProcessSample(AP4_DataBuffer& data_in,
                                            AP4_DataBuffer& data_out)
{
    AP4_Result result;
    
    const AP4_UI08* in = data_in.GetData();
    AP4_Size        in_size = data_in.GetDataSize();

    // default to 0 output 
    data_out.SetDataSize(0);

    // check that we have at least the minimum size
    if (in_size < 2*AP4_AES_BLOCK_SIZE) return AP4_ERROR_INVALID_FORMAT;

    // process the sample data
    AP4_Size out_size = in_size-AP4_AES_BLOCK_SIZE; // worst case
    data_out.SetDataSize(out_size);
    AP4_UI08* out = data_out.UseData();

    // decrypt the data
    m_Cipher->SetIV(in);
    result = m_Cipher->ProcessBuffer(in+AP4_AES_BLOCK_SIZE, 
                                     in_size-AP4_AES_BLOCK_SIZE, 
                                     out,
                                     &out_size,
                                     true);
    if (AP4_FAILED(result)) return result;
    
    // update the payload size
    data_out.SetDataSize(out_size);
    
    return AP4_SUCCESS;
}

/*----------------------------------------------------------------------
|   ShowSample
+---------------------------------------------------------------------*/
static void
ShowSample(AP4_Sample& sample, unsigned int index, AP4_SampleDecrypter* sample_decrypter)
{
    printf("[%06d] size=%6d duration=%6d", 
           index, 
           (int)sample.GetSize(), 
           (int)sample.GetDuration());
    printf(" offset=%10lld dts=%10lld cts=%10lld ", 
           sample.GetOffset(),
           sample.GetDts(), 
           sample.GetCts());
    if (sample.IsSync()) {
        printf(" [S] ");
    } else {
        printf("     ");
    }

    AP4_DataBuffer sample_data;
    sample.ReadData(sample_data);
    AP4_DataBuffer* data = &sample_data;
    
    AP4_DataBuffer decrypted_sample_data;
    if (sample_decrypter) {
        sample_decrypter->DecryptSampleData(sample_data, decrypted_sample_data);
        data = & decrypted_sample_data;
    }
    
    unsigned int show = data->GetDataSize();
    if (show > 12) show = 12; // max first 12 chars
    
    for (unsigned int i=0; i<show; i++) {
        printf("%02x", data->GetData()[i]);
    }
    if (show == data->GetDataSize()) {
        printf("\n");
    } else {
        printf("...\n");
    }
}

/*----------------------------------------------------------------------
|   WV_CencSingleSampleDecrypter::DecryptSampleData
+---------------------------------------------------------------------*/
AP4_Result WV_CencSingleSampleDecrypter::DecryptSampleData(
  AP4_DataBuffer& data_in,
  AP4_DataBuffer& data_out,
  const AP4_UI08* iv,
  unsigned int    subsample_count,
  const AP4_UI16* bytes_of_cleartext_data,
  const AP4_UI32* bytes_of_encrypted_data)
{
  // the output has the same size as the input
  data_out.SetDataSize(data_in.GetDataSize());

  if (!wv_adapter)
  {
    data_out.SetData(data_in.GetData(), data_in.GetDataSize());
    return AP4_SUCCESS;
  }

  // check input parameters
  if (iv == NULL) return AP4_ERROR_INVALID_PARAMETERS;
  if (subsample_count) {
    if (bytes_of_cleartext_data == NULL || bytes_of_encrypted_data == NULL) {
      return AP4_ERROR_INVALID_PARAMETERS;
    }
  }

  // transform ap4 format into cmd format
  cdm::InputBuffer cdm_in;
  if (subsample_count > max_subsample_count_)
  {
    subsample_buffer_ = (cdm::SubsampleEntry*)realloc(subsample_buffer_, subsample_count*sizeof(cdm::SubsampleEntry));
    max_subsample_count_ = subsample_count;
  }
  for (cdm::SubsampleEntry *b(subsample_buffer_), *e(subsample_buffer_ + subsample_count); b != e; ++b, ++bytes_of_cleartext_data, ++bytes_of_encrypted_data)
  {
    b->clear_bytes = *bytes_of_cleartext_data;
    b->cipher_bytes = *bytes_of_encrypted_data;
  }
  cdm_in.data = data_in.GetData();
  cdm_in.data_size = data_in.GetDataSize();
  cdm_in.iv = iv;
  cdm_in.iv_size = 16; //Always 16, see AP4_CencSingleSampleDecrypter declaration.
  cdm_in.key_id = wv_adapter->GetKeyId();
  cdm_in.key_id_size = wv_adapter->GetKeyIdSize();
  cdm_in.num_subsamples = subsample_count;
  cdm_in.subsamples = subsample_buffer_;

  CdmBuffer buf(&data_out);
  CdmDecryptedBlock cdm_out;
  cdm_out.SetDecryptedBuffer(&buf);

  cdm::Status ret = wv_adapter->Decrypt(cdm_in, &cdm_out);

  return (ret == cdm::Status::kSuccess) ? AP4_SUCCESS : AP4_ERROR_INVALID_PARAMETERS;
}

/*----------------------------------------------------------------------
|   AP4_LinearReader::PopSample
+---------------------------------------------------------------------*/
bool
AP4_LinearReader::PopSample(Tracker*        tracker,
                            AP4_Sample&     sample,
                            AP4_DataBuffer& sample_data)
{
    SampleBuffer* head = NULL;
    if (AP4_SUCCEEDED(tracker->m_Samples.PopHead(head))) {
        assert(head->m_Sample);
        sample = *head->m_Sample;
        sample_data.SetData(head->m_Data.GetData(), head->m_Data.GetDataSize());
        assert(m_BufferFullness >= sample.GetSize());
        m_BufferFullness -= sample.GetSize();
        delete head;
        return true;
    }

    return false;
}