private void ReadBlocks(BinaryReader reader, StringBuilder builder, long stopAddress)
{
while (reader.BaseStream.Position < stopAddress)
{
Mp4Block block = new Mp4Block();
block.Address = reader.BaseStream.Position;
block.Size = ReadUInt32(reader);
if (block.Size == 0)
{
break;
}
reader.Read(_buffer, 0, 4);
if (_buffer[0] < 'A' || (_buffer[0] > 'z' && _buffer[0] != 0xA9) ||
_buffer[1] < 'A' || _buffer[1] > 'z' ||
_buffer[2] < 'A' || _buffer[2] > 'z' ||
_buffer[3] < 'A' || _buffer[3] > 'z')
{
return;
}
if (builder.Length > 0)
{
builder.Append('.');
}
builder.Append((char)_buffer[0]);
builder.Append((char)_buffer[1]);
builder.Append((char)_buffer[2]);
builder.Append((char)_buffer[3]);
block.Tag = builder.ToString();
_blocks.Add(block);
if (block.Tag == "moov.udta.meta")
{
reader.BaseStream.Seek(4, SeekOrigin.Current);
}
ReadBlocks(reader, builder, block.Address + block.Size);
builder.Length -= 4;
if (builder.Length > 0)
{
builder.Length--;
}
reader.BaseStream.Seek(block.Address + block.Size, SeekOrigin.Begin);
}
}
private void MoveMetaBlock(Mp4Block block, long newAddress)
{
var adjustment = newAddress - block.Address;
using (var stream = File.Open(_path, FileMode.Open, FileAccess.ReadWrite))
{
var reader = new BinaryReader(stream);
var writer = new BinaryWriter(stream);
var buffer = new byte[block.Size];
stream.Position = block.Address;
reader.Read(buffer, 0, (int)block.Size);
stream.Position = newAddress;
writer.Write(buffer, 0, (int)block.Size);
var nextBlockAddress = block.Address + block.Size;
for (int i = 0; i < _blocks.Count; i++)
{
if (_blocks[i].Address == nextBlockAddress)
{
if (_blocks[i].Tag == "free")
{
var block2 = _blocks[i];
block2.Address += adjustment;
block2.Size -= adjustment;
_blocks[i] = block2;
stream.Position = block2.Address;
WriteUInt32(writer, (uint)block2.Size);
}
break;
}
}
}
for (int i = 0; i < _blocks.Count; i++)
{
if (_blocks[i].Address >= block.Address && _blocks[i].Address < block.Address + block.Size + adjustment)
{
var block2 = _blocks[i];
block2.Address += adjustment;
_blocks[i] = block2;
}
}
}
