public static IEnumerable <byte[]> Blocks(MYDBinaryReader br)
{
while (br.Position < br.Length)
{
MYDBlock root_block = MYDBlock.Read(br);
//root_block.DumpStats();
long post_block_processing_return_offset = br.Position;
// Only follow blocks that are a 'starting block'
if (!root_block.is_block_first)
{
continue;
}
// Concatenate all blocks
byte[] record_data = new byte[root_block.rec_len];
{
MYDBlock block = root_block;
int record_data_i = 0;
while (true)
{
Array.Copy(block.data, 0, record_data, record_data_i, block.data_len);
record_data_i += block.data_len;
if (block.is_block_last)
{
break;
}
if (0 == block.next_filepos)
{
throw new GenericException("Expecting a file offset if we have more blocks!");
}
br.Seek(block.next_filepos);
//Logging.Info("Appending additional data from block at {0}", block.next_filepos);
block = MYDBlock.Read(br);
//block.DumpStats("\t");
}
if (record_data_i != root_block.rec_len)
{
throw new GenericException("Block building length {0} is different to expected length of {1}!", record_data_i, root_block.rec_len);
}
}
br.Seek(post_block_processing_return_offset);
yield return(record_data);
}
}
internal static MYDBlock Read(MYDBinaryReader br)
{
MYDBlock block = new MYDBlock();
// Debugging purposes
block.start_position = br.Position;
// Start of header
block.header = br.ReadByte();
block.rec_len = 0;
block.data_len = 0;
block.block_len = 0;
block.next_filepos = 0;
// See http://dev.mysql.com/doc/internals/en/layout-record-storage-frame.html
// Or bottom of this code
switch (block.header)
{
case 0:
block.block_len = br.Read3();
block.block_len -= 4; // Deleted blocks include the header in their total length...sigh.
block.is_block_deleted = true;
break;
case 1:
block.rec_len = block.data_len = block.block_len = br.Read2();
block.is_block_first = block.is_block_last = true;
break;
case 2:
block.rec_len = block.data_len = block.block_len = br.Read3();
block.is_block_first = block.is_block_last = true;
break;
case 13:
block.rec_len = br.Read4();
block.data_len = block.block_len = br.Read3();
block.next_filepos = br.Read8();
block.is_block_first = true;
break;
case 3:
block.rec_len = block.data_len = br.Read2();
block.block_len = block.rec_len + br.Read1();
block.is_block_first = block.is_block_last = true;
break;
case 4:
block.rec_len = block.data_len = br.Read3();
block.block_len = block.rec_len + br.Read1();
block.is_block_first = block.is_block_last = true;
break;
case 5:
block.rec_len = br.Read2();
block.data_len = block.block_len = br.Read2();
block.next_filepos = br.Read8();
block.is_block_first = true;
break;
case 6:
block.rec_len = br.Read3();
block.data_len = block.block_len = br.Read3();
block.next_filepos = br.Read8();
block.is_block_first = true;
break;
case 7:
block.data_len = block.block_len = br.Read2();
block.is_block_last = true;
break;
case 8:
block.data_len = block.block_len = br.Read3();
block.is_block_last = true;
break;
case 9:
block.data_len = br.Read2();
block.block_len = block.data_len + br.Read1();
block.is_block_last = true;
break;
case 10:
block.data_len = br.Read3();
block.block_len = block.rec_len + br.Read1();
block.is_block_last = true;
break;
case 11:
block.data_len = block.block_len = br.Read2();
block.next_filepos = br.Read8();
break;
case 12:
block.data_len = block.block_len = br.Read3();
block.next_filepos = br.Read8();
break;
default:
break;
}
block.data = br.ReadBytes(block.block_len);
return(block);
}
