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Attempt to implement writing EBML compressed integers, needs heavy testing...

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This commit is contained in:
Michael Becker 2014-10-24 17:16:21 -04:00
parent 5430a48b6a
commit 3de240486c
1 changed files with 108 additions and 3 deletions
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111
CSharp/Plugins/UniversalEditor.Essential/DataFormats/Markup/EBML/EBMLDataFormat.cs
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@ -40,8 +40,8 @@ namespace UniversalEditor.DataFormats.Markup.EBML
private MarkupElement ReadEBMLElement(Reader reader)
{
long elementID = ReadEBMLElementID(reader);
long dataSize = ReadEBMLElementID(reader);
long elementID = ReadEBMLCompressedInteger(reader);
long dataSize = ReadEBMLCompressedInteger(reader);
byte[] data = reader.ReadBytes(dataSize);
MarkupTagElement tag = new MarkupTagElement();
@ -67,7 +67,7 @@ namespace UniversalEditor.DataFormats.Markup.EBML
return tag;
}
private long ReadEBMLElementID(Reader reader)
private long ReadEBMLCompressedInteger(Reader reader)
{
byte[] buffer = reader.ReadBytes(8);
reader.Seek(-8, SeekOrigin.Current);
@ -191,6 +191,111 @@ namespace UniversalEditor.DataFormats.Markup.EBML
// which will be sufficient for the time being.
throw new NotImplementedException("Unknown Element Size coding: 0x" + buffer[0].ToString("X"));
}
private void WriteEBMLCompressedInteger(Writer writer, long value)
{
if (value <= 0x7F)
{
writer.WriteByte((byte)(value & 0x80));
return;
}
else if (value <= 0x7FFF)
{
// two bytes
byte[] _buffer = new byte[2];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[1] | 0x40);
_buffer[1] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
else if (value <= 0x7FFFFF)
{
// three bytes
byte[] _buffer = new byte[3];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[2] | 0x20);
_buffer[1] = buffer[1];
_buffer[2] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
else if (value <= 0x7FFFFFFF)
{
// four bytes
byte[] _buffer = new byte[4];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[3] | 0x10);
_buffer[1] = buffer[2];
_buffer[2] = buffer[1];
_buffer[3] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
else if (value <= 0x7FFFFFFFFF)
{
// five bytes
byte[] _buffer = new byte[5];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[4] | 0x08);
_buffer[1] = buffer[3];
_buffer[2] = buffer[2];
_buffer[3] = buffer[1];
_buffer[4] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
else if (value <= 0x7FFFFFFFFFFF)
{
// six bytes
byte[] _buffer = new byte[6];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[5] | 0x04);
_buffer[1] = buffer[4];
_buffer[2] = buffer[3];
_buffer[3] = buffer[2];
_buffer[4] = buffer[1];
_buffer[5] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
else if (value <= 0x7FFFFFFFFFFFFF)
{
// seven bytes
byte[] _buffer = new byte[7];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[6] | 0x02);
_buffer[1] = buffer[5];
_buffer[2] = buffer[4];
_buffer[3] = buffer[3];
_buffer[4] = buffer[2];
_buffer[5] = buffer[1];
_buffer[6] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
else if (value <= 0x7FFFFFFFFFFFFFFF)
{
// eight bytes
byte[] _buffer = new byte[8];
byte[] buffer = BitConverter.GetBytes(value);
_buffer[0] = (byte)(buffer[7] | 0x01);
_buffer[1] = buffer[6];
_buffer[2] = buffer[5];
_buffer[3] = buffer[4];
_buffer[4] = buffer[3];
_buffer[5] = buffer[2];
_buffer[6] = buffer[1];
_buffer[7] = buffer[0];
writer.WriteBytes(_buffer);
return;
}
// Since modern computers do not easily deal with data coded in sizes greater than 64 bits,
// any larger Element Sizes are left undefined at the moment. Currently, the Element Size
// coding allows for an Element to grow to 72000 To, i.e. 7x10^16 octets or 72000 terabytes,
// which will be sufficient for the time being.
throw new NotImplementedException("Value cannot be represented as an EBML compressed integer: " + value.ToString());
}
protected override void SaveInternal(ObjectModel objectModel)
{