public static string ReadNullTerminatedUtf16String(this IReadOnlyBinaryDataAccessor accessor, long offset)
{
var encoding = Encoding.Unicode;
var output = new StringBuilder();
var index = offset;
Span <char> chars = stackalloc char[1];
do
{
var length = encoding.GetChars(accessor.ReadSpan(index, 2), chars);
if (length > 0)
{
output.Append(chars);
}
index += 2;
} while (chars[0] != '\0');
output.Length -= 1; // Trim the null char
return(output.ToString());
}
public static IBinaryDataAccessor Decompress(IReadOnlyBinaryDataAccessor data)
{
var Magic = data.ReadInt32(0);
var Length = data.ReadInt32(4);
IBinaryDataAccessor dest = new BinaryFile(new byte[Length]);
var dataIndex = 8;
var destIndex = 0;
while (true)
{
byte cur = data.ReadByte(dataIndex++);
if (cur < 0x80)
{
var next = data.ReadByte(dataIndex++);
// EOF marker
if (cur == 0x7F && next == 0xFF)
{
return(dest);
}
var offset = 0x400 - ((cur & 3) * 0x100 + next);
var bytes = dest.ReadSpan(destIndex - offset, (cur >> 2) + 2);
dest.Write(destIndex, bytes);
destIndex += bytes.Length;
continue;
}
var op = (Opcode)((cur >> 5) - 4);
var arg = cur & 0x1F;
switch (op)
{
case Opcode.Copy:
{
var bytes = data.ReadSpan(dataIndex, arg + 1);
dataIndex += bytes.Length;
dest.Write(destIndex, bytes);
destIndex += bytes.Length;
break;
}
case Opcode.SplitCopy:
{
var sep = data.ReadByte(dataIndex++);
var bytes = data.ReadSpan(dataIndex, arg + 2);
dataIndex += bytes.Length;
foreach (byte x in bytes)
{
dest.Write(destIndex++, sep);
dest.Write(destIndex++, x);
}
break;
}
case Opcode.Fill:
{
var fill = data.ReadByte(dataIndex++);
for (int i = 0; i < arg + 2; i++)
{
dest.Write(destIndex++, fill);
}
break;
}
case Opcode.Skip:
{
var count = arg < 0x1F ? arg + 1 : 0x20 + data.ReadByte(dataIndex++);
destIndex += count;
break;
}
}
}
}
