/// <summary>
/// Reads an automaton from a byte stream.
/// </summary>
/// <param name="stream">The stream to read.</param>
internal CFSA2(Stream stream)
{
using (DataInputStream input = new DataInputStream(stream, true))
{
// Read flags.
ushort flagBits = (ushort)input.ReadInt16();
flags = 0;
flags = (FSAFlags)flagBits;
if (flagBits != (ushort)flags)
{
throw new IOException($"Unrecognized flags: 0x{((int)flagBits).ToHexString()}");
}
this.hasNumbers = (flags & FSAFlags.Numbers) != 0;
/*
* Read mapping dictionary.
*/
int labelMappingSize = input.ReadByte() & 0xff;
LabelMapping = new byte[labelMappingSize];
input.ReadFully(LabelMapping);
/*
* Read arcs' data.
*/
Arcs = ReadRemaining(input);
}
}
/// <summary>
/// Creates a new automaton, reading it from a file in FSA format, version 5.
/// </summary>
internal CFSA(Stream stream)
{
using (DataInputStream input = new DataInputStream(stream, true))
{
// Skip legacy header fields.
input.ReadByte(); // filler
input.ReadByte(); // annotation
byte hgtl = (byte)input.ReadByte();
/*
* Determine if the automaton was compiled with NUMBERS. If so, modify
* ctl and goto fields accordingly.
*/
flags = FSAFlags.Flexible | FSAFlags.StopBit | FSAFlags.NextBit;
if ((hgtl & 0xf0) != 0)
{
this.NodeDataLength = (hgtl.TripleShift(4)) & 0x0f;
this.GoToLength = hgtl & 0x0f;
flags |= FSAFlags.Numbers;
}
else
{
this.NodeDataLength = 0;
this.GoToLength = hgtl & 0x0f;
}
/*
* Read mapping dictionary.
*/
LabelMapping = new byte[1 << 5];
input.ReadFully(LabelMapping);
/*
* Read arcs' data.
*/
Arcs = ReadRemaining(input);
}
}
/// <summary>
/// Read and wrap a binary automaton in FSA version 5.
/// </summary>
internal FSA5(Stream stream)
{
DataInputStream input = new DataInputStream(stream);
this.Filler = (byte)input.ReadByte();
this.Annotation = (byte)input.ReadByte();
byte hgtl = (byte)input.ReadByte();
/*
* Determine if the automaton was compiled with NUMBERS. If so, modify
* ctl and goto fields accordingly.
*/
flags = FSAFlags.Flexible | FSAFlags.StopBit | FSAFlags.NextBit;
if ((hgtl & 0xf0) != 0)
{
flags |= FSAFlags.Numbers;
}
this.NodeDataLength = (hgtl.TripleShift(4)) & 0x0f;
this.GoToLength = hgtl & 0x0f;
Arcs = ReadRemaining(input);
}
