public bool Enqueue(int level, string msg)
{
var c = Encoding.UTF8.GetBytes(msg);
var data = new byte[c.Length + HeaderSize];
var s = new MemoryStream(data);
using (var sw = new BinaryWriter(s))
{
sw.Write(level); // 4
sw.Write(DateTime.Now.Ticks); // 8
sw.Write(c.Length); // 4
sw.Write(c);
}
using (var stream = MMF.CreateViewStream())
{
stream.Position = Front;
if (IsFull)
{
// No space
Log("No space for writing data");
return(false);
}
else
{
if (Front + data.Length < stream.Length)
{
// Enough space to go
stream.Write(data, 0, data.Length);
Front = stream.Position;
Log("Enough space, enqueue data");
}
else
{
// No enough space, break into two parts
var firstLen = (int)(stream.Length - Front);
var secondLen = data.Length - firstLen;
stream.Write(data, 0, firstLen);
stream.Position = ReservedSize; // reset to begin
stream.Write(data, firstLen - 1, secondLen);
Front = stream.Position;
Log("Split data and enqueue");
}
IsEmpty = false;
}
// 1. Front is catching up Rear in next cycle
// 2. Front is near the end of the stream, and remaining data in the head is not enough
if ((Rear > Front && Rear - Front < HeaderSize) || (stream.Length - Front - 1 + (Rear - ReservedSize)) < HeaderSize)
{
IsFull = true;
}
Log("Front:{0}, Rear:{1}", Front, Rear);
return(true);
}
}
public SharedMessage Dequeue()
{
using (var stream = MMF.CreateViewStream())
{
if (IsEmpty)
{
Log("No Data");
return(null);
}
else
{
using (var sr = new BinaryReader(stream))
{
stream.Position = Rear;
var header = new byte[HeaderSize];
if (stream.Length - Rear >= HeaderSize)
{
header = sr.ReadBytes(HeaderSize);
}
else
{
var firstLen = (int)(stream.Length - stream.Position);
var secondLen = HeaderSize - firstLen;
var header1 = sr.ReadBytes(firstLen);
stream.Position = ReservedSize;
var header2 = sr.ReadBytes(secondLen);
Array.Copy(header1, header, firstLen);
Array.Copy(header2, 0, header, firstLen - 1, secondLen);
}
var level = BitConverter.ToInt32(header, 0);
var time = new DateTime(BitConverter.ToInt64(header, 4));
var len = BitConverter.ToInt32(header, 12);
var msg = new byte[len];
if (stream.Position + len <= stream.Length)
{
msg = sr.ReadBytes(len);
}
else
{
var firstLen = (int)(stream.Length - stream.Position);
var secondLen = len - firstLen;
var msg1 = sr.ReadBytes(firstLen);
stream.Position = ReservedSize;
var msg2 = sr.ReadBytes(secondLen);
Array.Copy(msg1, msg, firstLen);
Array.Copy(msg2, 0, msg, firstLen - 1, secondLen);
}
Rear = stream.Position;
IsFull = false;
// 1. Rear is catching up Front
// 2. Rear is near the end of the stream, the remaining data is not enough
if (Front - Rear < HeaderSize || (stream.Length - Rear - 1 + (Front - ReservedSize)) < HeaderSize)
{
IsEmpty = true;
}
Log("Front:{0}, Rear:{1}", Front, Rear);
var message = Encoding.UTF8.GetString(msg);
Log("Level:{0}, Time:{1}, Message:{2}", level, time, message);
return(new SharedMessage()
{
Level = level,
Timestamp = time,
Message = message
});
}
}
}
}
