/// <summary>
/// Processes a 2B "RadioText" frame type 0b00101
/// </summary>
/// <param name="frame"></param>
private void ProcessFramePayload_RadioTextB(RDSFrame frame)
{
//Read the header flags
bool flagAb = 1 == ((frame.b >> (HEADER_OFFSET - 0)) & 0b0000000000000001);
//Get the index and multiply it by 2, as that is the spacing
int addressIndex = (frame.b & 0b0000000000001111) * 2;
//Check if we should reset
if (flagAb != _rtLastAbFlag && addressIndex == 0)
{
//Clear buffer
for (int i = 0; i < rtBuffer.Length; i++)
{
rtBuffer[i] = (char)0x00;
}
//Update state
_rtLastAbFlag = flagAb;
//Send event
OnRtBufferCleared?.Invoke(this);
}
//Write all
rtBuffer[addressIndex + 0] = (char)((frame.d >> 8) & 0x00FF);
rtBuffer[addressIndex + 1] = (char)((frame.d >> 0) & 0x00FF);
//Search this string to see if we reached the end
int endIndex = -1;
for (int i = addressIndex; i < addressIndex + 4; i++)
{
if (rtBuffer[i] == (char)0x0A)
{
endIndex = i;
break;
}
}
//Send buffer updated events
OnRtBufferUpdated?.Invoke(this, rtBuffer);
//Handle ending if we did
if (endIndex != -1)
{
//Convert to string and update state
rtText = new string(rtBuffer, 0, endIndex);
rtComplete = true;
//Send event
OnRtTextUpdated?.Invoke(this, rtText);
}
}
public void ProcessFrame(RDSFrame frame)
{
//Get the PI code from the first block. We flip this because that's how it's familiar
ushort piCode = (ushort)((frame.a >> 8) | (frame.a << 8));
//Decode header data that will always exist
byte groupTypeCode = (byte)((frame.b >> (16 - 5)) & 0b0000000000011111);
bool trafficSupported = 1 == ((frame.b >> (16 - 6)) & 0b0000000000000001);
byte programTypeCode = (byte)((frame.b >> (16 - 11)) & 0b0000000000011111);
//Send updated events for these
if (this.piCode != piCode)
{
this.piCode = piCode;
OnPiCodeUpdated?.Invoke(this, piCode);
}
if (this.trafficSupported != trafficSupported)
{
this.trafficSupported = trafficSupported;
OnTrafficSupportedUpdated?.Invoke(this, trafficSupported);
}
if (this.programTypeCode != programTypeCode)
{
this.programTypeCode = programTypeCode;
OnProgramTypeUpdated?.Invoke(this, programTypeCode);
}
//We'll now handle decoding of this frame
switch (groupTypeCode)
{
case 0b00000: ProcessFramePayload_BasicInfo(frame); break;
case 0b00001: ProcessFramePayload_BasicInfo(frame); break;
case 0b00100: ProcessFramePayload_RadioTextA(frame); break;
case 0b00101: ProcessFramePayload_RadioTextB(frame); break;
case 0b01000: ProcessFramePayload_ClockTime(frame); break;
}
}
/// <summary>
/// Processes 0A and 0B "basic tuning and switching" frame types 0b00000 and 0b00001
/// </summary>
private void ProcessFramePayload_BasicInfo(RDSFrame frame)
{
//Read the header flags
bool flagTa = 1 == ((frame.b >> (HEADER_OFFSET - 0)) & 0b0000000000000001);
bool flagMs = 1 == ((frame.b >> (HEADER_OFFSET - 1)) & 0b0000000000000001);
bool flagDi = 1 == ((frame.b >> (HEADER_OFFSET - 2)) & 0b0000000000000001);
//Get the code bits. These are just used for the text for the most part just for the PS name
byte decoderControlCode = (byte)((frame.b >> (HEADER_OFFSET - 4)) & 0b0000000000000011);
//Get the two PS code characters
char psA = (char)((frame.d >> 8) & 0x00FF);
char psB = (char)((frame.d >> 0) & 0x00FF);
//Write to the PS buffer
psBuffer[(decoderControlCode * 2) + 0] = psA;
psBuffer[(decoderControlCode * 2) + 1] = psB;
//Set flags for the characters updated if they're in sequential order
if (decoderControlCode == psUpdatedFrameIndex)
{
psUpdatedFrameIndex++;
}
//Check if we've completed it
if (psUpdatedFrameIndex == 4)
{
//Completed!
//Update state
psName = new string(psBuffer);
psComplete = true;
psUpdatedFrameIndex = 0;
//Fire events
OnPsNameUpdated?.Invoke(this, psName);
}
//Send updated events
OnPsBufferUpdated?.Invoke(this, psBuffer);
}
/// <summary>
/// Processes a 4A "Clock-time and date" frame 0b01000
/// </summary>
private void ProcessFramePayload_ClockTime(RDSFrame frame)
{
//Read julian day code
uint dayCode = (uint)((frame.c >> 1) & 0b0111111111111111);
dayCode |= (uint)(((frame.b >> (HEADER_OFFSET - 4)) & 0b0000000000000011) << 15);
//Decode day code according to Annex G of the linked document
//This is in UTC
int year = (int)((dayCode - 15078.2f) / 365.25f);
int month = (int)((dayCode - 14956.1f - (int)(year * 365.25f)) / 30.6001f);
int day = (int)dayCode - 14956 - ((int)(year * 365.25f)) - ((int)(month * 30.6001f));
int k;
if (month == 14 || month == 15)
{
k = 1;
}
else
{
k = 0;
}
year += 1900 + k;
month -= 1 - (k * 12);
//Get the hour
int localHour = ((frame.d >> 12) & 0b0000000000001111);
localHour |= ((frame.c & 0b0000000000000001) << 4);
//Get the minute
int localMinute = ((frame.d >> 6) & 0b0000000000111111);
//Get the local time offset, in half hours. Also calculate the sign
int localOffsetParts = (frame.d & 0b0000000000011111);
if ((frame.d & 0b0000000000100000) != 0)
{
localOffsetParts = -localOffsetParts;
}
DateTime time;
TimeSpan localOffset;
DateTime localTime;
try
{
//Create a UTC DateTime from the UTC portion
time = new DateTime(year, month, day, 0, 0, 0, 0, DateTimeKind.Local);
//Convert the local hour and minute to a TimeSpan we'll save
localOffset = new TimeSpan(0, 30 * localOffsetParts, 0);
//Convert to local time
localTime = time.AddMinutes((localHour * 60) + (localOffsetParts * 30) + localMinute);
} catch
{
//Ignore. If this was a corrupted RDS frame, this would've thrown an exception
return;
}
//Set
this.timeLast = localTime;
this.timeOffset = localOffset;
this.timeComplete = true;
//Send event
OnTimeUpdated?.Invoke(this, localTime, localOffset);
}
/// <summary>
/// Processes a 2A "RadioText" frame type 0b00100
/// </summary>
/// <param name="frame"></param>
private void ProcessFramePayload_RadioTextA(RDSFrame frame)
{
//Read the header flags
bool flagAb = 1 == ((frame.b >> (HEADER_OFFSET - 0)) & 0b0000000000000001);
//Get the index and multiply it by 4, as that is the spacing
int addressIndex = (frame.b & 0b0000000000001111) * 4;
//Check if we should reset
if (flagAb != _rtLastAbFlag && addressIndex == 0)
{
//Clear buffer
for (int i = 0; i < rtBuffer.Length; i++)
{
rtBuffer[i] = (char)0x00;
}
//Update state
_rtLastAbFlag = flagAb;
//Send event
OnRtBufferCleared?.Invoke(this);
}
//Write all
rtBuffer[addressIndex + 0] = (char)((frame.c >> 8) & 0x00FF);
rtBuffer[addressIndex + 1] = (char)((frame.c >> 0) & 0x00FF);
rtBuffer[addressIndex + 2] = (char)((frame.d >> 8) & 0x00FF);
rtBuffer[addressIndex + 3] = (char)((frame.d >> 0) & 0x00FF);
//Search this string to see if we reached the end
int endIndex = -1;
for (int i = addressIndex; i < addressIndex + 4; i++)
{
//Official spec claims that the character 0x0A should be used to indicate the end, but some stations in my area don't do that.
//We also check \r for this reason. Cumulus Media stations are using \r instead.
if (rtBuffer[i] == (char)0x0A || rtBuffer[i] == '\r')
{
endIndex = i;
break;
}
}
//Send buffer updated events
OnRtBufferUpdated?.Invoke(this, rtBuffer);
//Handle ending if we did
if (endIndex != -1)
{
//Make sure this is really the end. We should have no null characters up to this point
for (int i = 0; i < endIndex; i++)
{
if (rtBuffer[i] == (char)0x00)
{
return;
}
}
//Convert to string and update state
rtText = new string(rtBuffer, 0, endIndex);
rtComplete = true;
//Send event
OnRtTextUpdated?.Invoke(this, rtText);
}
}
