Merge pull request #8 from dmadison/no-buffer

No buffer

Arduino/LEDstream_FastLED/LEDstream_FastLED.ino

@@ -4,7 +4,7 @@
  * library (http://fastled.io) for driving led strips.
  * 
  * http://github.com/dmadison/Adalight-FastLED
- * Last Updated: 2017-03-27
+ * Last Updated: 2017-04-08
  */
 
 // --- General Settings
@@ -52,10 +52,14 @@ uint8_t * ledsRaw = (uint8_t *)leds;
 static const uint8_t magic[] = {
 	'A','d','a'};
 #define MAGICSIZE  sizeof(magic)
-#define HEADERSIZE (MAGICSIZE + 3)
+
+// Check values are header byte # - 1, as they are indexed from 0
+#define HICHECK    (MAGICSIZE)
+#define LOCHECK    (MAGICSIZE + 1)
+#define CHECKSUM   (MAGICSIZE + 2)
 
 #define MODE_HEADER 0
-#define MODE_DATA   2
+#define MODE_DATA   1
 
 void setup(){
 	#ifdef GROUND_PIN
@@ -76,26 +80,16 @@ void setup(){
 }
 
 void adalight(){ 
-	// Dirty trick: the circular buffer for serial data is 256 bytes,
-	// and the "in" and "out" indices are unsigned 8-bit types -- this
-	// much simplifies the cases where in/out need to "wrap around" the
-	// beginning/end of the buffer. Otherwise there'd be a ton of bit-
-	// masking and/or conditional code every time one of these indices
-	// needs to change, slowing things down tremendously.
-
 	uint8_t
-		buffer[256],
-		indexIn       = 0,
-		indexOut      = 0,
-		mode          = MODE_HEADER,
-		hi, lo, chk, i;
+		mode = MODE_HEADER,
+		headPos,
+		hi, lo, chk;
 	int16_t
 		c;
 	uint16_t
-		bytesBuffered = 0;
-	uint32_t
-		bytesRemaining,
 		outPos;
+	uint32_t
+		bytesRemaining;
 	unsigned long
 		lastByteTime,
 		lastAckTime,
@@ -113,84 +107,83 @@ void adalight(){
 		// Implementation is a simple finite-state machine.
 		// Regardless of mode, check for serial input each time:
 		t = millis();
-		if((bytesBuffered < 256) && ((c = Serial.read()) >= 0)) {
-			buffer[indexIn++] = c;
-			bytesBuffered++;
+
+		if((c = Serial.read()) >= 0){
 			lastByteTime = lastAckTime = t; // Reset timeout counters
-		} 
-		else {
-			// No data received. If this persists, send an ACK packet
-			// to host once every second to alert it to our presence.
-			if((t - lastAckTime) > 1000) {
-				Serial.print("Ada\n"); // Send ACK string to host
-				lastAckTime = t; // Reset counter
-			}
-			// If no data received for an extended time, turn off all LEDs.
-			if((t - lastByteTime) > SerialTimeout) {
-				memset(leds, 0, Num_Leds * sizeof(struct CRGB)); //filling Led array by zeroes
-				FastLED.show();
-				lastByteTime = t; // Reset counter
-			}
-		}
-
-		switch(mode) {
-
-		case MODE_HEADER:
-
-			// In header-seeking mode. Is there enough data to check?
-			if(bytesBuffered >= HEADERSIZE) {
-				// Indeed. Check for a 'magic word' match.
-				for(i=0; (i<MAGICSIZE) && (buffer[indexOut++] == magic[i++]););
-				if(i == MAGICSIZE) {
-					// Magic word matches. Now how about the checksum?
-					hi  = buffer[indexOut++];
-					lo  = buffer[indexOut++];
-					chk = buffer[indexOut++];
-					if(chk == (hi ^ lo ^ 0x55)) {
-						// Checksum looks valid. Get 16-bit LED count, add 1
-						// (# LEDs is always > 0) and multiply by 3 for R,G,B.
-						bytesRemaining = 3L * (256L * (long)hi + (long)lo + 1L);
-						bytesBuffered -= 3;
-						outPos = 0;
-						memset(leds, 0, Num_Leds * sizeof(struct CRGB));
-						mode           = MODE_DATA; // Proceed to latch wait mode
-					} 
-					else {
-						// Checksum didn't match; search resumes after magic word.
-						indexOut -= 3; // Rewind
+
+			switch(mode) {
+
+			case MODE_HEADER:
+
+				if(headPos < MAGICSIZE){
+					if(c == magic[headPos]) headPos++;
+					else headPos = 0;
+				}
+				else{
+					switch(headPos){
+						case HICHECK:
+							hi = c;
+							headPos++;
+							break;
+						case LOCHECK:
+							lo = c;
+							headPos++;
+							break;
+						case CHECKSUM:
+							chk = c;
+							if(chk == (hi ^ lo ^ 0x55)) {
+								// Checksum looks valid. Get 16-bit LED count, add 1
+								// (# LEDs is always > 0) and multiply by 3 for R,G,B.
+								bytesRemaining = 3L * (256L * (long)hi + (long)lo + 1L);
+								outPos = 0;
+								memset(leds, 0, Num_Leds * sizeof(struct CRGB));
+								mode = MODE_DATA; // Proceed to latch wait mode
+							}
+							headPos = 0; // Reset header position regardless of checksum result
+							break;
 					}
-				} // else no header match. Resume at first mismatched byte.
-				bytesBuffered -= i;
-			}
-			break;
-
-		case MODE_DATA:
+				}
+				break;
+
+			case MODE_DATA:
 
-			if(bytesRemaining > 0) {
-				if(bytesBuffered > 0) {
+				if(bytesRemaining > 0) {
 					if (outPos < sizeof(leds)){
 						#ifdef CALIBRATE
 							if(outPos < 3)
-								ledsRaw[outPos++] = buffer[indexOut];
+								ledsRaw[outPos++] = c;
 							else{
 								ledsRaw[outPos] = ledsRaw[outPos%3]; // Sets RGB data to first LED color
 								outPos++;
 							}
 						#else
-							ledsRaw[outPos++] = buffer[indexOut]; // Issue next byte
+							ledsRaw[outPos++] = c; // Issue next byte
 						#endif
 					}
-					indexOut++;
-					bytesBuffered--;
 					bytesRemaining--;
 				}
+				if(bytesRemaining == 0) {
+					// End of data -- issue latch:
+					mode = MODE_HEADER; // Begin next header search
+					FastLED.show();
+				}
+				break;
+			} // end switch
+		} // end serial if
+		else {
+			// No data received. If this persists, send an ACK packet
+			// to host once every second to alert it to our presence.
+			if((t - lastAckTime) > 1000) {
+				Serial.print("Ada\n"); // Send ACK string to host
+				lastAckTime = t; // Reset counter
 			}
-			else {
-				// End of data -- issue latch:
-				mode       = MODE_HEADER; // Begin next header search
+			// If no data received for an extended time, turn off all LEDs.
+			if((t - lastByteTime) > SerialTimeout) {
+				memset(leds, 0, Num_Leds * sizeof(struct CRGB)); //filling Led array by zeroes
 				FastLED.show();
+				lastByteTime = t; // Reset counter
 			}
-		} // end switch
+		} // end else
 	} // end for(;;)
 }