--- a/Discovery/Src/logbook_miniLive.c	Mon Jan 04 21:38:28 2021 +0100
+++ b/Discovery/Src/logbook_miniLive.c	Mon Jan 04 21:41:51 2021 +0100
@@ -18,8 +18,12 @@
   */
 
 /* Includes ------------------------------------------------------------------*/
+
+
+#include <string.h>
 #include "logbook_miniLive.h"
 #include "data_exchange.h"
+#include "logbook.h"
 
  /*
   ******************************************************************************
@@ -35,7 +39,18 @@
 static uint16_t MLLdataDepth[MLLsize];
 static uint16_t MLLpointer  = 0;
 static uint8_t MLLtickIntervallSeconds = 2;
-	
+
+/* Replay Block data storage */
+#define DEPTH_DATA_LENGTH	(1800u)				/* Resolution: 5 hours dive, sampling every 10 seconds */
+uint16_t depthdata[DEPTH_DATA_LENGTH];
+uint16_t livedepthdata[DEPTH_DATA_LENGTH * 2];
+static uint16_t historyIndex = 0;
+
+static uint8_t	ReplayDataResolution = 2;		/* Time represented by one sample (second) */
+static uint16_t ReplayDataLength = 0;			/* Number of data entries */
+static uint16_t ReplayDataMaxDepth = 0;
+static uint16_t ReplayDataMinutes = 0;
+static uint16_t ReplayDataOffset = 0xFFFF;		/* Stepbackwards format used by log functions */
 
 uint16_t *getMiniLiveLogbookPointerToData(void)
 {
@@ -48,13 +63,28 @@
 	return MLLpointer;
 }
 	
+void compressBuffer_uint16(uint16_t* pdata, uint16_t size)
+{
+	uint16_t* pTarget = pdata;
+	uint16_t* pSource = pdata;
 	
+	uint16_t index = 0;
 	
+	for(index = 0; index < size/2; index++)
+	{
+		*pTarget = *pSource++;
+		*pTarget += *pSource++;
+		*pTarget++ /= 2;
+	}
+	memset(pTarget,0,size/2);
+}
+
 void updateMiniLiveLogbook( _Bool checkOncePerSecond)
 {
 	static uint8_t bDiveMode = 0;
 	static uint32_t last_second = 0;
 	static uint8_t secondsCount = 0;
+	static uint8_t historysecondsCount = 0;
 
 	if(checkOncePerSecond)
 	{
@@ -64,6 +94,7 @@
 		last_second = now;
 	}
 	secondsCount++;
+	historysecondsCount++;
 	
 	if(!bDiveMode)
 	{
@@ -75,6 +106,14 @@
 			MLLpointer = 1;
 			for(int i=0;i<MLLsize;i++)
 				MLLdataDepth[i] = 0;
+
+			for(historyIndex = 0; historyIndex < DEPTH_DATA_LENGTH; historyIndex++)
+			{
+				livedepthdata[historyIndex] = 0xFFFF;
+			}
+			historysecondsCount = 0;
+			historyIndex = 0;
+			livedepthdata[historyIndex++] = 0;	/* start at 0 */
 		}
 	}
 	else if(stateUsed->mode == MODE_DIVE)
@@ -84,23 +123,30 @@
 		if(secondsCount >= MLLtickIntervallSeconds)
 		{
 			secondsCount = 0;
+			/* in case of a buffer overrun the buffer is divided and the first half is filled with a compressed image of the complete buffer */
 			if((MLLpointer >= MLLsize) && (MLLtickIntervallSeconds < 127))
 			{
 				MLLpointer = 0;
 				MLLtickIntervallSeconds *= 2;
-				for(int i=0;i<MLLsize/2;i++)
-				{
-					MLLdataDepth[i] = MLLdataDepth[MLLpointer++];
-					MLLdataDepth[i] += MLLdataDepth[MLLpointer++];
-					MLLdataDepth[i] /= 2;
-				}
+
+				compressBuffer_uint16(MLLdataDepth,MLLsize);
 				MLLpointer = MLLsize/2;
-				for(int i=MLLsize/2;i<MLLsize;i++)
-					MLLdataDepth[i] = 0;
 			}
 			if(MLLpointer < MLLsize)
 				MLLdataDepth[MLLpointer++] = (int)(stateUsed->lifeData.depth_meter * 10);
 		}
+		if(historysecondsCount > ReplayDataResolution)
+		{
+			historysecondsCount = 0;
+
+			if(historyIndex >= 2*DEPTH_DATA_LENGTH)		/* compress data */
+			{
+				ReplayDataResolution *= 2;
+				compressBuffer_uint16(livedepthdata,2*DEPTH_DATA_LENGTH);
+				historyIndex = DEPTH_DATA_LENGTH;
+			}
+			livedepthdata[historyIndex++] = (int)(stateUsed->lifeData.depth_meter * 100);
+		}
 	}
 	else if(bDiveMode == 3)
 	{
@@ -111,6 +157,78 @@
 	}
 }
 
+uint8_t prepareReplayLog(uint8_t StepBackwards)
+{
+	uint8_t retVal = 0;
+	uint16_t dataLength = 0;
 
+    SLogbookHeader logbookHeader;
+
+    if(ReplayDataOffset == StepBackwards)				/* Entry already selected => reset selection */
+    {
+    	ReplayDataOffset = 0xFFFF;
+    	ReplayDataResolution = 2;
+    	retVal = 1;
+    }
+    else
+    {
+    	ReplayDataOffset = StepBackwards;
+		logbook_getHeader(StepBackwards ,&logbookHeader);
+
+		dataLength = logbook_readSampleData(StepBackwards, DEPTH_DATA_LENGTH, depthdata,NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
+
+		if( dataLength == DEPTH_DATA_LENGTH)		/* log data has been compressed to fit into buffer */
+		{
+			ReplayDataResolution = (logbookHeader.diveTimeMinutes * 60 + logbookHeader.diveTimeSeconds) / dataLength;
+		}
+		else
+		{
+			ReplayDataResolution = logbookHeader.samplingRate;
+		}
+		ReplayDataLength = dataLength;
+		ReplayDataMaxDepth = logbookHeader.maxDepth;
+		ReplayDataMinutes =  logbookHeader.diveTimeMinutes;
+		if(dataLength != 0)
+		{
+			retVal = 1;
+		}
+    }
+	return retVal;
+}
+
+uint8_t getReplayInfo(uint16_t** pReplayData, uint16_t* DataLength, uint16_t* MaxDepth, uint16_t* diveMinutes)
+{
+	uint8_t retVal = 0;
+
+	if((ReplayDataOffset != 0xFFFF) && (pReplayData != NULL) && (DataLength != NULL) && (MaxDepth != NULL))
+	{
+		*pReplayData = depthdata;
+		*DataLength = ReplayDataLength;
+		*MaxDepth = ReplayDataMaxDepth;
+		*diveMinutes = ReplayDataMinutes;
+		retVal = 1;
+	}
+
+	return retVal;
+}
+
+uint16_t *getMiniLiveReplayPointerToData(void)
+{
+	return livedepthdata;
+}
+uint16_t getMiniLiveReplayLength(void)
+{
+	return historyIndex;
+}
+
+uint16_t getReplayOffset(void)
+{
+	return ReplayDataOffset;
+}
+
+uint16_t getReplayDataResolution(void)
+{
+	return ReplayDataResolution;
+}
 
 /************************ (C) COPYRIGHT heinrichs weikamp *****END OF FILE****/