Modified code so frame references are fbs frames, not 0-based index numbers.

Added missing code to look for the latest available sample of a differential
channel when the beginning frame didn't have a sample.

DaqFileIO.cxx

@@ -2,7 +2,7 @@
 ///
 // DAQ low level IO Library
 // 
-// $Id: DaqFileIO.cxx,v 1.10 2005/03/22 20:12:17 yiannis Exp $
+// $Id: DaqFileIO.cxx,v 1.11 2005/04/14 14:19:17 yiannis Exp $
 // Date: March, 2005
 // Author: Yiannis Papelis
 //
@@ -1556,9 +1556,8 @@ CDaqLowLevelIo::LowLevelDataCopy(
 /// Finally, note that for differentially stored data, the extrapolation 
 /// method defaults to zero-hold.
 ///
-/// The frm1 and frm2 arguments specify the first/last frame to read, inclusively.
+/// The frm1 and frm2 arguments specify the first/last fbs frame to read, inclusively.
 /// Specify -1 to read from the start or to the end of file respectively.
-/// The frame numbers are 0 based, so the first frame would be 0.
 ///
 bool 
 CDaqLowLevelIo::GetFullData(
@@ -1660,29 +1659,27 @@ CDaqLowLevelIo::GetFullData(
 	CDaqLowLevelIo::TReadErrorCode rcode;
 
 	// 
-	// Adjust frame numbers so they reflect fbs frames.  Also, if frames are specified,
-	// adjust them to make sure they contain data; we look ahead for hte first frame
-	// and we look backwards for the last frame, that way we give the user slightly
-	// less than what was asked.
+	// Adjust frame numbers if the user specified -1.  Also, if frames are specified,
+	// adjust them to make sure they refer to frames that contain data; we look ahead for 
+	// the first frame and we look backwards for the last frame, that way we give 
+	// the user slightly less than what was asked.
 	//
-	if ( frm1 < 0 ) {
-		frm1 = GetFirstFrame(); 
-	}
-	else {
-		frm1 += GetFirstFrame();
+	if ( frm1 < 0 ) frm1 = GetFirstFrame(); 
+	if ( frm2 < 0 ) frm2 = GetLastFrame();
 
-		int triesLeft = 32;
-		while ( m_Toc.find(frm1) == m_Toc.end() && triesLeft-- > 0 ) frm1++;
+	if ( frm1 < GetFirstFrame() || frm1 > GetLastFrame() 
+				|| frm2 < GetFirstFrame() || frm2 > GetLastFrame() ) {
+		m_LastError = "invalid frame specification; remember frames are fbs based";
+		return false;
 	}
 
-	if ( frm2 < 0 ) {
-		frm2 = GetLastFrame(); 
-	}
-	else {
-		frm2 += GetFirstFrame();
-		int triesLeft = 32;
-		while ( m_Toc.find(frm2) == m_Toc.end() && triesLeft-- > 0 ) frm2--;
-	}
+	int triesLeft = 32;
+	while ( m_Toc.find(frm1) == m_Toc.end() && triesLeft-- > 0 ) frm1++;
+	assert(triesLeft>0);		// shouldn't really happen
+
+	triesLeft = 32;
+	while ( m_Toc.find(frm2) == m_Toc.end() && triesLeft-- > 0 ) frm2--;
+	assert(triesLeft>0);		// shouldn't really happen
 
 	//
 	// If the first frame to read is not the first one in the file, and if
@@ -1690,12 +1687,25 @@ CDaqLowLevelIo::GetFullData(
 	// of all differential channels, otherwise we may need to output data nad
 	// have none
 	//
-	if ( frm1 == GetFirstFrame() ) {
+	if ( frm1 != GetFirstFrame() ) {
 		for (size_t idx=0; idx < pChnList->size(); idx++) {
 			if ( m_Channels[(*pChnList)[idx]].GetCapRate() < 0 ) {
-				// TODO: here search backwards from frame frm1 until
+				// Search backwards from frame frm1 until
 				// we find data for the specific channel.  Store
 				// its values in latestData[idx]
+				bool done      = false;
+				int  candFrame = frm1;
+				int  theChan   = (*pChnList)[idx];
+
+				while ( !done && candFrame >= GetFirstFrame() ) {
+					ReadFrameHeader(candFrame, curFrame, numChan, bytesSkipped);
+					ReadChannelDataForOneFrame(numChan, theChan, latestData[idx], pTempSpace, done);
+					candFrame--;
+				}
+				if ( !done ) {
+					m_LastError = "could not find any data for var channel; possible internal error";
+					return false;
+				}
 			}
 		}
 	}
@@ -1708,7 +1718,7 @@ CDaqLowLevelIo::GetFullData(
 		return false;
 	}
 
-	while ( curFrame < frm2 ) {
+	while ( curFrame <= frm2 ) {
 		bool curFrameLost = FrameDropped(curFrame);
 
 		if ( curFrameLost ) {
@@ -1876,6 +1886,82 @@ CDaqLowLevelIo::ReadDataForOneFrame(
 	return eDAQ_READ_OK;
 }
 
+///////////////////////////////////////////////////////////////////////////////
+//
+// This function reads data for a specific channel from the current frame
+//
+CDaqLowLevelIo::TReadErrorCode
+CDaqLowLevelIo::ReadChannelDataForOneFrame(
+	int           numEntriesInThisRecord,
+	int           channel,
+	CDaqBuffer&   daqBuf,
+	void*         pTempSpace,
+	bool&         gotData
+)
+{
+	int idx;
+	char buf[256];
+
+	for (idx=0; idx<numEntriesInThisRecord; idx++) {
+		int chId;
+		if ( fread(&chId, sizeof(int), 1, m_pFile) != 1 ) return eDAQ_READ_ERROR;
+
+		if ( chId >= m_NumEntries || chId < 0 ) {
+			sprintf(buf, "Encountered invalid channel %d in data area", chId);
+			m_LastError = buf;
+			return eDAQ_READ_BAD_DATA;
+		}
+
+		CDaqChannelInfo& ch   = m_Channels[chId];
+		int              size;
+
+		if ( ch.IsVarLen() ) {
+			int actCount;
+			if ( fread(&actCount, sizeof(int), 1, m_pFile) != 1 ) {
+				sprintf(buf, "Could not read var size channel length; chId=%d, ofs=%d, abort",
+					chId, ftell(m_pFile));
+				m_LastError = buf;
+				(*m_UserErrorFunc)(m_Filename.c_str(), buf);
+				return eDAQ_READ_ERROR;
+			}
+			size = ch.GetItemSize() * actCount;
+		}
+		else {
+			size = ch.GetRecSize();
+		}
+
+		if ( chId == channel ) {	// we only care for the particular channel
+			if ( size > cMaxDaqRec ) {
+				sprintf(buf, "Daq record size too big, increase \"cMaxDaqRec\"");
+				m_LastError = buf;
+				return eDAQ_READ_INTERNAL_ERROR;
+			}
+
+			if ( size > 0 ) {
+				size_t n = fread(pTempSpace, size, 1, m_pFile);
+				if ( n != 1 ) {
+					sprintf(buf, "read data for channel %d failed", chId);
+					m_LastError = buf;
+					return eDAQ_READ_ERROR;
+				}
+			}
+
+			int fullSize = ch.GetRecSize();
+			if ( fullSize != size ) {
+				memset(((char *)pTempSpace) + size, 0, fullSize - size);
+			}
+			daqBuf.Replace(pTempSpace, fullSize, ch.GetItemCount());
+			gotData = true;
+			return eDAQ_READ_OK;
+		}
+		else {
+			// skip the data
+			fseek(m_pFile, size, SEEK_CUR);
+		}
+	}
+	return eDAQ_READ_OK;
+}
+
 
 /////////////////////////////////////////////////////////////////////////////
 //

DaqIo.h

@@ -82,6 +82,7 @@ private:
 	bool ReadTocFile(const string& fname);
 	TReadErrorCode ReadFrameHeader(int,	int& ,int&, int&);
 	TReadErrorCode ReadDataForOneFrame(int, TIntVec, TDataVec &, void *, vector<bool>&);
+	TReadErrorCode ReadChannelDataForOneFrame(int, int, CDaqBuffer&, void*, bool&);
 
 	string	m_Filename;
 	string  m_Version;			// file version