Fixed a bug related to the frame numbers. Something is still not quite right.

Added function to provide the information about a single channel.

DaqFileIO.cxx

@@ -70,6 +70,28 @@ CDaqLowLevelIo::SetCallbacks(
 }
 
 
+
+bool
+CDaqLowLevelIo::GetChannelInfo(
+	int              chId, 
+	CDaqChannelInfo& info) const
+{
+	if ( m_pFile == 0 ) {
+		m_LastError = "uninitialized class instance (call Open first)";
+		return false;
+	}
+
+	if ( chId < 0 || chId >= m_Channels.size() ) {
+		m_LastError = "invalid channel";
+		return false;
+	}
+	info = m_Channels[chId];
+
+	m_LastError = "";
+	return true;
+}
+
+
 void
 NearDump(FILE* p, int ofs)
 {
@@ -1281,7 +1303,7 @@ CDaqLowLevelIo::LowLevelDataCopy(
 	}
 
 	if ( m_HaveToc == false ) {
-		m_LastError = "need to buld table of contents first";
+		m_LastError = "need to build table of contents first";
 		return false;
 	}
 
@@ -1457,9 +1479,15 @@ CDaqLowLevelIo::LowLevelDataCopy(
 /// expands differentially stored data, and fills in data for dropped frames.
 /// If specified, it can read a subset of the data based on a start and end frame.
 ///
-/// The chans vector lists the identifiers for which channels to read. The 
-/// data vector contains data buffers onto which to store the samples of the 
-/// corresponding channels. 
+/// The pWhichChannels vector lists the identifiers for which channels to read. 
+///
+/// The userDataStorage argument is a vector of CDaqBuffer classes, each of which
+/// will contain the data for a channel.  The vector can be empty, in which case
+/// the function will expand it to be equal to the number of requested channels.
+/// If the vector is already properly sized, the function will simply put
+/// the data on the corresponding entry.  For example, the first requested channel will
+/// be stored in userDataStorage[0], the second requested channel will be stored
+/// in userDataStorage[1] etc.
 ///
 /// Finally, note that for differentially stored data, the extrapolation 
 /// method defaults to zero-hold.
@@ -1506,6 +1534,7 @@ CDaqLowLevelIo::GetFullData(
 	//
 	vector<int>  needChan;
 	if ( pWhichChannels ) {
+		if ( pWhichChannels->size() == 0 ) return true;
 		needChan.resize(m_NumEntries, -1);
 		for (unsigned i=0; i<pWhichChannels->size(); i++) {
 			if ( (*pWhichChannels)[i] < 0 || (*pWhichChannels)[i] >= m_NumEntries) {
@@ -1535,6 +1564,17 @@ CDaqLowLevelIo::GetFullData(
 		pChnList = &fullList;
 	}
 
+	// clear any buffers that the user has provided
+	for (unsigned ii=0; ii<userDataStorage.size(); ii++) {
+		userDataStorage[ii].Clear();
+	}
+
+	// make sure the storage vectory is properly dimensioned and initialized
+	if ( pChnList->size() > userDataStorage.size() ) {
+		CDaqBuffer empty;
+		userDataStorage.resize(pChnList->size(), empty);
+	}
+
 	// temporary storage; use a vector so we don't have to worry about
 	// memory leaks
 	vector<unsigned char>  tempSpace;
@@ -1556,10 +1596,29 @@ CDaqLowLevelIo::GetFullData(
 	CDaqLowLevelIo::TReadErrorCode rcode;
 
 	// 
-	// Adjust frame numbers so they reflect fbs frames
+	// 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.
 	//
-	if ( frm1 < 0 ) frm1 = GetFirstFrame(); else frm1 += GetFirstFrame();
-	if ( frm2 < 0 ) frm2 = GetLastFrame(); else frm2 += GetLastFrame();
+	if ( frm1 < 0 ) {
+		frm1 = GetFirstFrame(); 
+	}
+	else {
+		frm1 += GetFirstFrame();
+
+		int triesLeft = 32;
+		while ( m_Toc.find(frm1) == m_Toc.end() && triesLeft-- > 0 ) frm1++;
+	}
+
+	if ( frm2 < 0 ) {
+		frm2 = GetLastFrame(); 
+	}
+	else {
+		frm2 += GetLastFrame();
+		int triesLeft = 32;
+		while ( m_Toc.find(frm2) == m_Toc.end() && triesLeft-- > 0 ) frm2--;
+	}
 
 	//
 	// If the first frame to read is not the first one in the file, and if
@@ -1570,7 +1629,7 @@ CDaqLowLevelIo::GetFullData(
 	if ( frm1 == GetFirstFrame() ) {
 		for (size_t idx=0; idx < pChnList->size(); idx++) {
 			if ( m_Channels[(*pChnList)[idx]].GetCapRate() < 0 ) {
-				// here search backwards from frame frm1 until
+				// TODO: here search backwards from frame frm1 until
 				// we find data for the specific channel.  Store
 				// its values in latestData[idx]
 			}
@@ -1580,7 +1639,7 @@ CDaqLowLevelIo::GetFullData(
 	// Seek to the first frame we need
 	rcode = ReadFrameHeader(frm1, curFrame, numChan, bytesSkipped);
 	if ( rcode != eDAQ_READ_OK ) {
-		sprintf(buf, "First ReadFrameHeader() returned %d",  rcode);
+		sprintf(buf, "First ReadFrameHeader(frm1=%d) returned %d",  frm1, rcode);
 		m_LastError = buf;
 		return false;
 	}

DaqIo.h

@@ -313,6 +313,7 @@ public:
 
 	bool           Open(const string &);
 	void           GetChannels(TChanInfoVec& channels) const;
+	bool           GetChannelInfo(int chId, CDaqChannelInfo &info) const;
 	int            GetFirstFrame() const;
 	int            GetLastFrame() const;  
 	int            GetFrames() const;
@@ -397,7 +398,7 @@ private:
 	vector<int>	         m_DroppedFrames;
 	int					 m_FirstFrame;
 	int					 m_LastFrame;
-	string				 m_LastError;
+	mutable string		 m_LastError;
 	TDaqEofStatus        m_EofStatus;
 
 	// These are for data integrity