+// ***************************************************************************
+// BamStandardIndex.cpp (c) 2010 Derek Barnett
+// Marth Lab, Department of Biology, Boston College
+// All rights reserved.
+// ---------------------------------------------------------------------------
+// Last modified: 22 November 2010 (DB)
+// ---------------------------------------------------------------------------
+// Provides index operations for the standardized BAM index format (".bai")
+// ***************************************************************************
+
+#include <api/BamAlignment.h>
+#include <api/BamReader.h>
+#include <api/BGZF.h>
+#include <api/internal/BamStandardIndex_p.h>
+using namespace BamTools;
+using namespace BamTools::Internal;
+
+#include <cstdio>
+#include <cstdlib>
+#include <algorithm>
+#include <iostream>
+#include <map>
+using namespace std;
+
+BamStandardIndex::BamStandardIndex(BgzfData* bgzf, BamReader* reader)
+ : BamIndex(bgzf, reader)
+ , m_dataBeginOffset(0)
+ , m_hasFullDataCache(false)
+{
+ m_isBigEndian = BamTools::SystemIsBigEndian();
+}
+
+BamStandardIndex::~BamStandardIndex(void) {
+ ClearAllData();
+}
+
+// calculate bins that overlap region
+int BamStandardIndex::BinsFromRegion(const BamRegion& region,
+ const bool isRightBoundSpecified,
+ uint16_t bins[MAX_BIN])
+{
+ // get region boundaries
+ uint32_t begin = (unsigned int)region.LeftPosition;
+ uint32_t end;
+
+ // if right bound specified AND left&right bounds are on same reference
+ // OK to use right bound position
+ if ( isRightBoundSpecified && ( region.LeftRefID == region.RightRefID ) )
+ end = (unsigned int)region.RightPosition;
+
+ // otherwise, use end of left bound reference as cutoff
+ else
+ end = (unsigned int)m_references.at(region.LeftRefID).RefLength - 1;
+
+ // initialize list, bin '0' always a valid bin
+ int i = 0;
+ bins[i++] = 0;
+
+ // get rest of bins that contain this region
+ unsigned int k;
+ for (k = 1 + (begin>>26); k <= 1 + (end>>26); ++k) { bins[i++] = k; }
+ for (k = 9 + (begin>>23); k <= 9 + (end>>23); ++k) { bins[i++] = k; }
+ for (k = 73 + (begin>>20); k <= 73 + (end>>20); ++k) { bins[i++] = k; }
+ for (k = 585 + (begin>>17); k <= 585 + (end>>17); ++k) { bins[i++] = k; }
+ for (k = 4681 + (begin>>14); k <= 4681 + (end>>14); ++k) { bins[i++] = k; }
+
+ // return number of bins stored
+ return i;
+}
+
+// creates index data (in-memory) from current reader data
+bool BamStandardIndex::Build(void) {
+
+ // be sure reader & BGZF file are valid & open for reading
+ if ( m_reader == 0 || m_BGZF == 0 || !m_BGZF->IsOpen )
+ return false;
+
+ // move file pointer to beginning of alignments
+ m_reader->Rewind();
+
+ // get reference count, reserve index space
+ const int numReferences = (int)m_references.size();
+ m_indexData.clear();
+ m_hasFullDataCache = false;
+ SetReferenceCount(numReferences);
+
+ // sets default constant for bin, ID, offset, coordinate variables
+ const uint32_t defaultValue = 0xffffffffu;
+
+ // bin data
+ uint32_t saveBin(defaultValue);
+ uint32_t lastBin(defaultValue);
+
+ // reference ID data
+ int32_t saveRefID(defaultValue);
+ int32_t lastRefID(defaultValue);
+
+ // offset data
+ uint64_t saveOffset = m_BGZF->Tell();
+ uint64_t lastOffset = saveOffset;
+
+ // coordinate data
+ int32_t lastCoordinate = defaultValue;
+
+ BamAlignment bAlignment;
+ while ( m_reader->GetNextAlignmentCore(bAlignment) ) {
+
+ // change of chromosome, save ID, reset bin
+ if ( lastRefID != bAlignment.RefID ) {
+ lastRefID = bAlignment.RefID;
+ lastBin = defaultValue;
+ }
+
+ // if lastCoordinate greater than BAM position - file not sorted properly
+ else if ( lastCoordinate > bAlignment.Position ) {
+ fprintf(stderr, "BAM file not properly sorted:\n");
+ fprintf(stderr, "Alignment %s : %d > %d on reference (id = %d)", bAlignment.Name.c_str(),
+ lastCoordinate, bAlignment.Position, bAlignment.RefID);
+ exit(1);
+ }
+
+ // if valid reference && BAM bin spans some minimum cutoff (smaller bin ids span larger regions)
+ if ( (bAlignment.RefID >= 0) && (bAlignment.Bin < 4681) ) {
+
+ // save linear offset entry (matched to BAM entry refID)
+ BamStandardIndexData::iterator indexIter = m_indexData.find(bAlignment.RefID);
+ if ( indexIter == m_indexData.end() ) return false; // error
+ ReferenceIndex& refIndex = (*indexIter).second;
+ LinearOffsetVector& offsets = refIndex.Offsets;
+ SaveLinearOffset(offsets, bAlignment, lastOffset);
+ }
+
+ // if current BamAlignment bin != lastBin, "then possibly write the binning index"
+ if ( bAlignment.Bin != lastBin ) {
+
+ // if not first time through
+ if ( saveBin != defaultValue ) {
+
+ // save Bam bin entry
+ BamStandardIndexData::iterator indexIter = m_indexData.find(saveRefID);
+ if ( indexIter == m_indexData.end() ) return false; // error
+ ReferenceIndex& refIndex = (*indexIter).second;
+ BamBinMap& binMap = refIndex.Bins;
+ SaveBinEntry(binMap, saveBin, saveOffset, lastOffset);
+ }
+
+ // update saveOffset
+ saveOffset = lastOffset;
+
+ // update bin values
+ saveBin = bAlignment.Bin;
+ lastBin = bAlignment.Bin;
+
+ // update saveRefID
+ saveRefID = bAlignment.RefID;
+
+ // if invalid RefID, break out
+ if ( saveRefID < 0 ) break;
+ }
+
+ // make sure that current file pointer is beyond lastOffset
+ if ( m_BGZF->Tell() <= (int64_t)lastOffset ) {
+ fprintf(stderr, "Error in BGZF offsets.\n");
+ exit(1);
+ }
+
+ // update lastOffset
+ lastOffset = m_BGZF->Tell();
+
+ // update lastCoordinate
+ lastCoordinate = bAlignment.Position;
+ }
+
+ // save any leftover BAM data (as long as refID is valid)
+ if ( saveRefID >= 0 ) {
+ // save Bam bin entry
+ BamStandardIndexData::iterator indexIter = m_indexData.find(saveRefID);
+ if ( indexIter == m_indexData.end() ) return false; // error
+ ReferenceIndex& refIndex = (*indexIter).second;
+ BamBinMap& binMap = refIndex.Bins;
+ SaveBinEntry(binMap, saveBin, saveOffset, lastOffset);
+ }
+
+ // simplify index by merging chunks
+ MergeChunks();
+
+ // iterate through references in index
+ // sort offsets in linear offset vector
+ BamStandardIndexData::iterator indexIter = m_indexData.begin();
+ BamStandardIndexData::iterator indexEnd = m_indexData.end();
+ for ( int i = 0; indexIter != indexEnd; ++indexIter, ++i ) {
+
+ // get reference index data
+ ReferenceIndex& refIndex = (*indexIter).second;
+ LinearOffsetVector& offsets = refIndex.Offsets;
+
+ // sort linear offsets
+ sort(offsets.begin(), offsets.end());
+ }
+
+ // rewind file pointer to beginning of alignments, return success/fail
+ return m_reader->Rewind();
+}
+
+// check index file magic number, return true if OK
+bool BamStandardIndex::CheckMagicNumber(void) {
+
+ // read in magic number
+ char magic[4];
+ size_t elementsRead = fread(magic, sizeof(char), 4, m_indexStream);
+
+ // compare to expected value
+ if ( strncmp(magic, "BAI\1", 4) != 0 ) {
+ fprintf(stderr, "Problem with index file - invalid format.\n");
+ fclose(m_indexStream);
+ return false;
+ }
+
+ // return success/failure of load
+ return (elementsRead == 4);
+}
+
+// clear all current index offset data in memory
+void BamStandardIndex::ClearAllData(void) {
+ BamStandardIndexData::const_iterator indexIter = m_indexData.begin();
+ BamStandardIndexData::const_iterator indexEnd = m_indexData.end();
+ for ( ; indexIter != indexEnd; ++indexIter ) {
+ const int& refId = (*indexIter).first;
+ ClearReferenceOffsets(refId);
+ }
+}
+
+// clear all index offset data for desired reference
+void BamStandardIndex::ClearReferenceOffsets(const int& refId) {
+
+ // look up refId, skip if not found
+ BamStandardIndexData::iterator indexIter = m_indexData.find(refId);
+ if ( indexIter == m_indexData.end() ) return ;
+
+ // clear reference data
+ ReferenceIndex& refEntry = (*indexIter).second;
+ refEntry.Bins.clear();
+ refEntry.Offsets.clear();
+
+ // set flag
+ m_hasFullDataCache = false;
+}
+
+// return file position after header metadata
+const off_t BamStandardIndex::DataBeginOffset(void) const {
+ return m_dataBeginOffset;
+}
+
+// calculates offset(s) for a given region
+bool BamStandardIndex::GetOffsets(const BamRegion& region,
+ const bool isRightBoundSpecified,
+ vector<int64_t>& offsets,
+ bool* hasAlignmentsInRegion)
+{
+ // return false if leftBound refID is not found in index data
+ if ( m_indexData.find(region.LeftRefID) == m_indexData.end() )
+ return false;
+
+ // load index data for region if not already cached
+ if ( !IsDataLoaded(region.LeftRefID) ) {
+ bool loadedOk = true;
+ loadedOk &= SkipToReference(region.LeftRefID);
+ loadedOk &= LoadReference(region.LeftRefID);
+ if ( !loadedOk ) return false;
+ }
+
+ // calculate which bins overlap this region
+ uint16_t* bins = (uint16_t*)calloc(MAX_BIN, 2);
+ int numBins = BinsFromRegion(region, isRightBoundSpecified, bins);
+
+ // get bins for this reference
+ BamStandardIndexData::const_iterator indexIter = m_indexData.find(region.LeftRefID);
+ if ( indexIter == m_indexData.end() ) return false; // error
+ const ReferenceIndex& refIndex = (*indexIter).second;
+ const BamBinMap& binMap = refIndex.Bins;
+
+ // get minimum offset to consider
+ const LinearOffsetVector& linearOffsets = refIndex.Offsets;
+ const uint64_t minOffset = ( (unsigned int)(region.LeftPosition>>BAM_LIDX_SHIFT) >= linearOffsets.size() )
+ ? 0 : linearOffsets.at(region.LeftPosition>>BAM_LIDX_SHIFT);
+
+ // store all alignment 'chunk' starts (file offsets) for bins in this region
+ for ( int i = 0; i < numBins; ++i ) {
+
+ const uint16_t binKey = bins[i];
+ map<uint32_t, ChunkVector>::const_iterator binIter = binMap.find(binKey);
+ if ( (binIter != binMap.end()) && ((*binIter).first == binKey) ) {
+
+ // iterate over chunks
+ const ChunkVector& chunks = (*binIter).second;
+ std::vector<Chunk>::const_iterator chunksIter = chunks.begin();
+ std::vector<Chunk>::const_iterator chunksEnd = chunks.end();
+ for ( ; chunksIter != chunksEnd; ++chunksIter) {
+
+ // if valid chunk found, store its file offset
+ const Chunk& chunk = (*chunksIter);
+ if ( chunk.Stop > minOffset )
+ offsets.push_back( chunk.Start );
+ }
+ }
+ }
+
+ // clean up memory
+ free(bins);
+
+ // sort the offsets before returning
+ sort(offsets.begin(), offsets.end());
+
+ // set flag & return success
+ *hasAlignmentsInRegion = (offsets.size() != 0 );
+
+ // if cache mode set to none, dump the data we just loaded
+ if (m_cacheMode == BamIndex::NoIndexCaching )
+ ClearReferenceOffsets(region.LeftRefID);
+
+ // return succes
+ return true;
+}
+
+// returns whether reference has alignments or no
+bool BamStandardIndex::HasAlignments(const int& refId) const {
+ BamStandardIndexData::const_iterator indexIter = m_indexData.find(refId);
+ if ( indexIter == m_indexData.end() ) return false; // error
+ const ReferenceIndex& refEntry = (*indexIter).second;
+ return refEntry.HasAlignments;
+}
+
+// return true if all index data is cached
+bool BamStandardIndex::HasFullDataCache(void) const {
+ return m_hasFullDataCache;
+}
+
+// returns true if index cache has data for desired reference
+bool BamStandardIndex::IsDataLoaded(const int& refId) const {
+
+ // look up refId, return false if not found
+ BamStandardIndexData::const_iterator indexIter = m_indexData.find(refId);
+ if ( indexIter == m_indexData.end() ) return false;
+
+ // see if reference has alignments
+ // if not, it's not a problem to have no offset data
+ const ReferenceIndex& refEntry = (*indexIter).second;
+ if ( !refEntry.HasAlignments ) return true;
+
+ // return whether bin map contains data
+ return ( !refEntry.Bins.empty() );
+}
+
+// attempts to use index to jump to region; returns success/fail
+bool BamStandardIndex::Jump(const BamRegion& region, bool* hasAlignmentsInRegion) {
+
+ // be sure reader & BGZF file are valid & open for reading
+ if ( m_reader == 0 || m_BGZF == 0 || !m_BGZF->IsOpen )
+ return false;
+
+ // make sure left-bound position is valid
+ if ( region.LeftPosition > m_references.at(region.LeftRefID).RefLength )
+ return false;
+
+ // calculate offsets for this region
+ // if failed, print message, set flag, and return failure
+ vector<int64_t> offsets;
+ if ( !GetOffsets(region, region.isRightBoundSpecified(), offsets, hasAlignmentsInRegion) ) {
+ fprintf(stderr, "ERROR: Could not jump: unable to calculate offset(s) for specified region.\n");
+ *hasAlignmentsInRegion = false;
+ return false;
+ }
+
+ // iterate through offsets
+ BamAlignment bAlignment;
+ bool result = true;
+ for ( vector<int64_t>::const_iterator o = offsets.begin(); o != offsets.end(); ++o) {
+
+ // attempt seek & load first available alignment
+ // set flag to true if data exists
+ result &= m_BGZF->Seek(*o);
+ *hasAlignmentsInRegion = m_reader->GetNextAlignmentCore(bAlignment);
+
+ // if this alignment corresponds to desired position
+ // return success of seeking back to the offset before the 'current offset' (to cover overlaps)
+ if ( ((bAlignment.RefID == region.LeftRefID) &&
+ ((bAlignment.Position + bAlignment.Length) > region.LeftPosition)) ||
+ (bAlignment.RefID > region.LeftRefID) )
+ {
+ if ( o != offsets.begin() ) --o;
+ return m_BGZF->Seek(*o);
+ }
+ }
+
+ // if error in jumping, print message & set flag
+ if ( !result ) {
+ fprintf(stderr, "ERROR: Could not jump: unable to determine correct offset for specified region.\n");
+ *hasAlignmentsInRegion = false;
+ }
+
+ // return success/failure
+ return result;
+}
+
+// clears index data from all references except the first
+void BamStandardIndex::KeepOnlyFirstReferenceOffsets(void) {
+ BamStandardIndexData::const_iterator indexBegin = m_indexData.begin();
+ KeepOnlyReferenceOffsets((*indexBegin).first);
+}
+
+// clears index data from all references except the one specified
+void BamStandardIndex::KeepOnlyReferenceOffsets(const int& refId) {
+ BamStandardIndexData::iterator mapIter = m_indexData.begin();
+ BamStandardIndexData::iterator mapEnd = m_indexData.end();
+ for ( ; mapIter != mapEnd; ++mapIter ) {
+ const int entryRefId = (*mapIter).first;
+ if ( entryRefId != refId )
+ ClearReferenceOffsets(entryRefId);
+ }
+}
+
+bool BamStandardIndex::LoadAllReferences(bool saveData) {
+
+ // skip if data already loaded
+ if ( m_hasFullDataCache ) return true;
+
+ // get number of reference sequences
+ uint32_t numReferences;
+ if ( !LoadReferenceCount((int&)numReferences) )
+ return false;
+
+ // iterate over reference entries
+ bool loadedOk = true;
+ for ( int i = 0; i < (int)numReferences; ++i )
+ loadedOk &= LoadReference(i, saveData);
+
+ // set flag
+ if ( loadedOk && saveData )
+ m_hasFullDataCache = true;
+
+ // return success/failure of loading references
+ return loadedOk;
+}
+
+// load header data from index file, return true if loaded OK
+bool BamStandardIndex::LoadHeader(void) {
+
+ bool loadedOk = CheckMagicNumber();
+
+ // store offset of beginning of data
+ m_dataBeginOffset = ftell64(m_indexStream);
+
+ // return success/failure of load
+ return loadedOk;
+}
+
+// load a single index bin entry from file, return true if loaded OK
+// @saveData - save data in memory if true, just read & discard if false
+bool BamStandardIndex::LoadBin(ReferenceIndex& refEntry, bool saveData) {
+
+ size_t elementsRead = 0;
+
+ // get bin ID
+ uint32_t binId;
+ elementsRead += fread(&binId, sizeof(binId), 1, m_indexStream);
+ if ( m_isBigEndian ) SwapEndian_32(binId);
+
+ // load alignment chunks for this bin
+ ChunkVector chunks;
+ bool chunksOk = LoadChunks(chunks, saveData);
+
+ // store bin entry
+ if ( chunksOk && saveData )
+ refEntry.Bins.insert(pair<uint32_t, ChunkVector>(binId, chunks));
+
+ // return success/failure of load
+ return ( (elementsRead == 1) && chunksOk );
+}
+
+bool BamStandardIndex::LoadBins(ReferenceIndex& refEntry, bool saveData) {
+
+ size_t elementsRead = 0;
+
+ // get number of bins
+ int32_t numBins;
+ elementsRead += fread(&numBins, sizeof(numBins), 1, m_indexStream);
+ if ( m_isBigEndian ) SwapEndian_32(numBins);
+
+ // set flag
+ refEntry.HasAlignments = ( numBins != 0 );
+
+ // iterate over bins
+ bool binsOk = true;
+ for ( int i = 0; i < numBins; ++i )
+ binsOk &= LoadBin(refEntry, saveData);
+
+ // return success/failure of load
+ return ( (elementsRead == 1) && binsOk );
+}
+
+// load a single index bin entry from file, return true if loaded OK
+// @saveData - save data in memory if true, just read & discard if false
+bool BamStandardIndex::LoadChunk(ChunkVector& chunks, bool saveData) {
+
+ size_t elementsRead = 0;
+
+ // read in chunk data
+ uint64_t start;
+ uint64_t stop;
+ elementsRead += fread(&start, sizeof(start), 1, m_indexStream);
+ elementsRead += fread(&stop, sizeof(stop), 1, m_indexStream);
+
+ // swap endian-ness if necessary
+ if ( m_isBigEndian ) {
+ SwapEndian_64(start);
+ SwapEndian_64(stop);
+ }
+
+ // save data if requested
+ if ( saveData ) chunks.push_back( Chunk(start, stop) );
+
+ // return success/failure of load
+ return ( elementsRead == 2 );
+}
+
+bool BamStandardIndex::LoadChunks(ChunkVector& chunks, bool saveData) {
+
+ size_t elementsRead = 0;
+
+ // read in number of chunks
+ uint32_t numChunks;
+ elementsRead += fread(&numChunks, sizeof(numChunks), 1, m_indexStream);
+ if ( m_isBigEndian ) SwapEndian_32(numChunks);
+
+ // initialize space for chunks if we're storing this data
+ if ( saveData ) chunks.reserve(numChunks);
+
+ // iterate over chunks
+ bool chunksOk = true;
+ for ( int i = 0; i < (int)numChunks; ++i )
+ chunksOk &= LoadChunk(chunks, saveData);
+
+ // sort chunk vector
+ sort( chunks.begin(), chunks.end(), ChunkLessThan );
+
+ // return success/failure of load
+ return ( (elementsRead == 1) && chunksOk );
+}
+
+// load a single index linear offset entry from file, return true if loaded OK
+// @saveData - save data in memory if true, just read & discard if false
+bool BamStandardIndex::LoadLinearOffsets(ReferenceIndex& refEntry, bool saveData) {
+
+ size_t elementsRead = 0;
+
+ // read in number of linear offsets
+ int32_t numLinearOffsets;
+ elementsRead += fread(&numLinearOffsets, sizeof(numLinearOffsets), 1, m_indexStream);
+ if ( m_isBigEndian ) SwapEndian_32(numLinearOffsets);
+
+ // set up destination vector (if we're saving the data)
+ LinearOffsetVector linearOffsets;
+ if ( saveData ) linearOffsets.reserve(numLinearOffsets);
+
+ // iterate over linear offsets
+ uint64_t linearOffset;
+ for ( int i = 0; i < numLinearOffsets; ++i ) {
+ elementsRead += fread(&linearOffset, sizeof(linearOffset), 1, m_indexStream);
+ if ( m_isBigEndian ) SwapEndian_64(linearOffset);
+ if ( saveData ) linearOffsets.push_back(linearOffset);
+ }
+
+ // sort linear offsets
+ sort ( linearOffsets.begin(), linearOffsets.end() );
+
+ // save in reference index entry if desired
+ if ( saveData ) refEntry.Offsets = linearOffsets;
+
+ // return success/failure of load
+ return ( elementsRead == (size_t)(numLinearOffsets + 1) );
+}
+
+bool BamStandardIndex::LoadFirstReference(bool saveData) {
+ BamStandardIndexData::const_iterator indexBegin = m_indexData.begin();
+ return LoadReference((*indexBegin).first, saveData);
+}
+
+// load a single reference from file, return true if loaded OK
+// @saveData - save data in memory if true, just read & discard if false
+bool BamStandardIndex::LoadReference(const int& refId, bool saveData) {
+
+ // look up refId
+ BamStandardIndexData::iterator indexIter = m_indexData.find(refId);
+
+ // if reference not previously loaded, create new entry
+ if ( indexIter == m_indexData.end() ) {
+ ReferenceIndex newEntry;
+ newEntry.HasAlignments = false;
+ m_indexData.insert( pair<int32_t, ReferenceIndex>(refId, newEntry) );
+ }
+
+ // load reference data
+ indexIter = m_indexData.find(refId);
+ ReferenceIndex& entry = (*indexIter).second;
+ bool loadedOk = true;
+ loadedOk &= LoadBins(entry, saveData);
+ loadedOk &= LoadLinearOffsets(entry, saveData);
+ return loadedOk;
+}
+
+// loads number of references, return true if loaded OK
+bool BamStandardIndex::LoadReferenceCount(int& numReferences) {
+
+ size_t elementsRead = 0;
+
+ // read reference count
+ elementsRead += fread(&numReferences, sizeof(numReferences), 1, m_indexStream);
+ if ( m_isBigEndian ) SwapEndian_32(numReferences);
+
+ // return success/failure of load
+ return ( elementsRead == 1 );
+}
+
+// merges 'alignment chunks' in BAM bin (used for index building)
+void BamStandardIndex::MergeChunks(void) {
+
+ // iterate over reference enties
+ BamStandardIndexData::iterator indexIter = m_indexData.begin();
+ BamStandardIndexData::iterator indexEnd = m_indexData.end();
+ for ( ; indexIter != indexEnd; ++indexIter ) {
+
+ // get BAM bin map for this reference
+ ReferenceIndex& refIndex = (*indexIter).second;
+ BamBinMap& bamBinMap = refIndex.Bins;
+
+ // iterate over BAM bins
+ BamBinMap::iterator binIter = bamBinMap.begin();
+ BamBinMap::iterator binEnd = bamBinMap.end();
+ for ( ; binIter != binEnd; ++binIter ) {
+
+ // get chunk vector for this bin
+ ChunkVector& binChunks = (*binIter).second;
+ if ( binChunks.size() == 0 ) continue;
+
+ ChunkVector mergedChunks;
+ mergedChunks.push_back( binChunks[0] );
+
+ // iterate over chunks
+ int i = 0;
+ ChunkVector::iterator chunkIter = binChunks.begin();
+ ChunkVector::iterator chunkEnd = binChunks.end();
+ for ( ++chunkIter; chunkIter != chunkEnd; ++chunkIter) {
+
+ // get 'currentChunk' based on numeric index
+ Chunk& currentChunk = mergedChunks[i];
+
+ // get iteratorChunk based on vector iterator
+ Chunk& iteratorChunk = (*chunkIter);
+
+ // if chunk ends where (iterator) chunk starts, then merge
+ if ( currentChunk.Stop>>16 == iteratorChunk.Start>>16 )
+ currentChunk.Stop = iteratorChunk.Stop;
+
+ // otherwise
+ else {
+ // set currentChunk + 1 to iteratorChunk
+ mergedChunks.push_back(iteratorChunk);
+ ++i;
+ }
+ }
+
+ // saved merged chunk vector
+ (*binIter).second = mergedChunks;
+ }
+ }
+}
+
+// saves BAM bin entry for index
+void BamStandardIndex::SaveBinEntry(BamBinMap& binMap,
+ const uint32_t& saveBin,
+ const uint64_t& saveOffset,
+ const uint64_t& lastOffset)
+{
+ // look up saveBin
+ BamBinMap::iterator binIter = binMap.find(saveBin);
+
+ // create new chunk
+ Chunk newChunk(saveOffset, lastOffset);
+
+ // if entry doesn't exist
+ if ( binIter == binMap.end() ) {
+ ChunkVector newChunks;
+ newChunks.push_back(newChunk);
+ binMap.insert( pair<uint32_t, ChunkVector>(saveBin, newChunks));
+ }
+
+ // otherwise
+ else {
+ ChunkVector& binChunks = (*binIter).second;
+ binChunks.push_back( newChunk );
+ }
+}
+
+// saves linear offset entry for index
+void BamStandardIndex::SaveLinearOffset(LinearOffsetVector& offsets,
+ const BamAlignment& bAlignment,
+ const uint64_t& lastOffset)
+{
+ // get converted offsets
+ int beginOffset = bAlignment.Position >> BAM_LIDX_SHIFT;
+ int endOffset = (bAlignment.GetEndPosition() - 1) >> BAM_LIDX_SHIFT;
+
+ // resize vector if necessary
+ int oldSize = offsets.size();
+ int newSize = endOffset + 1;
+ if ( oldSize < newSize )
+ offsets.resize(newSize, 0);
+
+ // store offset
+ for( int i = beginOffset + 1; i <= endOffset; ++i ) {
+ if ( offsets[i] == 0 )
+ offsets[i] = lastOffset;
+ }
+}
+
+// initializes index data structure to hold @count references
+void BamStandardIndex::SetReferenceCount(const int& count) {
+ for ( int i = 0; i < count; ++i )
+ m_indexData[i].HasAlignments = false;
+}
+
+bool BamStandardIndex::SkipToFirstReference(void) {
+ BamStandardIndexData::const_iterator indexBegin = m_indexData.begin();
+ return SkipToReference( (*indexBegin).first );
+}
+
+// position file pointer to desired reference begin, return true if skipped OK
+bool BamStandardIndex::SkipToReference(const int& refId) {
+
+ // attempt rewind
+ if ( !Rewind() ) return false;
+
+ // read in number of references
+ uint32_t numReferences;
+ size_t elementsRead = fread(&numReferences, sizeof(numReferences), 1, m_indexStream);
+ if ( elementsRead != 1 ) return false;
+ if ( m_isBigEndian ) SwapEndian_32(numReferences);
+
+ // iterate over reference entries
+ bool skippedOk = true;
+ int currentRefId = 0;
+ while (currentRefId != refId) {
+ skippedOk &= LoadReference(currentRefId, false);
+ ++currentRefId;
+ }
+
+ // return success
+ return skippedOk;
+}
+
+// write header to new index file
+bool BamStandardIndex::WriteHeader(void) {
+
+ size_t elementsWritten = 0;
+
+ // write magic number
+ elementsWritten += fwrite("BAI\1", sizeof(char), 4, m_indexStream);
+
+ // store offset of beginning of data
+ m_dataBeginOffset = ftell64(m_indexStream);
+
+ // return success/failure of write
+ return (elementsWritten == 4);
+}
+
+// write index data for all references to new index file
+bool BamStandardIndex::WriteAllReferences(void) {
+
+ size_t elementsWritten = 0;
+
+ // write number of reference sequences
+ int32_t numReferenceSeqs = m_indexData.size();
+ if ( m_isBigEndian ) SwapEndian_32(numReferenceSeqs);
+ elementsWritten += fwrite(&numReferenceSeqs, sizeof(numReferenceSeqs), 1, m_indexStream);
+
+ // iterate over reference sequences
+ bool refsOk = true;
+ BamStandardIndexData::const_iterator indexIter = m_indexData.begin();
+ BamStandardIndexData::const_iterator indexEnd = m_indexData.end();
+ for ( ; indexIter != indexEnd; ++ indexIter )
+ refsOk &= WriteReference( (*indexIter).second );
+
+ // return success/failure of write
+ return ( (elementsWritten == 1) && refsOk );
+}
+
+// write index data for bin to new index file
+bool BamStandardIndex::WriteBin(const uint32_t& binId, const ChunkVector& chunks) {
+
+ size_t elementsWritten = 0;
+
+ // write BAM bin ID
+ uint32_t binKey = binId;
+ if ( m_isBigEndian ) SwapEndian_32(binKey);
+ elementsWritten += fwrite(&binKey, sizeof(binKey), 1, m_indexStream);
+
+ // write chunks
+ bool chunksOk = WriteChunks(chunks);
+
+ // return success/failure of write
+ return ( (elementsWritten == 1) && chunksOk );
+}
+
+// write index data for bins to new index file
+bool BamStandardIndex::WriteBins(const BamBinMap& bins) {
+
+ size_t elementsWritten = 0;
+
+ // write number of bins
+ int32_t binCount = bins.size();
+ if ( m_isBigEndian ) SwapEndian_32(binCount);
+ elementsWritten += fwrite(&binCount, sizeof(binCount), 1, m_indexStream);
+
+ // iterate over bins
+ bool binsOk = true;
+ BamBinMap::const_iterator binIter = bins.begin();
+ BamBinMap::const_iterator binEnd = bins.end();
+ for ( ; binIter != binEnd; ++binIter )
+ binsOk &= WriteBin( (*binIter).first, (*binIter).second );
+
+ // return success/failure of write
+ return ( (elementsWritten == 1) && binsOk );
+}
+
+// write index data for chunk entry to new index file
+bool BamStandardIndex::WriteChunk(const Chunk& chunk) {
+
+ size_t elementsWritten = 0;
+
+ // localize alignment chunk offsets
+ uint64_t start = chunk.Start;
+ uint64_t stop = chunk.Stop;
+
+ // swap endian-ness if necessary
+ if ( m_isBigEndian ) {
+ SwapEndian_64(start);
+ SwapEndian_64(stop);
+ }
+
+ // write to index file
+ elementsWritten += fwrite(&start, sizeof(start), 1, m_indexStream);
+ elementsWritten += fwrite(&stop, sizeof(stop), 1, m_indexStream);
+
+ // return success/failure of write
+ return ( elementsWritten == 2 );
+}
+
+// write index data for chunk entry to new index file
+bool BamStandardIndex::WriteChunks(const ChunkVector& chunks) {
+
+ size_t elementsWritten = 0;
+
+ // write chunks
+ int32_t chunkCount = chunks.size();
+ if ( m_isBigEndian ) SwapEndian_32(chunkCount);
+ elementsWritten += fwrite(&chunkCount, sizeof(chunkCount), 1, m_indexStream);
+
+ // iterate over chunks
+ bool chunksOk = true;
+ ChunkVector::const_iterator chunkIter = chunks.begin();
+ ChunkVector::const_iterator chunkEnd = chunks.end();
+ for ( ; chunkIter != chunkEnd; ++chunkIter )
+ chunksOk &= WriteChunk( (*chunkIter) );
+
+ // return success/failure of write
+ return ( (elementsWritten == 1) && chunksOk );
+}
+
+// write index data for linear offsets entry to new index file
+bool BamStandardIndex::WriteLinearOffsets(const LinearOffsetVector& offsets) {
+
+ size_t elementsWritten = 0;
+
+ // write number of linear offsets
+ int32_t offsetCount = offsets.size();
+ if ( m_isBigEndian ) SwapEndian_32(offsetCount);
+ elementsWritten += fwrite(&offsetCount, sizeof(offsetCount), 1, m_indexStream);
+
+ // iterate over linear offsets
+ LinearOffsetVector::const_iterator offsetIter = offsets.begin();
+ LinearOffsetVector::const_iterator offsetEnd = offsets.end();
+ for ( ; offsetIter != offsetEnd; ++offsetIter ) {
+
+ // write linear offset
+ uint64_t linearOffset = (*offsetIter);
+ if ( m_isBigEndian ) SwapEndian_64(linearOffset);
+ elementsWritten += fwrite(&linearOffset, sizeof(linearOffset), 1, m_indexStream);
+ }
+
+ // return success/failure of write
+ return ( elementsWritten == (size_t)(offsetCount + 1) );
+}
+
+// write index data for a single reference to new index file
+bool BamStandardIndex::WriteReference(const ReferenceIndex& refEntry) {
+ bool refOk = true;
+ refOk &= WriteBins(refEntry.Bins);
+ refOk &= WriteLinearOffsets(refEntry.Offsets);
+ return refOk;
+}