/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "Adaptor.hh"
#include "BloomFilter.hh"
#include "Options.hh"
#include "Reader.hh"
#include "Statistics.hh"
#include "StripeStream.hh"

#include "wrap/coded-stream-wrapper.h"

#include <algorithm>
#include <iostream>
#include <memory>
#include <sstream>
#include <string>
#include <vector>
#include <iterator>
#include <set>

namespace orc {

  const WriterVersionImpl &WriterVersionImpl::VERSION_HIVE_8732() {
    static const WriterVersionImpl version(WriterVersion_HIVE_8732);
    return version;
  }

  uint64_t getCompressionBlockSize(const proto::PostScript& ps) {
    if (ps.has_compressionblocksize()) {
      return ps.compressionblocksize();
    } else {
      return 256 * 1024;
    }
  }

  CompressionKind convertCompressionKind(const proto::PostScript& ps) {
    if (ps.has_compression()) {
      return static_cast<CompressionKind>(ps.compression());
    } else {
      throw ParseError("Unknown compression type");
    }
  }

  std::string ColumnSelector::toDotColumnPath() {
      if (columns.empty()) {
          return std::string();
      }
      std::ostringstream columnStream;
      std::copy(columns.begin(), columns.end(),
              std::ostream_iterator<std::string>(columnStream, "."));
      std::string columnPath = columnStream.str();
      return columnPath.substr(0, columnPath.length() - 1);
  }


  void ColumnSelector::selectChildren(std::vector<bool>& selectedColumns, const Type& type) {
    size_t id = static_cast<size_t>(type.getColumnId());
    if (!selectedColumns[id]) {
      selectedColumns[id] = true;
      for(size_t c = id; c <= type.getMaximumColumnId(); ++c){
        selectedColumns[c] = true;
      }
    }
  }

  /**
   * Recurses over a type tree and selects the parents of every selected type.
   * @return true if any child was selected.
   */
  bool ColumnSelector::selectParents(std::vector<bool>& selectedColumns, const Type& type) {
    size_t id = static_cast<size_t>(type.getColumnId());
    bool result = selectedColumns[id];
    for(uint64_t c=0; c < type.getSubtypeCount(); ++c) {
      result |= selectParents(selectedColumns, *type.getSubtype(c));
    }
    selectedColumns[id] = result;
    return result;
  }

  /**
   * Recurses over a type tree and build two maps
   * map<TypeName, TypeId>, map<TypeId, Type>
   */
  void ColumnSelector::buildTypeNameIdMap(const Type* type) {
    // map<type_id, Type*>
    idTypeMap[type->getColumnId()] = type;

    if (STRUCT == type->getKind()) {
      for (size_t i = 0; i < type->getSubtypeCount(); ++i) {
        const std::string& fieldName = type->getFieldName(i);
        columns.push_back(fieldName);
        nameIdMap[toDotColumnPath()] = type->getSubtype(i)->getColumnId();
        buildTypeNameIdMap(type->getSubtype(i));
        columns.pop_back();
      }
    } else {
      // other non-primitive type
      for (size_t j = 0; j < type->getSubtypeCount(); ++j) {
        buildTypeNameIdMap(type->getSubtype(j));
      }
    }
  }

  void ColumnSelector::updateSelected(std::vector<bool>& selectedColumns,
                                      const RowReaderOptions& options) {
    selectedColumns.assign(static_cast<size_t>(contents->footer->types_size()), false);
    if (contents->schema->getKind() == STRUCT && options.getIndexesSet()) {
      for(std::list<uint64_t>::const_iterator field = options.getInclude().begin();
          field != options.getInclude().end(); ++field) {
        updateSelectedByFieldId(selectedColumns, *field);
      }
    } else if (contents->schema->getKind() == STRUCT && options.getNamesSet()) {
      for(std::list<std::string>::const_iterator field = options.getIncludeNames().begin();
          field != options.getIncludeNames().end(); ++field) {
        updateSelectedByName(selectedColumns, *field);
      }
    } else if (options.getTypeIdsSet()) {
      for(std::list<uint64_t>::const_iterator typeId = options.getInclude().begin();
          typeId != options.getInclude().end(); ++typeId) {
        updateSelectedByTypeId(selectedColumns, *typeId);
      }
    } else {
      // default is to select all columns
      std::fill(selectedColumns.begin(), selectedColumns.end(), true);
    }
    selectParents(selectedColumns, *contents->schema.get());
    selectedColumns[0] = true; // column 0 is selected by default
  }

  void ColumnSelector::updateSelectedByFieldId(std::vector<bool>& selectedColumns,
                                               uint64_t fieldId) {
    if (fieldId < contents->schema->getSubtypeCount()) {
      selectChildren(selectedColumns, *contents->schema->getSubtype(fieldId));
    } else {
      std::stringstream buffer;
      buffer << "Invalid column selected " << fieldId << " out of "
             << contents->schema->getSubtypeCount();
      throw ParseError(buffer.str());
    }
  }

  void ColumnSelector::updateSelectedByTypeId(std::vector<bool>& selectedColumns, uint64_t typeId) {
    if (typeId < selectedColumns.size()) {
      const Type& type = *idTypeMap[typeId];
      selectChildren(selectedColumns, type);
    } else {
      std::stringstream buffer;
      buffer << "Invalid type id selected " << typeId << " out of "
             << selectedColumns.size();
      throw ParseError(buffer.str());
    }
  }

  void ColumnSelector::updateSelectedByName(std::vector<bool>& selectedColumns,
                                            const std::string& fieldName) {
    std::map<std::string, uint64_t>::const_iterator ite = nameIdMap.find(fieldName);
    if (ite != nameIdMap.end()) {
      updateSelectedByTypeId(selectedColumns, ite->second);
    } else {
      throw ParseError("Invalid column selected " + fieldName);
    }
  }

  ColumnSelector::ColumnSelector(const FileContents* _contents): contents(_contents) {
    buildTypeNameIdMap(contents->schema.get());
  }

  RowReaderImpl::RowReaderImpl(std::shared_ptr<FileContents> _contents,
                               const RowReaderOptions& opts
                         ): localTimezone(getLocalTimezone()),
                            contents(_contents),
                            throwOnHive11DecimalOverflow(opts.getThrowOnHive11DecimalOverflow()),
                            forcedScaleOnHive11Decimal(opts.getForcedScaleOnHive11Decimal()),
                            footer(contents->footer.get()),
                            firstRowOfStripe(*contents->pool, 0),
                            enableEncodedBlock(opts.getEnableLazyDecoding()) {
    uint64_t numberOfStripes;
    numberOfStripes = static_cast<uint64_t>(footer->stripes_size());
    currentStripe = numberOfStripes;
    lastStripe = 0;
    currentRowInStripe = 0;
    rowsInCurrentStripe = 0;
    uint64_t rowTotal = 0;

    firstRowOfStripe.resize(numberOfStripes);
    for(size_t i=0; i < numberOfStripes; ++i) {
      firstRowOfStripe[i] = rowTotal;
      proto::StripeInformation stripeInfo =
        footer->stripes(static_cast<int>(i));
      rowTotal += stripeInfo.numberofrows();
      bool isStripeInRange = stripeInfo.offset() >= opts.getOffset() &&
        stripeInfo.offset() < opts.getOffset() + opts.getLength();
      if (isStripeInRange) {
        if (i < currentStripe) {
          currentStripe = i;
        }
        if (i >= lastStripe) {
          lastStripe = i + 1;
        }
      }
    }
    firstStripe = currentStripe;

    if (currentStripe == 0) {
      previousRow = (std::numeric_limits<uint64_t>::max)();
    } else if (currentStripe == numberOfStripes) {
      previousRow = footer->numberofrows();
    } else {
      previousRow = firstRowOfStripe[firstStripe]-1;
    }

    ColumnSelector column_selector(contents.get());
    column_selector.updateSelected(selectedColumns, opts);
  }

  CompressionKind RowReaderImpl::getCompression() const {
    return contents->compression;
  }

  uint64_t RowReaderImpl::getCompressionSize() const {
    return contents->blockSize;
  }

  const std::vector<bool> RowReaderImpl::getSelectedColumns() const {
    return selectedColumns;
  }

  const Type& RowReaderImpl::getSelectedType() const {
    if (selectedSchema.get() == nullptr) {
      selectedSchema = buildSelectedType(contents->schema.get(),
                                         selectedColumns);
    }
    return *(selectedSchema.get());
  }

  uint64_t RowReaderImpl::getRowNumber() const {
    return previousRow;
  }

  void RowReaderImpl::seekToRow(uint64_t rowNumber) {
    // Empty file
    if (lastStripe == 0) {
      return;
    }

    // If we are reading only a portion of the file
    // (bounded by firstStripe and lastStripe),
    // seeking before or after the portion of interest should return no data.
    // Implement this by setting previousRow to the number of rows in the file.

    // seeking past lastStripe
    uint64_t num_stripes = static_cast<uint64_t>(footer->stripes_size());
    if ( (lastStripe == num_stripes
            && rowNumber >= footer->numberofrows())  ||
         (lastStripe < num_stripes
            && rowNumber >= firstRowOfStripe[lastStripe])   ) {
      currentStripe = num_stripes;
      previousRow = footer->numberofrows();
      return;
    }

    uint64_t seekToStripe = 0;
    while (seekToStripe+1 < lastStripe &&
                  firstRowOfStripe[seekToStripe+1] <= rowNumber) {
      seekToStripe++;
    }

    // seeking before the first stripe
    if (seekToStripe < firstStripe) {
      currentStripe = num_stripes;
      previousRow = footer->numberofrows();
      return;
    }

    currentStripe = seekToStripe;
    currentRowInStripe = rowNumber - firstRowOfStripe[currentStripe];
    previousRow = rowNumber;
    startNextStripe();

    uint64_t rowsToSkip = currentRowInStripe;

    if (footer->rowindexstride() > 0 &&
        currentStripeInfo.indexlength() > 0) {
      uint32_t rowGroupId =
        static_cast<uint32_t>(currentRowInStripe / footer->rowindexstride());
      rowsToSkip -= rowGroupId * footer->rowindexstride();

      if (rowGroupId != 0) {
        seekToRowGroup(rowGroupId);
      }
    }

    reader->skip(rowsToSkip);
  }

  void RowReaderImpl::seekToRowGroup(uint32_t rowGroupEntryId) {
    // reset all previous row indexes
    rowIndexes.clear();

    // obtain row indexes for selected columns
    uint64_t offset = currentStripeInfo.offset();
    for (int i = 0; i < currentStripeFooter.streams_size(); ++i) {
      const proto::Stream& pbStream = currentStripeFooter.streams(i);
      uint64_t colId = pbStream.column();
      if (selectedColumns[colId] && pbStream.has_kind()
          && pbStream.kind() == proto::Stream_Kind_ROW_INDEX) {
        std::unique_ptr<SeekableInputStream> inStream =
          createDecompressor(getCompression(),
                             std::unique_ptr<SeekableInputStream>
                               (new SeekableFileInputStream
                                  (contents->stream.get(),
                                   offset,
                                   pbStream.length(),
                                   *contents->pool)),
                             getCompressionSize(),
                             *contents->pool);

        proto::RowIndex rowIndex;
        if (!rowIndex.ParseFromZeroCopyStream(inStream.get())) {
          throw ParseError("Failed to parse the row index");
        }

        rowIndexes[colId] = rowIndex;
      }
      offset += pbStream.length();
    }

    // store positions for selected columns
    std::vector<std::list<uint64_t>> positions;
    // store position providers for selected colimns
    std::unordered_map<uint64_t, PositionProvider> positionProviders;

    for (auto rowIndex = rowIndexes.cbegin();
         rowIndex != rowIndexes.cend(); ++rowIndex) {
      uint64_t colId = rowIndex->first;
      const proto::RowIndexEntry& entry =
        rowIndex->second.entry(static_cast<int32_t>(rowGroupEntryId));

      // copy index positions for a specific column
      positions.push_back({});
      auto& position = positions.back();
      for (int pos = 0; pos != entry.positions_size(); ++pos) {
        position.push_back(entry.positions(pos));
      }
      positionProviders.insert(std::make_pair(colId, PositionProvider(position)));
    }

    reader->seekToRowGroup(positionProviders);
  }

  const FileContents& RowReaderImpl::getFileContents() const {
    return *contents;
  }

  bool RowReaderImpl::getThrowOnHive11DecimalOverflow() const {
    return throwOnHive11DecimalOverflow;
  }

  int32_t RowReaderImpl::getForcedScaleOnHive11Decimal() const {
    return forcedScaleOnHive11Decimal;
  }

  proto::StripeFooter getStripeFooter(const proto::StripeInformation& info,
                                      const FileContents& contents) {
    uint64_t stripeFooterStart = info.offset() + info.indexlength() +
      info.datalength();
    uint64_t stripeFooterLength = info.footerlength();
    std::unique_ptr<SeekableInputStream> pbStream =
      createDecompressor(contents.compression,
                         std::unique_ptr<SeekableInputStream>
                         (new SeekableFileInputStream(contents.stream.get(),
                                                      stripeFooterStart,
                                                      stripeFooterLength,
                                                      *contents.pool)),
                         contents.blockSize,
                         *contents.pool);
    proto::StripeFooter result;
    if (!result.ParseFromZeroCopyStream(pbStream.get())) {
      throw ParseError(std::string("bad StripeFooter from ") +
                       pbStream->getName());
    }
    return result;
  }

  ReaderImpl::ReaderImpl(std::shared_ptr<FileContents> _contents,
                         const ReaderOptions& opts,
                         uint64_t _fileLength,
                         uint64_t _postscriptLength
                         ): contents(std::move(_contents)),
                            options(opts),
                            fileLength(_fileLength),
                            postscriptLength(_postscriptLength),
                            footer(contents->footer.get()) {
    isMetadataLoaded = false;
    checkOrcVersion();
    numberOfStripes = static_cast<uint64_t>(footer->stripes_size());
    contents->schema = REDUNDANT_MOVE(convertType(footer->types(0), *footer));
    contents->blockSize = getCompressionBlockSize(*contents->postscript);
    contents->compression= convertCompressionKind(*contents->postscript);
  }

  std::string ReaderImpl::getSerializedFileTail() const {
    proto::FileTail tail;
    proto::PostScript *mutable_ps = tail.mutable_postscript();
    mutable_ps->CopyFrom(*contents->postscript);
    proto::Footer *mutableFooter = tail.mutable_footer();
    mutableFooter->CopyFrom(*footer);
    tail.set_filelength(fileLength);
    tail.set_postscriptlength(postscriptLength);
    TString result;
    if (!tail.SerializeToString(&result)) {
      throw ParseError("Failed to serialize file tail");
    }
    return result;
  }

  const ReaderOptions& ReaderImpl::getReaderOptions() const {
    return options;
  }

  CompressionKind ReaderImpl::getCompression() const {
    return contents->compression;
  }

  uint64_t ReaderImpl::getCompressionSize() const {
    return contents->blockSize;
  }

  uint64_t ReaderImpl::getNumberOfStripes() const {
    return numberOfStripes;
  }

  uint64_t ReaderImpl::getNumberOfStripeStatistics() const {
    if (!isMetadataLoaded) {
      readMetadata();
    }
    return metadata.get() == nullptr ? 0 :
      static_cast<uint64_t>(metadata->stripestats_size());
  }

  std::unique_ptr<StripeInformation>
  ReaderImpl::getStripe(uint64_t stripeIndex) const {
    if (stripeIndex > getNumberOfStripes()) {
      throw std::logic_error("stripe index out of range");
    }
    proto::StripeInformation stripeInfo =
      footer->stripes(static_cast<int>(stripeIndex));

    return std::unique_ptr<StripeInformation>
      (new StripeInformationImpl
       (stripeInfo.offset(),
        stripeInfo.indexlength(),
        stripeInfo.datalength(),
        stripeInfo.footerlength(),
        stripeInfo.numberofrows(),
        contents->stream.get(),
        *contents->pool,
        contents->compression,
        contents->blockSize));
  }

  FileVersion ReaderImpl::getFormatVersion() const {
    if (contents->postscript->version_size() != 2) {
      return FileVersion::v_0_11();
    }
    return FileVersion(
                contents->postscript->version(0),
                contents->postscript->version(1));
  }

  uint64_t ReaderImpl::getNumberOfRows() const {
    return footer->numberofrows();
  }

  WriterId ReaderImpl::getWriterId() const {
    if (footer->has_writer()) {
      uint32_t id = footer->writer();
      if (id > WriterId::TRINO_WRITER) {
        return WriterId::UNKNOWN_WRITER;
      } else {
	return static_cast<WriterId>(id);
      }
    }
    return WriterId::ORC_JAVA_WRITER;
  }

  uint32_t ReaderImpl::getWriterIdValue() const {
    if (footer->has_writer()) {
      return footer->writer();
    } else {
      return WriterId::ORC_JAVA_WRITER;
    }
  }

  std::string ReaderImpl::getSoftwareVersion() const {
    std::ostringstream buffer;
    buffer << writerIdToString(getWriterIdValue());
    if (footer->has_softwareversion()) {
      buffer << " " << footer->softwareversion();
    }
    return buffer.str();
  }

  WriterVersion ReaderImpl::getWriterVersion() const {
    if (!contents->postscript->has_writerversion()) {
      return WriterVersion_ORIGINAL;
    }
    return static_cast<WriterVersion>(contents->postscript->writerversion());
  }

  uint64_t ReaderImpl::getContentLength() const {
    return footer->contentlength();
  }

  uint64_t ReaderImpl::getStripeStatisticsLength() const {
    return contents->postscript->metadatalength();
  }

  uint64_t ReaderImpl::getFileFooterLength() const {
    return contents->postscript->footerlength();
  }

  uint64_t ReaderImpl::getFilePostscriptLength() const {
    return postscriptLength;
  }

  uint64_t ReaderImpl::getFileLength() const {
    return fileLength;
  }

  uint64_t ReaderImpl::getRowIndexStride() const {
    return footer->rowindexstride();
  }

  const std::string& ReaderImpl::getStreamName() const {
    return contents->stream->getName();
  }

  std::list<std::string> ReaderImpl::getMetadataKeys() const {
    std::list<std::string> result;
    for(int i=0; i < footer->metadata_size(); ++i) {
      result.push_back(footer->metadata(i).name());
    }
    return result;
  }

  std::string ReaderImpl::getMetadataValue(const std::string& key) const {
    for(int i=0; i < footer->metadata_size(); ++i) {
      if (footer->metadata(i).name() == TString(key)) {
        return footer->metadata(i).value();
      }
    }
    throw std::range_error("key not found");
  }

  void ReaderImpl::getRowIndexStatistics(const proto::StripeInformation& stripeInfo,
      uint64_t stripeIndex, const proto::StripeFooter& currentStripeFooter,
      std::vector<std::vector<proto::ColumnStatistics> >* indexStats) const {
    int num_streams = currentStripeFooter.streams_size();
    uint64_t offset = stripeInfo.offset();
    uint64_t indexEnd = stripeInfo.offset() + stripeInfo.indexlength();
    for (int i = 0; i < num_streams; i++) {
      const proto::Stream& stream = currentStripeFooter.streams(i);
      StreamKind streamKind = static_cast<StreamKind>(stream.kind());
      uint64_t length = static_cast<uint64_t>(stream.length());
      if (streamKind == StreamKind::StreamKind_ROW_INDEX) {
        if (offset + length > indexEnd) {
          std::stringstream msg;
          msg << "Malformed RowIndex stream meta in stripe " << stripeIndex
              << ": streamOffset=" << offset << ", streamLength=" << length
              << ", stripeOffset=" << stripeInfo.offset() << ", stripeIndexLength="
              << stripeInfo.indexlength();
          throw ParseError(msg.str());
        }
        std::unique_ptr<SeekableInputStream> pbStream =
          createDecompressor(contents->compression,
                  std::unique_ptr<SeekableInputStream>
                  (new SeekableFileInputStream(contents->stream.get(),
                                                offset,
                                                length,
                                                *contents->pool)),
                  contents->blockSize,
                  *(contents->pool));

        proto::RowIndex rowIndex;
        if (!rowIndex.ParseFromZeroCopyStream(pbStream.get())) {
          throw ParseError("Failed to parse RowIndex from stripe footer");
        }
        int num_entries = rowIndex.entry_size();
        size_t column = static_cast<size_t>(stream.column());
        for (int j = 0; j < num_entries; j++) {
          const proto::RowIndexEntry& entry = rowIndex.entry(j);
          (*indexStats)[column].push_back(entry.statistics());
        }
      }
      offset += length;
    }
  }

  bool ReaderImpl::hasMetadataValue(const std::string& key) const {
    for(int i=0; i < footer->metadata_size(); ++i) {
      if (footer->metadata(i).name() == TString(key)) {
        return true;
      }
    }
    return false;
  }

  const Type& ReaderImpl::getType() const {
    return *(contents->schema.get());
  }

  std::unique_ptr<StripeStatistics>
  ReaderImpl::getStripeStatistics(uint64_t stripeIndex) const {
    if (!isMetadataLoaded) {
      readMetadata();
    }
    if (metadata.get() == nullptr) {
      throw std::logic_error("No stripe statistics in file");
    }
    size_t num_cols = static_cast<size_t>(
                          metadata->stripestats(
                              static_cast<int>(stripeIndex)).colstats_size());
    std::vector<std::vector<proto::ColumnStatistics> > indexStats(num_cols);

    proto::StripeInformation currentStripeInfo =
        footer->stripes(static_cast<int>(stripeIndex));
    proto::StripeFooter currentStripeFooter =
        getStripeFooter(currentStripeInfo, *contents.get());

    getRowIndexStatistics(currentStripeInfo, stripeIndex, currentStripeFooter, &indexStats);

    const Timezone& writerTZ =
      currentStripeFooter.has_writertimezone() ?
        getTimezoneByName(currentStripeFooter.writertimezone()) :
        getLocalTimezone();
    StatContext statContext(hasCorrectStatistics(), &writerTZ);
    return std::unique_ptr<StripeStatistics>
           (new StripeStatisticsImpl(metadata->stripestats(static_cast<int>(stripeIndex)),
                                                   indexStats, statContext));
  }

  std::unique_ptr<Statistics> ReaderImpl::getStatistics() const {
    StatContext statContext(hasCorrectStatistics());
    return std::unique_ptr<Statistics>
      (new StatisticsImpl(*footer, statContext));
  }

  std::unique_ptr<ColumnStatistics>
  ReaderImpl::getColumnStatistics(uint32_t index) const {
    if (index >= static_cast<uint64_t>(footer->statistics_size())) {
      throw std::logic_error("column index out of range");
    }
    proto::ColumnStatistics col =
      footer->statistics(static_cast<int32_t>(index));

    StatContext statContext(hasCorrectStatistics());
    return std::unique_ptr<ColumnStatistics> (convertColumnStatistics(col, statContext));
  }

  void ReaderImpl::readMetadata() const {
    uint64_t metadataSize = contents->postscript->metadatalength();
    uint64_t footerLength = contents->postscript->footerlength();
    if (fileLength < metadataSize + footerLength + postscriptLength + 1) {
      std::stringstream msg;
      msg << "Invalid Metadata length: fileLength=" << fileLength
          << ", metadataLength=" << metadataSize << ", footerLength=" << footerLength
          << ", postscriptLength=" << postscriptLength;
      throw ParseError(msg.str());
    }
    uint64_t metadataStart = fileLength - metadataSize - footerLength - postscriptLength - 1;
    if (metadataSize != 0) {
      std::unique_ptr<SeekableInputStream> pbStream =
        createDecompressor(contents->compression,
                           std::unique_ptr<SeekableInputStream>
                             (new SeekableFileInputStream(contents->stream.get(),
                                                          metadataStart,
                                                          metadataSize,
                                                          *contents->pool)),
                           contents->blockSize,
                           *contents->pool);
      metadata.reset(new proto::Metadata());
      if (!metadata->ParseFromZeroCopyStream(pbStream.get())) {
        throw ParseError("Failed to parse the metadata");
      }
    }
    isMetadataLoaded = true;
  }

  bool ReaderImpl::hasCorrectStatistics() const {
    return !WriterVersionImpl::VERSION_HIVE_8732().compareGT(getWriterVersion());
  }

  void ReaderImpl::checkOrcVersion() {
    FileVersion version = getFormatVersion();
    if (version != FileVersion(0, 11) && version != FileVersion(0, 12)) {
      *(options.getErrorStream())
        << "Warning: ORC file " << contents->stream->getName()
        << " was written in an unknown format version "
        << version.toString() << "\n";
    }
  }

  std::unique_ptr<RowReader> ReaderImpl::createRowReader() const {
    RowReaderOptions defaultOpts;
    return createRowReader(defaultOpts);
  }

  std::unique_ptr<RowReader> ReaderImpl::createRowReader(
           const RowReaderOptions& opts) const {
    return std::unique_ptr<RowReader>(new RowReaderImpl(contents, opts));
  }

  uint64_t maxStreamsForType(const proto::Type& type) {
    switch (static_cast<int64_t>(type.kind())) {
      case proto::Type_Kind_STRUCT:
        return 1;
      case proto::Type_Kind_INT:
      case proto::Type_Kind_LONG:
      case proto::Type_Kind_SHORT:
      case proto::Type_Kind_FLOAT:
      case proto::Type_Kind_DOUBLE:
      case proto::Type_Kind_BOOLEAN:
      case proto::Type_Kind_BYTE:
      case proto::Type_Kind_DATE:
      case proto::Type_Kind_LIST:
      case proto::Type_Kind_MAP:
      case proto::Type_Kind_UNION:
        return 2;
      case proto::Type_Kind_BINARY:
      case proto::Type_Kind_DECIMAL:
      case proto::Type_Kind_TIMESTAMP:
        return 3;
      case proto::Type_Kind_CHAR:
      case proto::Type_Kind_STRING:
      case proto::Type_Kind_VARCHAR:
        return 4;
      default:
          return 0;
      }
  }

  uint64_t ReaderImpl::getMemoryUse(int stripeIx) {
    std::vector<bool> selectedColumns;
    selectedColumns.assign(static_cast<size_t>(contents->footer->types_size()), true);
    return getMemoryUse(stripeIx, selectedColumns);
  }

  uint64_t ReaderImpl::getMemoryUseByFieldId(const std::list<uint64_t>& include, int stripeIx) {
    std::vector<bool> selectedColumns;
    selectedColumns.assign(static_cast<size_t>(contents->footer->types_size()), false);
    ColumnSelector column_selector(contents.get());
    if (contents->schema->getKind() == STRUCT && include.begin() != include.end()) {
      for(std::list<uint64_t>::const_iterator field = include.begin();
          field != include.end(); ++field) {
        column_selector.updateSelectedByFieldId(selectedColumns, *field);
      }
    } else {
      // default is to select all columns
      std::fill(selectedColumns.begin(), selectedColumns.end(), true);
    }
    column_selector.selectParents(selectedColumns, *contents->schema.get());
    selectedColumns[0] = true; // column 0 is selected by default
    return getMemoryUse(stripeIx, selectedColumns);
  }

  uint64_t ReaderImpl::getMemoryUseByName(const std::list<std::string>& names, int stripeIx) {
    std::vector<bool> selectedColumns;
    selectedColumns.assign(static_cast<size_t>(contents->footer->types_size()), false);
    ColumnSelector column_selector(contents.get());
    if (contents->schema->getKind() == STRUCT && names.begin() != names.end()) {
      for(std::list<std::string>::const_iterator field = names.begin();
          field != names.end(); ++field) {
        column_selector.updateSelectedByName(selectedColumns, *field);
      }
    } else {
      // default is to select all columns
      std::fill(selectedColumns.begin(), selectedColumns.end(), true);
    }
    column_selector.selectParents(selectedColumns, *contents->schema.get());
    selectedColumns[0] = true; // column 0 is selected by default
    return getMemoryUse(stripeIx, selectedColumns);
  }

  uint64_t ReaderImpl::getMemoryUseByTypeId(const std::list<uint64_t>& include, int stripeIx) {
    std::vector<bool> selectedColumns;
    selectedColumns.assign(static_cast<size_t>(contents->footer->types_size()), false);
    ColumnSelector column_selector(contents.get());
    if (include.begin() != include.end()) {
      for(std::list<uint64_t>::const_iterator field = include.begin();
          field != include.end(); ++field) {
        column_selector.updateSelectedByTypeId(selectedColumns, *field);
      }
    } else {
      // default is to select all columns
      std::fill(selectedColumns.begin(), selectedColumns.end(), true);
    }
    column_selector.selectParents(selectedColumns, *contents->schema.get());
    selectedColumns[0] = true; // column 0 is selected by default
    return getMemoryUse(stripeIx, selectedColumns);
  }

  uint64_t ReaderImpl::getMemoryUse(int stripeIx, std::vector<bool>& selectedColumns) {
    uint64_t maxDataLength = 0;

    if (stripeIx >= 0 && stripeIx < footer->stripes_size()) {
      uint64_t stripe = footer->stripes(stripeIx).datalength();
      if (maxDataLength < stripe) {
        maxDataLength = stripe;
      }
    } else {
      for (int i=0; i < footer->stripes_size(); i++) {
        uint64_t stripe = footer->stripes(i).datalength();
        if (maxDataLength < stripe) {
          maxDataLength = stripe;
        }
      }
    }

    bool hasStringColumn = false;
    uint64_t nSelectedStreams = 0;
    for (int i=0; !hasStringColumn && i < footer->types_size(); i++) {
      if (selectedColumns[static_cast<size_t>(i)]) {
        const proto::Type& type = footer->types(i);
        nSelectedStreams += maxStreamsForType(type) ;
        switch (static_cast<int64_t>(type.kind())) {
          case proto::Type_Kind_CHAR:
          case proto::Type_Kind_STRING:
          case proto::Type_Kind_VARCHAR:
          case proto::Type_Kind_BINARY: {
            hasStringColumn = true;
            break;
          }
          default: {
            break;
          }
        }
      }
    }

    /* If a string column is read, use stripe datalength as a memory estimate
     * because we don't know the dictionary size. Multiply by 2 because
     * a string column requires two buffers:
     * in the input stream and in the seekable input stream.
     * If no string column is read, estimate from the number of streams.
     */
    uint64_t memory = hasStringColumn ? 2 * maxDataLength :
        std::min(uint64_t(maxDataLength),
                 nSelectedStreams * contents->stream->getNaturalReadSize());

    // Do we need even more memory to read the footer or the metadata?
    if (memory < contents->postscript->footerlength() + DIRECTORY_SIZE_GUESS) {
      memory =  contents->postscript->footerlength() + DIRECTORY_SIZE_GUESS;
    }
    if (memory < contents->postscript->metadatalength()) {
      memory =  contents->postscript->metadatalength();
    }

    // Account for firstRowOfStripe.
    memory += static_cast<uint64_t>(footer->stripes_size()) * sizeof(uint64_t);

    // Decompressors need buffers for each stream
    uint64_t decompressorMemory = 0;
    if (contents->compression != CompressionKind_NONE) {
      for (int i=0; i < footer->types_size(); i++) {
        if (selectedColumns[static_cast<size_t>(i)]) {
          const proto::Type& type = footer->types(i);
          decompressorMemory += maxStreamsForType(type) * contents->blockSize;
        }
      }
      if (contents->compression == CompressionKind_SNAPPY) {
        decompressorMemory *= 2;  // Snappy decompressor uses a second buffer
      }
    }

    return memory + decompressorMemory ;
  }

  void RowReaderImpl::startNextStripe() {
    reader.reset(); // ColumnReaders use lots of memory; free old memory first
    currentStripeInfo = footer->stripes(static_cast<int>(currentStripe));
    uint64_t fileLength = contents->stream->getLength();
    if (currentStripeInfo.offset() + currentStripeInfo.indexlength() +
        currentStripeInfo.datalength() + currentStripeInfo.footerlength() >= fileLength) {
      std::stringstream msg;
      msg << "Malformed StripeInformation at stripe index " << currentStripe << ": fileLength="
          << fileLength << ", StripeInfo=(offset=" << currentStripeInfo.offset() << ", indexLength="
          << currentStripeInfo.indexlength() << ", dataLength=" << currentStripeInfo.datalength()
          << ", footerLength=" << currentStripeInfo.footerlength() << ")";
      throw ParseError(msg.str());
    }
    currentStripeFooter = getStripeFooter(currentStripeInfo, *contents.get());
    rowsInCurrentStripe = currentStripeInfo.numberofrows();
    const Timezone& writerTimezone =
      currentStripeFooter.has_writertimezone() ?
        getTimezoneByName(currentStripeFooter.writertimezone()) :
        localTimezone;
    StripeStreamsImpl stripeStreams(*this, currentStripe, currentStripeInfo,
                                    currentStripeFooter,
                                    currentStripeInfo.offset(),
                                    *(contents->stream.get()),
                                    writerTimezone);
    reader = buildReader(*contents->schema.get(), stripeStreams);
  }

  bool RowReaderImpl::next(ColumnVectorBatch& data) {
    if (currentStripe >= lastStripe) {
      data.numElements = 0;
      if (lastStripe > 0) {
        previousRow = firstRowOfStripe[lastStripe - 1] +
          footer->stripes(static_cast<int>(lastStripe - 1)).numberofrows();
      } else {
        previousRow = 0;
      }
      return false;
    }
    if (currentRowInStripe == 0) {
      startNextStripe();
    }
    uint64_t rowsToRead =
      std::min(static_cast<uint64_t>(data.capacity),
               rowsInCurrentStripe - currentRowInStripe);
    data.numElements = rowsToRead;
    if (enableEncodedBlock) {
      reader->nextEncoded(data, rowsToRead, nullptr);
    }
    else {
      reader->next(data, rowsToRead, nullptr);
    }
    // update row number
    previousRow = firstRowOfStripe[currentStripe] + currentRowInStripe;
    currentRowInStripe += rowsToRead;
    if (currentRowInStripe >= rowsInCurrentStripe) {
      currentStripe += 1;
      currentRowInStripe = 0;
    }
    return rowsToRead != 0;
  }

  std::unique_ptr<ColumnVectorBatch> RowReaderImpl::createRowBatch
                                              (uint64_t capacity) const {
    return getSelectedType().createRowBatch(capacity, *contents->pool, enableEncodedBlock);
  }

  void ensureOrcFooter(InputStream* stream,
                       DataBuffer<char> *buffer,
                       uint64_t postscriptLength) {

    const std::string MAGIC("ORC");
    const uint64_t magicLength = MAGIC.length();
    const char * const bufferStart = buffer->data();
    const uint64_t bufferLength = buffer->size();

    if (postscriptLength < magicLength || bufferLength < magicLength) {
      throw ParseError("Invalid ORC postscript length");
    }
    const char* magicStart = bufferStart + bufferLength - 1 - magicLength;

    // Look for the magic string at the end of the postscript.
    if (memcmp(magicStart, MAGIC.c_str(), magicLength) != 0) {
      // If there is no magic string at the end, check the beginning.
      // Only files written by Hive 0.11.0 don't have the tail ORC string.
      std::unique_ptr<char[]> frontBuffer( new char[magicLength] );
      stream->read(frontBuffer.get(), magicLength, 0);
      bool foundMatch = memcmp(frontBuffer.get(), MAGIC.c_str(), magicLength) == 0;

      if (!foundMatch) {
        throw ParseError("Not an ORC file");
      }
    }
  }

  /**
   * Read the file's postscript from the given buffer.
   * @param stream the file stream
   * @param buffer the buffer with the tail of the file.
   * @param postscriptSize the length of postscript in bytes
   */
  std::unique_ptr<proto::PostScript> readPostscript(InputStream *stream,
                                                    DataBuffer<char> *buffer,
                                                    uint64_t postscriptSize) {
    char *ptr = buffer->data();
    uint64_t readSize = buffer->size();

    ensureOrcFooter(stream, buffer, postscriptSize);

    std::unique_ptr<proto::PostScript> postscript =
      std::unique_ptr<proto::PostScript>(new proto::PostScript());
    if (readSize < 1 + postscriptSize) {
      std::stringstream msg;
      msg << "Invalid ORC postscript length: " << postscriptSize << ", file length = "
          << stream->getLength();
      throw ParseError(msg.str());
    }
    if (!postscript->ParseFromArray(ptr + readSize - 1 - postscriptSize,
                                   static_cast<int>(postscriptSize))) {
      throw ParseError("Failed to parse the postscript from " +
                       stream->getName());
    }
    return REDUNDANT_MOVE(postscript);
  }

  /**
   * Check that indices in the type tree are valid, so we won't crash
   * when we convert the proto::Types to TypeImpls.
   */
  void checkProtoTypeIds(const proto::Footer &footer) {
    std::stringstream msg;
    int maxId = footer.types_size();
    if (maxId <= 0) {
      throw ParseError("Footer is corrupt: no types found");
    }
    for (int i = 0; i < maxId; ++i) {
      const proto::Type& type = footer.types(i);
      for (int j = 0; j < type.subtypes_size(); ++j) {
        int subTypeId = static_cast<int>(type.subtypes(j));
        if (subTypeId <= i) {
          msg << "Footer is corrupt: malformed link from type " << i << " to "
              << subTypeId;
          throw ParseError(msg.str());
        }
        if (subTypeId >= maxId) {
          msg << "Footer is corrupt: types(" << subTypeId << ") not exists";
          throw ParseError(msg.str());
        }
        if (j > 0 && static_cast<int>(type.subtypes(j - 1)) >= subTypeId) {
          msg << "Footer is corrupt: subType(" << (j-1) << ") >= subType(" << j
              << ") in types(" << i << "). (" << type.subtypes(j - 1) << " >= "
              << subTypeId << ")";
          throw ParseError(msg.str());
        }
      }
    }
  }

  /**
   * Parse the footer from the given buffer.
   * @param stream the file's stream
   * @param buffer the buffer to parse the footer from
   * @param footerOffset the offset within the buffer that contains the footer
   * @param ps the file's postscript
   * @param memoryPool the memory pool to use
   */
  std::unique_ptr<proto::Footer> readFooter(InputStream* stream,
                                            const DataBuffer<char> *buffer,
                                            uint64_t footerOffset,
                                            const proto::PostScript& ps,
                                            MemoryPool& memoryPool) {
    const char *footerPtr = buffer->data() + footerOffset;

    std::unique_ptr<SeekableInputStream> pbStream =
      createDecompressor(convertCompressionKind(ps),
                         std::unique_ptr<SeekableInputStream>
                         (new SeekableArrayInputStream(footerPtr,
                                                       ps.footerlength())),
                         getCompressionBlockSize(ps),
                         memoryPool);

    std::unique_ptr<proto::Footer> footer =
      std::unique_ptr<proto::Footer>(new proto::Footer());
    if (!footer->ParseFromZeroCopyStream(pbStream.get())) {
      throw ParseError("Failed to parse the footer from " +
                       stream->getName());
    }

    checkProtoTypeIds(*footer);
    return REDUNDANT_MOVE(footer);
  }

  std::unique_ptr<Reader> createReader(std::unique_ptr<InputStream> stream,
                                       const ReaderOptions& options) {
    std::shared_ptr<FileContents> contents = std::shared_ptr<FileContents>(new FileContents());
    contents->pool = options.getMemoryPool();
    contents->errorStream = options.getErrorStream();
    std::string serializedFooter = options.getSerializedFileTail();
    uint64_t fileLength;
    uint64_t postscriptLength;
    if (serializedFooter.length() != 0) {
      // Parse the file tail from the serialized one.
      proto::FileTail tail;
      if (!tail.ParseFromString(TString(serializedFooter))) {
        throw ParseError("Failed to parse the file tail from string");
      }
      contents->postscript.reset(new proto::PostScript(tail.postscript()));
      contents->footer.reset(new proto::Footer(tail.footer()));
      fileLength = tail.filelength();
      postscriptLength = tail.postscriptlength();
    } else {
      // figure out the size of the file using the option or filesystem
      fileLength = std::min(options.getTailLocation(),
                            static_cast<uint64_t>(stream->getLength()));

      //read last bytes into buffer to get PostScript
      uint64_t readSize = std::min(fileLength, DIRECTORY_SIZE_GUESS);
      if (readSize < 4) {
        throw ParseError("File size too small");
      }
      std::unique_ptr<DataBuffer<char>> buffer( new DataBuffer<char>(*contents->pool, readSize) );
      stream->read(buffer->data(), readSize, fileLength - readSize);

      postscriptLength = buffer->data()[readSize - 1] & 0xff;
      contents->postscript = REDUNDANT_MOVE(readPostscript(stream.get(),
        buffer.get(), postscriptLength));
      uint64_t footerSize = contents->postscript->footerlength();
      uint64_t tailSize = 1 + postscriptLength + footerSize;
      if (tailSize >= fileLength) {
        std::stringstream msg;
        msg << "Invalid ORC tailSize=" << tailSize << ", fileLength=" << fileLength;
        throw ParseError(msg.str());
      }
      uint64_t footerOffset;

      if (tailSize > readSize) {
        buffer->resize(footerSize);
        stream->read(buffer->data(), footerSize, fileLength - tailSize);
        footerOffset = 0;
      } else {
        footerOffset = readSize - tailSize;
      }

      contents->footer = REDUNDANT_MOVE(readFooter(stream.get(), buffer.get(),
        footerOffset, *contents->postscript,  *contents->pool));
    }
    contents->stream = std::move(stream);
    return std::unique_ptr<Reader>(new ReaderImpl(std::move(contents),
                                                  options,
                                                  fileLength,
                                                  postscriptLength));
  }

  std::map<uint32_t, BloomFilterIndex>
  ReaderImpl::getBloomFilters(uint32_t stripeIndex,
                              const std::set<uint32_t>& included) const {
    std::map<uint32_t, BloomFilterIndex> ret;

    // find stripe info
    if (stripeIndex >= static_cast<uint32_t>(footer->stripes_size())) {
      throw std::logic_error("Illegal stripe index: " + to_string(static_cast<int64_t>(stripeIndex)));
    }
    const proto::StripeInformation currentStripeInfo =
      footer->stripes(static_cast<int>(stripeIndex));
    const proto::StripeFooter currentStripeFooter =
      getStripeFooter(currentStripeInfo, *contents);

    // iterate stripe footer to get stream of bloomfilter
    uint64_t offset = static_cast<uint64_t>(currentStripeInfo.offset());
    for (int i = 0; i < currentStripeFooter.streams_size(); i++) {
      const proto::Stream& stream = currentStripeFooter.streams(i);
      uint32_t column = static_cast<uint32_t>(stream.column());
      uint64_t length = static_cast<uint64_t>(stream.length());

      // a bloom filter stream from a selected column is found
      if (stream.kind() == proto::Stream_Kind_BLOOM_FILTER_UTF8 &&
          (included.empty() || included.find(column) != included.end())) {

        std::unique_ptr<SeekableInputStream> pbStream =
          createDecompressor(contents->compression,
                             std::unique_ptr<SeekableInputStream>
                               (new SeekableFileInputStream(contents->stream.get(),
                                                            offset,
                                                            length,
                                                            *contents->pool)),
                             contents->blockSize,
                             *(contents->pool));

        proto::BloomFilterIndex pbBFIndex;
        if (!pbBFIndex.ParseFromZeroCopyStream(pbStream.get())) {
          throw ParseError("Failed to parse BloomFilterIndex");
        }

        BloomFilterIndex bfIndex;
        for (int j = 0; j < pbBFIndex.bloomfilter_size(); j++) {
	  std::unique_ptr<BloomFilter> entry = BloomFilterUTF8Utils::deserialize(
            stream.kind(),
            currentStripeFooter.columns(static_cast<int>(stream.column())),
            pbBFIndex.bloomfilter(j));
          bfIndex.entries.push_back(std::shared_ptr<BloomFilter>(std::move(entry)));
        }

        // add bloom filters to result for one column
        ret[column] = bfIndex;
      }

      offset += length;
    }

    return ret;
  }

  RowReader::~RowReader() {
    // PASS
  }

  Reader::~Reader() {
    // PASS
  }

  InputStream::~InputStream() {
    // PASS
  };



}// namespace