RMiniFile.cxx

Go to the documentation of this file.

/// \file RMiniFile.cxx
/// \ingroup NTuple ROOT7
/// \author Jakob Blomer <jblomer@cern.ch>
/// \date 2019-12-22
/// \warning This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback
/// is welcome!
 
/*************************************************************************
 * Copyright (C) 1995-2019, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include <ROOT/RConfig.hxx>
#include <ROOT/RError.hxx>
 
#include "ROOT/RMiniFile.hxx"
 
#include <ROOT/RRawFile.hxx>
#include <ROOT/RNTupleZip.hxx>
 
#include <TError.h>
#include <TFile.h>
#include <TKey.h>
 
#include <xxhash.h>
 
#include <algorithm>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <memory>
#include <new>
#include <string>
#include <utility>
#include <chrono>
 
namespace {
 
// The following types are used to read and write the TFile binary format
 
/// Big-endian 16-bit unsigned integer
class RUInt16BE {
private:
   std::uint16_t fValBE = 0;
   static std::uint16_t Swap(std::uint16_t val) {
      return (val & 0x00FF) << 8 | (val & 0xFF00) >> 8;
   }
public:
   RUInt16BE() = default;
   explicit RUInt16BE(const std::uint16_t val) : fValBE(Swap(val)) {}
   operator std::uint16_t() const {
      return Swap(fValBE);
   }
   RUInt16BE& operator =(const std::uint16_t val) {
      fValBE = Swap(val);
      return *this;
   }
};
 
/// Big-endian 32-bit unsigned integer
class RUInt32BE {
private:
   std::uint32_t fValBE = 0;
   static std::uint32_t Swap(std::uint32_t val) {
      auto x = (val & 0x0000FFFF) << 16 | (val & 0xFFFF0000) >> 16;
      return (x & 0x00FF00FF) << 8 | (x & 0xFF00FF00) >> 8;
   }
public:
   RUInt32BE() = default;
   explicit RUInt32BE(const std::uint32_t val) : fValBE(Swap(val)) {}
   operator std::uint32_t() const {
      return Swap(fValBE);
   }
   RUInt32BE& operator =(const std::uint32_t val) {
      fValBE = Swap(val);
      return *this;
   }
};
 
/// Big-endian 32-bit signed integer
class RInt32BE {
private:
   std::int32_t fValBE = 0;
   static std::int32_t Swap(std::int32_t val) {
      auto x = (val & 0x0000FFFF) << 16 | (val & 0xFFFF0000) >> 16;
      return (x & 0x00FF00FF) << 8 | (x & 0xFF00FF00) >> 8;
   }
public:
   RInt32BE() = default;
   explicit RInt32BE(const std::int32_t val) : fValBE(Swap(val)) {}
   operator std::int32_t() const {
      return Swap(fValBE);
   }
   RInt32BE& operator =(const std::int32_t val) {
      fValBE = Swap(val);
      return *this;
   }
};
 
/// Big-endian 64-bit unsigned integer
class RUInt64BE {
private:
   std::uint64_t fValBE = 0;
   static std::uint64_t Swap(std::uint64_t val) {
      auto x = (val & 0x00000000FFFFFFFF) << 32 | (val & 0xFFFFFFFF00000000) >> 32;
      x = (x & 0x0000FFFF0000FFFF) << 16 | (x & 0xFFFF0000FFFF0000) >> 16;
      return (x & 0x00FF00FF00FF00FF) << 8  | (x & 0xFF00FF00FF00FF00) >> 8;
   }
public:
   RUInt64BE() = default;
   explicit RUInt64BE(const std::uint64_t val) : fValBE(Swap(val)) {}
   operator std::uint64_t() const {
      return Swap(fValBE);
   }
   RUInt64BE& operator =(const std::uint64_t val) {
      fValBE = Swap(val);
      return *this;
   }
};
 
constexpr std::int32_t ChecksumRNTupleClass() {
   const char ident[] = "ROOT::Experimental::RNTuple"
                        "fVersionEpoch"
                        "unsigned short"
                        "fVersionMajor"
                        "unsigned short"
                        "fVersionMinor"
                        "unsigned short"
                        "fVersionPatch"
                        "unsigned short"
                        "fSeekHeader"
                        "unsigned long"
                        "fNBytesHeader"
                        "unsigned long"
                        "fLenHeader"
                        "unsigned long"
                        "fSeekFooter"
                        "unsigned long"
                        "fNBytesFooter"
                        "unsigned long"
                        "fLenFooter"
                        "unsigned long"
                        "fChecksum"
                        "unsigned long";
   std::int32_t id = 0;
   for (unsigned i = 0; i < (sizeof(ident) - 1); i++)
      id = static_cast<std::int32_t>(static_cast<std::int64_t>(id) * 3 + ident[i]);
   return id;
}
 
 
#pragma pack(push, 1)
/// A name (type, identifies, ...) in the TFile binary format
struct RTFString {
   unsigned char fLName{0};
   char fData[255];
   RTFString() = default;
   RTFString(const std::string &str) {
      // The length of strings with 255 characters and longer are encoded with a 32-bit integer following the first
      // byte. This is currently not handled.
      R__ASSERT(str.length() < 255);
      fLName = str.length();
      memcpy(fData, str.data(), fLName);
   }
   std::size_t GetSize() const
   {
      // A length of 255 is special and means that the first byte is followed by a 32-bit integer with the actual
      // length.
      R__ASSERT(fLName != 255);
      return 1 + fLName;
   }
};
 
/// The timestamp format used in TFile; the default constructor initializes with the current time
struct RTFDatetime {
   RUInt32BE fDatetime;
   RTFDatetime() {
      auto now = std::chrono::system_clock::now();
      auto tt = std::chrono::system_clock::to_time_t(now);
      auto tm = *localtime(&tt);
      fDatetime = (tm.tm_year + 1900 - 1995) << 26 | (tm.tm_mon + 1) << 22 | tm.tm_mday << 17 |
                  tm.tm_hour << 12 | tm.tm_min << 6 | tm.tm_sec;
   }
   explicit RTFDatetime(RUInt32BE val) : fDatetime(val) {}
};
 
/// The key part of a TFile record excluding the class, object, and title names
struct RTFKey {
   RInt32BE fNbytes{0};
   RUInt16BE fVersion{4};
   RUInt32BE fObjLen{0};
   RTFDatetime fDatetime;
   RUInt16BE fKeyLen{0};
   RUInt16BE fCycle{1};
   union {
      struct {
         RUInt32BE fSeekKey{0};
         RUInt32BE fSeekPdir{0};
      } fInfoShort;
      struct {
         RUInt64BE fSeekKey{0};
         RUInt64BE fSeekPdir{0};
      } fInfoLong;
   };
 
   std::uint32_t fKeyHeaderSize{18 + sizeof(fInfoShort)};  // not part of serialization
 
   RTFKey() : fInfoShort() {}
   RTFKey(std::uint64_t seekKey, std::uint64_t seekPdir,
          const RTFString &clName, const RTFString &objName, const RTFString &titleName,
          std::size_t szObjInMem, std::size_t szObjOnDisk = 0)
   {
      R__ASSERT(szObjInMem < std::numeric_limits<std::int32_t>::max());
      R__ASSERT(szObjOnDisk < std::numeric_limits<std::int32_t>::max());
      fObjLen = szObjInMem;
      if ((seekKey > static_cast<unsigned int>(std::numeric_limits<std::int32_t>::max())) ||
          (seekPdir > static_cast<unsigned int>(std::numeric_limits<std::int32_t>::max())))
      {
         fKeyHeaderSize = 18 + sizeof(fInfoLong);
         fKeyLen = fKeyHeaderSize + clName.GetSize() + objName.GetSize() + titleName.GetSize();
         fInfoLong.fSeekKey = seekKey;
         fInfoLong.fSeekPdir = seekPdir;
         fVersion = fVersion + 1000;
      } else {
         fKeyHeaderSize = 18 + sizeof(fInfoShort);
         fKeyLen = fKeyHeaderSize + clName.GetSize() + objName.GetSize() + titleName.GetSize();
         fInfoShort.fSeekKey = seekKey;
         fInfoShort.fSeekPdir = seekPdir;
      }
      fNbytes = fKeyLen + ((szObjOnDisk == 0) ? szObjInMem : szObjOnDisk);
   }
 
   void MakeBigKey()
   {
      if (fVersion >= 1000)
         return;
      std::uint32_t seekKey = fInfoShort.fSeekKey;
      std::uint32_t seekPdir = fInfoShort.fSeekPdir;
      fInfoLong.fSeekKey = seekKey;
      fInfoLong.fSeekPdir = seekPdir;
      fKeyHeaderSize = fKeyHeaderSize + sizeof(fInfoLong) - sizeof(fInfoShort);
      fKeyLen = fKeyLen + sizeof(fInfoLong) - sizeof(fInfoShort);
      fNbytes = fNbytes + sizeof(fInfoLong) - sizeof(fInfoShort);
      fVersion = fVersion + 1000;
   }
 
   std::uint32_t GetSize() const {
      // Negative size indicates a gap in the file
      if (fNbytes < 0)
         return -fNbytes;
      return fNbytes;
   }
 
   std::uint32_t GetHeaderSize() const {
      if (fVersion >= 1000)
         return 18 + sizeof(fInfoLong);
      return 18 + sizeof(fInfoShort);
   }
 
   std::uint64_t GetSeekKey() const {
      if (fVersion >= 1000)
         return fInfoLong.fSeekKey;
      return fInfoShort.fSeekKey;
   }
};
 
/// The TFile global header
struct RTFHeader {
   char fMagic[4]{ 'r', 'o', 'o', 't' };
   RUInt32BE fVersion{(ROOT_VERSION_CODE >> 16)*10000 +
                      ((ROOT_VERSION_CODE & 0xFF00) >> 8) * 100 +
                      (ROOT_VERSION_CODE & 0xFF)};
   RUInt32BE fBEGIN{100};
   union {
      struct {
         RUInt32BE fEND{0};
         RUInt32BE fSeekFree{0};
         RUInt32BE fNbytesFree{0};
         RUInt32BE fNfree{1};
         RUInt32BE fNbytesName{0};
         unsigned char fUnits{4};
         RUInt32BE fCompress{0};
         RUInt32BE fSeekInfo{0};
         RUInt32BE fNbytesInfo{0};
      } fInfoShort;
      struct {
         RUInt64BE fEND{0};
         RUInt64BE fSeekFree{0};
         RUInt32BE fNbytesFree{0};
         RUInt32BE fNfree{1};
         RUInt32BE fNbytesName{0};
         unsigned char fUnits{8};
         RUInt32BE fCompress{0};
         RUInt64BE fSeekInfo{0};
         RUInt32BE fNbytesInfo{0};
      } fInfoLong;
   };
 
   RTFHeader() : fInfoShort() {}
   RTFHeader(int compression) : fInfoShort() {
      fInfoShort.fCompress = compression;
   }
 
   void SetBigFile() {
      if (fVersion >= 1000000)
         return;
 
      std::uint32_t end        = fInfoShort.fEND;
      std::uint32_t seekFree   = fInfoShort.fSeekFree;
      std::uint32_t nbytesFree = fInfoShort.fNbytesFree;
      std::uint32_t nFree      = fInfoShort.fNfree;
      std::uint32_t nbytesName = fInfoShort.fNbytesName;
      std::uint32_t compress   = fInfoShort.fCompress;
      std::uint32_t seekInfo   = fInfoShort.fSeekInfo;
      std::uint32_t nbytesInfo = fInfoShort.fNbytesInfo;
      fInfoLong.fEND        = end;
      fInfoLong.fSeekFree   = seekFree;
      fInfoLong.fNbytesFree = nbytesFree;
      fInfoLong.fNfree      = nFree;
      fInfoLong.fNbytesName = nbytesName;
      fInfoLong.fUnits      = 8;
      fInfoLong.fCompress   = compress;
      fInfoLong.fSeekInfo   = seekInfo;
      fInfoLong.fNbytesInfo = nbytesInfo;
      fVersion = fVersion + 1000000;
   }
 
   bool IsBigFile(std::uint64_t offset = 0) const {
      return (fVersion >= 1000000) || (offset > static_cast<unsigned int>(std::numeric_limits<std::int32_t>::max()));
   }
 
   std::uint32_t GetSize() const {
      std::uint32_t sizeHead = 4 + sizeof(fVersion) + sizeof(fBEGIN);
      if (IsBigFile()) return sizeHead + sizeof(fInfoLong);
      return sizeHead + sizeof(fInfoShort);
   }
 
   std::uint64_t GetEnd() const {
      if (IsBigFile()) return fInfoLong.fEND;
      return fInfoShort.fEND;
   }
 
   void SetEnd(std::uint64_t value) {
      if (IsBigFile(value)) {
         SetBigFile();
         fInfoLong.fEND = value;
      } else {
         fInfoShort.fEND = value;
      }
   }
 
   std::uint64_t GetSeekFree() const {
      if (IsBigFile()) return fInfoLong.fSeekFree;
      return fInfoShort.fSeekFree;
   }
 
   void SetSeekFree(std::uint64_t value) {
      if (IsBigFile(value)) {
         SetBigFile();
         fInfoLong.fSeekFree = value;
      } else {
         fInfoShort.fSeekFree = value;
      }
   }
 
   void SetNbytesFree(std::uint32_t value) {
      if (IsBigFile()) {
         fInfoLong.fNbytesFree = value;
      } else {
         fInfoShort.fNbytesFree = value;
      }
   }
 
   void SetNbytesName(std::uint32_t value) {
      if (IsBigFile()) {
         fInfoLong.fNbytesName = value;
      } else {
         fInfoShort.fNbytesName = value;
      }
   }
 
   std::uint64_t GetSeekInfo() const {
      if (IsBigFile()) return fInfoLong.fSeekInfo;
      return fInfoShort.fSeekInfo;
   }
 
   void SetSeekInfo(std::uint64_t value) {
      if (IsBigFile(value)) {
         SetBigFile();
         fInfoLong.fSeekInfo = value;
      } else {
         fInfoShort.fSeekInfo = value;
      }
   }
 
   void SetNbytesInfo(std::uint32_t value) {
      if (IsBigFile()) {
         fInfoLong.fNbytesInfo = value;
      } else {
         fInfoShort.fNbytesInfo = value;
      }
   }
 
   void SetCompression(std::uint32_t value) {
      if (IsBigFile()) {
         fInfoLong.fCompress = value;
      } else {
         fInfoShort.fCompress = value;
      }
   }
};
 
 
/// A reference to an unused byte-range in a TFile
struct RTFFreeEntry {
   RUInt16BE fVersion{1};
   union {
      struct {
         RUInt32BE fFirst{0};
         RUInt32BE fLast{0};
      } fInfoShort;
      struct {
         RUInt64BE fFirst{0};
         RUInt64BE fLast{0};
      } fInfoLong;
   };
 
   RTFFreeEntry() : fInfoShort() {}
   void Set(std::uint64_t first, std::uint64_t last) {
      if (last > static_cast<unsigned int>(std::numeric_limits<std::int32_t>::max())) {
         fVersion = fVersion + 1000;
         fInfoLong.fFirst = first;
         fInfoLong.fLast = last;
      } else {
         fInfoShort.fFirst = first;
         fInfoShort.fLast = last;
      }
   }
   std::uint32_t GetSize() { return (fVersion >= 1000) ? 18 : 10; }
};
 
/// Streamer info for TObject
struct RTFObject {
   RUInt16BE fVersion{1};
   RUInt32BE fUniqueID{0};  // unused
   RUInt32BE fBits;
   explicit RTFObject(std::uint32_t bits) : fBits(bits) {}
};
 
/// Streamer info for data member RNTuple::fVersionEpoch
struct RTFStreamerElementVersionEpoch {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementVersionEpoch) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 | (sizeof(RUInt16BE) + sizeof(RTFObject) + 15)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 13;
   char fName[13]{'f', 'V', 'e', 'r', 's', 'i', 'o', 'n', 'E', 'p', 'o', 'c', 'h'};
   char fLTitle = 0;
 
   RUInt32BE fType{12};
   RUInt32BE fSize{2};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
   char fLTypeName = 14;
   char fTypeName[14]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 's', 'h', 'o', 'r', 't'};
};
 
/// Streamer info for data member RNTuple::fVersionMajor
struct RTFStreamerElementVersionMajor {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementVersionMajor) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 | (sizeof(RUInt16BE) + sizeof(RTFObject) + 15)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 13;
   char fName[13]{'f', 'V', 'e', 'r', 's', 'i', 'o', 'n', 'M', 'a', 'j', 'o', 'r'};
   char fLTitle = 0;
 
   RUInt32BE fType{12};
   RUInt32BE fSize{2};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 14;
   char fTypeName[14]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 's', 'h', 'o', 'r', 't'};
};
 
/// Streamer info for data member RNTuple::fVersionMajor
struct RTFStreamerElementVersionMinor {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementVersionMinor) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 | (sizeof(RUInt16BE) + sizeof(RTFObject) + 15)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 13;
   char fName[13]{'f', 'V', 'e', 'r', 's', 'i', 'o', 'n', 'M', 'i', 'n', 'o', 'r'};
   char fLTitle = 0;
 
   RUInt32BE fType{12};
   RUInt32BE fSize{2};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 14;
   char fTypeName[14]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 's', 'h', 'o', 'r', 't'};
};
 
/// Streamer info for data member RNTuple::fVersionPatch
struct RTFStreamerElementVersionPatch {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementVersionPatch) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 | (sizeof(RUInt16BE) + sizeof(RTFObject) + 15)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 13;
   char fName[13]{'f', 'V', 'e', 'r', 's', 'i', 'o', 'n', 'P', 'a', 't', 'c', 'h'};
   char fLTitle = 0;
 
   RUInt32BE fType{12};
   RUInt32BE fSize{2};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
   char fLTypeName = 14;
   char fTypeName[14]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 's', 'h', 'o', 'r', 't'};
};
 
/// Streamer info for data member RNTuple::fSeekHeader
struct RTFStreamerElementSeekHeader {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementSeekHeader) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 13)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 11;
   char fName[11]{ 'f', 'S', 'e', 'e', 'k', 'H', 'e', 'a', 'd', 'e', 'r' };
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{ 'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g' };
};
 
/// Streamer info for data member RNTuple::fNbytesHeader
struct RTFStreamerElementNBytesHeader {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementNBytesHeader) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 15)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 13;
   char fName[13]{ 'f', 'N', 'B', 'y', 't', 'e', 's', 'H', 'e', 'a', 'd', 'e', 'r' };
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g'};
};
 
/// Streamer info for data member RNTuple::fLenHeader
struct RTFStreamerElementLenHeader {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementLenHeader) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 12)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 10;
   char fName[10]{ 'f', 'L', 'e', 'n', 'H', 'e', 'a', 'd', 'e', 'r' };
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g'};
};
 
/// Streamer info for data member RNTuple::fSeekFooter
struct RTFStreamerElementSeekFooter {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementSeekFooter) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 13)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 11;
   char fName[11]{ 'f', 'S', 'e', 'e', 'k', 'F', 'o', 'o', 't', 'e', 'r' };
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{ 'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g' };
};
 
/// Streamer info for data member RNTuple::fNbytesFooter
struct RTFStreamerElementNBytesFooter {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementNBytesFooter) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 | (sizeof(RUInt16BE) + sizeof(RTFObject) + 15)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 13;
   char fName[13]{ 'f', 'N', 'B', 'y', 't', 'e', 's', 'F', 'o', 'o', 't', 'e', 'r' };
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g'};
};
 
/// Streamer info for data member RNTuple::fLenFooter
struct RTFStreamerElementLenFooter {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementLenFooter) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 | (sizeof(RUInt16BE) + sizeof(RTFObject) + 12)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 10;
   char fName[10]{ 'f', 'L', 'e', 'n', 'F', 'o', 'o', 't', 'e', 'r' };
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g'};
};
 
/// Streamer info for data member RNTuple::fChecksum
struct RTFStreamerElementChecksum {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerElementChecksum) - sizeof(RUInt32BE))};
   RUInt16BE fVersion{4};
 
   RUInt32BE fByteCountNamed{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 11)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000};
   char fLName = 9;
   char fName[9]{'f', 'C', 'h', 'e', 'c', 'k', 's', 'u', 'm'};
   char fLTitle = 0;
 
   RUInt32BE fType{14};
   RUInt32BE fSize{8};
   RUInt32BE fArrLength{0};
   RUInt32BE fArrDim{0};
   char fMaxIndex[20]{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
   char fLTypeName = 13;
   char fTypeName[13]{ 'u', 'n', 's', 'i', 'g', 'n', 'e', 'd', ' ', 'l', 'o', 'n', 'g' };
};
 
/// Streamer info frame for data member RNTuple::fVersionEpoch
struct RTFStreamerVersionEpoch {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerVersionEpoch) - sizeof(RUInt32BE))};
   RUInt32BE fNewClassTag{0xffffffff};
   char fClassName[19]{'T', 'S', 't', 'r', 'e', 'a', 'm', 'e', 'r', 'B', 'a', 's', 'i', 'c', 'T', 'y', 'p', 'e', '\0'};
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerVersionEpoch) - 2 * sizeof(RUInt32BE) -
                                               19 /* strlen(fClassName) + 1 */ - sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementVersionEpoch fStreamerElementVersionEpoch;
};
 
/// Streamer info frame for data member RNTuple::fVersionMajor
struct RTFStreamerVersionMajor {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerVersionMajor) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000}; // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerVersionMajor) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementVersionMajor fStreamerElementVersionMajor;
};
 
/// Streamer info frame for data member RNTuple::fVersionMinor
struct RTFStreamerVersionMinor {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerVersionMinor) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000}; // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerVersionMinor) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementVersionMinor fStreamerElementVersionMinor;
};
 
/// Streamer info frame for data member RNTuple::fVersionPatch
struct RTFStreamerVersionPatch {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerVersionPatch) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerVersionPatch) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementVersionPatch fStreamerElementVersionPatch;
};
 
/// Streamer info frame for data member RNTuple::fSeekHeader
struct RTFStreamerSeekHeader {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerSeekHeader) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerSeekHeader) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementSeekHeader fStreamerElementSeekHeader;
};
 
/// Streamer info frame for data member RNTuple::fNbytesHeader
struct RTFStreamerNBytesHeader {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerNBytesHeader) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerNBytesHeader) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementNBytesHeader fStreamerElementNBytesHeader;
};
 
/// Streamer info frame for data member RNTuple::fLenHeader
struct RTFStreamerLenHeader {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerLenHeader) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerLenHeader) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementLenHeader fStreamerElementLenHeader;
};
 
/// Streamer info frame for data member RNTuple::fSeekFooter
struct RTFStreamerSeekFooter {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerSeekFooter) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerSeekFooter) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementSeekFooter fStreamerElementSeekFooter;
};
 
/// Streamer info frame for data member RNTuple::fNBytesFooter
struct RTFStreamerNBytesFooter {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerNBytesFooter) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerNBytesFooter) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementNBytesFooter fStreamerElementNBytesFooter;
};
 
/// Streamer info frame for data member RNTuple::fLenFooter
struct RTFStreamerLenFooter {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerLenFooter) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerLenFooter) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementLenFooter fStreamerElementLenFooter;
};
 
/// Streamer info frame for data member RNTuple::fChecksum
struct RTFStreamerChecksum {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerChecksum) - sizeof(RUInt32BE))};
   RUInt32BE fClassTag{0x80000000};  // Fix-up after construction, or'd with 0x80000000
   RUInt32BE fByteCountRemaining{0x40000000 | (sizeof(RTFStreamerChecksum) - 3 * sizeof(RUInt32BE))};
   RUInt16BE fVersion{2};
   RTFStreamerElementChecksum fStreamerElementChecksum;
};
 
/// Streamer info for class RNTuple
struct RTFStreamerInfoObject {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerInfoObject) - sizeof(fByteCount))};
   RUInt32BE fNewClassTag{0xffffffff};
   char fClassName[14]{ 'T', 'S', 't', 'r', 'e', 'a', 'm', 'e', 'r', 'I', 'n', 'f', 'o', '\0' };
   RUInt32BE fByteCountRemaining{0x40000000 |
      (sizeof(RTFStreamerInfoObject) - 2 * sizeof(RUInt32BE) - 14 - sizeof(RUInt32BE))};
   RUInt16BE fVersion{9};
 
   RUInt32BE fByteCountNamed{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 29 /* strlen("ROOT::Experimental::RNTuple") + 2 */)};
   RUInt16BE fVersionNamed{1};
   RTFObject fObjectNamed{0x02000000 | 0x01000000 | 0x00010000};
   char fLName = 27;
   char fName[27]{ 'R', 'O', 'O', 'T', ':', ':',
      'E', 'x', 'p', 'e', 'r', 'i', 'm', 'e', 'n', 't', 'a', 'l', ':', ':',
      'R', 'N', 'T', 'u', 'p', 'l', 'e'};
   char fLTitle = 0;
 
   RInt32BE fChecksum{ChecksumRNTupleClass()};
   RUInt32BE fVersionRNTuple{4};
 
   RUInt32BE fByteCountObjArr{0x40000000 |
      (sizeof(RUInt32BE) + 10 /* strlen(TObjArray) + 1 */ + sizeof(RUInt32BE) +
       sizeof(RUInt16BE) + sizeof(RTFObject) + 1 + 2*sizeof(RUInt32BE) +
       sizeof(fStreamers))};
   RUInt32BE fNewClassTagObjArray{0xffffffff};
   char fClassNameObjArray[10]{'T', 'O', 'b', 'j', 'A', 'r', 'r', 'a', 'y', '\0'};
   RUInt32BE fByteCountObjArrRemaining{0x40000000 |
      (sizeof(RUInt16BE) + sizeof(RTFObject) + 1 + 2*sizeof(RUInt32BE) +
       sizeof(fStreamers))};
   RUInt16BE fVersionObjArr{3};
   RTFObject fObjectObjArr{0x02000000};
   char fNameObjArr{0};
 
   RUInt32BE fNObjects{11};
   RUInt32BE fLowerBound{0};
 
   struct {
      RTFStreamerVersionEpoch fStreamerVersionEpoch;
      RTFStreamerVersionMajor fStreamerVersionMajor;
      RTFStreamerVersionMinor fStreamerVersionMinor;
      RTFStreamerVersionPatch fStreamerVersionPatch;
      RTFStreamerSeekHeader fStreamerSeekHeader;
      RTFStreamerNBytesHeader fStreamerNBytesHeader;
      RTFStreamerLenHeader fStreamerLenHeader;
      RTFStreamerSeekFooter fStreamerSeekFooter;
      RTFStreamerNBytesFooter fStreamerNBytesFooter;
      RTFStreamerLenFooter fStreamerLenFooter;
      RTFStreamerChecksum fStreamerChecksum;
   } fStreamers;
};
 
/// The list of streamer info objects, for a new ntuple contains only the RNTuple class
struct RTFStreamerInfoList {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFStreamerInfoList) - sizeof(fByteCount))};
   RUInt16BE fVersion{5};
   RTFObject fObject{0x02000000};
   char fName{0};
   RUInt32BE fNObjects{1};
   RTFStreamerInfoObject fStreamerInfo;
   char fEnd{0};
 
   std::uint32_t GetSize() const { return sizeof(RTFStreamerInfoList); }
};
 
/// The header of the directory key index
struct RTFKeyList {
   RUInt32BE fNKeys;
   std::uint32_t GetSize() const { return sizeof(RTFKeyList); }
   explicit RTFKeyList(std::uint32_t nKeys) : fNKeys(nKeys) {}
};
 
/// A streamed TFile object
struct RTFFile {
   RUInt16BE fClassVersion{5};
   RTFDatetime fDateC;
   RTFDatetime fDateM;
   RUInt32BE fNBytesKeys{0};
   RUInt32BE fNBytesName{0};
   // The version of the key has to tell whether offsets are 32bit or 64bit long
   union {
      struct {
         RUInt32BE fSeekDir{100};
         RUInt32BE fSeekParent{0};
         RUInt32BE fSeekKeys{0};
      } fInfoShort;
      struct {
         RUInt64BE fSeekDir{100};
         RUInt64BE fSeekParent{0};
         RUInt64BE fSeekKeys{0};
      } fInfoLong;
   };
 
   RTFFile() : fInfoShort() {}
 
   // In case of a short TFile record (<2G), 3 padding ints are written after the UUID
   std::uint32_t GetSize() const
   {
      if (fClassVersion >= 1000)
         return sizeof(RTFFile);
      return 18 + sizeof(fInfoShort);
   }
 
   std::uint64_t GetSeekKeys() const
   {
      if (fClassVersion >= 1000)
         return fInfoLong.fSeekKeys;
      return fInfoShort.fSeekKeys;
   }
 
   void SetSeekKeys(std::uint64_t seekKeys)
   {
      if (seekKeys > static_cast<unsigned int>(std::numeric_limits<std::int32_t>::max())) {
         std::uint32_t seekDir = fInfoShort.fSeekDir;
         std::uint32_t seekParent = fInfoShort.fSeekParent;
         fInfoLong.fSeekDir = seekDir;
         fInfoLong.fSeekParent = seekParent;
         fInfoLong.fSeekKeys = seekKeys;
         fClassVersion = fClassVersion + 1000;
      } else {
         fInfoShort.fSeekKeys = seekKeys;
      }
   }
};
 
/// A zero UUID stored at the end of the TFile record
struct RTFUUID {
   RUInt16BE fVersionClass{1};
   unsigned char fUUID[16] = {0};
 
   RTFUUID() = default;
   std::uint32_t GetSize() const { return sizeof(RTFUUID); }
};
 
/// A streamed RNTuple class
struct RTFNTuple {
   RUInt32BE fByteCount{0x40000000 | (sizeof(RTFNTuple) - sizeof(fByteCount))};
   RUInt16BE fVersionClass{4};
   RUInt16BE fVersionEpoch{0};
   RUInt16BE fVersionMajor{0};
   RUInt16BE fVersionMinor{0};
   RUInt16BE fVersionPatch{0};
   RUInt64BE fSeekHeader{0};
   RUInt64BE fNBytesHeader{0};
   RUInt64BE fLenHeader{0};
   RUInt64BE fSeekFooter{0};
   RUInt64BE fNBytesFooter{0};
   RUInt64BE fLenFooter{0};
   RUInt64BE fChecksum{0};
 
   RTFNTuple() = default;
   explicit RTFNTuple(const ROOT::Experimental::RNTuple &inMemoryAnchor)
   {
      fVersionEpoch = inMemoryAnchor.GetVersionEpoch();
      fVersionMajor = inMemoryAnchor.GetVersionMajor();
      fVersionMinor = inMemoryAnchor.GetVersionMinor();
      fVersionPatch = inMemoryAnchor.GetVersionPatch();
      fSeekHeader = inMemoryAnchor.GetSeekHeader();
      fNBytesHeader = inMemoryAnchor.GetNBytesHeader();
      fLenHeader = inMemoryAnchor.GetLenHeader();
      fSeekFooter = inMemoryAnchor.GetSeekFooter();
      fNBytesFooter = inMemoryAnchor.GetNBytesFooter();
      fLenFooter = inMemoryAnchor.GetLenFooter();
      fChecksum = XXH3_64bits(GetPtrCkData(), GetSizeCkData());
   }
   std::uint32_t GetSize() const { return sizeof(RTFNTuple); }
   // The byte count and class version members are not checksummed
   std::uint32_t GetOffsetCkData() { return sizeof(fByteCount) + sizeof(fVersionClass); }
   std::uint32_t GetSizeCkData() { return GetSize() - GetOffsetCkData() - sizeof(fChecksum); }
   unsigned char *GetPtrCkData() { return reinterpret_cast<unsigned char *>(this) + GetOffsetCkData(); }
};
 
/// The bare file global header
struct RBareFileHeader {
   char fMagic[7]{ 'r', 'n', 't', 'u', 'p', 'l', 'e' };
   RUInt32BE fRootVersion{(ROOT_VERSION_CODE >> 16) * 10000 +
                          ((ROOT_VERSION_CODE & 0xFF00) >> 8) * 100 +
                          (ROOT_VERSION_CODE & 0xFF)};
   RUInt32BE fFormatVersion{1};
   RUInt32BE fCompress{0};
   RTFNTuple fNTuple;
   // followed by the ntuple name
};
#pragma pack(pop)
 
/// The artifical class name shown for opaque RNTuple keys (see TBasket)
constexpr char const *kBlobClassName = "RBlob";
/// The class name of the RNTuple anchor
constexpr char const *kNTupleClassName = "ROOT::Experimental::RNTuple";
 
/// The RKeyBlob writes an invisible key into a TFile.  That is, a key that is not indexed in the list of keys,
/// like a TBasket.
class RKeyBlob : public TKey {
public:
   explicit RKeyBlob(TFile *file) : TKey(file) {
      fClassName = kBlobClassName;
      fVersion += 1000;
      fKeylen = Sizeof();
   }
 
   /// Register a new key for a data record of size nbytes
   void Reserve(size_t nbytes, std::uint64_t *seekKey)
   {
      Create(nbytes);
      *seekKey = fSeekKey;
   }
};
 
} // anonymous namespace
 
 
namespace ROOT {
namespace Experimental {
namespace Internal {
/// If a TFile container is written by a C stream (simple file), on dataset commit, the file header
/// and the TFile record need to be updated
struct RTFileControlBlock {
   RTFHeader fHeader;
   RTFFile fFileRecord;
   std::uint64_t fSeekNTuple{0}; // Remember the offset for the keys list
   std::uint64_t fSeekFileRecord{0};
};
} // namespace ROOT
} // namespace Experimental
} // namespace Internal
 
 
ROOT::Experimental::Internal::RMiniFileReader::RMiniFileReader(ROOT::Internal::RRawFile *rawFile)
   : fRawFile(rawFile)
{
}
 
ROOT::Experimental::RNTuple ROOT::Experimental::Internal::RMiniFileReader::CreateAnchor(
   std::uint16_t versionEpoch, std::uint16_t versionMajor, std::uint16_t versionMinor, std::uint16_t versionPatch,
   std::uint64_t seekHeader, std::uint64_t nbytesHeader, std::uint64_t lenHeader, std::uint64_t seekFooter,
   std::uint64_t nbytesFooter, std::uint64_t lenFooter, std::uint64_t checksum)
{
   RNTuple ntuple;
   ntuple.fVersionEpoch = versionEpoch;
   ntuple.fVersionMajor = versionMajor;
   ntuple.fVersionMinor = versionMinor;
   ntuple.fVersionPatch = versionPatch;
   ntuple.fSeekHeader = seekHeader;
   ntuple.fNBytesHeader = nbytesHeader;
   ntuple.fLenHeader = lenHeader;
   ntuple.fSeekFooter = seekFooter;
   ntuple.fNBytesFooter = nbytesFooter;
   ntuple.fLenFooter = lenFooter;
   ntuple.fChecksum = checksum;
   return ntuple;
}
 
ROOT::Experimental::RResult<ROOT::Experimental::RNTuple>
ROOT::Experimental::Internal::RMiniFileReader::GetNTuple(std::string_view ntupleName)
{
   char ident[4];
   ReadBuffer(ident, 4, 0);
   if (std::string(ident, 4) == "root")
      return GetNTupleProper(ntupleName);
   fIsBare = true;
   return GetNTupleBare(ntupleName);
}
 
ROOT::Experimental::RResult<ROOT::Experimental::RNTuple>
ROOT::Experimental::Internal::RMiniFileReader::GetNTupleProper(std::string_view ntupleName)
{
   RTFHeader fileHeader;
   ReadBuffer(&fileHeader, sizeof(fileHeader), 0);
 
   RTFKey key;
   RTFString name;
   ReadBuffer(&key, sizeof(key), fileHeader.fBEGIN);
   // Skip over the entire key length, including the class name, object name, and title stored in it.
   std::uint64_t offset = fileHeader.fBEGIN + key.fKeyLen;
   // Skip over the name and title of the TNamed preceding the TFile entry.
   ReadBuffer(&name, 1, offset);
   offset += name.GetSize();
   ReadBuffer(&name, 1, offset);
   offset += name.GetSize();
   RTFFile file;
   ReadBuffer(&file, sizeof(file), offset);
 
   RUInt32BE nKeys;
   offset = file.GetSeekKeys();
   ReadBuffer(&key, sizeof(key), offset);
   offset += key.fKeyLen;
   ReadBuffer(&nKeys, sizeof(nKeys), offset);
   offset += sizeof(nKeys);
   bool found = false;
   for (unsigned int i = 0; i < nKeys; ++i) {
      ReadBuffer(&key, sizeof(key), offset);
      auto offsetNextKey = offset + key.fKeyLen;
 
      offset += key.GetHeaderSize();
      ReadBuffer(&name, 1, offset);
      ReadBuffer(&name, name.GetSize(), offset);
      if (std::string_view(name.fData, name.fLName) != kNTupleClassName) {
         offset = offsetNextKey;
         continue;
      }
      offset += name.GetSize();
      ReadBuffer(&name, 1, offset);
      ReadBuffer(&name, name.GetSize(), offset);
      if (std::string_view(name.fData, name.fLName) == ntupleName) {
         found = true;
         break;
      }
      offset = offsetNextKey;
   }
   if (!found) {
      return R__FAIL("no RNTuple named '" + std::string(ntupleName)
         + "' in file '" + fRawFile->GetUrl() + "'");
   }
 
   ReadBuffer(&key, sizeof(key), key.GetSeekKey());
   offset = key.GetSeekKey() + key.fKeyLen;
 
   if (key.fObjLen < sizeof(RTFNTuple)) {
      return R__FAIL("invalid anchor size: " + std::to_string(key.fObjLen) + " < " + std::to_string(sizeof(RTFNTuple)));
   }
   // The object length can be larger than the size of RTFNTuple if it comes from a future RNTuple class version.
   auto bufAnchor = std::make_unique<unsigned char[]>(key.fObjLen);
   RTFNTuple *ntuple = new (bufAnchor.get()) RTFNTuple;
 
   auto objNbytes = key.GetSize() - key.fKeyLen;
   ReadBuffer(ntuple, objNbytes, offset);
   if (objNbytes != key.fObjLen) {
      RNTupleDecompressor decompressor;
      decompressor.Unzip(bufAnchor.get(), objNbytes, key.fObjLen);
   }
 
   if (ntuple->fVersionClass < 4) {
      return R__FAIL("invalid anchor, unsupported pre-release of RNTuple");
   }
 
   // We require that future class versions only append members and store the checksum in the last 8 bytes
   // Checksum calculation: strip byte count, class version, fChecksum member
   RUInt64BE *ckOnDisk = reinterpret_cast<RUInt64BE *>(bufAnchor.get() + key.fObjLen - sizeof(RUInt64BE));
   auto lenCkData = ntuple->GetSizeCkData() + key.fObjLen - sizeof(RTFNTuple);
   auto ckCalc = XXH3_64bits(ntuple->GetPtrCkData(), lenCkData);
   if (ckCalc != (uint64_t)(*ckOnDisk)) {
      return R__FAIL("RNTuple anchor checksum mismatch");
   }
 
   return CreateAnchor(ntuple->fVersionEpoch, ntuple->fVersionMajor, ntuple->fVersionMinor, ntuple->fVersionPatch,
                       ntuple->fSeekHeader, ntuple->fNBytesHeader, ntuple->fLenHeader, ntuple->fSeekFooter,
                       ntuple->fNBytesFooter, ntuple->fLenFooter, ntuple->fChecksum);
}
 
ROOT::Experimental::RResult<ROOT::Experimental::RNTuple>
ROOT::Experimental::Internal::RMiniFileReader::GetNTupleBare(std::string_view ntupleName)
{
   RBareFileHeader fileHeader;
   ReadBuffer(&fileHeader, sizeof(fileHeader), 0);
   RTFString name;
   auto offset = sizeof(fileHeader);
   ReadBuffer(&name, 1, offset);
   ReadBuffer(&name, name.GetSize(), offset);
   std::string_view foundName(name.fData, name.fLName);
   if (foundName != ntupleName) {
      return R__FAIL("expected RNTuple named '" + std::string(ntupleName)
         + "' but instead found '" + std::string(foundName)
         + "' in file '" + fRawFile->GetUrl() + "'");
   }
   offset += name.GetSize();
 
   RTFNTuple ntuple;
   ReadBuffer(&ntuple, sizeof(ntuple), offset);
   auto checksum = XXH3_64bits(ntuple.GetPtrCkData(), ntuple.GetSizeCkData());
   if (checksum != static_cast<uint64_t>(ntuple.fChecksum))
      return R__FAIL("RNTuple bare file: anchor checksum mismatch");
   return CreateAnchor(ntuple.fVersionEpoch, ntuple.fVersionMajor, ntuple.fVersionMinor, ntuple.fVersionPatch,
                       ntuple.fSeekHeader, ntuple.fNBytesHeader, ntuple.fLenHeader, ntuple.fSeekFooter,
                       ntuple.fNBytesFooter, ntuple.fLenFooter, ntuple.fChecksum);
}
 
 
void ROOT::Experimental::Internal::RMiniFileReader::ReadBuffer(void *buffer, size_t nbytes, std::uint64_t offset)
{
   auto nread = fRawFile->ReadAt(buffer, nbytes, offset);
   R__ASSERT(nread == nbytes);
}
 
 
////////////////////////////////////////////////////////////////////////////////
 
 
ROOT::Experimental::Internal::RNTupleFileWriter::RFileSimple::~RFileSimple()
{
   if (fFile)
      fclose(fFile);
}
 
 
void ROOT::Experimental::Internal::RNTupleFileWriter::RFileSimple::Write(
   const void *buffer, size_t nbytes, std::int64_t offset)
{
   R__ASSERT(fFile);
   size_t retval;
   if ((offset >= 0) && (static_cast<std::uint64_t>(offset) != fFilePos)) {
#ifdef R__SEEK64
      retval = fseeko64(fFile, offset, SEEK_SET);
#else
      retval = fseek(fFile, offset, SEEK_SET);
#endif
      if (retval)
         throw RException(R__FAIL(std::string("Seek failed: ") + strerror(errno)));
      fFilePos = offset;
   }
   retval = fwrite(buffer, 1, nbytes, fFile);
   if (retval != nbytes)
      throw RException(R__FAIL(std::string("write failed: ") + strerror(errno)));
   fFilePos += nbytes;
}
 
 
std::uint64_t ROOT::Experimental::Internal::RNTupleFileWriter::RFileSimple::WriteKey(
   const void *buffer, std::size_t nbytes, std::size_t len, std::int64_t offset,
   std::uint64_t directoryOffset,
   const std::string &className,
   const std::string &objectName,
   const std::string &title)
{
   if (offset > 0)
      fKeyOffset = offset;
   RTFString strClass{className};
   RTFString strObject{objectName};
   RTFString strTitle{title};
 
   RTFKey key(fKeyOffset, directoryOffset, strClass, strObject, strTitle, len, nbytes);
   Write(&key, key.fKeyHeaderSize, fKeyOffset);
   Write(&strClass, strClass.GetSize());
   Write(&strObject, strObject.GetSize());
   Write(&strTitle, strTitle.GetSize());
   auto offsetData = fFilePos;
   // The next key starts after the data.
   fKeyOffset = offsetData + nbytes;
   if (buffer)
      Write(buffer, nbytes);
 
   return offsetData;
}
 
 
////////////////////////////////////////////////////////////////////////////////
 
 
void ROOT::Experimental::Internal::RNTupleFileWriter::RFileProper::Write(
   const void *buffer, size_t nbytes, std::int64_t offset)
{
   R__ASSERT(fFile);
   fFile->Seek(offset);
   bool rv = fFile->WriteBuffer((char *)(buffer), nbytes);
   if (rv)
      throw RException(R__FAIL("WriteBuffer failed."));
}
 
 
std::uint64_t ROOT::Experimental::Internal::RNTupleFileWriter::RFileProper::WriteKey(
   const void *buffer, size_t nbytes, size_t len)
{
   std::uint64_t offsetKey;
   RKeyBlob keyBlob(fFile);
   // Since it is unknown beforehand if offsetKey is beyond the 2GB limit or not,
   // RKeyBlob will always reserve space for a big key (version >= 1000)
   keyBlob.Reserve(nbytes, &offsetKey);
 
   auto offset = offsetKey;
   RTFString strClass{kBlobClassName};
   RTFString strObject;
   RTFString strTitle;
   RTFKey keyHeader(offset, offset, strClass, strObject, strTitle, len, nbytes);
   // Follow the fact that RKeyBlob is a big key unconditionally (see above)
   keyHeader.MakeBigKey();
 
   Write(&keyHeader, keyHeader.fKeyHeaderSize, offset);
   offset += keyHeader.fKeyHeaderSize;
   Write(&strClass, strClass.GetSize(), offset);
   offset += strClass.GetSize();
   Write(&strObject, strObject.GetSize(), offset);
   offset += strObject.GetSize();
   Write(&strTitle, strTitle.GetSize(), offset);
   offset += strTitle.GetSize();
   auto offsetData = offset;
   if (buffer)
      Write(buffer, nbytes, offset);
 
   return offsetData;
}
 
 
////////////////////////////////////////////////////////////////////////////////
 
 
ROOT::Experimental::Internal::RNTupleFileWriter::RNTupleFileWriter(std::string_view name)
   : fNTupleName(name)
{
   fFileSimple.fControlBlock = std::make_unique<ROOT::Experimental::Internal::RTFileControlBlock>();
}
 
 
ROOT::Experimental::Internal::RNTupleFileWriter::~RNTupleFileWriter()
{
}
 
ROOT::Experimental::Internal::RNTupleFileWriter *
ROOT::Experimental::Internal::RNTupleFileWriter::Recreate(std::string_view ntupleName, std::string_view path,
                                                          int defaultCompression, EContainerFormat containerFormat)
{
   std::string fileName(path);
   size_t idxDirSep = fileName.find_last_of("\\/");
   if (idxDirSep != std::string::npos) {
      fileName.erase(0, idxDirSep + 1);
   }
#ifdef R__SEEK64
   FILE *fileStream = fopen64(std::string(path.data(), path.size()).c_str(), "wb");
#else
   FILE *fileStream = fopen(std::string(path.data(), path.size()).c_str(), "wb");
#endif
   R__ASSERT(fileStream);
 
   auto writer = new RNTupleFileWriter(ntupleName);
   writer->fFileSimple.fFile = fileStream;
   writer->fFileName = fileName;
 
   switch (containerFormat) {
   case EContainerFormat::kTFile: writer->WriteTFileSkeleton(defaultCompression); break;
   case EContainerFormat::kBare:
      writer->fIsBare = true;
      writer->WriteBareFileSkeleton(defaultCompression);
      break;
   default:
      R__ASSERT(false && "Internal error: unhandled container format");
   }
 
   return writer;
}
 
 
ROOT::Experimental::Internal::RNTupleFileWriter *ROOT::Experimental::Internal::RNTupleFileWriter::Append(
   std::string_view ntupleName, TFile &file)
{
   auto writer = new RNTupleFileWriter(ntupleName);
   writer->fFileProper.fFile = &file;
   return writer;
}
 
 
void ROOT::Experimental::Internal::RNTupleFileWriter::Commit()
{
   if (fFileProper) {
      // Easy case, the ROOT file header and the RNTuple streaming is taken care of by TFile
      fFileProper.fFile->WriteObject(&fNTupleAnchor, fNTupleName.c_str());
      fFileProper.fFile->Write();
      return;
   }
 
   // Writing by C file stream: prepare the container format header and stream the RNTuple anchor object
   R__ASSERT(fFileSimple);
 
   if (fIsBare) {
      RTFNTuple ntupleOnDisk(fNTupleAnchor);
      fFileSimple.Write(&ntupleOnDisk, ntupleOnDisk.GetSize(), fFileSimple.fControlBlock->fSeekNTuple);
      fflush(fFileSimple.fFile);
      return;
   }
 
   WriteTFileNTupleKey();
   WriteTFileKeysList();
   WriteTFileStreamerInfo();
   WriteTFileFreeList();
 
   // Update header and TFile record
   fFileSimple.Write(&fFileSimple.fControlBlock->fHeader, fFileSimple.fControlBlock->fHeader.GetSize(), 0);
   fFileSimple.Write(&fFileSimple.fControlBlock->fFileRecord, fFileSimple.fControlBlock->fFileRecord.GetSize(),
                     fFileSimple.fControlBlock->fSeekFileRecord);
   fflush(fFileSimple.fFile);
}
 
 
std::uint64_t ROOT::Experimental::Internal::RNTupleFileWriter::WriteBlob(const void *data, size_t nbytes, size_t len)
{
   std::uint64_t offset;
   if (fFileSimple) {
      if (fIsBare) {
         offset = fFileSimple.fKeyOffset;
         fFileSimple.Write(data, nbytes);
         fFileSimple.fKeyOffset += nbytes;
      } else {
         offset = fFileSimple.WriteKey(data, nbytes, len, -1, 100, kBlobClassName);
      }
   } else {
      offset = fFileProper.WriteKey(data, nbytes, len);
   }
   return offset;
}
 
std::uint64_t ROOT::Experimental::Internal::RNTupleFileWriter::ReserveBlob(size_t nbytes, size_t len)
{
   std::uint64_t offset;
   if (fFileSimple) {
      if (fIsBare) {
         offset = fFileSimple.fKeyOffset;
         fFileSimple.fKeyOffset += nbytes;
      } else {
         offset = fFileSimple.WriteKey(/*buffer=*/nullptr, nbytes, len, -1, 100, kBlobClassName);
      }
   } else {
      offset = fFileProper.WriteKey(/*buffer=*/nullptr, nbytes, len);
   }
   return offset;
}
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteIntoReservedBlob(const void *buffer, size_t nbytes,
                                                                            std::int64_t offset)
{
   if (fFileSimple) {
      fFileSimple.Write(buffer, nbytes, offset);
   } else {
      fFileProper.Write(buffer, nbytes, offset);
   }
}
 
std::uint64_t ROOT::Experimental::Internal::RNTupleFileWriter::WriteNTupleHeader(
   const void *data, size_t nbytes, size_t lenHeader)
{
   auto offset = WriteBlob(data, nbytes, lenHeader);
   fNTupleAnchor.fLenHeader = lenHeader;
   fNTupleAnchor.fNBytesHeader = nbytes;
   fNTupleAnchor.fSeekHeader = offset;
   return offset;
}
 
 
std::uint64_t ROOT::Experimental::Internal::RNTupleFileWriter::WriteNTupleFooter(
   const void *data, size_t nbytes, size_t lenFooter)
{
   auto offset = WriteBlob(data, nbytes, lenFooter);
   fNTupleAnchor.fLenFooter = lenFooter;
   fNTupleAnchor.fNBytesFooter = nbytes;
   fNTupleAnchor.fSeekFooter = offset;
   return offset;
}
 
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteBareFileSkeleton(int defaultCompression)
{
   RBareFileHeader bareHeader;
   bareHeader.fCompress = defaultCompression;
   fFileSimple.Write(&bareHeader, sizeof(bareHeader), 0);
   RTFString ntupleName{fNTupleName};
   fFileSimple.Write(&ntupleName, ntupleName.GetSize());
 
   // Write zero-initialized ntuple to reserve the space; will be overwritten on commit
   RTFNTuple ntupleOnDisk;
   fFileSimple.fControlBlock->fSeekNTuple = fFileSimple.fFilePos;
   fFileSimple.Write(&ntupleOnDisk, ntupleOnDisk.GetSize());
   fFileSimple.fKeyOffset = fFileSimple.fFilePos;
}
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteTFileStreamerInfo()
{
   RTFString strTList{"TList"};
   RTFString strStreamerInfo{"StreamerInfo"};
   RTFString strStreamerTitle{"Doubly linked list"};
 
   fFileSimple.fControlBlock->fHeader.SetSeekInfo(fFileSimple.fKeyOffset);
   RTFKey keyStreamerInfo(
      fFileSimple.fControlBlock->fHeader.GetSeekInfo(), 100, strTList, strStreamerInfo, strStreamerTitle, 0);
   RTFStreamerInfoList streamerInfo;
   auto classTagOffset = keyStreamerInfo.fKeyLen + offsetof(struct RTFStreamerInfoList, fStreamerInfo) +
                         offsetof(struct RTFStreamerInfoObject, fStreamers) +
                         offsetof(struct RTFStreamerVersionEpoch, fNewClassTag) + 2;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerVersionMajor.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerVersionMinor.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerVersionPatch.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerSeekHeader.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerNBytesHeader.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerLenHeader.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerSeekFooter.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerNBytesFooter.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerLenFooter.fClassTag = 0x80000000 | classTagOffset;
   streamerInfo.fStreamerInfo.fStreamers.fStreamerChecksum.fClassTag = 0x80000000 | classTagOffset;
   RNTupleCompressor compressor;
   auto szStreamerInfo = compressor.Zip(&streamerInfo, streamerInfo.GetSize(), 1);
   fFileSimple.WriteKey(compressor.GetZipBuffer(), szStreamerInfo, streamerInfo.GetSize(),
                        fFileSimple.fControlBlock->fHeader.GetSeekInfo(), 100,
                        "TList", "StreamerInfo", "Doubly linked list");
   fFileSimple.fControlBlock->fHeader.SetNbytesInfo(
      fFileSimple.fFilePos - fFileSimple.fControlBlock->fHeader.GetSeekInfo());
}
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteTFileKeysList()
{
   RTFString strEmpty;
   RTFString strRNTupleClass{"ROOT::Experimental::RNTuple"};
   RTFString strRNTupleName{fNTupleName};
   RTFString strFileName{fFileName};
 
   RTFKey keyRNTuple(fFileSimple.fControlBlock->fSeekNTuple, 100, strRNTupleClass, strRNTupleName, strEmpty,
                     RTFNTuple().GetSize());
 
   fFileSimple.fControlBlock->fFileRecord.SetSeekKeys(fFileSimple.fKeyOffset);
   RTFKeyList keyList{1};
   RTFKey keyKeyList(fFileSimple.fControlBlock->fFileRecord.GetSeekKeys(), 100, strEmpty, strFileName, strEmpty,
                     keyList.GetSize() + keyRNTuple.fKeyLen);
   fFileSimple.Write(&keyKeyList, keyKeyList.fKeyHeaderSize, fFileSimple.fControlBlock->fFileRecord.GetSeekKeys());
   fFileSimple.Write(&strEmpty, strEmpty.GetSize());
   fFileSimple.Write(&strFileName, strFileName.GetSize());
   fFileSimple.Write(&strEmpty, strEmpty.GetSize());
   fFileSimple.Write(&keyList, keyList.GetSize());
   fFileSimple.Write(&keyRNTuple, keyRNTuple.fKeyHeaderSize);
   // Write class name, object name, and title for this key.
   fFileSimple.Write(&strRNTupleClass, strRNTupleClass.GetSize());
   fFileSimple.Write(&strRNTupleName, strRNTupleName.GetSize());
   fFileSimple.Write(&strEmpty, strEmpty.GetSize());
   fFileSimple.fControlBlock->fFileRecord.fNBytesKeys =
      fFileSimple.fFilePos - fFileSimple.fControlBlock->fFileRecord.GetSeekKeys();
   fFileSimple.fKeyOffset = fFileSimple.fFilePos;
}
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteTFileFreeList()
{
   fFileSimple.fControlBlock->fHeader.SetSeekFree(fFileSimple.fKeyOffset);
   RTFString strEmpty;
   RTFString strFileName{fFileName};
   RTFFreeEntry freeEntry;
   RTFKey keyFreeList(fFileSimple.fControlBlock->fHeader.GetSeekFree(), 100, strEmpty, strFileName, strEmpty,
                      freeEntry.GetSize());
   std::uint64_t firstFree = fFileSimple.fControlBlock->fHeader.GetSeekFree() + keyFreeList.GetSize();
   freeEntry.Set(firstFree, std::max(2000000000ULL, ((firstFree / 1000000000ULL) + 1) * 1000000000ULL));
   fFileSimple.WriteKey(&freeEntry, freeEntry.GetSize(), freeEntry.GetSize(),
                        fFileSimple.fControlBlock->fHeader.GetSeekFree(), 100, "", fFileName, "");
   fFileSimple.fControlBlock->fHeader.SetNbytesFree(fFileSimple.fFilePos -
                                                    fFileSimple.fControlBlock->fHeader.GetSeekFree());
   fFileSimple.fControlBlock->fHeader.SetEnd(fFileSimple.fFilePos);
}
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteTFileNTupleKey()
{
   RTFString strRNTupleClass{"ROOT::Experimental::RNTuple"};
   RTFString strRNTupleName{fNTupleName};
   RTFString strEmpty;
 
   RTFNTuple ntupleOnDisk(fNTupleAnchor);
   fFileSimple.fControlBlock->fSeekNTuple = fFileSimple.fKeyOffset;
   fFileSimple.WriteKey(&ntupleOnDisk, ntupleOnDisk.GetSize(), ntupleOnDisk.GetSize(),
                        fFileSimple.fControlBlock->fSeekNTuple, 100, "ROOT::Experimental::RNTuple", fNTupleName, "");
}
 
void ROOT::Experimental::Internal::RNTupleFileWriter::WriteTFileSkeleton(int defaultCompression)
{
   RTFString strTFile{"TFile"};
   RTFString strFileName{fFileName};
   RTFString strEmpty;
 
   fFileSimple.fControlBlock->fHeader = RTFHeader(defaultCompression);
 
   RTFUUID uuid;
 
   // First record of the file: the TFile object at offset 100
   RTFKey keyRoot(100, 0, strTFile, strFileName, strEmpty,
                  sizeof(RTFFile) + strFileName.GetSize() + strEmpty.GetSize() + uuid.GetSize());
   std::uint32_t nbytesName = keyRoot.fKeyLen + strFileName.GetSize() + 1;
   fFileSimple.fControlBlock->fFileRecord.fNBytesName = nbytesName;
   fFileSimple.fControlBlock->fHeader.SetNbytesName(nbytesName);
 
   fFileSimple.Write(&keyRoot, keyRoot.fKeyHeaderSize, 100);
   // Write class name, object name, and title for the TFile key.
   fFileSimple.Write(&strTFile, strTFile.GetSize());
   fFileSimple.Write(&strFileName, strFileName.GetSize());
   fFileSimple.Write(&strEmpty, strEmpty.GetSize());
   // Write the name and title of the TNamed preceding the TFile entry.
   fFileSimple.Write(&strFileName, strFileName.GetSize());
   fFileSimple.Write(&strEmpty, strEmpty.GetSize());
   // Will be overwritten on commit
   fFileSimple.fControlBlock->fSeekFileRecord = fFileSimple.fFilePos;
   fFileSimple.Write(&fFileSimple.fControlBlock->fFileRecord, fFileSimple.fControlBlock->fFileRecord.GetSize());
   fFileSimple.Write(&uuid, uuid.GetSize());
 
   // Padding bytes to allow the TFile record to grow for a big file
   RUInt32BE padding{0};
   for (int i = 0; i < 3; ++i)
      fFileSimple.Write(&padding, sizeof(padding));
   fFileSimple.fKeyOffset = fFileSimple.fFilePos;
}