/* gpt.cc -- Functions for loading, saving, and manipulating legacy MBR and GPT partition
   data. */

/* By Rod Smith, initial coding January to February, 2009 */

/* This program is copyright (c) 2009-2024 by Roderick W. Smith. It is distributed
  under the terms of the GNU GPL version 2, as detailed in the COPYING file. */

#define __STDC_LIMIT_MACROS
#define __STDC_CONSTANT_MACROS

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <fcntl.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <sys/stat.h>
#include <errno.h>
#include <iostream>
#include <algorithm>
#include "crc32.h"
#include "gpt.h"
#include "bsd.h"
#include "support.h"
#include "parttypes.h"
#include "attributes.h"
#include "diskio.h"

using namespace std;

#ifdef __FreeBSD__
#define log2(x) (log(x) / M_LN2)
#endif // __FreeBSD__

#ifdef _MSC_VER
#define log2(x) (log((double) x) / log(2.0))
#endif // Microsoft Visual C++

#ifdef EFI
// in UEFI mode MMX registers are not yet available so using the
// x86_64 ABI to move "double" values around is not an option.
#ifdef log2
#undef log2
#endif
#define log2(x) log2_32( x )
static inline uint32_t log2_32(uint32_t v) {
   int r = -1;
   while (v >= 1) {
      r++;
      v >>= 1;
   }
   return r;
}
#endif

/****************************************
 *                                      *
 * GPTData class and related structures *
 *                                      *
 ****************************************/

// Default constructor
GPTData::GPTData(void) {
   blockSize = SECTOR_SIZE; // set a default
   physBlockSize = 0; // 0 = can't be determined
   diskSize = 0;
   partitions = NULL;
   state = gpt_valid;
   device = "";
   justLooking = 0;
   mainCrcOk = 0;
   secondCrcOk = 0;
   mainPartsCrcOk = 0;
   secondPartsCrcOk = 0;
   apmFound = 0;
   bsdFound = 0;
   sectorAlignment = MIN_AF_ALIGNMENT; // Align partitions on 4096-byte boundaries by default
   beQuiet = 0;
   whichWasUsed = use_new;
   mainHeader.numParts = 0;
   mainHeader.firstUsableLBA = 0;
   mainHeader.lastUsableLBA = 0;
   numParts = 0;
   SetGPTSize(NUM_GPT_ENTRIES);
   // Initialize CRC functions...
   chksum_crc32gentab();
} // GPTData default constructor

GPTData::GPTData(const GPTData & orig) {
   uint32_t i;

   if (&orig != this) {
      mainHeader = orig.mainHeader;
      numParts = orig.numParts;
      secondHeader = orig.secondHeader;
      protectiveMBR = orig.protectiveMBR;
      device = orig.device;
      blockSize = orig.blockSize;
      physBlockSize = orig.physBlockSize;
      diskSize = orig.diskSize;
      state = orig.state;
      justLooking = orig.justLooking;
      mainCrcOk = orig.mainCrcOk;
      secondCrcOk = orig.secondCrcOk;
      mainPartsCrcOk = orig.mainPartsCrcOk;
      secondPartsCrcOk = orig.secondPartsCrcOk;
      apmFound = orig.apmFound;
      bsdFound = orig.bsdFound;
      sectorAlignment = orig.sectorAlignment;
      beQuiet = orig.beQuiet;
      whichWasUsed = orig.whichWasUsed;

      myDisk.OpenForRead(orig.myDisk.GetName());

      delete[] partitions;
      partitions = new GPTPart [numParts];
      if (partitions == NULL) {
         cerr << "Error! Could not allocate memory for partitions in GPTData::operator=()!\n"
              << "Terminating!\n";
         exit(1);
      } // if
      for (i = 0; i < numParts; i++) {
         partitions[i] = orig.partitions[i];
      } // for
   } // if
} // GPTData copy constructor

// The following constructor loads GPT data from a device file
GPTData::GPTData(string filename) {
   blockSize = SECTOR_SIZE; // set a default
   diskSize = 0;
   partitions = NULL;
   state = gpt_invalid;
   device = "";
   justLooking = 0;
   mainCrcOk = 0;
   secondCrcOk = 0;
   mainPartsCrcOk = 0;
   secondPartsCrcOk = 0;
   apmFound = 0;
   bsdFound = 0;
   sectorAlignment = MIN_AF_ALIGNMENT; // Align partitions on 4096-byte boundaries by default
   beQuiet = 0;
   whichWasUsed = use_new;
   mainHeader.numParts = 0;
   mainHeader.lastUsableLBA = 0;
   numParts = 0;
   // Initialize CRC functions...
   chksum_crc32gentab();
   if (!LoadPartitions(filename))
      exit(2);
} // GPTData(string filename) constructor

// Destructor
GPTData::~GPTData(void) {
   delete[] partitions;
} // GPTData destructor

// Assignment operator
GPTData & GPTData::operator=(const GPTData & orig) {
   uint32_t i;

   if (&orig != this) {
      mainHeader = orig.mainHeader;
      numParts = orig.numParts;
      secondHeader = orig.secondHeader;
      protectiveMBR = orig.protectiveMBR;
      device = orig.device;
      blockSize = orig.blockSize;
      physBlockSize = orig.physBlockSize;
      diskSize = orig.diskSize;
      state = orig.state;
      justLooking = orig.justLooking;
      mainCrcOk = orig.mainCrcOk;
      secondCrcOk = orig.secondCrcOk;
      mainPartsCrcOk = orig.mainPartsCrcOk;
      secondPartsCrcOk = orig.secondPartsCrcOk;
      apmFound = orig.apmFound;
      bsdFound = orig.bsdFound;
      sectorAlignment = orig.sectorAlignment;
      beQuiet = orig.beQuiet;
      whichWasUsed = orig.whichWasUsed;

      myDisk.OpenForRead(orig.myDisk.GetName());

      delete[] partitions;
      partitions = new GPTPart [numParts];
      if (partitions == NULL) {
         cerr << "Error! Could not allocate memory for partitions in GPTData::operator=()!\n"
              << "Terminating!\n";
         exit(1);
      } // if
      for (i = 0; i < numParts; i++) {
         partitions[i] = orig.partitions[i];
      } // for
   } // if

   return *this;
} // GPTData::operator=()

/*********************************************************************
 *                                                                   *
 * Begin functions that verify data, or that adjust the verification *
 * information (compute CRCs, rebuild headers)                       *
 *                                                                   *
 *********************************************************************/

// Perform detailed verification, reporting on any problems found, but
// do *NOT* recover from these problems. Returns the total number of
// problems identified.
int GPTData::Verify(void) {
   int problems = 0, alignProbs = 0;
   uint32_t i, numSegments, testAlignment = sectorAlignment;
   uint64_t totalFree, largestSegment;

   // First, check for CRC errors in the GPT data....
   if (!mainCrcOk) {
      problems++;
      cout << "\nProblem: The CRC for the main GPT header is invalid. The main GPT header may\n"
           << "be corrupt. Consider loading the backup GPT header to rebuild the main GPT\n"
           << "header ('b' on the recovery & transformation menu). This report may be a false\n"
           << "alarm if you've already corrected other problems.\n";
   } // if
   if (!mainPartsCrcOk) {
      problems++;
      cout << "\nProblem: The CRC for the main partition table is invalid. This table may be\n"
           << "corrupt. Consider loading the backup partition table ('c' on the recovery &\n"
           << "transformation menu). This report may be a false alarm if you've already\n"
           << "corrected other problems.\n";
   } // if
   if (!secondCrcOk) {
      problems++;
      cout << "\nProblem: The CRC for the backup GPT header is invalid. The backup GPT header\n"
           << "may be corrupt. Consider using the main GPT header to rebuild the backup GPT\n"
           << "header ('d' on the recovery & transformation menu). This report may be a false\n"
           << "alarm if you've already corrected other problems.\n";
   } // if
   if (!secondPartsCrcOk) {
      problems++;
      cout << "\nCaution: The CRC for the backup partition table is invalid. This table may\n"
           << "be corrupt. This program will automatically create a new backup partition\n"
           << "table when you save your partitions.\n";
   } // if

   // Now check that the main and backup headers both point to themselves....
   if (mainHeader.currentLBA != 1) {
      problems++;
      cout << "\nProblem: The main header's self-pointer doesn't point to itself. This problem\n"
           << "is being automatically corrected, but it may be a symptom of more serious\n"
           << "problems. Think carefully before saving changes with 'w' or using this disk.\n";
      mainHeader.currentLBA = 1;
   } // if
   if (secondHeader.currentLBA != (diskSize - UINT64_C(1))) {
      problems++;
      cout << "\nProblem: The secondary header's self-pointer indicates that it doesn't reside\n"
           << "at the end of the disk. If you've added a disk to a RAID array, use the 'e'\n"
           << "option on the experts' menu to adjust the secondary header's and partition\n"
           << "table's locations.\n";
   } // if

   // Now check that critical main and backup GPT entries match each other
   if (mainHeader.currentLBA != secondHeader.backupLBA) {
      problems++;
      cout << "\nProblem: main GPT header's current LBA pointer (" << mainHeader.currentLBA
           << ") doesn't\nmatch the backup GPT header's alternate LBA pointer("
           << secondHeader.backupLBA << ").\n";
   } // if
   if (mainHeader.backupLBA != secondHeader.currentLBA) {
      problems++;
      cout << "\nProblem: main GPT header's backup LBA pointer (" << mainHeader.backupLBA
           << ") doesn't\nmatch the backup GPT header's current LBA pointer ("
           << secondHeader.currentLBA << ").\n"
           << "The 'e' option on the experts' menu may fix this problem.\n";
   } // if
   if (mainHeader.firstUsableLBA != secondHeader.firstUsableLBA) {
      problems++;
      cout << "\nProblem: main GPT header's first usable LBA pointer (" << mainHeader.firstUsableLBA
           << ") doesn't\nmatch the backup GPT header's first usable LBA pointer ("
           << secondHeader.firstUsableLBA << ")\n";
   } // if
   if (mainHeader.lastUsableLBA != secondHeader.lastUsableLBA) {
      problems++;
      cout << "\nProblem: main GPT header's last usable LBA pointer (" << mainHeader.lastUsableLBA
           << ") doesn't\nmatch the backup GPT header's last usable LBA pointer ("
           << secondHeader.lastUsableLBA << ")\n"
           << "The 'e' option on the experts' menu can probably fix this problem.\n";
   } // if
   if ((mainHeader.diskGUID != secondHeader.diskGUID)) {
      problems++;
      cout << "\nProblem: main header's disk GUID (" << mainHeader.diskGUID
           << ") doesn't\nmatch the backup GPT header's disk GUID ("
           << secondHeader.diskGUID << ")\n"
           << "You should use the 'b' or 'd' option on the recovery & transformation menu to\n"
           << "select one or the other header.\n";
   } // if
   if (mainHeader.numParts != secondHeader.numParts) {
      problems++;
      cout << "\nProblem: main GPT header's number of partitions (" << mainHeader.numParts
           << ") doesn't\nmatch the backup GPT header's number of partitions ("
           << secondHeader.numParts << ")\n"
           << "Resizing the partition table ('s' on the experts' menu) may help.\n";
   } // if
   if (mainHeader.sizeOfPartitionEntries != secondHeader.sizeOfPartitionEntries) {
      problems++;
      cout << "\nProblem: main GPT header's size of partition entries ("
           << mainHeader.sizeOfPartitionEntries << ") doesn't\n"
           << "match the backup GPT header's size of partition entries ("
           << secondHeader.sizeOfPartitionEntries << ")\n"
           << "You should use the 'b' or 'd' option on the recovery & transformation menu to\n"
           << "select one or the other header.\n";
   } // if

   // Now check for a few other miscellaneous problems...
   // Check that the disk size will hold the data...
   if (mainHeader.backupLBA >= diskSize) {
      problems++;
      cout << "\nProblem: Disk is too small to hold all the data!\n"
           << "(Disk size is " << diskSize << " sectors, needs to be "
           << mainHeader.backupLBA + UINT64_C(1) << " sectors.)\n"
           << "The 'e' option on the experts' menu may fix this problem.\n";
   } // if

   // Check the main and backup partition tables for overlap with things and unusual gaps
   if (mainHeader.partitionEntriesLBA + GetTableSizeInSectors() > mainHeader.firstUsableLBA) {
       problems++;
       cout << "\nProblem: Main partition table extends past the first usable LBA.\n"
            << "Using 'j' on the experts' menu may enable fixing this problem.\n";
   } // if
   if (mainHeader.partitionEntriesLBA < 2) {
       problems++;
       cout << "\nProblem: Main partition table appears impossibly early on the disk.\n"
            << "Using 'j' on the experts' menu may enable fixing this problem.\n";
   } // if
   if (secondHeader.partitionEntriesLBA + GetTableSizeInSectors() > secondHeader.currentLBA) {
       problems++;
       cout << "\nProblem: The backup partition table overlaps the backup header.\n"
            << "Using 'e' on the experts' menu may fix this problem.\n";
   } // if
   if (mainHeader.partitionEntriesLBA != 2) {
       cout << "\nWarning: There is a gap between the main metadata (sector 1) and the main\n"
            << "partition table (sector " << mainHeader.partitionEntriesLBA
            << "). This is helpful in some exotic configurations,\n"
            << "but is generally ill-advised. Using 'j' on the experts' menu can adjust this\n"
            << "gap.\n";
   } // if
   if (secondHeader.partitionEntriesLBA != diskSize - GetTableSizeInSectors() - 1) {
       cout << "\nWarning: There is a gap between the secondary partition table (ending at sector\n"
            << secondHeader.partitionEntriesLBA + GetTableSizeInSectors() - 1
            << ") and the secondary metadata (sector " << mainHeader.backupLBA << ").\n"
            << "This is helpful in some exotic configurations, but is generally ill-advised.\n"
            << "Using 'k' on the experts' menu can adjust this gap.\n";
   } // if
   if (mainHeader.partitionEntriesLBA + GetTableSizeInSectors() != mainHeader.firstUsableLBA) {
       cout << "\nWarning: There is a gap between the main partition table (ending sector "
            << mainHeader.partitionEntriesLBA + GetTableSizeInSectors() - 1 << ")\n"
            << "and the first usable sector (" << mainHeader.firstUsableLBA << "). This is helpful in some exotic configurations,\n"
            << "but is unusual. The util-linux fdisk program often creates disks like this.\n"
            << "Using 'j' on the experts' menu can adjust this gap.\n";
   } // if

   if (mainHeader.sizeOfPartitionEntries * mainHeader.numParts < 16384) {
      cout << "\nWarning: The size of the partition table (" << mainHeader.sizeOfPartitionEntries * mainHeader.numParts
           << " bytes) is less than the minimum\n"
           << "required by the GPT specification. Most OSes and tools seem to work fine on\n"
           << "such disks, but this is a violation of the GPT specification and so may cause\n"
           << "problems.\n";
   } // if

   if ((mainHeader.lastUsableLBA >= diskSize) || (mainHeader.lastUsableLBA > mainHeader.backupLBA)) {
      problems++;
      cout << "\nProblem: GPT claims the disk is larger than it is! (Claimed last usable\n"
           << "sector is " << mainHeader.lastUsableLBA << ", but backup header is at\n"
           << mainHeader.backupLBA << " and disk size is " << diskSize << " sectors.\n"
           << "The 'e' option on the experts' menu will probably fix this problem\n";
   }

   // Check for overlapping partitions....
   problems += FindOverlaps();

   // Check for insane partitions (start after end, hugely big, etc.)
   problems += FindInsanePartitions();

   // Check for mismatched MBR and GPT partitions...
   problems += FindHybridMismatches();

   // Check for MBR-specific problems....
   problems += VerifyMBR();

   // Check for a 0xEE protective partition that's marked as active....
   if (protectiveMBR.IsEEActive()) {
      cout << "\nWarning: The 0xEE protective partition in the MBR is marked as active. This is\n"
           << "technically a violation of the GPT specification, and can cause some EFIs to\n"
           << "ignore the disk, but it is required to boot from a GPT disk on some BIOS-based\n"
           << "computers. You can clear this flag by creating a fresh protective MBR using\n"
           << "the 'n' option on the experts' menu.\n";
   }

   // Verify that partitions don't run into GPT data areas....
   problems += CheckGPTSize();

   if (!protectiveMBR.DoTheyFit()) {
      cout << "\nPartition(s) in the protective MBR are too big for the disk! Creating a\n"
           << "fresh protective or hybrid MBR is recommended.\n";
      problems++;
   }

   // Check that partitions are aligned on proper boundaries (for WD Advanced
   // Format and similar disks)....
   if ((physBlockSize != 0) && (blockSize != 0))
      testAlignment = physBlockSize / blockSize;
   testAlignment = max(testAlignment, sectorAlignment);
   if (testAlignment == 0) // Should not happen; just being paranoid.
      testAlignment = sectorAlignment;
   for (i = 0; i < numParts; i++) {
      if ((partitions[i].IsUsed()) && (partitions[i].GetFirstLBA() % testAlignment) != 0) {
         cout << "\nCaution: Partition " << i + 1 << " doesn't begin on a "
              << testAlignment << "-sector boundary. This may\nresult "
              << "in degraded performance on some modern (2009 and later) hard disks.\n";
         alignProbs++;
      } // if
      if ((partitions[i].IsUsed()) && ((partitions[i].GetLastLBA() + 1) % testAlignment) != 0) {
         cout << "\nCaution: Partition " << i + 1 << " doesn't end on a "
              << testAlignment << "-sector boundary. This may\nresult "
              << "in problems with some disk encryption tools.\n";
      } // if
   } // for
   if (alignProbs > 0)
      cout << "\nConsult http://www.ibm.com/developerworks/linux/library/l-4kb-sector-disks/\n"
      << "for information on disk alignment.\n";

   // Now compute available space, but only if no problems found, since
   // problems could affect the results
   if (problems == 0) {
      totalFree = FindFreeBlocks(&numSegments, &largestSegment);
      cout << "\nNo problems found. " << totalFree << " free sectors ("
           << BytesToIeee(totalFree, blockSize) << ") available in "
           << numSegments << "\nsegments, the largest of which is "
           << largestSegment << " (" << BytesToIeee(largestSegment, blockSize)
           << ") in size.\n";
   } else {
      cout << "\nIdentified " << problems << " problems!\n";
   } // if/else

   return (problems);
} // GPTData::Verify()

// Checks to see if the GPT tables overrun existing partitions; if they
// do, issues a warning but takes no action. Returns number of problems
// detected (0 if OK, 1 to 2 if problems).
int GPTData::CheckGPTSize(void) {
   uint64_t overlap, firstUsedBlock, lastUsedBlock;
   uint32_t i;
   int numProbs = 0;

   // first, locate the first & last used blocks
   firstUsedBlock = UINT64_MAX;
   lastUsedBlock = 0;
   for (i = 0; i < numParts; i++) {
      if (partitions[i].IsUsed()) {
         if (partitions[i].GetFirstLBA() < firstUsedBlock)
            firstUsedBlock = partitions[i].GetFirstLBA();
         if (partitions[i].GetLastLBA() > lastUsedBlock) {
            lastUsedBlock = partitions[i].GetLastLBA();
         } // if
      } // if
   } // for

   // If the disk size is 0 (the default), then it means that various
   // variables aren't yet set, so the below tests will be useless;
   // therefore we should skip everything
   if (diskSize != 0) {
      if (mainHeader.firstUsableLBA > firstUsedBlock) {
         overlap = mainHeader.firstUsableLBA - firstUsedBlock;
         cout << "Warning! Main partition table overlaps the first partition by "
              << overlap << " blocks!\n";
         if (firstUsedBlock > 2) {
            cout << "Try reducing the partition table size by " << overlap * 4
                 << " entries.\n(Use the 's' item on the experts' menu.)\n";
         } else {
            cout << "You will need to delete this partition or resize it in another utility.\n";
         } // if/else
         numProbs++;
      } // Problem at start of disk
      if (mainHeader.lastUsableLBA < lastUsedBlock) {
         overlap = lastUsedBlock - mainHeader.lastUsableLBA;
         cout << "\nWarning! Secondary partition table overlaps the last partition by\n"
              << overlap << " blocks!\n";
         if (lastUsedBlock > (diskSize - 2)) {
            cout << "You will need to delete this partition or resize it in another utility.\n";
         } else {
            cout << "Try reducing the partition table size by " << overlap * 4
                 << " entries.\n(Use the 's' item on the experts' menu.)\n";
         } // if/else
         numProbs++;
      } // Problem at end of disk
   } // if (diskSize != 0)
   return numProbs;
} // GPTData::CheckGPTSize()

// Check the validity of the GPT header. Returns 1 if the main header
// is valid, 2 if the backup header is valid, 3 if both are valid, and
// 0 if neither is valid. Note that this function checks the GPT signature,
// revision value, and CRCs in both headers.
int GPTData::CheckHeaderValidity(void) {
   int valid = 3;

   cout.setf(ios::uppercase);
   cout.fill('0');

   // Note: failed GPT signature checks produce no error message because
   // a message is displayed in the ReversePartitionBytes() function
   if ((mainHeader.signature != GPT_SIGNATURE) || (!CheckHeaderCRC(&mainHeader, 1))) {
      valid -= 1;
   } else if ((mainHeader.revision != 0x00010000) && valid) {
      valid -= 1;
      cout << "Unsupported GPT version in main header; read 0x";
      cout.width(8);
      cout << hex << mainHeader.revision << ", should be\n0x";
      cout.width(8);
      cout << UINT32_C(0x00010000) << dec << "\n";
   } // if/else/if

   if ((secondHeader.signature != GPT_SIGNATURE) || (!CheckHeaderCRC(&secondHeader))) {
      valid -= 2;
   } else if ((secondHeader.revision != 0x00010000) && valid) {
      valid -= 2;
      cout << "Unsupported GPT version in backup header; read 0x";
      cout.width(8);
      cout << hex << secondHeader.revision << ", should be\n0x";
      cout.width(8);
      cout << UINT32_C(0x00010000) << dec << "\n";
   } // if/else/if

   // Check for an Apple disk signature
   if (((mainHeader.signature << 32) == APM_SIGNATURE1) ||
        (mainHeader.signature << 32) == APM_SIGNATURE2) {
      apmFound = 1; // Will display warning message later
   } // if
   cout.fill(' ');

   return valid;
} // GPTData::CheckHeaderValidity()

// Check the header CRC to see if it's OK...
// Note: Must be called with header in platform-ordered byte order.
// Returns 1 if header's computed CRC matches the stored value, 0 if the
// computed and stored values don't match
int GPTData::CheckHeaderCRC(struct GPTHeader* header, int warn) {
   uint32_t oldCRC, newCRC, hSize;
   uint8_t *temp;

   // Back up old header CRC and then blank it, since it must be 0 for
   // computation to be valid
   oldCRC = header->headerCRC;
   header->headerCRC = UINT32_C(0);

   hSize = header->headerSize;

   if (IsLittleEndian() == 0)
      ReverseHeaderBytes(header);

   if ((hSize > blockSize) || (hSize < HEADER_SIZE)) {
      if (warn) {
         cerr << "\aWarning! Header size is specified as " << hSize << ", which is invalid.\n";
         cerr << "Setting the header size for CRC computation to " << HEADER_SIZE << "\n";
      } // if
      hSize = HEADER_SIZE;
   } else if ((hSize > sizeof(GPTHeader)) && warn) {
      cout << "\aCaution! Header size for CRC check is " << hSize << ", which is greater than " << sizeof(GPTHeader) << ".\n";
      cout << "If stray data exists after the header on the header sector, it will be ignored,\n"
           << "which may result in a CRC false alarm.\n";
   } // if/elseif
   temp = new uint8_t[hSize];
   if (temp != NULL) {
      memset(temp, 0, hSize);
      if (hSize < sizeof(GPTHeader))
         memcpy(temp, header, hSize);
      else
         memcpy(temp, header, sizeof(GPTHeader));

      newCRC = chksum_crc32((unsigned char*) temp, hSize);
      delete[] temp;
   } else {
      cerr << "Could not allocate memory in GPTData::CheckHeaderCRC()! Aborting!\n";
      exit(1);
   }
   if (IsLittleEndian() == 0)
      ReverseHeaderBytes(header);
   header->headerCRC = oldCRC;
   return (oldCRC == newCRC);
} // GPTData::CheckHeaderCRC()

// Recompute all the CRCs. Must be called before saving if any changes have
// been made. Must be called on platform-ordered data (this function reverses
// byte order and then undoes that reversal.)
void GPTData::RecomputeCRCs(void) {
   uint32_t crc, hSize;
   int littleEndian;

   // If the header size is bigger than the GPT header data structure, reset it;
   // otherwise, set both header sizes to whatever the main one is....
   if (mainHeader.headerSize > sizeof(GPTHeader))
      hSize = secondHeader.headerSize = mainHeader.headerSize = HEADER_SIZE;
   else
      hSize = secondHeader.headerSize = mainHeader.headerSize;

   if ((littleEndian = IsLittleEndian()) == 0) {
      ReversePartitionBytes();
      ReverseHeaderBytes(&mainHeader);
      ReverseHeaderBytes(&secondHeader);
   } // if

   // Compute CRC of partition tables & store in main and secondary headers
   crc = chksum_crc32((unsigned char*) partitions, numParts * GPT_SIZE);
   mainHeader.partitionEntriesCRC = crc;
   secondHeader.partitionEntriesCRC = crc;
   if (littleEndian == 0) {
      ReverseBytes(&mainHeader.partitionEntriesCRC, 4);
      ReverseBytes(&secondHeader.partitionEntriesCRC, 4);
   } // if

   // Zero out GPT headers' own CRCs (required for correct computation)
   mainHeader.headerCRC = 0;
   secondHeader.headerCRC = 0;

   crc = chksum_crc32((unsigned char*) &mainHeader, hSize);
   if (littleEndian == 0)
      ReverseBytes(&crc, 4);
   mainHeader.headerCRC = crc;
   crc = chksum_crc32((unsigned char*) &secondHeader, hSize);
   if (littleEndian == 0)
      ReverseBytes(&crc, 4);
   secondHeader.headerCRC = crc;

   if (littleEndian == 0) {
      ReverseHeaderBytes(&mainHeader);
      ReverseHeaderBytes(&secondHeader);
      ReversePartitionBytes();
   } // if
} // GPTData::RecomputeCRCs()

// Rebuild the main GPT header, using the secondary header as a model.
// Typically called when the main header has been found to be corrupt.
void GPTData::RebuildMainHeader(void) {
   mainHeader.signature = GPT_SIGNATURE;
   mainHeader.revision = secondHeader.revision;
   mainHeader.headerSize = secondHeader.headerSize;
   mainHeader.headerCRC = UINT32_C(0);
   mainHeader.reserved = secondHeader.reserved;
   mainHeader.currentLBA = secondHeader.backupLBA;
   mainHeader.backupLBA = secondHeader.currentLBA;
   mainHeader.firstUsableLBA = secondHeader.firstUsableLBA;
   mainHeader.lastUsableLBA = secondHeader.lastUsableLBA;
   mainHeader.diskGUID = secondHeader.diskGUID;
   mainHeader.numParts = secondHeader.numParts;
   mainHeader.partitionEntriesLBA = secondHeader.firstUsableLBA - GetTableSizeInSectors();
   mainHeader.sizeOfPartitionEntries = secondHeader.sizeOfPartitionEntries;
   mainHeader.partitionEntriesCRC = secondHeader.partitionEntriesCRC;
   memcpy(mainHeader.reserved2, secondHeader.reserved2, sizeof(mainHeader.reserved2));
   mainCrcOk = secondCrcOk;
   SetGPTSize(mainHeader.numParts, 0);
} // GPTData::RebuildMainHeader()

// Rebuild the secondary GPT header, using the main header as a model.
void GPTData::RebuildSecondHeader(void) {
   secondHeader.signature = GPT_SIGNATURE;
   secondHeader.revision = mainHeader.revision;
   secondHeader.headerSize = mainHeader.headerSize;
   secondHeader.headerCRC = UINT32_C(0);
   secondHeader.reserved = mainHeader.reserved;
   secondHeader.currentLBA = mainHeader.backupLBA;
   secondHeader.backupLBA = mainHeader.currentLBA;
   secondHeader.firstUsableLBA = mainHeader.firstUsableLBA;
   secondHeader.lastUsableLBA = mainHeader.lastUsableLBA;
   secondHeader.diskGUID = mainHeader.diskGUID;
   secondHeader.partitionEntriesLBA = secondHeader.lastUsableLBA + UINT64_C(1);
   secondHeader.numParts = mainHeader.numParts;
   secondHeader.sizeOfPartitionEntries = mainHeader.sizeOfPartitionEntries;
   secondHeader.partitionEntriesCRC = mainHeader.partitionEntriesCRC;
   memcpy(secondHeader.reserved2, mainHeader.reserved2, sizeof(secondHeader.reserved2));
   secondCrcOk = mainCrcOk;
   SetGPTSize(secondHeader.numParts, 0);
} // GPTData::RebuildSecondHeader()

// Search for hybrid MBR entries that have no corresponding GPT partition.
// Returns number of such mismatches found
int GPTData::FindHybridMismatches(void) {
   int i, found, numFound = 0;
   uint32_t j;
   uint64_t mbrFirst, mbrLast;

   for (i = 0; i < 4; i++) {
      if ((protectiveMBR.GetType(i) != 0xEE) && (protectiveMBR.GetType(i) != 0x00)) {
         j = 0;
         found = 0;
         mbrFirst = (uint64_t) protectiveMBR.GetFirstSector(i);
         mbrLast = mbrFirst + (uint64_t) protectiveMBR.GetLength(i) - UINT64_C(1);
         do {
            if ((j < numParts) && (partitions[j].GetFirstLBA() == mbrFirst) &&
                (partitions[j].GetLastLBA() == mbrLast) && (partitions[j].IsUsed()))
               found = 1;
            j++;
         } while ((!found) && (j < numParts));
         if (!found) {
            numFound++;
            cout << "\nWarning! Mismatched GPT and MBR partition! MBR partition "
                 << i + 1 << ", of type 0x";
            cout.fill('0');
            cout.setf(ios::uppercase);
            cout.width(2);
            cout << hex << (int) protectiveMBR.GetType(i) << ",\n"
                 << "has no corresponding GPT partition! You may continue, but this condition\n"
                 << "might cause data loss in the future!\a\n" << dec;
            cout.fill(' ');
         } // if
      } // if
   } // for
   return numFound;
} // GPTData::FindHybridMismatches

// Find overlapping partitions and warn user about them. Returns number of
// overlapping partitions.
// Returns number of overlapping segments found.
int GPTData::FindOverlaps(void) {
   int problems = 0;
   uint32_t i, j;

   for (i = 1; i < numParts; i++) {
      for (j = 0; j < i; j++) {
         if ((partitions[i].IsUsed()) && (partitions[j].IsUsed()) &&
             (partitions[i].DoTheyOverlap(partitions[j]))) {
            problems++;
            cout << "\nProblem: partitions " << i + 1 << " and " << j + 1 << " overlap:\n";
            cout << "  Partition " << i + 1 << ": " << partitions[i].GetFirstLBA()
                 << " to " << partitions[i].GetLastLBA() << "\n";
            cout << "  Partition " << j + 1 << ": " << partitions[j].GetFirstLBA()
                 << " to " << partitions[j].GetLastLBA() << "\n";
         } // if
      } // for j...
   } // for i...
   return problems;
} // GPTData::FindOverlaps()

// Find partitions that are insane -- they start after they end or are too
// big for the disk. (The latter should duplicate detection of overlaps
// with GPT backup data structures, but better to err on the side of
// redundant tests than to miss something....)
// Returns number of problems found.
int GPTData::FindInsanePartitions(void) {
   uint32_t i;
   int problems = 0;

   for (i = 0; i < numParts; i++) {
      if (partitions[i].IsUsed()) {
         if (partitions[i].GetFirstLBA() > partitions[i].GetLastLBA()) {
            problems++;
            cout << "\nProblem: partition " << i + 1 << " ends before it begins.\n";
         } // if
         if (partitions[i].GetLastLBA() >= diskSize) {
            problems++;
            cout << "\nProblem: partition " << i + 1 << " is too big for the disk.\n";
         } // if
      } // if
   } // for
   return problems;
} // GPTData::FindInsanePartitions(void)


/******************************************************************
 *                                                                *
 * Begin functions that load data from disk or save data to disk. *
 *                                                                *
 ******************************************************************/

// Change the filename associated with the GPT. Used for duplicating
// the partition table to a new disk and saving backups.
// Returns 1 on success, 0 on failure.
int GPTData::SetDisk(const string & deviceFilename) {
   int err, allOK = 1;

   device = deviceFilename;
   if (allOK && myDisk.OpenForRead(deviceFilename)) {
      // store disk information....
      diskSize = myDisk.DiskSize(&err);
      blockSize = (uint32_t) myDisk.GetBlockSize();
      physBlockSize = (uint32_t) myDisk.GetPhysBlockSize();
   } // if
   protectiveMBR.SetDisk(&myDisk);
   protectiveMBR.SetDiskSize(diskSize);
   protectiveMBR.SetBlockSize(blockSize);
   return allOK;
} // GPTData::SetDisk()

// Scan for partition data. This function loads the MBR data (regular MBR or
// protective MBR) and loads BSD disklabel data (which is probably invalid).
// It also looks for APM data, forces a load of GPT data, and summarizes
// the results.
void GPTData::PartitionScan(void) {
   BSDData bsdDisklabel;

   // Read the MBR & check for BSD disklabel
   protectiveMBR.ReadMBRData(&myDisk);
   bsdDisklabel.ReadBSDData(&myDisk, 0, diskSize - 1);

   // Load the GPT data, whether or not it's valid
   ForceLoadGPTData();

   // Some tools create a 0xEE partition that's too big. If this is detected,
   // normalize it....
   if ((state == gpt_valid) && !protectiveMBR.DoTheyFit() && (protectiveMBR.GetValidity() == gpt)) {
      if (!beQuiet) {
         cerr << "\aThe protective MBR's 0xEE partition is oversized! Auto-repairing.\n\n";
      } // if
      protectiveMBR.MakeProtectiveMBR();
   } // if

   if (!beQuiet) {
      cout << "Partition table scan:\n";
      protectiveMBR.ShowState();
      bsdDisklabel.ShowState();
      ShowAPMState(); // Show whether there's an Apple Partition Map present
      ShowGPTState(); // Show GPT status
      cout << "\n";
   } // if

   if (apmFound) {
      cout << "\n*******************************************************************\n"
           << "This disk appears to contain an Apple-format (APM) partition table!\n";
      if (!justLooking) {
         cout << "It will be destroyed if you continue!\n";
      } // if
      cout << "*******************************************************************\n\n\a";
   } // if
} // GPTData::PartitionScan()

// Read GPT data from a disk.
int GPTData::LoadPartitions(const string & deviceFilename) {
   BSDData bsdDisklabel;
   int err, allOK = 1;
   MBRValidity mbrState;

   if (!justLooking) {
      if (myDisk.OpenForRead(deviceFilename)) {
         err = myDisk.OpenForWrite(deviceFilename);
         if (err == 0) {
            cout << "\aNOTE: Write test failed with error number " << errno
                 << ". It will be impossible to save\nchanges to this disk's partition table!\n";
#if defined (__FreeBSD__) || defined (__FreeBSD_kernel__)
            cout << "You may be able to enable writes by exiting this program, typing\n"
                 << "'sysctl kern.geom.debugflags=16' at a shell prompt, and re-running this\n"
                 << "program.\n";
#endif
#if defined (__APPLE__)
            cout << "You may need to deactivate System Integrity Protection to use this program. See\n"
                 << "https://www.quora.com/How-do-I-turn-off-the-rootless-in-OS-X-El-Capitan-10-11\n"
                 << "for more information.\n";
#endif
                 cout << "\n";
         } // if
         myDisk.Close(); // Close and re-open read-only in case of bugs
      } else allOK = 0; // if
   }

   if (allOK && myDisk.OpenForRead(deviceFilename)) {
      // store disk information....
      diskSize = myDisk.DiskSize(&err);
      blockSize = (uint32_t) myDisk.GetBlockSize();
      physBlockSize = (uint32_t) myDisk.GetPhysBlockSize();
      device = deviceFilename;
      PartitionScan(); // Check for partition types, load GPT, & print summary

      whichWasUsed = UseWhichPartitions();
      switch (whichWasUsed) {
         case use_mbr:
            XFormPartitions();
            break;
         case use_bsd:
            bsdDisklabel.ReadBSDData(&myDisk, 0, diskSize - 1);
//            bsdDisklabel.DisplayBSDData();
            ClearGPTData();
            protectiveMBR.MakeProtectiveMBR(1); // clear boot area (option 1)
            XFormDisklabel(&bsdDisklabel);
            break;
         case use_gpt:
            mbrState = protectiveMBR.GetValidity();
            if ((mbrState == invalid) || (mbrState == mbr))
               protectiveMBR.MakeProtectiveMBR();
            break;
         case use_new:
            ClearGPTData();
            protectiveMBR.MakeProtectiveMBR();
            break;
         case use_abort:
            allOK = 0;
            cerr << "Invalid partition data!\n";
            break;
      } // switch

      if (allOK) {
         CheckGPTSize();
         // Below is unlikely to happen on real disks, but could happen if
         // the user is manipulating a truncated image file....
         if (diskSize <= GetTableSizeInSectors() * 2 + 3) {
             allOK = 0;
             cout << "Disk is too small to hold GPT data (" << diskSize
                  << " sectors)! Aborting!\n";
         }
      }
      myDisk.Close();
      ComputeAlignment();
   } else {
      allOK = 0;
   } // if/else
   return (allOK);
} // GPTData::LoadPartitions()

// Loads the GPT, as much as possible. Returns 1 if this seems to have
// succeeded, 0 if there are obvious problems....
int GPTData::ForceLoadGPTData(void) {
   int allOK, validHeaders, loadedTable = 1;

   allOK = LoadHeader(&mainHeader, myDisk, 1, &mainCrcOk);

   if (mainCrcOk && (mainHeader.backupLBA < diskSize)) {
      allOK = LoadHeader(&secondHeader, myDisk, mainHeader.backupLBA, &secondCrcOk) && allOK;
   } else {
      allOK = LoadHeader(&secondHeader, myDisk, diskSize - UINT64_C(1), &secondCrcOk) && allOK;
      if (mainCrcOk && (mainHeader.backupLBA >= diskSize))
         cout << "Warning! Disk size is smaller than the main header indicates! Loading\n"
              << "secondary header from the last sector of the disk! You should use 'v' to\n"
              << "verify disk integrity, and perhaps options on the experts' menu to repair\n"
              << "the disk.\n";
   } // if/else
   if (!allOK)
      state = gpt_invalid;

   // Return valid headers code: 0 = both headers bad; 1 = main header
   // good, backup bad; 2 = backup header good, main header bad;
   // 3 = both headers good. Note these codes refer to valid GPT
   // signatures, version numbers, and CRCs.
   validHeaders = CheckHeaderValidity();

   // Read partitions (from primary array)
   if (validHeaders > 0) { // if at least one header is OK....
      // GPT appears to be valid....
      state = gpt_valid;

      // We're calling the GPT valid, but there's a possibility that one
      // of the two headers is corrupt. If so, use the one that seems to
      // be in better shape to regenerate the bad one
      if (validHeaders == 1) { // valid main header, invalid backup header
         cerr << "\aCaution: invalid backup GPT header, but valid main header; regenerating\n"
              << "backup header from main header.\n\n";
         RebuildSecondHeader();
         state = gpt_corrupt;
         secondCrcOk = mainCrcOk; // Since regenerated, use CRC validity of main
      } else if (validHeaders == 2) { // valid backup header, invalid main header
         cerr << "\aCaution: invalid main GPT header, but valid backup; regenerating main header\n"
              << "from backup!\n\n";
         RebuildMainHeader();
         state = gpt_corrupt;
         mainCrcOk = secondCrcOk; // Since copied, use CRC validity of backup
      } // if/else/if

      // Figure out which partition table to load....
      // Load the main partition table, if its header's CRC is OK
      if (validHeaders != 2) {
         if (LoadMainTable() == 0)
            allOK = 0;
      } else { // bad main header CRC and backup header CRC is OK
         state = gpt_corrupt;
         if (LoadSecondTableAsMain()) {
            loadedTable = 2;
            cerr << "\aWarning: Invalid CRC on main header data; loaded backup partition table.\n";
         } else { // backup table bad, bad main header CRC, but try main table in desperation....
            if (LoadMainTable() == 0) {
               allOK = 0;
               loadedTable = 0;
               cerr << "\a\aWarning! Unable to load either main or backup partition table!\n";
            } // if
         } // if/else (LoadSecondTableAsMain())
      } // if/else (load partition table)

      if (loadedTable == 1)
         secondPartsCrcOk = CheckTable(&secondHeader);
      else if (loadedTable == 2)
         mainPartsCrcOk = CheckTable(&mainHeader);
      else
         mainPartsCrcOk = secondPartsCrcOk = 0;

      // Problem with main partition table; if backup is OK, use it instead....
      if (secondPartsCrcOk && secondCrcOk && !mainPartsCrcOk) {
         state = gpt_corrupt;
         allOK = allOK && LoadSecondTableAsMain();
         mainPartsCrcOk = 0; // LoadSecondTableAsMain() resets this, so re-flag as bad
         cerr << "\aWarning! Main partition table CRC mismatch! Loaded backup "
              << "partition table\ninstead of main partition table!\n\n";
      } // if */

      // Check for valid CRCs and warn if there are problems
      if ((validHeaders != 3) || (mainPartsCrcOk == 0) ||
           (secondPartsCrcOk == 0)) {
         cerr << "Warning! One or more CRCs don't match. You should repair the disk!\n";
         // Show detail status of header and table
         if (validHeaders & 0x1)
            cerr << "Main header: OK\n";
         else
            cerr << "Main header: ERROR\n";
         if (validHeaders & 0x2)
            cerr << "Backup header: OK\n";
         else
            cerr << "Backup header: ERROR\n";
         if (mainPartsCrcOk)
            cerr << "Main partition table: OK\n";
         else
            cerr << "Main partition table: ERROR\n";
         if (secondPartsCrcOk)
            cerr << "Backup partition table: OK\n";
         else
            cerr << "Backup partition table: ERROR\n";
         cerr << "\n";
         state = gpt_corrupt;
      } // if
   } else {
      state = gpt_invalid;
   } // if/else
   return allOK;
} // GPTData::ForceLoadGPTData()

// Loads the partition table pointed to by the main GPT header. The
// main GPT header in memory MUST be valid for this call to do anything
// sensible!
// Returns 1 on success, 0 on failure. CRC errors do NOT count as failure.
int GPTData::LoadMainTable(void) {
   return LoadPartitionTable(mainHeader, myDisk);
} // GPTData::LoadMainTable()

// Load the second (backup) partition table as the primary partition
// table. Used in repair functions, and when starting up if the main
// partition table is damaged.
// Returns 1 on success, 0 on failure. CRC errors do NOT count as failure.
int GPTData::LoadSecondTableAsMain(void) {
   return LoadPartitionTable(secondHeader, myDisk);
} // GPTData::LoadSecondTableAsMain()

// Load a single GPT header (main or backup) from the specified disk device and
// sector. Applies byte-order corrections on big-endian platforms. Sets crcOk
// value appropriately.
// Returns 1 on success, 0 on failure. Note that CRC errors do NOT qualify as
// failure.
int GPTData::LoadHeader(struct GPTHeader *header, DiskIO & disk, uint64_t sector, int *crcOk) {
   int allOK = 1;
   GPTHeader tempHeader;

   disk.Seek(sector);
   if (disk.Read(&tempHeader, 512) != 512) {
      cerr << "Warning! Read error " << errno << "; strange behavior now likely!\n";
      allOK = 0;
   } // if

   // Reverse byte order, if necessary
   if (IsLittleEndian() == 0) {
      ReverseHeaderBytes(&tempHeader);
   } // if
   *crcOk = CheckHeaderCRC(&tempHeader);

   if (tempHeader.sizeOfPartitionEntries != sizeof(GPTPart)) {
      // Print the below warning only if the CRC is OK -- but correct the
      // problem either way. The warning is printed only on a valid CRC
      // because otherwise this warning will display inappropriately when
      // reading MBR disks. If the CRC is invalid, then a warning about
      // that will be shown later, so the user will still know that
      // something is wrong.
      if (*crcOk) {
         cerr << "Warning: Partition table header claims that the size of partition table\n";
         cerr << "entries is " << tempHeader.sizeOfPartitionEntries << " bytes, but this program ";
         cerr << " supports only " << sizeof(GPTPart) << "-byte entries.\n";
         cerr << "Adjusting accordingly, but partition table may be garbage.\n";
      }
      tempHeader.sizeOfPartitionEntries = sizeof(GPTPart);
   }

   if (allOK && (numParts != tempHeader.numParts) && *crcOk) {
      allOK = SetGPTSize(tempHeader.numParts, 0);
   }

   *header = tempHeader;
   return allOK;
} // GPTData::LoadHeader

// Load a partition table (either main or secondary) from the specified disk,
// using header as a reference for what to load. If sector != 0 (the default
// is 0), loads from the specified sector; otherwise loads from the sector
// indicated in header.
// Returns 1 on success, 0 on failure. CRC errors do NOT count as failure.
int GPTData::LoadPartitionTable(const struct GPTHeader & header, DiskIO & disk, uint64_t sector) {
   uint32_t sizeOfParts, newCRC;
   int retval;

   if (header.sizeOfPartitionEntries != sizeof(GPTPart)) {
      cerr << "Error! GPT header contains invalid partition entry size!\n";
      retval = 0;
   } else if (disk.OpenForRead()) {
      if (sector == 0) {
         retval = disk.Seek(header.partitionEntriesLBA);
      } else {
         retval = disk.Seek(sector);
      } // if/else
      if (retval == 1)
         retval = SetGPTSize(header.numParts, 0);
      if (retval == 1) {
         sizeOfParts = header.numParts * header.sizeOfPartitionEntries;
         if (disk.Read(partitions, sizeOfParts) != (int) sizeOfParts) {
            cerr << "Warning! Read error " << errno << "! Misbehavior now likely!\n";
            retval = 0;
         } // if
         newCRC = chksum_crc32((unsigned char*) partitions, sizeOfParts);
         mainPartsCrcOk = secondPartsCrcOk = (newCRC == header.partitionEntriesCRC);
         if (IsLittleEndian() == 0)
            ReversePartitionBytes();
         if (!mainPartsCrcOk) {
            cout << "Caution! After loading partitions, the CRC doesn't check out!\n";
         } // if
      } else {
         cerr << "Error! Couldn't seek to partition table!\n";
      } // if/else
   } else {
      cerr << "Error! Couldn't open device " << device
           << " when reading partition table!\n";
      retval = 0;
   } // if/else
   return retval;
} // GPTData::LoadPartitionsTable()

// Check the partition table pointed to by header, but don't keep it
// around.
// Returns 1 if the CRC is OK & this table matches the one already in memory,
// 0 if not or if there was a read error.
int GPTData::CheckTable(struct GPTHeader *header) {
   uint32_t sizeOfParts, newCRC;
   GPTPart *partsToCheck;
   GPTHeader *otherHeader;
   int allOK = 0;

   // Load partition table into temporary storage to check
   // its CRC and store the results, then discard this temporary
   // storage, since we don't use it in any but recovery operations
   if (myDisk.Seek(header->partitionEntriesLBA)) {
      partsToCheck = new GPTPart[header->numParts];
      sizeOfParts = header->numParts * header->sizeOfPartitionEntries;
      if (partsToCheck == NULL) {
         cerr << "Could not allocate memory in GPTData::CheckTable()! Terminating!\n";
         exit(1);
      } // if
      if (myDisk.Read(partsToCheck, sizeOfParts) != (int) sizeOfParts) {
         cerr << "Warning! Error " << errno << " reading partition table for CRC check!\n";
      } else {
         newCRC = chksum_crc32((unsigned char*) partsToCheck, sizeOfParts);
         allOK = (newCRC == header->partitionEntriesCRC);
         if (header == &mainHeader)
            otherHeader = &secondHeader;
         else
            otherHeader = &mainHeader;
         if (newCRC != otherHeader->partitionEntriesCRC) {
            cerr << "Warning! Main and backup partition tables differ! Use the 'c' and 'e' options\n"
                 << "on the recovery & transformation menu to examine the two tables.\n\n";
            allOK = 0;
         } // if
      } // if/else
      delete[] partsToCheck;
   } // if
   return allOK;
} // GPTData::CheckTable()

// Writes GPT (and protective MBR) to disk. If quiet==1, moves the second
// header later on the disk without asking for permission, if necessary, and
// doesn't confirm the operation before writing. If quiet==0, asks permission
// before moving the second header and asks for final confirmation of any
// write.
// Returns 1 on successful write, 0 if there was a problem.
int GPTData::SaveGPTData(int quiet) {
   int allOK = 1, syncIt = 1;
   char answer;

   // First do some final sanity checks....

   // This test should only fail on read-only disks....
   if (justLooking) {
      cout << "The justLooking flag is set. This probably means you can't write to the disk.\n";
      allOK = 0;
   } // if

   // Check that disk is really big enough to handle the second header...
   if (mainHeader.backupLBA >= diskSize) {
      cerr << "Caution! Secondary header was placed beyond the disk's limits! Moving the\n"
           << "header, but other problems may occur!\n";
      MoveSecondHeaderToEnd();
   } // if

   // Is there enough space to hold the GPT headers and partition tables,
   // given the partition sizes?
   if (CheckGPTSize() > 0) {
      allOK = 0;
   } // if

   // Check that second header is properly placed. Warn and ask if this should
   // be corrected if the test fails....
   if (mainHeader.backupLBA < (diskSize - UINT64_C(1))) {
      if (quiet == 0) {
         cout << "Warning! Secondary header is placed too early on the disk! Do you want to\n"
              << "correct this problem? ";
         if (GetYN() == 'Y') {
            MoveSecondHeaderToEnd();
            cout << "Have moved second header and partition table to correct location.\n";
         } else {
            cout << "Have not corrected the problem. Strange problems may occur in the future!\n";
         } // if correction requested
      } else { // Go ahead and do correction automatically
         MoveSecondHeaderToEnd();
      } // if/else quiet
   } // if

   if ((mainHeader.lastUsableLBA >= diskSize) || (mainHeader.lastUsableLBA > mainHeader.backupLBA)) {
      if (quiet == 0) {
         cout << "Warning! The claimed last usable sector is incorrect! Do you want to correct\n"
              << "this problem? ";
         if (GetYN() == 'Y') {
            MoveSecondHeaderToEnd();
            cout << "Have adjusted the second header and last usable sector value.\n";
         } else {
            cout << "Have not corrected the problem. Strange problems may occur in the future!\n";
         } // if correction requested
      } else { // go ahead and do correction automatically
         MoveSecondHeaderToEnd();
      } // if/else quiet
   } // if

   // Check for overlapping or insane partitions....
   if ((FindOverlaps() > 0) || (FindInsanePartitions() > 0)) {
      allOK = 0;
      cerr << "Aborting write operation!\n";
   } // if

   // Check that protective MBR fits, and warn if it doesn't....
   if (!protectiveMBR.DoTheyFit()) {
      cerr << "\nPartition(s) in the protective MBR are too big for the disk! Creating a\n"
           << "fresh protective or hybrid MBR is recommended.\n";
   }

   // Check for mismatched MBR and GPT data, but let it pass if found
   // (function displays warning message)
   FindHybridMismatches();

   RecomputeCRCs();

   if ((allOK) && (!quiet)) {
      cout << "\nFinal checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING\n"
           << "PARTITIONS!!\n\nDo you want to proceed? ";
      answer = GetYN();
      if (answer == 'Y') {
         cout << "OK; writing new GUID partition table (GPT) to " << myDisk.GetName() << ".\n";
      } else {
         allOK = 0;
      } // if/else
   } // if

   // Do it!
   if (allOK) {
      if (myDisk.OpenForWrite()) {
         // As per UEFI specs, write the secondary table and GPT first....
         allOK = SavePartitionTable(myDisk, secondHeader.partitionEntriesLBA);
         if (!allOK) {
            cerr << "Unable to save backup partition table! Perhaps the 'e' option on the experts'\n"
                 << "menu will resolve this problem.\n";
            syncIt = 0;
         } // if

         // Now write the secondary GPT header...
         allOK = allOK && SaveHeader(&secondHeader, myDisk, mainHeader.backupLBA);

         // Now write the main partition tables...
         allOK = allOK && SavePartitionTable(myDisk, mainHeader.partitionEntriesLBA);

         // Now write the main GPT header...
         allOK = allOK && SaveHeader(&mainHeader, myDisk, 1);

         // To top it off, write the protective MBR...
         allOK = allOK && protectiveMBR.WriteMBRData(&myDisk);

         // re-read the partition table
         // Note: Done even if some write operations failed, but not if all of them failed.
         // Done this way because I've received one problem report from a user one whose
         // system the MBR write failed but everything else was OK (on a GPT disk under
         // Windows), and the failure to sync therefore caused Windows to restore the
         // original partition table from its cache. OTOH, such restoration might be
         // desirable if the error occurs later; but that seems unlikely unless the initial
         // write fails....
         if (syncIt)
            myDisk.DiskSync();

         if (allOK) { // writes completed OK
            cout << "The operation has completed successfully.\n";
         } else {
            cerr << "Warning! An error was reported when writing the partition table! This error\n"
                 << "MIGHT be harmless, or the disk might be damaged! Checking it is advisable.\n";
         } // if/else

         myDisk.Close();
      } else {
         cerr << "Unable to open device '" << myDisk.GetName() << "' for writing! Errno is "
              << errno << "! Aborting write!\n";
         allOK = 0;
      } // if/else
   } else {
      cout << "Aborting write of new partition table.\n";
   } // if

   return (allOK);
} // GPTData::SaveGPTData()

// Save GPT data to a backup file. This function does much less error
// checking than SaveGPTData(). It can therefore preserve many types of
// corruption for later analysis; however, it preserves only the MBR,
// the main GPT header, the backup GPT header, and the main partition
// table; it discards the backup partition table, since it should be
// identical to the main partition table on healthy disks.
int GPTData::SaveGPTBackup(const string & filename) {
   int allOK = 1;
   DiskIO backupFile;

   if (backupFile.OpenForWrite(filename)) {
      // Recomputing the CRCs is likely to alter them, which could be bad
      // if the intent is to save a potentially bad GPT for later analysis;
      // but if we don't do this, we get bogus errors when we load the
      // backup. I'm favoring misses over false alarms....
      RecomputeCRCs();

      protectiveMBR.WriteMBRData(&backupFile);
      protectiveMBR.SetDisk(&myDisk);

      if (allOK) {
         // MBR write closed disk, so re-open and seek to end....
         backupFile.OpenForWrite();
         allOK = SaveHeader(&mainHeader, backupFile, 1);
      } // if (allOK)

      if (allOK)
         allOK = SaveHeader(&secondHeader, backupFile, 2);

      if (allOK)
         allOK = SavePartitionTable(backupFile, 3);

      if (allOK) { // writes completed OK
         cout << "The operation has completed successfully.\n";
      } else {
         cerr << "Warning! An error was reported when writing the backup file.\n"
              << "It may not be usable!\n";
      } // if/else
      backupFile.Close();
   } else {
      cerr << "Unable to open file '" << filename << "' for writing! Aborting!\n";
      allOK = 0;
   } // if/else
   return allOK;
} // GPTData::SaveGPTBackup()

// Write a GPT header (main or backup) to the specified sector. Used by both
// the SaveGPTData() and SaveGPTBackup() functions.
// Should be passed an architecture-appropriate header (DO NOT call
// ReverseHeaderBytes() on the header before calling this function)
// Returns 1 on success, 0 on failure
int GPTData::SaveHeader(struct GPTHeader *header, DiskIO & disk, uint64_t sector) {
   int littleEndian, allOK = 1;

   littleEndian = IsLittleEndian();
   if (!littleEndian)
      ReverseHeaderBytes(header);
   if (disk.Seek(sector)) {
      if (disk.Write(header, 512) == -1)
         allOK = 0;
   } else allOK = 0; // if (disk.Seek()...)
   if (!littleEndian)
      ReverseHeaderBytes(header);
   return allOK;
} // GPTData::SaveHeader()

// Save the partitions to the specified sector. Used by both the SaveGPTData()
// and SaveGPTBackup() functions.
// Should be passed an architecture-appropriate header (DO NOT call
// ReverseHeaderBytes() on the header before calling this function)
// Returns 1 on success, 0 on failure
int GPTData::SavePartitionTable(DiskIO & disk, uint64_t sector) {
   int littleEndian, allOK = 1;

   littleEndian = IsLittleEndian();
   if (disk.Seek(sector)) {
      if (!littleEndian)
         ReversePartitionBytes();
      if (disk.Write(partitions, mainHeader.sizeOfPartitionEntries * numParts) == -1)
         allOK = 0;
      if (!littleEndian)
         ReversePartitionBytes();
   } else allOK = 0; // if (myDisk.Seek()...)
   return allOK;
} // GPTData::SavePartitionTable()

// Load GPT data from a backup file created by SaveGPTBackup(). This function
// does minimal error checking. It returns 1 if it completed successfully,
// 0 if there was a problem. In the latter case, it creates a new empty
// set of partitions.
int GPTData::LoadGPTBackup(const string & filename) {
   int allOK = 1, val, err;
   int shortBackup = 0;
   DiskIO backupFile;

   if (backupFile.OpenForRead(filename)) {
      // Let the MBRData class load the saved MBR...
      protectiveMBR.ReadMBRData(&backupFile, 0); // 0 = don't check block size
      protectiveMBR.SetDisk(&myDisk);

      LoadHeader(&mainHeader, backupFile, 1, &mainCrcOk);

      // Check backup file size and rebuild second header if file is right
      // size to be direct dd copy of MBR, main header, and main partition
      // table; if other size, treat it like a GPT fdisk-generated backup
      // file
      shortBackup = ((backupFile.DiskSize(&err) * backupFile.GetBlockSize()) ==
                     (mainHeader.numParts * mainHeader.sizeOfPartitionEntries) + 1024);
      if (shortBackup) {
         RebuildSecondHeader();
         secondCrcOk = mainCrcOk;
      } else {
         LoadHeader(&secondHeader, backupFile, 2, &secondCrcOk);
      } // if/else

      // Return valid headers code: 0 = both headers bad; 1 = main header
      // good, backup bad; 2 = backup header good, main header bad;
      // 3 = both headers good. Note these codes refer to valid GPT
      // signatures and version numbers; more subtle problems will elude
      // this check!
      if ((val = CheckHeaderValidity()) > 0) {
         if (val == 2) { // only backup header seems to be good
            SetGPTSize(secondHeader.numParts, 0);
         } else { // main header is OK
            SetGPTSize(mainHeader.numParts, 0);
         } // if/else

         if (secondHeader.currentLBA != diskSize - UINT64_C(1)) {
            cout << "Warning! Current disk size doesn't match that of the backup!\n"
                 << "Adjusting sizes to match, but subsequent problems are possible!\n";
            MoveSecondHeaderToEnd();
         } // if

         if (!LoadPartitionTable(mainHeader, backupFile, (uint64_t) (3 - shortBackup)))
            cerr << "Warning! Read error " << errno
                 << " loading partition table; strange behavior now likely!\n";
      } else {
         allOK = 0;
      } // if/else
      // Something went badly wrong, so blank out partitions
      if (allOK == 0) {
         cerr << "Improper backup file! Clearing all partition data!\n";
         ClearGPTData();
         protectiveMBR.MakeProtectiveMBR();
      } // if
   } else {
      allOK = 0;
      cerr << "Unable to open file '" << filename << "' for reading! Aborting!\n";
   } // if/else

   return allOK;
} // GPTData::LoadGPTBackup()

int GPTData::SaveMBR(void) {
   return protectiveMBR.WriteMBRData(&myDisk);
} // GPTData::SaveMBR()

// This function destroys the on-disk GPT structures, but NOT the on-disk
// MBR.
// Returns 1 if the operation succeeds, 0 if not.
int GPTData::DestroyGPT(void) {
   int sum, tableSize, allOK = 1;
   uint8_t blankSector[512];
   uint8_t* emptyTable;

   memset(blankSector, 0, sizeof(blankSector));
   ClearGPTData();

   if (myDisk.OpenForWrite()) {
      if (!myDisk.Seek(mainHeader.currentLBA))
         allOK = 0;
      if (myDisk.Write(blankSector, 512) != 512) { // blank it out
         cerr << "Warning! GPT main header not overwritten! Error is " << errno << "\n";
         allOK = 0;
      } // if
      if (!myDisk.Seek(mainHeader.partitionEntriesLBA))
         allOK = 0;
      tableSize = numParts * mainHeader.sizeOfPartitionEntries;
      emptyTable = new uint8_t[tableSize];
      if (emptyTable == NULL) {
         cerr << "Could not allocate memory in GPTData::DestroyGPT()! Terminating!\n";
         exit(1);
      } // if
      memset(emptyTable, 0, tableSize);
      if (allOK) {
         sum = myDisk.Write(emptyTable, tableSize);
         if (sum != tableSize) {
            cerr << "Warning! GPT main partition table not overwritten! Error is " << errno << "\n";
            allOK = 0;
         } // if write failed
      } // if
      if (!myDisk.Seek(secondHeader.partitionEntriesLBA))
         allOK = 0;
      if (allOK) {
         sum = myDisk.Write(emptyTable, tableSize);
         if (sum != tableSize) {
            cerr << "Warning! GPT backup partition table not overwritten! Error is "
                 << errno << "\n";
            allOK = 0;
         } // if wrong size written
      } // if
      if (!myDisk.Seek(secondHeader.currentLBA))
         allOK = 0;
      if (allOK) {
         if (myDisk.Write(blankSector, 512) != 512) { // blank it out
            cerr << "Warning! GPT backup header not overwritten! Error is " << errno << "\n";
            allOK = 0;
         } // if
      } // if
      myDisk.DiskSync();
      myDisk.Close();
      cout << "GPT data structures destroyed! You may now partition the disk using fdisk or\n"
           << "other utilities.\n";
      delete[] emptyTable;
   } else {
      cerr << "Problem opening '" << device << "' for writing! Program will now terminate.\n";
   } // if/else (fd != -1)
   return (allOK);
} // GPTDataTextUI::DestroyGPT()

// Wipe MBR data from the disk (zero it out completely)
// Returns 1 on success, 0 on failure.
int GPTData::DestroyMBR(void) {
   int allOK;
   uint8_t blankSector[512];

   memset(blankSector, 0, sizeof(blankSector));

   allOK = myDisk.OpenForWrite() && myDisk.Seek(0) && (myDisk.Write(blankSector, 512) == 512);

   if (!allOK)
      cerr << "Warning! MBR not overwritten! Error is " << errno << "!\n";
   return allOK;
} // GPTData::DestroyMBR(void)

// Tell user whether Apple Partition Map (APM) was discovered....
void GPTData::ShowAPMState(void) {
   if (apmFound)
      cout << "  APM: present\n";
   else
      cout << "  APM: not present\n";
} // GPTData::ShowAPMState()

// Tell user about the state of the GPT data....
void GPTData::ShowGPTState(void) {
   switch (state) {
      case gpt_invalid:
         cout << "  GPT: not present\n";
         break;
      case gpt_valid:
         cout << "  GPT: present\n";
         break;
      case gpt_corrupt:
         cout << "  GPT: damaged\n";
         break;
      default:
         cout << "\a  GPT: unknown -- bug!\n";
         break;
   } // switch
} // GPTData::ShowGPTState()

// Display the basic GPT data
void GPTData::DisplayGPTData(void) {
   uint32_t i;
   uint64_t temp, totalFree;

   cout << "Disk " << device << ": " << diskSize << " sectors, "
        << BytesToIeee(diskSize, blockSize) << "\n";
   if (myDisk.GetModel() != "")
      cout << "Model: " << myDisk.GetModel() << "\n";
   if (physBlockSize > 0)
      cout << "Sector size (logical/physical): " << blockSize << "/" << physBlockSize << " bytes\n";
   else
      cout << "Sector size (logical): " << blockSize << " bytes\n";
   cout << "Disk identifier (GUID): " << mainHeader.diskGUID << "\n";
   cout << "Partition table holds up to " << numParts << " entries\n";
   cout << "Main partition table begins at sector " << mainHeader.partitionEntriesLBA
        << " and ends at sector " << mainHeader.partitionEntriesLBA + GetTableSizeInSectors() - 1 << "\n";
   cout << "First usable sector is " << mainHeader.firstUsableLBA
        << ", last usable sector is " << mainHeader.lastUsableLBA << "\n";
   totalFree = FindFreeBlocks(&i, &temp);
   cout << "Partitions will be aligned on " << sectorAlignment << "-sector boundaries\n";
   cout << "Total free space is " << totalFree << " sectors ("
        << BytesToIeee(totalFree, blockSize) << ")\n";
   cout << "\nNumber  Start (sector)    End (sector)  Size       Code  Name\n";
   for (i = 0; i < numParts; i++) {
      partitions[i].ShowSummary(i, blockSize);
   } // for
} // GPTData::DisplayGPTData()

// Show detailed information on the specified partition
void GPTData::ShowPartDetails(uint32_t partNum) {
   if ((partNum < numParts) && !IsFreePartNum(partNum)) {
      partitions[partNum].ShowDetails(blockSize);
   } else {
      cout << "Partition #" << partNum + 1 << " does not exist.\n";
   } // if
} // GPTData::ShowPartDetails()

/**************************************************************************
 *                                                                        *
 * Partition table transformation functions (MBR or BSD disklabel to GPT) *
 * (some of these functions may require user interaction)                 *
 *                                                                        *
 **************************************************************************/

// Examines the MBR & GPT data to determine which set of data to use: the
// MBR (use_mbr), the GPT (use_gpt), the BSD disklabel (use_bsd), or create
// a new set of partitions (use_new). A return value of use_abort indicates
// that this function couldn't determine what to do. Overriding functions
// in derived classes may ask users questions in such cases.
WhichToUse GPTData::UseWhichPartitions(void) {
   WhichToUse which = use_new;
   MBRValidity mbrState;

   mbrState = protectiveMBR.GetValidity();

   if ((state == gpt_invalid) && ((mbrState == mbr) || (mbrState == hybrid))) {
      cout << "\n***************************************************************\n"
           << "Found invalid GPT and valid MBR; converting MBR to GPT format\n"
           << "in memory. ";
      if (!justLooking) {
         cout << "\aTHIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by\n"
              << "typing 'q' if you don't want to convert your MBR partitions\n"
              << "to GPT format!";
      } // if
      cout << "\n***************************************************************\n\n";
      which = use_mbr;
   } // if

   if ((state == gpt_invalid) && bsdFound) {
      cout << "\n**********************************************************************\n"
           << "Found invalid GPT and valid BSD disklabel; converting BSD disklabel\n"
           << "to GPT format.";
      if ((!justLooking) && (!beQuiet)) {
      cout << "\a THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Your first\n"
           << "BSD partition will likely be unusable. Exit by typing 'q' if you don't\n"
           << "want to convert your BSD partitions to GPT format!";
      } // if
      cout << "\n**********************************************************************\n\n";
      which = use_bsd;
   } // if

   if ((state == gpt_valid) && (mbrState == gpt)) {
      which = use_gpt;
      if (!beQuiet)
         cout << "Found valid GPT with protective MBR; using GPT.\n";
   } // if
   if ((state == gpt_valid) && (mbrState == hybrid)) {
      which = use_gpt;
      if (!beQuiet)
         cout << "Found valid GPT with hybrid MBR; using GPT.\n";
   } // if
   if ((state == gpt_valid) && (mbrState == invalid)) {
      cout << "\aFound valid GPT with corrupt MBR; using GPT and will write new\n"
           << "protective MBR on save.\n";
      which = use_gpt;
   } // if
   if ((state == gpt_valid) && (mbrState == mbr)) {
      which = use_abort;
   } // if

   if (state == gpt_corrupt) {
      if (mbrState == gpt) {
         cout << "\a\a****************************************************************************\n"
              << "Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk\n"
              << "verification and recovery are STRONGLY recommended.\n"
              << "****************************************************************************\n";
         which = use_gpt;
      } else {
         which = use_abort;
      } // if/else MBR says disk is GPT
   } // if GPT corrupt

   if (which == use_new)
      cout << "Creating new GPT entries in memory.\n";

   return which;
} // UseWhichPartitions()

// Convert MBR partition table into GPT form.
void GPTData::XFormPartitions(void) {
   int i, numToConvert;
   uint8_t origType;

   // Clear out old data & prepare basics....
   ClearGPTData();

   // Convert the smaller of the # of GPT or MBR partitions
   if (numParts > MAX_MBR_PARTS)
      numToConvert = MAX_MBR_PARTS;
   else
      numToConvert = numParts;

   for (i = 0; i < numToConvert; i++) {
      origType = protectiveMBR.GetType(i);
      // don't waste CPU time trying to convert extended, hybrid protective, or
      // null (non-existent) partitions
      if ((origType != 0x05) && (origType != 0x0f) && (origType != 0x85) &&
          (origType != 0x00) && (origType != 0xEE))
         partitions[i] = protectiveMBR.AsGPT(i);
   } // for

   // Convert MBR into protective MBR
   protectiveMBR.MakeProtectiveMBR();

   // Record that all original CRCs were OK so as not to raise flags
   // when doing a disk verification
   mainCrcOk = secondCrcOk = mainPartsCrcOk = secondPartsCrcOk = 1;
} // GPTData::XFormPartitions()

// Transforms BSD disklabel on the specified partition (numbered from 0).
// If an invalid partition number is given, the program does nothing.
// Returns the number of new partitions created.
int GPTData::XFormDisklabel(uint32_t partNum) {
   uint32_t low, high;
   int goOn = 1, numDone = 0;
   BSDData disklabel;

   if (GetPartRange(&low, &high) == 0) {
      goOn = 0;
      cout << "No partitions!\n";
   } // if
   if (partNum > high) {
      goOn = 0;
      cout << "Specified partition is invalid!\n";
   } // if

   // If all is OK, read the disklabel and convert it.
   if (goOn) {
      goOn = disklabel.ReadBSDData(&myDisk, partitions[partNum].GetFirstLBA(),
                                   partitions[partNum].GetLastLBA());
      if ((goOn) && (disklabel.IsDisklabel())) {
         numDone = XFormDisklabel(&disklabel);
         if (numDone == 1)
            cout << "Converted 1 BSD partition.\n";
         else
            cout << "Converted " << numDone << " BSD partitions.\n";
      } else {
         cout << "Unable to convert partitions! Unrecognized BSD disklabel.\n";
      } // if/else
   } // if
   if (numDone > 0) { // converted partitions; delete carrier
      partitions[partNum].BlankPartition();
   } // if
   return numDone;
} // GPTData::XFormDisklabel(uint32_t i)

// Transform the partitions on an already-loaded BSD disklabel...
int GPTData::XFormDisklabel(BSDData* disklabel) {
   int i, partNum = 0, numDone = 0;

   if (disklabel->IsDisklabel()) {
      for (i = 0; i < disklabel->GetNumParts(); i++) {
         partNum = FindFirstFreePart();
         if (partNum >= 0) {
            partitions[partNum] = disklabel->AsGPT(i);
            if (partitions[partNum].IsUsed())
               numDone++;
         } // if
      } // for
      if (partNum == -1)
         cerr << "Warning! Too many partitions to convert!\n";
   } // if

   // Record that all original CRCs were OK so as not to raise flags
   // when doing a disk verification
   mainCrcOk = secondCrcOk = mainPartsCrcOk = secondPartsCrcOk = 1;

   return numDone;
} // GPTData::XFormDisklabel(BSDData* disklabel)

// Add one GPT partition to MBR. Used by PartsToMBR() functions. Created
// partition has the active/bootable flag UNset and uses the GPT fdisk
// type code divided by 0x0100 as the MBR type code.
// Returns 1 if operation was 100% successful, 0 if there were ANY
// problems.
int GPTData::OnePartToMBR(uint32_t gptPart, int mbrPart) {
   int allOK = 1;

   if ((mbrPart < 0) || (mbrPart > 3)) {
      cout << "MBR partition " << mbrPart + 1 << " is out of range; omitting it.\n";
      allOK = 0;
   } // if
   if (gptPart >= numParts) {
      cout << "GPT partition " << gptPart + 1 << " is out of range; omitting it.\n";
      allOK = 0;
   } // if
   if (allOK && (partitions[gptPart].GetLastLBA() == UINT64_C(0))) {
      cout << "GPT partition " << gptPart + 1 << " is undefined; omitting it.\n";
      allOK = 0;
   } // if
   if (allOK && (partitions[gptPart].GetFirstLBA() <= UINT32_MAX) &&
       (partitions[gptPart].GetLengthLBA() <= UINT32_MAX)) {
      if (partitions[gptPart].GetLastLBA() > UINT32_MAX) {
         cout << "Caution: Partition end point past 32-bit pointer boundary;"
              << " some OSes may\nreact strangely.\n";
      } // if
      protectiveMBR.MakePart(mbrPart, (uint32_t) partitions[gptPart].GetFirstLBA(),
                             (uint32_t) partitions[gptPart].GetLengthLBA(),
                             partitions[gptPart].GetHexType() / 256, 0);
   } else { // partition out of range
      if (allOK) // Display only if "else" triggered by out-of-bounds condition
         cout << "Partition " << gptPart + 1 << " begins beyond the 32-bit pointer limit of MBR "
              << "partitions, or is\n too big; omitting it.\n";
      allOK = 0;
   } // if/else
   return allOK;
} // GPTData::OnePartToMBR()


/**********************************************************************
 *                                                                    *
 * Functions that adjust GPT data structures WITHOUT user interaction *
 * (they may display information for the user's benefit, though)      *
 *                                                                    *
 **********************************************************************/

// Resizes GPT to specified number of entries. Creates a new table if
// necessary, copies data if it already exists. If fillGPTSectors is 1
// (the default), rounds numEntries to fill all the sectors necessary to
// hold the GPT.
// Returns 1 if all goes well, 0 if an error is encountered.
int GPTData::SetGPTSize(uint32_t numEntries, int fillGPTSectors) {
   GPTPart* newParts;
   uint32_t i, high, copyNum, entriesPerSector;
   int allOK = 1;

   // First, adjust numEntries upward, if necessary, to get a number
   // that fills the allocated sectors
   entriesPerSector = blockSize / GPT_SIZE;
   if (fillGPTSectors && ((numEntries % entriesPerSector) != 0)) {
      cout << "Adjusting GPT size from " << numEntries << " to ";
      numEntries = ((numEntries / entriesPerSector) + 1) * entriesPerSector;
      cout << numEntries << " to fill the sector\n";
   } // if

   // Do the work only if the # of partitions is changing. Along with being
   // efficient, this prevents mucking with the location of the secondary
   // partition table, which causes problems when loading data from a RAID
   // array that's been expanded because this function is called when loading
   // data.
   if (((numEntries != numParts) || (partitions == NULL)) && (numEntries > 0)) {
      newParts = new GPTPart [numEntries];
      if (newParts != NULL) {
         if (partitions != NULL) { // existing partitions; copy them over
            GetPartRange(&i, &high);
            if (numEntries < (high + 1)) { // Highest entry too high for new #
               cout << "The highest-numbered partition is " << high + 1
                    << ", which is greater than the requested\n"
                    << "partition table size of " << numEntries
                    << "; cannot resize. Perhaps sorting will help.\n";
               allOK = 0;
               delete[] newParts;
            } else { // go ahead with copy
               if (numEntries < numParts)
                  copyNum = numEntries;
               else
                  copyNum = numParts;
               for (i = 0; i < copyNum; i++) {
                  newParts[i] = partitions[i];
               } // for
               delete[] partitions;
               partitions = newParts;
            } // if
         } else { // No existing partition table; just create it
            partitions = newParts;
         } // if/else existing partitions
         numParts = numEntries;
         mainHeader.firstUsableLBA = GetTableSizeInSectors() + mainHeader.partitionEntriesLBA;
         secondHeader.firstUsableLBA = mainHeader.firstUsableLBA;
         MoveSecondHeaderToEnd();
         if (diskSize > 0)
            CheckGPTSize();
      } else { // Bad memory allocation
         cerr << "Error allocating memory for partition table! Size is unchanged!\n";
         allOK = 0;
      } // if/else
   } // if/else
   mainHeader.numParts = numParts;
   secondHeader.numParts = numParts;
   return (allOK);
} // GPTData::SetGPTSize()

// Change the start sector for the main partition table.
// Returns 1 on success, 0 on failure
int GPTData::MoveMainTable(uint64_t pteSector) {
    uint64_t pteSize = GetTableSizeInSectors();
    int retval = 1;

    if ((pteSector >= 2) && ((pteSector + pteSize) <= FindFirstUsedLBA())) {
       mainHeader.partitionEntriesLBA = pteSector;
       mainHeader.firstUsableLBA = pteSector + pteSize;
       RebuildSecondHeader();
    } else {
       cerr << "Unable to set the main partition table's location to " << pteSector << "!\n";
       retval = 0;
    } // if/else
    return retval;
} // GPTData::MoveMainTable()

// Change the start sector for the secondary partition table.
// Returns 1 on success, 0 on failure
int GPTData::MoveSecondTable(uint64_t pteSector) {
   uint64_t pteSize = GetTableSizeInSectors();
   int retval = 1;

   if ((pteSector > FindLastUsedLBA()) && ((pteSector + pteSize) < diskSize)) {
      secondHeader.partitionEntriesLBA = pteSector; // (RebuildSecondHeader actually replaces this with lastUsableLBA+1)
      mainHeader.lastUsableLBA = secondHeader.partitionEntriesLBA - UINT64_C(1);
      RebuildSecondHeader();
   } else {
      cerr << "Unable to set the secondary partition table's location to " << pteSector << "!\n";
      retval = 0;
   } // if/else
   return retval;
} // GPTData::MoveSecondTable()

// Blank the partition array
void GPTData::BlankPartitions(void) {
   uint32_t i;

   for (i = 0; i < numParts; i++) {
      partitions[i].BlankPartition();
   } // for
} // GPTData::BlankPartitions()

// Delete a partition by number. Returns 1 if successful,
// 0 if there was a problem. Returns 1 if partition was in
// range, 0 if it was out of range.
int GPTData::DeletePartition(uint32_t partNum) {
   uint64_t startSector, length;
   uint32_t low, high, numUsedParts, retval = 1;;

   numUsedParts = GetPartRange(&low, &high);
   if ((numUsedParts > 0) && (partNum >= low) && (partNum <= high)) {
      // In case there's a protective MBR, look for & delete matching
      // MBR partition....
      startSector = partitions[partNum].GetFirstLBA();
      length = partitions[partNum].GetLengthLBA();
      protectiveMBR.DeleteByLocation(startSector, length);

      // Now delete the GPT partition
      partitions[partNum].BlankPartition();
   } else {
      cerr << "Partition number " << partNum + 1 << " out of range!\n";
      retval = 0;
   } // if/else
   return retval;
} // GPTData::DeletePartition(uint32_t partNum)

// Non-interactively create a partition.
// Returns 1 if the operation was successful, 0 if a problem was discovered.
uint32_t GPTData::CreatePartition(uint32_t partNum, uint64_t startSector, uint64_t endSector) {
   int retval = 1; // assume there'll be no problems
   uint64_t origSector = startSector;

   if (IsFreePartNum(partNum)) {
      if (Align(&startSector)) {
         cout << "Information: Moved requested sector from " << origSector << " to "
              << startSector << " in\norder to align on " << sectorAlignment
              << "-sector boundaries.\n";
      } // if
      if (IsFree(startSector) && (startSector <= endSector)) {
         if (FindLastInFree(startSector) >= endSector) {
            partitions[partNum].SetFirstLBA(startSector);
            partitions[partNum].SetLastLBA(endSector);
            partitions[partNum].SetType(DEFAULT_GPT_TYPE);
            partitions[partNum].RandomizeUniqueGUID();
         } else retval = 0; // if free space until endSector
      } else retval = 0; // if startSector is free
   } else retval = 0; // if legal partition number
   return retval;
} // GPTData::CreatePartition(partNum, startSector, endSector)

// Sort the GPT entries, eliminating gaps and making for a logical
// ordering.
void GPTData::SortGPT(void) {
   if (numParts > 0)
      sort(partitions, partitions + numParts);
} // GPTData::SortGPT()

// Swap the contents of two partitions.
// Returns 1 if successful, 0 if either partition is out of range
// (that is, not a legal number; either or both can be empty).
// Note that if partNum1 = partNum2 and this number is in range,
// it will be considered successful.
int GPTData::SwapPartitions(uint32_t partNum1, uint32_t partNum2) {
   GPTPart temp;
   int allOK = 1;

   if ((partNum1 < numParts) && (partNum2 < numParts)) {
      if (partNum1 != partNum2) {
         temp = partitions[partNum1];
         partitions[partNum1] = partitions[partNum2];
         partitions[partNum2] = temp;
      } // if
   } else allOK = 0; // partition numbers are valid
   return allOK;
} // GPTData::SwapPartitions()

// Set up data structures for entirely new set of partitions on the
// specified device. Returns 1 if OK, 0 if there were problems.
// Note that this function does NOT clear the protectiveMBR data
// structure, since it may hold the original MBR partitions if the
// program was launched on an MBR disk, and those may need to be
// converted to GPT format.
int GPTData::ClearGPTData(void) {
   int goOn = 1, i;

   // Set up the partition table....
   delete[] partitions;
   partitions = NULL;
   SetGPTSize(NUM_GPT_ENTRIES);

   // Now initialize a bunch of stuff that's static....
   mainHeader.signature = GPT_SIGNATURE;
   mainHeader.revision = 0x00010000;
   mainHeader.headerSize = HEADER_SIZE;
   mainHeader.reserved = 0;
   mainHeader.currentLBA = UINT64_C(1);
   mainHeader.partitionEntriesLBA = (uint64_t) 2;
   mainHeader.sizeOfPartitionEntries = GPT_SIZE;
   mainHeader.firstUsableLBA = GetTableSizeInSectors() + mainHeader.partitionEntriesLBA;
   for (i = 0; i < GPT_RESERVED; i++) {
      mainHeader.reserved2[i] = '\0';
   } // for
   if (blockSize > 0)
      sectorAlignment = DEFAULT_ALIGNMENT * SECTOR_SIZE / blockSize;
   else
      sectorAlignment = DEFAULT_ALIGNMENT;

   // Now some semi-static items (computed based on end of disk)
   mainHeader.backupLBA = diskSize - UINT64_C(1);
   mainHeader.lastUsableLBA = diskSize - mainHeader.firstUsableLBA;

   // Set a unique GUID for the disk, based on random numbers
   mainHeader.diskGUID.Randomize();

   // Copy main header to backup header
   RebuildSecondHeader();

   // Blank out the partitions array....
   BlankPartitions();

   // Flag all CRCs as being OK....
   mainCrcOk = 1;
   secondCrcOk = 1;
   mainPartsCrcOk = 1;
   secondPartsCrcOk = 1;

   return (goOn);
} // GPTData::ClearGPTData()

// Set the location of the second GPT header data to the end of the disk.
// If the disk size has actually changed, this also adjusts the protective
// entry in the MBR, since it's probably no longer correct.
// Used internally and called by the 'e' option on the recovery &
// transformation menu, to help users of RAID arrays who add disk space
// to their arrays or to adjust data structures in restore operations
// involving unequal-sized disks.
void GPTData::MoveSecondHeaderToEnd() {
   mainHeader.backupLBA = secondHeader.currentLBA = diskSize - UINT64_C(1);
   if (mainHeader.lastUsableLBA != diskSize - mainHeader.firstUsableLBA) {
      if (protectiveMBR.GetValidity() == hybrid) {
         protectiveMBR.OptimizeEESize();
         RecomputeCHS();
      } // if
      if (protectiveMBR.GetValidity() == gpt)
         MakeProtectiveMBR();
   } // if
   mainHeader.lastUsableLBA = secondHeader.lastUsableLBA = diskSize - mainHeader.firstUsableLBA;
   secondHeader.partitionEntriesLBA = secondHeader.lastUsableLBA + UINT64_C(1);
   // TODO: Whenever this gets called, it moves the backup table to be the same distance from the backup header as the primary one it from its header. This seems highly problematic, since MoveMainTable does not call this, but then further actions may or may not do so. Moving the primary table may thus imply moving the backup table, or it may leave it where it was. There is also no guarantee that the space where the backup table is moved to is actually available.
} // GPTData::FixSecondHeaderLocation()

// Sets the partition's name to the specified UnicodeString without
// user interaction.
// Returns 1 on success, 0 on failure (invalid partition number).
int GPTData::SetName(uint32_t partNum, const UnicodeString & theName) {
   int retval = 1;

   if (IsUsedPartNum(partNum))
      partitions[partNum].SetName(theName);
   else
      retval = 0;

   return retval;
} // GPTData::SetName

// Set the disk GUID to the specified value. Note that the header CRCs must
// be recomputed after calling this function.
void GPTData::SetDiskGUID(GUIDData newGUID) {
   mainHeader.diskGUID = newGUID;
   secondHeader.diskGUID = newGUID;
} // SetDiskGUID()

// Set the unique GUID of the specified partition. Returns 1 on
// successful completion, 0 if there were problems (invalid
// partition number).
int GPTData::SetPartitionGUID(uint32_t pn, GUIDData theGUID) {
   int retval = 0;

   if (pn < numParts) {
      if (partitions[pn].IsUsed()) {
         partitions[pn].SetUniqueGUID(theGUID);
         retval = 1;
      } // if
   } // if
   return retval;
} // GPTData::SetPartitionGUID()

// Set new random GUIDs for the disk and all partitions. Intended to be used
// after disk cloning or similar operations that don't randomize the GUIDs.
void GPTData::RandomizeGUIDs(void) {
   uint32_t i;

   mainHeader.diskGUID.Randomize();
   secondHeader.diskGUID = mainHeader.diskGUID;
   for (i = 0; i < numParts; i++)
      if (partitions[i].IsUsed())
         partitions[i].RandomizeUniqueGUID();
} // GPTData::RandomizeGUIDs()

// Change partition type code non-interactively. Returns 1 if
// successful, 0 if not....
int GPTData::ChangePartType(uint32_t partNum, PartType theGUID) {
   int retval = 1;

   if (!IsFreePartNum(partNum)) {
      partitions[partNum].SetType(theGUID);
   } else retval = 0;
   return retval;
} // GPTData::ChangePartType()

// Recompute the CHS values of all the MBR partitions. Used to reset
// CHS values that some BIOSes require, despite the fact that the
// resulting CHS values violate the GPT standard.
void GPTData::RecomputeCHS(void) {
   int i;

   for (i = 0; i < 4; i++)
      protectiveMBR.RecomputeCHS(i);
} // GPTData::RecomputeCHS()

// Adjust sector number so that it falls on a sector boundary that's a
// multiple of sectorAlignment. This is done to improve the performance
// of Western Digital Advanced Format disks and disks with similar
// technology from other companies, which use 4096-byte sectors
// internally although they translate to 512-byte sectors for the
// benefit of the OS. If partitions aren't properly aligned on these
// disks, some filesystem data structures can span multiple physical
// sectors, degrading performance. This function should be called
// only on the FIRST sector of the partition, not the last!
// This function returns 1 if the alignment was altered, 0 if it
// was unchanged.
int GPTData::Align(uint64_t* sector) {
   int retval = 0, sectorOK = 0;
   uint64_t earlier, later, testSector;

   if ((*sector % sectorAlignment) != 0) {
      earlier = (*sector / sectorAlignment) * sectorAlignment;
      later = earlier + (uint64_t) sectorAlignment;

      // Check to see that every sector between the earlier one and the
      // requested one is clear, and that it's not too early....
      if (earlier >= mainHeader.firstUsableLBA) {
         testSector = earlier;
         do {
            sectorOK = IsFree(testSector++);
         } while ((sectorOK == 1) && (testSector < *sector));
         if (sectorOK == 1) {
            *sector = earlier;
            retval = 1;
         } // if
      } // if firstUsableLBA check

      // If couldn't move the sector earlier, try to move it later instead....
      if ((sectorOK != 1) && (later <= mainHeader.lastUsableLBA)) {
         testSector = later;
         do {
            sectorOK = IsFree(testSector--);
         } while ((sectorOK == 1) && (testSector > *sector));
         if (sectorOK == 1) {
            *sector = later;
            retval = 1;
         } // if
      } // if
   } // if
   return retval;
} // GPTData::Align()

/********************************************************
 *                                                      *
 * Functions that return data about GPT data structures *
 * (most of these are inline in gpt.h)                  *
 *                                                      *
 ********************************************************/

// Find the low and high used partition numbers (numbered from 0).
// Return value is the number of partitions found. Note that the
// *low and *high values are both set to 0 when no partitions
// are found, as well as when a single partition in the first
// position exists. Thus, the return value is the only way to
// tell when no partitions exist.
int GPTData::GetPartRange(uint32_t *low, uint32_t *high) {
   uint32_t i;
   int numFound = 0;

   *low = numParts + 1; // code for "not found"
   *high = 0;
   for (i = 0; i < numParts; i++) {
      if (partitions[i].IsUsed()) { // it exists
         *high = i; // since we're counting up, set the high value
         // Set the low value only if it's not yet found...
         if (*low == (numParts + 1)) *low = i;
            numFound++;
      } // if
   } // for

   // Above will leave *low pointing to its "not found" value if no partitions
   // are defined, so reset to 0 if this is the case....
   if (*low == (numParts + 1))
      *low = 0;
   return numFound;
} // GPTData::GetPartRange()

// Returns the value of the first free partition, or -1 if none is
// unused.
int GPTData::FindFirstFreePart(void) {
   int i = 0;

   if (partitions != NULL) {
      while ((i < (int) numParts) && (partitions[i].IsUsed()))
         i++;
      if (i >= (int) numParts)
         i = -1;
   } else i = -1;
   return i;
} // GPTData::FindFirstFreePart()

// Returns the number of defined partitions.
uint32_t GPTData::CountParts(void) {
   uint32_t i, counted = 0;

   for (i = 0; i < numParts; i++) {
      if (partitions[i].IsUsed())
         counted++;
   } // for
   return counted;
} // GPTData::CountParts()

/****************************************************
 *                                                  *
 * Functions that return data about disk free space *
 *                                                  *
 ****************************************************/

// Find the first available block after the starting point; returns 0 if
// there are no available blocks left
uint64_t GPTData::FindFirstAvailable(uint64_t start) {
   uint64_t first;
   uint32_t i;
   int firstMoved = 0;

   // Begin from the specified starting point or from the first usable
   // LBA, whichever is greater...
   if (start < mainHeader.firstUsableLBA)
      first = mainHeader.firstUsableLBA;
   else
      first = start;

   // ...now search through all partitions; if first is within an
   // existing partition, move it to the next sector after that
   // partition and repeat. If first was moved, set firstMoved
   // flag; repeat until firstMoved is not set, so as to catch
   // cases where partitions are out of sequential order....
   do {
      firstMoved = 0;
      for (i = 0; i < numParts; i++) {
         if ((partitions[i].IsUsed()) && (first >= partitions[i].GetFirstLBA()) &&
             (first <= partitions[i].GetLastLBA())) { // in existing part.
            first = partitions[i].GetLastLBA() + 1;
            firstMoved = 1;
         } // if
      } // for
   } while (firstMoved == 1);
   if (first > mainHeader.lastUsableLBA)
      first = 0;
   return (first);
} // GPTData::FindFirstAvailable()

// Returns the LBA of the start of the first partition on the disk (by
// sector number), or UINT64_MAX if there are no partitions defined.
uint64_t GPTData::FindFirstUsedLBA(void) {
    uint32_t i;
    uint64_t firstFound = UINT64_MAX;

    for (i = 0; i < numParts; i++) {
        if ((partitions[i].IsUsed()) && (partitions[i].GetFirstLBA() < firstFound)) {
            firstFound = partitions[i].GetFirstLBA();
        } // if
    } // for
    return firstFound;
} // GPTData::FindFirstUsedLBA()

// Returns the LBA of the end of the last partition on the disk (by
// sector number), or 0 if there are no partitions defined.
uint64_t GPTData::FindLastUsedLBA(void) {
   uint32_t i;
   uint64_t lastFound = 0;

   for (i = 0; i < numParts; i++) {
      if ((partitions[i].IsUsed()) && (partitions[i].GetFirstLBA() > lastFound)) {
         lastFound = partitions[i].GetLastLBA();
      } // if
   } // for
   return lastFound;
} // GPTData::FindLastUsedLBA()

// Finds the first available sector in the largest block of unallocated
// space on the disk. Returns 0 if there are no available blocks left
uint64_t GPTData::FindFirstInLargest(void) {
   uint64_t start, firstBlock, lastBlock, segmentSize, selectedSize = 0, selectedSegment = 0;

   start = 0;
   do {
      firstBlock = FindFirstAvailable(start);
      if (firstBlock != UINT32_C(0)) { // something's free...
         lastBlock = FindLastInFree(firstBlock);
         segmentSize = lastBlock - firstBlock + UINT32_C(1);
         if (segmentSize > selectedSize) {
            selectedSize = segmentSize;
            selectedSegment = firstBlock;
         } // if
         start = lastBlock + 1;
      } // if
   } while (firstBlock != 0);
   return selectedSegment;
} // GPTData::FindFirstInLargest()

// Find the last available block on the disk.
// Returns 0 if there are no available sectors
uint64_t GPTData::FindLastAvailable(void) {
   uint64_t last;
   uint32_t i;
   int lastMoved = 0;

   // Start by assuming the last usable LBA is available....
   last = mainHeader.lastUsableLBA;

   // ...now, similar to algorithm in FindFirstAvailable(), search
   // through all partitions, moving last when it's in an existing
   // partition. Set the lastMoved flag so we repeat to catch cases
   // where partitions are out of logical order.
   do {
      lastMoved = 0;
      for (i = 0; i < numParts; i++) {
         if ((last >= partitions[i].GetFirstLBA()) &&
             (last <= partitions[i].GetLastLBA())) { // in existing part.
            last = partitions[i].GetFirstLBA() - 1;
            lastMoved = 1;
         } // if
      } // for
   } while (lastMoved == 1);
   if (last < mainHeader.firstUsableLBA)
      last = 0;
   return (last);
} // GPTData::FindLastAvailable()

// Find the last available block in the free space pointed to by start.
// If align == true, returns the last sector that's aligned on the
// system alignment value (unless that's less than the start value);
// if align == false, returns the last available block regardless of
// alignment. (The align variable is set to false by default.)
uint64_t GPTData::FindLastInFree(uint64_t start, bool align) {
   uint64_t nearestEnd, endPlus;
   uint32_t i;

   nearestEnd = mainHeader.lastUsableLBA;
   for (i = 0; i < numParts; i++) {
      if ((nearestEnd > partitions[i].GetFirstLBA()) &&
          (partitions[i].GetFirstLBA() > start)) {
         nearestEnd = partitions[i].GetFirstLBA() - 1;
      } // if
   } // for
   if (align) {
       endPlus = nearestEnd + 1;
       if (Align(&endPlus) && IsFree(endPlus - 1) && (endPlus > start)) {
           nearestEnd = endPlus - 1;
       } // if
   } // if
   return (nearestEnd);
} // GPTData::FindLastInFree()

// Finds the total number of free blocks, the number of segments in which
// they reside, and the size of the largest of those segments
uint64_t GPTData::FindFreeBlocks(uint32_t *numSegments, uint64_t *largestSegment) {
   uint64_t start = UINT64_C(0); // starting point for each search
   uint64_t totalFound = UINT64_C(0); // running total
   uint64_t firstBlock; // first block in a segment
   uint64_t lastBlock; // last block in a segment
   uint64_t segmentSize; // size of segment in blocks
   uint32_t num = 0;

   *largestSegment = UINT64_C(0);
   if (diskSize > 0) {
      do {
         firstBlock = FindFirstAvailable(start);
         if (firstBlock != UINT64_C(0)) { // something's free...
            lastBlock = FindLastInFree(firstBlock);
            segmentSize = lastBlock - firstBlock + UINT64_C(1);
            if (segmentSize > *largestSegment) {
               *largestSegment = segmentSize;
            } // if
            totalFound += segmentSize;
            num++;
            start = lastBlock + 1;
         } // if
      } while (firstBlock != 0);
   } // if
   *numSegments = num;
   return totalFound;
} // GPTData::FindFreeBlocks()

// Returns 1 if sector is unallocated, 0 if it's allocated to a partition.
// If it's allocated, return the partition number to which it's allocated
// in partNum, if that variable is non-NULL. (A value of UINT32_MAX is
// returned in partNum if the sector is in use by basic GPT data structures.)
int GPTData::IsFree(uint64_t sector, uint32_t *partNum) {
   int isFree = 1;
   uint32_t i;

   for (i = 0; i < numParts; i++) {
      if ((sector >= partitions[i].GetFirstLBA()) &&
           (sector <= partitions[i].GetLastLBA())) {
         isFree = 0;
         if (partNum != NULL)
            *partNum = i;
      } // if
   } // for
   if ((sector < mainHeader.firstUsableLBA) ||
        (sector > mainHeader.lastUsableLBA)) {
      isFree = 0;
      if (partNum != NULL)
         *partNum = UINT32_MAX;
   } // if
   return (isFree);
} // GPTData::IsFree()

// Returns 1 if partNum is unused AND if it's a legal value.
int GPTData::IsFreePartNum(uint32_t partNum) {
   return ((partNum < numParts) && (partitions != NULL) &&
           (!partitions[partNum].IsUsed()));
} // GPTData::IsFreePartNum()

// Returns 1 if partNum is in use.
int GPTData::IsUsedPartNum(uint32_t partNum) {
   return ((partNum < numParts) && (partitions != NULL) &&
           (partitions[partNum].IsUsed()));
} // GPTData::IsUsedPartNum()

/***********************************************************
 *                                                         *
 * Change how functions work or return information on them *
 *                                                         *
 ***********************************************************/

// Set partition alignment value; partitions will begin on multiples of
// the specified value, and the default end values will be set so that
// partition sizes are multiples of this value in cgdisk and gdisk, too.
// (In sgdisk, end-alignment is done only if the '-I' command-line option
// is used.)
void GPTData::SetAlignment(uint32_t n) {
   if (n > 0) {
      sectorAlignment = n;
      if ((physBlockSize > 0) && (n % (physBlockSize / blockSize) != 0)) {
         cout << "Warning: Setting alignment to a value that does not match the disk's\n"
              << "physical block size! Performance degradation may result!\n"
              << "Physical block size = " << physBlockSize << "\n"
              << "Logical block size = " << blockSize << "\n"
              << "Optimal alignment = " << physBlockSize / blockSize << " or multiples thereof.\n";
      } // if
   } else {
      cerr << "Attempt to set partition alignment to 0!\n";
   } // if/else
} // GPTData::SetAlignment()

// Compute sector alignment based on the current partitions (if any). Each
// partition's starting LBA is examined, and if it's divisible by a power-of-2
// value less than or equal to the DEFAULT_ALIGNMENT value (adjusted for the
// sector size), but not by the previously-located alignment value, then the
// alignment value is adjusted down. If the computed alignment is less than 8
// and the disk is bigger than SMALLEST_ADVANCED_FORMAT, resets it to 8. This
// is a safety measure for Advanced Format drives. If no partitions are
// defined, the alignment value is set to DEFAULT_ALIGNMENT (2048) (or an
// adjustment of that based on the current sector size). The result is that new
// drives are aligned to 2048-sector multiples but the program won't complain
// about other alignments on existing disks unless a smaller-than-8 alignment
// is used on big disks (as safety for Advanced Format drives).
// Returns the computed alignment value.
uint32_t GPTData::ComputeAlignment(void) {
   uint32_t i = 0, found, exponent;
   uint32_t align = DEFAULT_ALIGNMENT;

   if (blockSize > 0)
      align = DEFAULT_ALIGNMENT * SECTOR_SIZE / blockSize;
   exponent = (uint32_t) log2(align);
   for (i = 0; i < numParts; i++) {
      if (partitions[i].IsUsed()) {
         found = 0;
         while (!found) {
            align = UINT64_C(1) << exponent;
            if ((partitions[i].GetFirstLBA() % align) == 0) {
               found = 1;
            } else {
               exponent--;
            } // if/else
         } // while
      } // if
   } // for
   if ((align < MIN_AF_ALIGNMENT) && (diskSize >= SMALLEST_ADVANCED_FORMAT))
      align = MIN_AF_ALIGNMENT;
   sectorAlignment = align;
   return align;
} // GPTData::ComputeAlignment()

/********************************
 *                              *
 * Endianness support functions *
 *                              *
 ********************************/

void GPTData::ReverseHeaderBytes(struct GPTHeader* header) {
   ReverseBytes(&header->signature, 8);
   ReverseBytes(&header->revision, 4);
   ReverseBytes(&header->headerSize, 4);
   ReverseBytes(&header->headerCRC, 4);
   ReverseBytes(&header->reserved, 4);
   ReverseBytes(&header->currentLBA, 8);
   ReverseBytes(&header->backupLBA, 8);
   ReverseBytes(&header->firstUsableLBA, 8);
   ReverseBytes(&header->lastUsableLBA, 8);
   ReverseBytes(&header->partitionEntriesLBA, 8);
   ReverseBytes(&header->numParts, 4);
   ReverseBytes(&header->sizeOfPartitionEntries, 4);
   ReverseBytes(&header->partitionEntriesCRC, 4);
   ReverseBytes(header->reserved2, GPT_RESERVED);
} // GPTData::ReverseHeaderBytes()

// Reverse byte order for all partitions.
void GPTData::ReversePartitionBytes() {
   uint32_t i;

   for (i = 0; i < numParts; i++) {
      partitions[i].ReversePartBytes();
   } // for
} // GPTData::ReversePartitionBytes()

// Validate partition number
bool GPTData::ValidPartNum (const uint32_t partNum) {
   if (partNum >= numParts) {
      cerr << "Partition number out of range: " << partNum << "\n";
      return false;
   } // if
   return true;
} // GPTData::ValidPartNum

// Return a single partition for inspection (not modification!) by other
// functions.
const GPTPart & GPTData::operator[](uint32_t partNum) const {
   if (partNum >= numParts) {
      cerr << "Partition number out of range (" << partNum << " requested, but only "
           << numParts << " available)\n";
      exit(1);
   } // if
   if (partitions == NULL) {
      cerr << "No partitions defined in GPTData::operator[]; fatal error!\n";
      exit(1);
   } // if
   return partitions[partNum];
} // operator[]

// Return (not for modification!) the disk's GUID value
const GUIDData & GPTData::GetDiskGUID(void) const {
   return mainHeader.diskGUID;
} // GPTData::GetDiskGUID()

// Manage attributes for a partition, based on commands passed to this function.
// (Function is non-interactive.)
// Returns 1 if a modification command succeeded, 0 if the command should not have
// modified data, and -1 if a modification command failed.
int GPTData::ManageAttributes(int partNum, const string & command, const string & bits) {
   int retval = 0;
   Attributes theAttr;

   if (partNum >= (int) numParts) {
      cerr << "Invalid partition number (" << partNum + 1 << ")\n";
      retval = -1;
   } else {
      if (command == "show") {
         ShowAttributes(partNum);
      } else if (command == "get") {
         GetAttribute(partNum, bits);
      } else {
         theAttr = partitions[partNum].GetAttributes();
         if (theAttr.OperateOnAttributes(partNum, command, bits)) {
            partitions[partNum].SetAttributes(theAttr.GetAttributes());
            retval = 1;
         } else {
            retval = -1;
         } // if/else
      } // if/elseif/else
   } // if/else invalid partition #

   return retval;
} // GPTData::ManageAttributes()

// Show all attributes for a specified partition....
void GPTData::ShowAttributes(const uint32_t partNum) {
   if ((partNum < numParts) && partitions[partNum].IsUsed())
      partitions[partNum].ShowAttributes(partNum);
} // GPTData::ShowAttributes

// Show whether a single attribute bit is set (terse output)...
void GPTData::GetAttribute(const uint32_t partNum, const string& attributeBits) {
   if (partNum < numParts)
      partitions[partNum].GetAttributes().OperateOnAttributes(partNum, "get", attributeBits);
} // GPTData::GetAttribute


/******************************************
 *                                        *
 * Additional non-class support functions *
 *                                        *
 ******************************************/

// Check to be sure that data type sizes are correct. The basic types (uint*_t) should
// never fail these tests, but the struct types may fail depending on compile options.
// Specifically, the -fpack-struct option to gcc may be required to ensure proper structure
// sizes.
int SizesOK(void) {
   int allOK = 1;

   if (sizeof(uint8_t) != 1) {
      cerr << "uint8_t is " << sizeof(uint8_t) << " bytes, should be 1 byte; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(uint16_t) != 2) {
      cerr << "uint16_t is " << sizeof(uint16_t) << " bytes, should be 2 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(uint32_t) != 4) {
      cerr << "uint32_t is " << sizeof(uint32_t) << " bytes, should be 4 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(uint64_t) != 8) {
      cerr << "uint64_t is " << sizeof(uint64_t) << " bytes, should be 8 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(struct MBRRecord) != 16) {
      cerr << "MBRRecord is " << sizeof(MBRRecord) << " bytes, should be 16 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(struct TempMBR) != 512) {
      cerr << "TempMBR is " <<  sizeof(TempMBR) << " bytes, should be 512 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(struct GPTHeader) != 512) {
      cerr << "GPTHeader is " << sizeof(GPTHeader) << " bytes, should be 512 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(GPTPart) != 128) {
      cerr << "GPTPart is " << sizeof(GPTPart) << " bytes, should be 128 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(GUIDData) != 16) {
      cerr << "GUIDData is " << sizeof(GUIDData) << " bytes, should be 16 bytes; aborting!\n";
      allOK = 0;
   } // if
   if (sizeof(PartType) != 16) {
      cerr << "PartType is " << sizeof(PartType) << " bytes, should be 16 bytes; aborting!\n";
      allOK = 0;
   } // if
   return (allOK);
} // SizesOK()