xref: /third_party/gptfdisk/gptcl.cc (revision cf200d32)
1/*
2    Implementation of GPTData class derivative with popt-based command
3    line processing
4    Copyright (C) 2010-2024 Roderick W. Smith
5
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 2 of the License, or
9    (at your option) any later version.
10
11    This program is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15
16    You should have received a copy of the GNU General Public License along
17    with this program; if not, write to the Free Software Foundation, Inc.,
18    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19*/
20
21#include <string.h>
22#include <string>
23#include <iostream>
24#include <sstream>
25#include <errno.h>
26#include <popt.h>
27#include "gptcl.h"
28
29using namespace std;
30
31GPTDataCL::GPTDataCL(void) {
32   attributeOperation = backupFile = partName = hybrids = newPartInfo = NULL;
33   mbrParts = twoParts = outDevice = typeCode = partGUID = diskGUID = NULL;
34   alignment = DEFAULT_ALIGNMENT;
35   alignEnd = false;
36   deletePartNum = infoPartNum = largestPartNum = bsdPartNum = 0;
37   tableSize = GPT_SIZE;
38} // GPTDataCL constructor
39
40GPTDataCL::GPTDataCL(string filename) {
41} // GPTDataCL constructor with filename
42
43GPTDataCL::~GPTDataCL(void) {
44} // GPTDataCL destructor
45
46void GPTDataCL::LoadBackupFile(string backupFile, int &saveData, int &neverSaveData) {
47   if (LoadGPTBackup(backupFile) == 1) {
48      JustLooking(0);
49      saveData = 1;
50   } else {
51      saveData = 0;
52      neverSaveData = 1;
53      cerr << "Error loading backup file!\n";
54   } // else
55} // GPTDataCL::LoadBackupFile()
56
57// Perform the actions specified on the command line. This is necessarily one
58// monster of a function!
59// Returns values:
60// 0 = success
61// 1 = too few arguments
62// 2 = error when reading partition table
63// 3 = non-GPT disk and no -g option
64// 4 = unable to save changes
65// 8 = disk replication operation (-R) failed
66int GPTDataCL::DoOptions(int argc, char* argv[]) {
67   GPTData secondDevice;
68   int opt, numOptions = 0, saveData = 0, neverSaveData = 0;
69   int partNum = 0, newPartNum = -1, saveNonGPT = 1, retval = 0, pretend = 0;
70   int byteSwapPartNum = 0;
71   uint64_t low, high, startSector, endSector, sSize, mainTableLBA, secondTableLBA;
72   uint64_t temp; // temporary variable; free to use in any case
73   char *device;
74   string cmd, typeGUID, name;
75   PartType typeHelper;
76
77   struct poptOption theOptions[] =
78   {
79      {"attributes", 'A', POPT_ARG_STRING, &attributeOperation, 'A', "operate on partition attributes",
80          "list|[partnum:show|or|nand|xor|=|set|clear|toggle|get[:bitnum|hexbitmask]]"},
81      {"set-alignment", 'a', POPT_ARG_INT, &alignment, 'a', "set sector alignment", "value"},
82      {"backup", 'b', POPT_ARG_STRING, &backupFile, 'b', "backup GPT to file", "file"},
83      {"byte-swap-name", 'B',  POPT_ARG_INT, &byteSwapPartNum, 'B', "byte-swap partition's name", "partnum"},
84      {"change-name", 'c', POPT_ARG_STRING, &partName, 'c', "change partition's name", "partnum:name"},
85      {"recompute-chs", 'C', POPT_ARG_NONE, NULL, 'C', "recompute CHS values in protective/hybrid MBR", ""},
86      {"delete", 'd', POPT_ARG_INT, &deletePartNum, 'd', "delete a partition", "partnum"},
87      {"display-alignment", 'D', POPT_ARG_NONE, NULL, 'D', "show number of sectors per allocation block", ""},
88      {"move-second-header", 'e', POPT_ARG_NONE, NULL, 'e', "move second/backup header to end of disk", ""},
89      {"end-of-largest", 'E', POPT_ARG_NONE, NULL, 'E', "show end of largest free block", ""},
90      {"first-in-largest", 'f', POPT_ARG_NONE, NULL, 'f', "show start of the largest free block", ""},
91      {"first-aligned-in-largest", 'F', POPT_ARG_NONE, NULL, 'F', "show start of the largest free block, aligned", ""},
92      {"mbrtogpt", 'g', POPT_ARG_NONE, NULL, 'g', "convert MBR to GPT", ""},
93      {"randomize-guids", 'G', POPT_ARG_NONE, NULL, 'G', "randomize disk and partition GUIDs", ""},
94      {"hybrid", 'h', POPT_ARG_STRING, &hybrids, 'h', "create hybrid MBR", "partnum[:partnum...][:EE]"},
95      {"info", 'i', POPT_ARG_INT, &infoPartNum, 'i', "show detailed information on partition", "partnum"},
96      {"align-end", 'I', POPT_ARG_NONE, NULL, 'I', "align partition end points", ""},
97      {"move-main-table", 'j', POPT_ARG_INT, &mainTableLBA, 'j', "change the start sector of the main partition table", "sector"},
98      {"move-backup-table", 'k', POPT_ARG_INT, &secondTableLBA, 'k', "change the start sector of the second/backup partition table", "sector"},
99      {"load-backup", 'l', POPT_ARG_STRING, &backupFile, 'l', "load GPT backup from file", "file"},
100      {"list-types", 'L', POPT_ARG_NONE, NULL, 'L', "list known partition types", ""},
101      {"gpttombr", 'm', POPT_ARG_STRING, &mbrParts, 'm', "convert GPT to MBR", "partnum[:partnum...]"},
102      {"new", 'n', POPT_ARG_STRING, &newPartInfo, 'n', "create new partition", "partnum:start:end"},
103      {"largest-new", 'N', POPT_ARG_INT, &largestPartNum, 'N', "create largest possible new partition", "partnum"},
104      {"clear", 'o', POPT_ARG_NONE, NULL, 'o', "clear partition table", ""},
105      {"print-mbr", 'O', POPT_ARG_NONE, NULL, 'O', "print MBR partition table", ""},
106      {"print", 'p', POPT_ARG_NONE, NULL, 'p', "print partition table", ""},
107      {"pretend", 'P', POPT_ARG_NONE, NULL, 'P', "make changes in memory, but don't write them", ""},
108      {"transpose", 'r', POPT_ARG_STRING, &twoParts, 'r', "transpose two partitions", "partnum:partnum"},
109      {"replicate", 'R', POPT_ARG_STRING, &outDevice, 'R', "replicate partition table", "device_filename"},
110      {"sort", 's', POPT_ARG_NONE, NULL, 's', "sort partition table entries", ""},
111      {"resize-table", 'S', POPT_ARG_INT, &tableSize, 'S', "resize partition table", "numparts"},
112      {"typecode", 't', POPT_ARG_STRING, &typeCode, 't', "change partition type code", "partnum:{hexcode|GUID}"},
113      {"transform-bsd", 'T', POPT_ARG_INT, &bsdPartNum, 'T', "transform BSD disklabel partition to GPT", "partnum"},
114      {"partition-guid", 'u', POPT_ARG_STRING, &partGUID, 'u', "set partition GUID", "partnum:guid"},
115      {"disk-guid", 'U', POPT_ARG_STRING, &diskGUID, 'U', "set disk GUID", "guid"},
116      {"verify", 'v', POPT_ARG_NONE, NULL, 'v', "check partition table integrity", ""},
117      {"version", 'V', POPT_ARG_NONE, NULL, 'V', "display version information", ""},
118      {"zap", 'z', POPT_ARG_NONE, NULL, 'z', "zap (destroy) GPT (but not MBR) data structures", ""},
119      {"zap-all", 'Z', POPT_ARG_NONE, NULL, 'Z', "zap (destroy) GPT and MBR data structures", ""},
120      POPT_AUTOHELP { NULL, 0, 0, NULL, 0 }
121   };
122
123   // Create popt context...
124   poptCon = poptGetContext(NULL, argc, (const char**) argv, theOptions, 0);
125
126   poptSetOtherOptionHelp(poptCon, " [OPTION...] <device>");
127
128   if (argc < 2) {
129      poptPrintUsage(poptCon, stderr, 0);
130      return 1;
131   }
132
133   // Do one loop through the options to find the device filename and deal
134   // with options that don't require a device filename, to flag destructive
135   // (o, z, or Z) options, and to flag presence of a --pretend/-P option
136   while ((opt = poptGetNextOpt(poptCon)) > 0) {
137      switch (opt) {
138         case 'A':
139            cmd = GetString(attributeOperation, 1);
140            if (cmd == "list")
141               Attributes::ListAttributes();
142            break;
143         case 'L':
144            typeHelper.ShowAllTypes(0);
145            break;
146         case 'P':
147            pretend = 1;
148            break;
149         case 'V':
150            cout << "GPT fdisk (sgdisk) version " << GPTFDISK_VERSION << "\n\n";
151            break;
152         default:
153            break;
154      } // switch
155      numOptions++;
156   } // while
157
158   // Assume first non-option argument is the device filename....
159   device = (char*) poptGetArg(poptCon);
160
161   if (device != NULL) {
162      device = strdup(device);
163      poptResetContext(poptCon);
164      JustLooking(); // reset as necessary
165      BeQuiet(); // Tell called functions to be less verbose & interactive
166      if (LoadPartitions((string) device)) {
167         if ((WhichWasUsed() == use_mbr) || (WhichWasUsed() == use_bsd))
168            saveNonGPT = 0; // flag so we don't overwrite unless directed to do so
169         sSize = GetBlockSize();
170         while ((opt = poptGetNextOpt(poptCon)) > 0) {
171            switch (opt) {
172               case 'A': {
173                  if (cmd != "list") {
174                     partNum = (int) GetInt(attributeOperation, 1) - 1;
175                     if (partNum < 0)
176                        partNum = newPartNum;
177                     if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
178                        switch (ManageAttributes(partNum, GetString(attributeOperation, 2),
179                           GetString(attributeOperation, 3))) {
180                           case -1:
181                              saveData = 0;
182                              neverSaveData = 1;
183                              break;
184                           case 1:
185                              JustLooking(0);
186                              saveData = 1;
187                              break;
188                           default:
189                              break;
190                        } // switch
191                     } else {
192                        cerr << "Error: Invalid partition number " << partNum + 1 << "\n";
193                        saveData = 0;
194                        neverSaveData = 1;
195                     } // if/else reasonable partition #
196                  } // if (cmd != "list")
197                  break;
198               } // case 'A':
199               case 'a':
200                  SetAlignment(alignment);
201                  break;
202               case 'B':
203                  if (IsUsedPartNum(byteSwapPartNum - 1)) {
204                     partitions[byteSwapPartNum - 1].ReverseNameBytes();
205                     cout << "Changed partition " << byteSwapPartNum << "'s name to "
206                          << partitions[byteSwapPartNum - 1].GetDescription() << "\n";
207                     JustLooking(0);
208                     saveData = 1;
209                  }
210                  break;
211               case 'b':
212                  SaveGPTBackup(backupFile);
213                  free(backupFile);
214                  break;
215               case 'c':
216                  JustLooking(0);
217                  partNum = (int) GetInt(partName, 1) - 1;
218                  if (partNum < 0)
219                     partNum = newPartNum;
220                  if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
221                     name = GetString(partName, 2);
222                     if (SetName(partNum, (UnicodeString) name.c_str())) {
223                        saveData = 1;
224                     } else {
225                        cerr << "Unable to set partition " << partNum + 1
226                             << "'s name to '" << GetString(partName, 2) << "'!\n";
227                        neverSaveData = 1;
228                     } // if/else
229                     free(partName);
230                  }
231                  break;
232               case 'C':
233                  JustLooking(0);
234                  RecomputeCHS();
235                  saveData = 1;
236                  break;
237               case 'd':
238                  JustLooking(0);
239                  if (DeletePartition(deletePartNum - 1) == 0) {
240                     cerr << "Error " << errno << " deleting partition!\n";
241                     neverSaveData = 1;
242                  } else saveData = 1;
243                                                      break;
244               case 'D':
245                  cout << GetAlignment() << "\n";
246                  break;
247               case 'e':
248                  JustLooking(0);
249                  MoveSecondHeaderToEnd();
250                  saveData = 1;
251                  break;
252               case 'E':
253                  cout << FindLastInFree(FindFirstInLargest()) << "\n";
254                  break;
255               case 'f':
256                  cout << FindFirstInLargest() << "\n";
257                  break;
258               case 'F':
259                  temp = FindFirstInLargest();
260                  Align(&temp);
261                  cout << temp << "\n";
262                  break;
263               case 'g':
264                  JustLooking(0);
265                  saveData = 1;
266                  saveNonGPT = 1;
267                  break;
268               case 'G':
269                  JustLooking(0);
270                  saveData = 1;
271                  RandomizeGUIDs();
272                  break;
273               case 'h':
274                  JustLooking(0);
275                  if (BuildMBR(hybrids, 1) == 1)
276                     saveData = 1;
277                  break;
278               case 'i':
279                  ShowPartDetails(infoPartNum - 1);
280                  break;
281               case 'I':
282                  alignEnd = true;
283                  break;
284               case 'j':
285                   if (MoveMainTable(mainTableLBA)) {
286                       JustLooking(0);
287                       saveData = 1;
288                   } else {
289                       neverSaveData = 1;
290                   } // if/else
291                   break;
292               case 'k':
293                   if (MoveSecondTable(secondTableLBA)) {
294                       JustLooking(0);
295                       saveData = 1;
296                   } else {
297                       neverSaveData = 1;
298                   } // if/else
299                    break;
300               case 'l':
301                  LoadBackupFile(backupFile, saveData, neverSaveData);
302                  free(backupFile);
303                  break;
304               case 'L':
305                  break;
306               case 'm':
307                  JustLooking(0);
308                  if (BuildMBR(mbrParts, 0) == 1) {
309                     if (!pretend) {
310                        if (SaveMBR()) {
311                           DestroyGPT();
312                        } else
313                           cerr << "Problem saving MBR!\n";
314                     } // if
315                     saveNonGPT = 0;
316                     pretend = 1; // Not really, but works around problem if -g is used with this...
317                     saveData = 0;
318                  } // if
319                  break;
320               case 'n':
321                  JustLooking(0);
322                  newPartNum = (int) GetInt(newPartInfo, 1) - 1;
323                  if (newPartNum < 0)
324                     newPartNum = FindFirstFreePart();
325                  low = FindFirstInLargest();
326                  Align(&low);
327                  high = FindLastInFree(low, alignEnd);
328                  startSector = IeeeToInt(GetString(newPartInfo, 2), sSize, low, high, sectorAlignment, low);
329                  endSector = IeeeToInt(GetString(newPartInfo, 3), sSize, startSector, high, sectorAlignment, high);
330                  if (CreatePartition(newPartNum, startSector, endSector)) {
331                     saveData = 1;
332                  } else {
333                     cerr << "Could not create partition " << newPartNum + 1 << " from "
334                          << startSector << " to " << endSector << "\n";
335                     neverSaveData = 1;
336                  } // if/else
337                  free(newPartInfo);
338                  break;
339               case 'N':
340                  JustLooking(0);
341                  startSector = FindFirstInLargest();
342                  Align(&startSector);
343                  endSector = FindLastInFree(startSector, alignEnd);
344                  if (largestPartNum <= 0) {
345                     largestPartNum = FindFirstFreePart() + 1;
346                     newPartNum = largestPartNum - 1;
347                  }
348                  if (CreatePartition(largestPartNum - 1, startSector, endSector)) {
349                     saveData = 1;
350                  } else {
351                     cerr << "Could not create partition " << largestPartNum << " from "
352                     << startSector << " to " << endSector << "\n";
353                     neverSaveData = 1;
354                  } // if/else
355                  break;
356               case 'o':
357                  JustLooking(0);
358                  ClearGPTData();
359                  saveData = 1;
360                  break;
361               case 'O':
362                   DisplayMBRData();
363                   break;
364               case 'p':
365                  DisplayGPTData();
366                  break;
367               case 'P':
368                  pretend = 1;
369                  break;
370               case 'r':
371                  JustLooking(0);
372                  uint64_t p1, p2;
373                  p1 = GetInt(twoParts, 1) - 1;
374                  p2 = GetInt(twoParts, 2) - 1;
375                  if (SwapPartitions((uint32_t) p1, (uint32_t) p2) == 0) {
376                     neverSaveData = 1;
377                     cerr << "Cannot swap partitions " << p1 + 1 << " and " << p2 + 1 << "\n";
378                  } else saveData = 1;
379                                                      break;
380               case 'R':
381                  secondDevice = *this;
382                  secondDevice.SetDisk(outDevice);
383                  secondDevice.JustLooking(0);
384                  if (!secondDevice.SaveGPTData(1))
385                     retval = 8;
386                  break;
387               case 's':
388                  JustLooking(0);
389                  SortGPT();
390                  saveData = 1;
391                  break;
392               case 'S':
393                  JustLooking(0);
394                  if (SetGPTSize(tableSize) == 0)
395                     neverSaveData = 1;
396                  else
397                     saveData = 1;
398                  break;
399               case 't':
400                  JustLooking(0);
401                  partNum = (int) GetInt(typeCode, 1) - 1;
402                  if (partNum < 0)
403                     partNum = newPartNum;
404                  if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
405                     typeHelper = GetString(typeCode, 2);
406                     if ((typeHelper != PartType::unusedPartType) &&
407                         (ChangePartType(partNum, typeHelper))) {
408                        saveData = 1;
409                        } else {
410                           cerr << "Could not change partition " << partNum + 1
411                           << "'s type code to " << GetString(typeCode, 2) << "!\n";
412                           neverSaveData = 1;
413                        } // if/else
414                     free(typeCode);
415                  }
416                  break;
417               case 'T':
418                  JustLooking(0);
419                  XFormDisklabel(bsdPartNum - 1);
420                  saveData = 1;
421                  break;
422               case 'u':
423                  JustLooking(0);
424                  saveData = 1;
425                  partNum = (int) GetInt(partGUID, 1) - 1;
426                  if (partNum < 0)
427                     partNum = newPartNum;
428                  if ((partNum >= 0) && (partNum < (int) GetNumParts())) {
429                     SetPartitionGUID(partNum, GetString(partGUID, 2).c_str());
430                  }
431                  break;
432               case 'U':
433                  JustLooking(0);
434                  saveData = 1;
435                  SetDiskGUID(diskGUID);
436                  break;
437               case 'v':
438                  Verify();
439                  break;
440               case 'z':
441                  if (!pretend) {
442                     DestroyGPT();
443                  } // if
444                  saveNonGPT = 1;
445                  saveData = 0;
446                  break;
447               case 'Z':
448                  if (!pretend) {
449                     DestroyGPT();
450                     DestroyMBR();
451                  } // if
452                  saveNonGPT = 1;
453                  saveData = 0;
454                  break;
455               default:
456                  cerr << "Unknown option (-" << opt << ")!\n";
457                  break;
458               } // switch
459         } // while
460      } else { // if loaded OK
461         poptResetContext(poptCon);
462         // Do a few types of operations even if there are problems....
463         while ((opt = poptGetNextOpt(poptCon)) > 0) {
464            switch (opt) {
465               case 'l':
466                  LoadBackupFile(backupFile, saveData, neverSaveData);
467                  cout << "Information: Loading backup partition table; will override earlier problems!\n";
468                  free(backupFile);
469                  retval = 0;
470                  break;
471               case 'o':
472                  JustLooking(0);
473                  ClearGPTData();
474                  saveData = 1;
475                  cout << "Information: Creating fresh partition table; will override earlier problems!\n";
476                  retval = 0;
477                  break;
478               case 'v':
479                  cout << "Verification may miss some problems or report too many!\n";
480                  Verify();
481                  break;
482               case 'z':
483                  if (!pretend) {
484                     DestroyGPT();
485                  } // if
486                  saveNonGPT = 1;
487                  saveData = 0;
488                  break;
489               case 'Z':
490                  if (!pretend) {
491                     DestroyGPT();
492                     DestroyMBR();
493                  } // if
494                  saveNonGPT = 1;
495                  saveData = 0;
496                  break;
497            } // switch
498         } // while
499         retval = 2;
500      } // if/else loaded OK
501      if ((saveData) && (!neverSaveData) && (saveNonGPT) && (!pretend)) {
502         if (!SaveGPTData(1))
503            retval = 4;
504      }
505      if (saveData && (!saveNonGPT)) {
506         cout << "Non-GPT disk; not saving changes. Use -g to override.\n";
507         retval = 3;
508      } // if
509      if (neverSaveData) {
510         cerr << "Error encountered; not saving changes.\n";
511         retval = 4;
512      } // if
513      free(device);
514   } // if (device != NULL)
515   poptFreeContext(poptCon);
516   return retval;
517} // GPTDataCL::DoOptions()
518
519// Create a hybrid or regular MBR from GPT data structures
520int GPTDataCL::BuildMBR(char* argument, int isHybrid) {
521   int numParts, allOK = 1, i, origPartNum;
522   int eeLast = 0, mbrNum = 0;
523   MBRPart newPart;
524   BasicMBRData newMBR;
525
526   if (argument != NULL) {
527      numParts = CountColons(argument) + 1;
528      if (isHybrid) {
529         eeLast = GetString(argument, numParts) == "EE";
530         if (eeLast) {
531            numParts--;
532         }
533      }
534
535      if (numParts <= (4 - isHybrid)) {
536         newMBR.SetDisk(GetDisk());
537         for (i = 0; i < numParts; i++) {
538            origPartNum = GetInt(argument, i + 1) - 1;
539            if (IsUsedPartNum(origPartNum) && (partitions[origPartNum].IsSizedForMBR() == MBR_SIZED_GOOD)) {
540               mbrNum = i + (isHybrid && ! eeLast);
541               newPart.SetInclusion(PRIMARY);
542               newPart.SetLocation(operator[](origPartNum).GetFirstLBA(),
543                                   operator[](origPartNum).GetLengthLBA());
544               newPart.SetStatus(0);
545               newPart.SetType((uint8_t)(operator[](origPartNum).GetHexType() / 0x0100));
546               newMBR.AddPart(mbrNum, newPart);
547            } else {
548               cerr << "Original partition " << origPartNum + 1 << " does not exist or is too big! Aborting operation!\n";
549               allOK = 0;
550            } // if/else
551         } // for
552         if (isHybrid) {
553            if (eeLast) {
554               mbrNum = i;
555            } else {
556               mbrNum = 0;
557            }
558            newPart.SetInclusion(PRIMARY);
559            newPart.SetLocation(1, newMBR.FindLastInFree(1));
560            newPart.SetStatus(0);
561            newPart.SetType(0xEE);
562            newMBR.AddPart(mbrNum, newPart);
563         } // if
564         if (allOK)
565            SetProtectiveMBR(newMBR);
566      } else allOK = 0;
567   } else allOK = 0;
568   if (!allOK)
569      cerr << "Problem creating MBR!\n";
570   return allOK;
571} // GPTDataCL::BuildMBR()
572
573// Returns the number of colons in argument string, ignoring the
574// first character (thus, a leading colon is ignored, as GetString()
575// does).
576int CountColons(char* argument) {
577   int num = 0;
578
579   while ((argument[0] != '\0') && (argument = strchr(&argument[1], ':')))
580      num++;
581
582   return num;
583} // GPTDataCL::CountColons()
584
585// Extract integer data from argument string, which should be colon-delimited
586uint64_t GetInt(const string & argument, int itemNum) {
587   uint64_t retval;
588
589   istringstream inString(GetString(argument, itemNum));
590   inString >> retval;
591   return retval;
592} // GPTDataCL::GetInt()
593
594// Extract string data from argument string, which should be colon-delimited
595// If string begins with a colon, that colon is skipped in the counting. If an
596// invalid itemNum is specified, returns an empty string.
597string GetString(string argument, int itemNum) {
598   size_t startPos = 0, endPos = 0;
599   string retVal = "";
600   int foundLast = 0;
601   int numFound = 0;
602
603   if (argument[0] == ':')
604      argument.erase(0, 1);
605   while ((numFound < itemNum) && (!foundLast)) {
606      endPos = argument.find(':', startPos);
607      numFound++;
608      if (endPos == string::npos) {
609         foundLast = 1;
610         endPos = argument.length();
611      } else if (numFound < itemNum) {
612         startPos = endPos + 1;
613      } // if/elseif
614   } // while
615   if ((numFound == itemNum) && (numFound > 0))
616      retVal = argument.substr(startPos, endPos - startPos);
617
618   return retVal;
619} // GetString()
620