Tech Arsenal 1/Tech Arsenal (Arsenal Computer).ISO/tek-02/btv115.zip/BTV.PAS

Pascal/Delphi Source File | 1992-06-02 | 114KB | 2,777 lines

{*
* ┌───────────────────────────────────────────────────────────────┐
* │ BTV.PAS  Version 1.15                                         │
* │                                                               │
* │ BTRIEVE object oriented interface for Turbo Pascal 6.0.       │
* │                                                               │
* │ Copyright (c) 1992 by Richard W. Hansen, all rights reserved. │
* └───────────────────────────────────────────────────────────────┘
*
*
*  Requires Turbo Pascal version 6.0
*
*
*  Registration and payment of a license fee is required for any use, whether
*  in whole or part, of this source code.
*
*}

{****************************************************************************}
{*   REVISION HISTORY                                                       *}
{*                                                                          *}
{*  Date     Who  What                                                      *}
{* ======================================================================== *}
{* 02/01/92  RWH  Changed DataSize, BytesRead, BytesToWrite from Integer to *}
{*                Word so variable length records can be up to 64K.         *}
{* 02/04/92  RWH  Check that memory allocation size > 0 before issuing an   *}
{*                out of memory error.                                      *}
{*                Added ErrorHandler calls for out of memory errors.        *}
{* 02/08/92  RWH  Added error setting routines to the file object, so calls *}
{*                through the error handler object pointer are not needed.  *}
{* 02/20/92  RWH  Fixed bug in Clone. Wrong file name being used caused     *}
{*                lockup.                                                   *}
{* 02/28/92  RWH  Added Recover, Save and Load methods.                     *}
{* 03/14/92  RWH  Open was not calculating the largest key correctly.       *}
{* 04/25/92  RWH  Added the FillKeyBuffer method.                           *}
{* 05/13/92  RWH  Fixed problem with KeyStart buffer not being setup when   *}
{*                key segments not defined before opening a file.           *}
{*                Changed Error Handler and Error Display in fields in all  *}
{*                objects, and the corresponding parameters in methods, to  *}
{*                pointers. This allows nil objects.                        *}
{****************************************************************************}

Unit Btv;
{$F-}
{$V-}
{$X+}
{$A-}


{$DEFINE BCHECK}    { Define this to check for Btrieve during initialization }
{$DEFINE BTRIEVE50} { Define this to make all opcodes new in V 5.0 available }


INTERFACE


USES
  Dos,    { Turbo DOS interface         }
  Btrv6,  { Btrieve Interrupt Interface }
  Tone;   { This unit has substitute Delay and Sound routines for }
          { use with Turbo Vision and is used here instead of the }
          { Turbo CRT unit. The only routine needed is Delay. You }
          { may substitute CRT if desired.                        }


CONST
  {----- Btrieve operation codes -----}
  bOpen               = 0;
  bClose              = 1;
  bInsert             = 2;
  bUpdate             = 3;
  bDelete             = 4;
  bGetEqual           = 5;
  bGetNext            = 6;
  bGetPrev            = 7;
  bGetGreat           = 8;
  bGetGreatEqual      = 9;
  bGetLess            = 10;
  bGetLessEqual       = 11;
  bGetFirst           = 12;
  bGetLast            = 13;
  bCreate             = 14;
  bStat               = 15;
  bBeginTransaction   = 19;
  bEndTransaction     = 20;
  bAbortTransaction   = 21;
  bGetPosition        = 22;
  bGetDirect          = 23;
  bStepNext           = 24;
  bStop               = 25;
  bVersion            = 26;
  bUnlock             = 27;
  bReset              = 28;
  bSetOwner           = 29;
  bClearOwner         = 30;
  bCreateIndex        = 31;
  bDropIndex          = 32;
  bStepFirst          = 33;
  bStepLast           = 34;
  bStepPrev           = 35;
  bGetNextExt         = 36;
  bGetPrevExt         = 37;
  bStepNextExt        = 38;
  bStepPrevExt        = 39;
  bInsertExt          = 40;

  bGetKey             = 50;

  {----- Btrieve Status Codes -----}
  bOkay               = 0;
  bInvalidOp          = 1;
  bIOerror            = 2;
  bFileNotOpen        = 3;
  bKeyNotFound        = 4;
  bDuplicateKey       = 5;
  bInvalidKey         = 6;
  bDifferentKey       = 7;
  bInvalidPos         = 8;
  bEOF                = 9;
  bKeyModifyErr       = 10;
  bInvalidName        = 11;
  bFileNotFound       = 12;
  bExtendedFileErr    = 13;
  bPreImageOpenErr    = 14;
  bPreImageIOErr      = 15;
  bExpansionErr       = 16;
  bCloseErr           = 17;
  bDiskFull           = 18;
  bUnRecoverableErr   = 19;
  bNotLoaded          = 20;
  bKeyBufferShort     = 21;
  bDataBufferShort    = 22;
  bPosBlockShort      = 23;
  bPageSizeErr        = 24;
  bCreateIOErr        = 25;
  bNumberKeys         = 26;
  bInvalidKeyPos      = 27;
  bRecordLenErr       = 28;
  bKeyLenErr          = 29;
  bNotBtrieveFile     = 30;
  bFileExtended       = 31;
  bExtendIOErr        = 32;
  bExtendNameErr      = 34;
  bDirectoryErr       = 35;
  bTransactionErr     = 36;
  bTransactionActive  = 37;
  bTransactionFileErr = 38;
  bTransactionEndErr  = 39;
  bTransactionMaxFiles= 40;
  bOpNotAllowed       = 41;
  bAcceleratedErr     = 42;
  bInvalidAddress     = 43;
  bNullKeypath        = 44;
  bBadKeyFlags        = 45;
  bFileAccessDenied   = 46;
  bMaxOpenFiles       = 47;
  bInvalidAltSequence = 48;
  bKeyTypeErr         = 49;
  bOwnerIsSet         = 50;
  bInvalidOwner       = 51;
  bCacheWriteErr      = 52;
  bInvalidVersion     = 53;
  bVariablePageErr    = 54;
  bAutoIncrementErr   = 55;
  bBadIndex           = 56;
  bExpandedMemoryErr  = 57;
  bCompressBuffShort  = 58;
  bFileExists         = 59;
  bRejectMax          = 60;
  bWorkSpaceShort     = 61;
  bDescriptorErr      = 62;
  bExtInsertBuffErr   = 63;
  bFilterLimit        = 64;
  bFieldOffsetErr     = 65;
  bTTSabort           = 74;
  bDeadlock           = 78;
  bConflict           = 80;
  bLockErr            = 81;
  bLostPosition       = 82;
  bOutOfTransaction   = 83;
  bRecordInUse        = 84;
  bFileInUse          = 85;
  bFileTblFull        = 86;
  bHandleTblFull      = 87;
  bBadModeErr         = 88;
  bDeviceTableFull    = 90;
  bServerErr          = 91;
  bTranTableFull      = 92;
  bBadLockType        = 93;
  bPermissionErr      = 94;
  bSessionInvalid     = 95;
  bCommunicationErr   = 96;
  bDataMessageShort   = 97;
  bInternalTTSerr     = 98;
  bOutOfMemory        = 120;
  bDuplicateFilename  = bOutOfMemory + 1;
  bLoadInputErr       = bDuplicateFilename + 1;
  bLastError          = bLoadInputErr;

  {----- Btrieve constants -----}
  bNormal             = 0;

  bRJustify           = 1;        { String justification types }
  bLJustify           = 2;

  bNoOverWrite        = -1;       { File create mode }

  bReadAccess         = 1;        { File owner access modes }
  bWriteAccessEncrypt = 2;
  bReadAccessEncrypt  = 3;

  bVariableLen        = 1;        { File flags }
  bBlankTruncate      = 2;
  bPreallocate        = 4;
  bDataCompress       = 8;
  bKeyOnly            = 16;
  b10Free             = 64;
  b20Free             = 128;
  b30Free             = 192;

  bAccelerated        = -1;       { File open modes }
  bReadOnly           = -2;
  bVerify             = -3;
  bExclusive          = -4;

  bDuplicates         = 1;        { Key flags }
  bModifiable         = 2;
  bBinary             = 4;
  bNull               = 8;
  bSegmented          = 16;
  bAltSequence        = 32;
  bDescending         = 64;
  bSupplemental       = 128;
  bExtended           = 256;
  bManual             = 512;

  bString             = 0;        { Key types }
  bInteger            = 1;
  bFloat              = 2;
  bDate               = 3;
  bTime               = 4;
  bDecimal            = 5;
  bMoney              = 6;
  bLogical            = 7;
  bNumeric            = 8;
  bBfloat             = 9;
  bLstring            = 10;
  bZstring            = 11;
  bUnsigned           = 14;
  bAutoIncrement      = 15;

  bNoLock             = 0;        { Lock types }
  bSingleWait         = 100;
  bSingleNoWait       = 200;
  bMultipleWait       = 300;
  bMultipleNoWait     = 400;


  PosBlockSize        = 128;

  MaxSegments         = 24;       { maximum number of segments in a key   }
  MaxBuffSize         : Word = 16 * 1024; { 16k max buffer size in bytes  }



TYPE
  AllErrors     = bInvalidOp..bLastError;
    {- a superset of all Btrieve errors allowing for customization }

  ErrorSet      = Set of AllErrors;
    {- will hold Btrieve errors and possibly some custom error codes }

  ErrorAction = (erAbort, erDone, erRetry);
    {- the possible return states from an error              }
    {- these codes are returned by the error display routine }


  PBytes        = ^Bytes;
  Bytes         = Array[1..65534] of Byte;
    {- define a byte array and pointer to make access easier }


  PProgress = ^TProgress;
  TProgress = Object
    Constructor Init;
    Procedure   Display(Count : LongInt);         Virtual;
  end;
    {- object to display progress for recover, save and load }


  { Btrieve key specs record }
  KeySpec       = record
    KeyPos    : Word;           { position of key or segment in data      }
    KeyLen    : Word;           { length of the key or segment            }
    KeyFlags  : Word;           { key flags as defined by Btrieve         }
    KeyCount  : LongInt;        { not used except for STAT                }
    KeyType   : Byte;           { extended key type                       }
    NullValue : Byte;           { null character if defined               }
    Reserved  : Array[1..4] of Byte;
  end;

  KeySpecArray   = Array[1..MaxSegments] of KeySpec;


  { Our own key definition record }
  KeyDef        = record
    KeyPos    : Word;         { position of key or segment in data      }
    KeyLen    : Word;         { length of the key or segment            }
    KeyFlags  : Word;         { key flags as defined by Btrieve         }
    KeyType   : Byte;         { extended key type                       }
    NullValue : Byte;         { null character if defined               }
    Justify   : Byte;         { lString justification type              }
  end;

  KeyDefArray     = Array[1..MaxSegments] of KeyDef;


  { Btrieve file specs record }
  FileSpec      = record
    RecordLen : Word;           { length of a record in the file          }
    PageSize  : Word;           { physical page size for file             }
    Indexes   : Word;           { number of keys                          }
    Records   : LongInt;        { not used except for STAT                }
    FileFlags : Word;           { file flags as defined by Btrieve        }
    Reserved  : Array[1..2] of Byte;
    FreePages : Word;           { pages to pre allocate                   }
    KeyBuff   : KeySpecArray;   { array of key info (one for each segment)}
    Extra     : Array[1..265] of Byte; { might be needed for alt. sequence}
  end;



  { This is the object that will display errors to the user.              }
  { This is an ABSTRACT object and should never be instantiated, you must }
  { define a descendant object that does what you want in each program.   }
  PErrorDisplay  = ^ErrorDisplay;
  ErrorDisplay   = Object
    Constructor Init;
      {- init the error display }

    Function    Display(Error     : Integer;
                        ErrorMsg  : String;
                        OpCode    : Byte;
                        OpCodeMsg : String;
                        FileName  : PathStr
                        ): ErrorAction;             Virtual;
      {- display the error, returns True if program should abort }

    Destructor  Done;                               Virtual;
      {- destroy the object }
  end;



  { This is the error object used by the file to trap IO errors.  }
  PErrorHandler   = ^ErrorHandler;
  ErrorHandler    = Object
    RetryCount    : Word;         { current number of retries on an error   }
    MaxRetry      : Word;         { maximum number of retries on an error   }
    RetryDelay    : Word;         { milliseconds between retries            }
    TrappedErrors : ErrorSet;     { errors this object will handle          }
    ErrDisplay    : PErrorDisplay;{ pointer to an error display object      }

    Constructor Init(DisplayObject : PErrorDisplay);
      {- initialize the error object }

    Function    ErrorDispacther(ErrorCode : Integer;
                                OpCode    : Byte;
                                FileName  : PathStr
                               ): ErrorAction;      Virtual;
      {- send errors and messages to the user error display }

    Function    Error(Status   : Integer;
                      OpCode   : Byte;
                      FileName : PathStr
                     ): Boolean;                    Virtual;
      {- check for errors and control the number of retries after an error }

    Procedure   SetMaxRetry(Retry : Word);
      {- set the maximum retries per error }

    Function    GetMaxRetry: Word;
      {- return the maximum retries per error }

    Procedure   ClearRetry;
      {- clear the current count of retries }

    Procedure   SetDelay(Seconds : Word);
      {- set the delay in seconds between retries }

    Function    GetDelay: Word;
      {- return the delay in seconds between retries }

    Procedure   AddErrors(ErrorCodes : ErrorSet);
      {- add an error to the set of errors trapped }

    Procedure   RemoveErrors(ErrorCodes : ErrorSet);
      {- remove an error from the set of errors trapped }

    Procedure   SetErrors(ErrorCodes : ErrorSet);
      {- set the entire trapped error set }

    Procedure   GetErrors(var ErrorCodes : ErrorSet);
      {- get the trapped error set }

    Function    ErrorMsg(ErrorCode : Integer): String; Virtual;
      {- return an error message for a Btrieve error code }

    Function    OpMsg(OpCode : Integer): String; Virtual;
      {- return a message for a Btrieve operation code }

    Destructor  Done;                               Virtual;
      {- destroy the object }
  end;



  { This is the Btrieve file file interface object  }
  PBtrieveFile  = ^BtrieveFile;
  BtrieveFile   = Object
    Path        : PathStr;            { File name and path                }
    AltPath     : PathStr;            { Alternate collating seq. file     }
    Data        : Pointer;            { pointer to record data buffer     }
    DataSize    : Word;               { length of record data buffer      }
    Allocate    : Boolean;            { allocate data buffer memory       }
    BytesRead   : Word;               { number of bytes on last file read }
    BytesToWrite: Word;               { number of bytes to write to file  }
    Key         : Pointer;            { pointer to the file key buffer    }
    KeySize     : Byte;               { actual size of the key buffer     }
    SegmentCnt  : Byte;               { total number of key segments      }
    CurIndex    : Word;               { current key being used            }
    IndexCnt    : Byte;               { number of defined keys            }
    Status      : Integer;            { status of last Btrieve operation  }
    FileOpen    : Boolean;            { is the file open                  }
    ErrHandler  : PErrorHandler;      { pointer to the error handler      }
    KeyList     : KeyDefArray;        { list of key definitions           }
                                      { offset of 1st segment in each key }
    KeyStart    : Array[0..MaxSegments - 1] of Byte;
                                      { position block for Btrieve        }
    PosBlock    : Array[1..PosBlockSize] of Byte;
    VariableLen : Boolean;            { does file use var length records  }
    SISegments  : Byte;
    ReadKeyDefs : Boolean;
    CurrentKeySize : Byte;

    Constructor Init(FilePath    : PathStr;
                     ErrorObject : PErrorHandler;
                     DataBuf     : Pointer;
                     DataBufSize : Word);
      {- initialize a file object }

    Destructor  Done;                               Virtual;
      {- destroy the object }

    Procedure   AddAltSequence(AltSeqPath : PathStr);
      {- add an alternate collating sequence file }

    Procedure   AddKeySegment(Position  : Word;
                              Size      : Word;
                              Flags     : Word;
                              KeyType   : Byte;
                              NullValue : Byte;
                              Justify   : Byte);
      {- define a key segment }

    Procedure   Open(Mode : Integer;
                     Owner: String);
      {- open the file }

    Procedure   Close;
      {- close the file }

    Procedure   Create(Flags      : Word;
                       RecordSize : Word;
                       PageSize   : Word;
                       Pages      : Word;
                       Mode       : Integer);
      {- create the file }

    Procedure   Clone(NewFilePath : PathStr;
                      Mode        : Integer);
      {- clone an empty copy of the file }

    Function    Error(ErrStatus : Integer;
                      OpCode    : Byte;
                      FileName  : PathStr
                     ): Boolean;
      {- call the error handler to check for errors }

    Function    Recover(NewFilePath : PathStr;
                        DisplayObj  : PProgress): Integer;
      {- copy all possible records to a new Btrieve file }

    Function    Save(NewFilePath : PathStr;
                     DisplayObj  : PProgress): Integer;
      {- write the contents of the file to a DOS file }

    Function    Load(InputFilePath : PathStr;
                     DisplayObj    : PProgress): Integer;
      {- read the contents of a DOS file and insert }

    Procedure   AddSupplKeySegment(Position  : Word;
                                   Size      : Word;
                                   Flags     : Word;
                                   KeyType   : Byte;
                                   NullValue : Byte;
                                   Justify   : Byte);
      {- define a key segment for a supplemental index }

    Procedure   CreateIndex;
      {- add a supplemental index to the file }

    Procedure   DropIndex(Index : Integer);
      {- remove a supplemental index from the file }

    Procedure   SetOwner(Owner  : String;
                         Mode   : Integer);
      {- set the file owner }

    Procedure   ClearOwner;
      {- set the file owner }

    Procedure   SetKeyPath(Number : Word);
      {- change the current file key path }

    Procedure   MakeKey(V1 : Pointer;
                        V2 : Pointer;
                        V3 : Pointer;
                        V4 : Pointer;
                        V5 : Pointer;
                        V6 : Pointer);
      {- copy the passed fields into the key buffer }

    Procedure   Get(Op   : Word;
                    Lock : Word);
      {- read a record using by a key }

    Procedure   GetDirect(Lock     : Word;
                          Position : LongInt);
      {- read a record by file position }

    Function    GetPosition: LongInt;
      {- return the position of the record }

    Procedure   UnlockAll(Lock : Word);
      {- unlock all records in the file }

    Procedure   Insert;
      {- add a new record to the file }

    Procedure   Update;
      {- update an existing record in the file }

    Procedure   SetOutputSize(Size : Word);
      {- use for variable length records only, sets the size of the
         record to be written to the file  }

    Procedure   AddErrors(ErrorCodes : ErrorSet);
      {- add an error to the set of errors trapped }

    Procedure   RemoveErrors(ErrorCodes : ErrorSet);
      {- remove an error from the set of errors trapped }

    Procedure   SetErrors(ErrorCodes : ErrorSet);
      {- set the entire trapped error set }

    Procedure   GetErrors(var ErrorCodes : ErrorSet);
      {- get the trapped error set }

    Procedure   Delete;
      {- delete the current record }

    Procedure   ClearBuffer;
      {- zero fill the file data buffer }

    Procedure   ClearKey;
      {- zero fill the file key buffer }

    Procedure   FillKeyBuffer(var Buff; Size : Byte);
      {- fill the key buffer from the data in Buff }

    Procedure   ChangeBufferSize(Size : Word);
      {- change the size of the output buffer }

    Procedure   Stat(var FData : FileSpec);
      {- get the file statistics }

    Function    bResult: Integer;
      {- return the last IO status }

    Function    IsOpen: Boolean;
      {- return True if the file is open }

    Function    NumberOfRecords: LongInt;
      {- return the number of records in the file }

    Procedure   StartTransaction(Lock : Word);
    Procedure   EndTransaction;
    Procedure   AbortTransaction;
      {- routines to control transaction processing }

    Procedure   Unload;
      {- unload Btrieve }

    Procedure   Reset;
      {- reset Btrieve }

    Procedure   Version(var Ver    : Word;
                        var Rev    : Word;
                        var OSFlag : Char);
      {- get Btrieve version }

    Procedure   FixKeyStrings;
  end;


Procedure CheckForBtrieve;


{============================================================================}
IMPLEMENTATION


Procedure Pad(var S   : String;
                  Len : Byte);
  {-Return a string right-padded to length len with blanks}
  var
    SLen : Byte Absolute S;

  begin
    if (SLen < Len) then
    begin
      FillChar(S[SLen + 1], Len - SLen, ' ');
      SLen := Len;
    end;
  end;

Procedure LeftPad(var S   : String;
                      Len : Byte);
  {-Return a string left-padded to length len with blanks}
  var
    SLen : Byte Absolute S;
    X    : Byte;

  begin
    if (SLen < Len) then
    begin
      X := Len - SLen;
      Move(S[1], S[X + 1], SLen);
      FillChar(S[1], X, ' ');
      SLen := Len;
    end;
  end;

Procedure Trim(var S : String);
  {- Return a string with leading and trailing blanks removed }
  var
    I    : Word;
    SLen : Byte absolute S;

  begin
    while (SLen > 0) and (S[SLen] <= ' ') do
      Dec(SLen);

    I := 1;

    while (I <= SLen) and (S[I] <= ' ') do
      Inc(I);

    if (I > 1) then
    begin
      SLen := SLen - I + 1;
      Move(S[I], S[1], SLen);
    end;
  end;


{****************************************************************************
                            File Object
****************************************************************************}
{+--------------------------------------------------------------------------+}
{| Name       : Init                                                        |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Initialize the file object                                  |}
{| Parameters : FilePath     - Path name of the data file.                  |}
{|              ErrorObject  - Pointer to an error handler object.          |}
{|              DataBuf      - Pointer to a data buffer, set to nil and     |}
{|                             memory will be automatically allocated when  |}
{|                             the file is opened.                          |}
{|              DataBufSize  - Size of what DataBuf points at, can be zero  |}
{|                             if DataBuf is nil.                           |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Constructor BtrieveFile.Init(FilePath    : PathStr;
                             ErrorObject : PErrorHandler;
                             DataBuf     : Pointer;
                             DataBufSize : Word);
  begin
    Path        := FilePath;
    AltPath     := '';
    Data        := DataBuf;
    Allocate    := (Data = nil);

    if Allocate then
      DataSize  := 0
    else
      DataSize  := DataBufSize;

    BytesRead   := 0;
    BytesToWrite:= 0;
    Key         := nil;
    KeySize     := 0;
    CurrentKeySize := 0;
    SegmentCnt  := 0;
    SISegments  := 0;
    IndexCnt    := 0;
    Status      := bOkay;
    FileOpen    := False;
    ErrHandler  := ErrorObject;
    CurIndex    := 0;
    ReadKeyDefs := True;
    FillChar(KeyList,  SizeOf(KeyList), 0);
    FillChar(KeyStart, SizeOf(KeyStart), 0);
    FillChar(PosBlock, SizeOf(PosBlock), 0);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetKeyPath                                                  |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Set the number of the key that will be used for all read and|}
{|              write operations.                                           |}
{| Parameters : Number - the key path to be used                            |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.SetKeyPath(Number : Word);
  begin
    if (Number <= IndexCnt) then
      CurIndex := Number;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : AddAltSequence                                              |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Define the Path of a disk file that holds an alternate      |}
{|              collating sequence.                                         |}
{| Parameters : AltSeqPath - Alt. sequence file path name.                  |}
{| Returns    : none                                                        |}
{| Notes      : This is an optional feature.                                |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.AddAltSequence(AltSeqPath : PathStr);
  begin
    AltPath := AltSeqPath;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : AddKeySegment                                               |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Define the next key segment.                                |}
{| Parameters : Position - where it starts in the key                       |}
{|              Size     - number of bytes in this segment                  |}
{|              Flags    - btrieve file flags                               |}
{|              KeyType  - btrieve key type                                 |}
{|              NullValue- null value for this segment                      |}
{|              Justify  - Applies to lStrings only.                        |}
{|                         0 for the string to be left as is.               |}
{|                         1 for the string to be right justified.          |}
{|                         2 for the string to be left justified.           |}
{| Returns    : none                                                        |}
{| Notes      : Segments must be defined in order.                          |}
{|              Must be done once before a file created. May optionally be  |}
{|              done before a file is opened.                               |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.AddKeySegment(Position  : Word;
                                    Size      : Word;
                                    Flags     : Word;
                                    KeyType   : Byte;
                                    NullValue : Byte;
                                    Justify   : Byte);
  begin
    { Open will not read keys definitions from the file }
    ReadKeyDefs := False;

    { if more segments are allowed  }
    if (SegmentCnt < MaxSegments) then
    begin
      { increase the current key size by the size of this segment }
      CurrentKeySize := CurrentKeySize + Size;

      Inc(SegmentCnt);

      { if this is the first segment in the current key
        then add to list of key starting segments
      }
      if (KeyStart[IndexCnt] = 0) then
        KeyStart[IndexCnt] := SegmentCnt;

      { add it to the list of key definitions }
      KeyList[SegmentCnt].KeyPos    := Position;
      KeyList[SegmentCnt].KeyLen    := Size;
      KeyList[SegmentCnt].KeyFlags  := Flags;
      KeyList[SegmentCnt].KeyType   := KeyType;
      KeyList[SegmentCnt].NullValue := NullValue;
      KeyList[SegmentCnt].Justify   := Justify;

      { if this is the end of all segments for the current key }
      if (Flags And bSegmented = 0) then
      begin
        { bump the number of keys }
        Inc(IndexCnt);

        { find the largest key so far }
        if (CurrentKeySize > KeySize) then
          KeySize := CurrentKeySize;

        { set for the next key }
        CurrentKeySize := 0;
      end;
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Open                                                        |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Open a btrieve file                                         |}
{| Parameters : Mode - mode to open the file in                             |}
{|              Owner- up to 8 character file owner name                    |}
{| Returns    : none                                                        |}
{| Notes      : Allocates memory for key and data buffers.                  |}
{|              If keys are not setup manually, then reads key defs from the|}
{|              file.                                                       |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Open(Mode  : Integer;
                           Owner : String);

  var
    i,j     : Byte;
    OwnerLen: Word;
    FName   : Array[0..80] of Char;
    FData   : FileSpec;

  begin
    if not FileOpen then
    begin
      { turn path and name into an ascii zero terminated string }
      Move(Path[1], FName[0], Length(Path));
      FName[Length(Path)] := Chr(0);
      FillChar(FData, SizeOf(FData), 0);
      OwnerLen := 0;

      if (Owner <> '') then
      begin
        OwnerLen := Length(Owner);

        if (OwnerLen > 8) then
          OwnerLen := 8;

        Move(Owner[1], FData, OwnerLen);
      end;

      Repeat
        Status := Btrv(bOpen, PosBlock, FData, OwnerLen, FName, Mode);
      Until (not Error(Status, bOpen, Path));

      FileOpen := (Status = bOkay);

      if FileOpen then
      begin
        { read in all the file data needed  }
        Stat(FData);

        if (Status = bOkay) then
        begin
          { set some flags from the file definition }
          IndexCnt    := FData.Indexes;
          VariableLen := ((FData.FileFlags and bVariableLen) <> 0);
          { write size defaults to fixed length size }
          BytesToWrite:= FData.RecordLen;

          { if the keys were not setup manually then read from the file }
          if ReadKeyDefs then
          begin
            { check all keys for the largest key size }
            SegmentCnt := 0;

            for i := 1 to IndexCnt do
            begin
              { set start of key segments for this key  }
              KeyStart[i] := SegmentCnt + 1;

              Repeat
                { add this length to size of the current key }
                Inc(SegmentCnt);

                CurrentKeySize := CurrentKeySize +
                                  FData.KeyBuff[SegmentCnt].KeyLen;
              Until ((FData.KeyBuff[SegmentCnt].KeyFlags and bSegmented) = 0);

              { compare the size }
              if (CurrentKeySize > KeySize) then
                KeySize := CurrentKeySize;

              { set for the next key }
              CurrentKeySize := 0;
            end; {FOR}

            { move key segment data from stat buffer to key def buffer }
            for i := 1 to SegmentCnt do
            begin
              KeyList[i].KeyPos    := FData.KeyBuff[i].KeyPos;
              KeyList[i].KeyLen    := FData.KeyBuff[i].KeyLen;
              KeyList[i].KeyFlags  := FData.KeyBuff[i].KeyFlags;
              KeyList[i].KeyType   := FData.KeyBuff[i].KeyType;
              KeyList[i].NullValue := FData.KeyBuff[i].NullValue;
              KeyList[i].Justify   := bNormal;
            end;  {FOR}
          end;

          { allocate memory for the data and key buffers  }
          { if Data does not point at anything then get   }
          { some memory for it                            }
          if Allocate then
          begin
            { if variable length then allocate a bunch of memory  }
            { else just allocate the minium needed                }
            if VariableLen then
              DataSize := MaxBuffSize
            else
              DataSize := FData.RecordLen;

            GetMem(Data, DataSize);
          end;

          GetMem(Key, KeySize);

          if ((Data = nil) and (DataSize > 0)) or
             ((Key = nil)  and (KeySize > 0)) then
          begin
            Status := bOutOfMemory;
            Error(Status, bOpen, Path);
            EXIT;
          end;

          { clear the buffers }
          FillChar(Data^, DataSize, ' ');
          FillChar(Key^,  KeySize,  ' ');
          CurrentKeySize  := 0;
        end;
      end;
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Create                                                      |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Create a new file                                           |}
{| Parameters : Flags      - Btrieve file flags                             |}
{|              RecordSize - length of the fixed length portion of record   |}
{|              PageSize   - number of bytes in a file page                 |}
{|              Pages      - number of pages to preallocate to the file     |}
{|              Mode       - indicates overwrite or warn mode               |}
{| Returns    : none                                                        |}
{| Notes      : Make sure the keys have been defined.                       |}
{|              Call Open immediately after Create.                         |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Create(Flags      : Word;
                             RecordSize : Word;
                             PageSize   : Word;
                             Pages      : Word;
                             Mode       : Integer);

  var
    i       : Integer;
    BufSize : Word;
    FName   : Array[0..80] of Char;
    Buff    : FileSpec;
    Temp    : Array[1..1024] of Byte Absolute Buff;
    AltFile : File;

  begin
    { clear the data buffer }
    FillChar(Buff, SizeOf(Buff), 0);

    { copy the file info to the data buffer }
    Buff.RecordLen  := RecordSize;
    Buff.PageSize   := PageSize;
    Buff.Indexes    := IndexCnt;
    Buff.FileFlags  := Flags;
    Buff.FreePages  := Pages;

    { copy the key info for each segment to the data buffer }
    for i := 1 to SegmentCnt do
    begin
      Buff.KeyBuff[i].KeyPos    := KeyList[i].KeyPos;
      Buff.KeyBuff[i].KeyLen    := KeyList[i].KeyLen;
      Buff.KeyBuff[i].KeyFlags  := KeyList[i].KeyFlags;
      Buff.KeyBuff[i].KeyType   := KeyList[i].KeyType;
      Buff.KeyBuff[i].NullValue := KeyList[i].NullValue;
    end;

    { calculate the buffer size so far                    }
    {       Segments * Segment data size + file data size }
    BufSize := SegmentCnt * SizeOf(KeySpec) + 16;

    { read the alternate collating sequence if any        }
    {$I-}
    if (AltPath <> '') then
    begin
      System.Assign(AltFile, AltPath);
      System.Reset(AltFile, 1);

      if (IoResult = 0) then
      begin
        System.BlockRead(AltFile, Temp[BufSize+1], 265);{ Read file   }
        System.Close(AltFile);
        BufSize := BufSize + 265;
        AltPath := '';
        i := IoResult;
      end;
    end;
    {$I+}

    { turn path and name into an ascii zero terminated string }
    Move(Path[1], FName[0], Length(Path));
    FName[Length(Path)] := Chr(0);

    Repeat
      Status := Btrv(bCreate, PosBlock, Buff, BufSize, FName, Mode);
    Until (not Error(Status, bCreate, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Recover                                                     |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Read records and write to a new file.                       |}
{| Parameters : NewFilePath - File path name of new file                    |}
{|              DisplayObj  - pointer to a object that can display progress |}
{| Returns    : Integer - zero if sucessful                                 |}
{| Notes      : Reads in Read Only mode and writes to new file.             |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.Recover(NewFilePath : PathStr;
                             DisplayObj  : PProgress): Integer;

  var
    OutFile : BtrieveFile;
    X       : Byte;
    Total   : LongInt;

  begin
    if (Path = NewFilePath) then
    begin
      Recover := bDuplicateFilename;
      EXIT;
    end;

    Clone(NewFilePath, bNoOverWrite);

    if (Status <> bOkay) then
    begin
      Recover := Status;
      EXIT;
    end;

    OutFile.Init(NewFilePath, ErrHandler, Data, DataSize);
    OutFile.Open(bAccelerated, '');

    {$IFNDEF BTRIEVE50}
    Get(bStepNext, bNoLock);
    {$ELSE}
    Get(bStepFirst, bNoLock);
    {$ENDIF}
    X     := 0;
    Total := 0;

    While (Status <> bEOF) and (OutFile.bResult = bOkay) do
    begin
      if (Status = bOkay) then
      begin
        OutFile.Insert;
        Inc(X);
        Inc(Total);

        if (X = 10) then
        begin
          if (DisplayObj <> nil) then
            DisplayObj^.Display(Total);

          X := 0;
        end;
      end;

      Get(bStepNext, bNoLock);
    end; {WHILE}

    if (DisplayObj <> nil) then
      DisplayObj^.Display(Total);

    if (Status <> bEOF) then
      Recover := Status
    else if (OutFile.bResult <> bOkay) then
      Recover := OutFile.bResult
    else
      Recover := 0;

    OutFile.Close;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Save                                                        |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Save records to a DOS file.                                 |}
{| Parameters : NewFilePath - File path name of new file                    |}
{|              DisplayObj  - pointer to a object that can display progress |}
{| Returns    : Integer - zero if sucessful                                 |}
{| Notes      : Writes records to a DOS file. The file will be in the same  |}
{|              format that the BUTIL RECOVER utility creates.              |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.Save(NewFilePath : PathStr;
                          DisplayObj  : PProgress): Integer;

  var
    X       : Byte;
    Err     : Integer;
    Total   : LongInt;
    St      : String[6];
    OutFile : File;

  begin
    if (Path = NewFilePath) then
    begin
      Save := bDuplicateFilename;
      EXIT;
    end;

    {$I-}
    Assign(OutFile, NewFilePath);
    ReWrite(OutFile, 1);
    Err := IoResult;

    {$IFNDEF BTRIEVE50}
    Get(bStepNext, bNoLock);
    {$ELSE}
    Get(bStepFirst, bNoLock);
    {$ENDIF}
    X     := 0;
    Total := 0;

    While (Status <> bEOF) and (Err = 0) do
    begin
      if (Status = bOkay) then
      begin
        Str(BytesRead, St);
        St := St + ',';
        BlockWrite(OutFile, St[1], Length(St));
        Err := IoResult;

        if (Err = 0) then
        begin
          BlockWrite(OutFile, Data^, BytesRead);
          Err := IoResult;
        end;

        if (Err = 0) then
        begin
          St := #13#10;
          BlockWrite(OutFile, St[1], 2);
          Err := IoResult;
          Inc(Total);
          Inc(X);

          if (X = 10) then
          begin
            if (DisplayObj <> nil) then
              DisplayObj^.Display(Total);

            X := 0;
          end;
        end;
      end;

      Get(bStepNext, bNoLock);
    end; {WHILE}

    St := #26;
    BlockWrite(OutFile, St[1], 1);

    if (DisplayObj <> nil) then
      DisplayObj^.Display(Total);

    if (Err = 0) then
      Err := IoResult;

    if (Status <> bEOF) then
      Save := Status
    else if (Err <> 0) then
      Save := Err
    else
      Save := 0;

    System.Close(OutFile);
    {$I+}
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Load                                                        |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Load records from a DOS file.                               |}
{| Parameters : InputFilePath - File path name of new file                  |}
{|              DisplayObj  - pointer to a object that can display progress |}
{| Returns    : Integer - zero if sucessful                                 |}
{| Notes      : Reads records from a DOS file and inserts. The file must be |}
{|              in the same format that the BUTIL RECOVER utility creates.  |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.Load(InputFilePath : PathStr;
                          DisplayObj    : PProgress): Integer;

  var
    X       : Byte;
    Ch      : Char;
    Err     : Integer;
    Size    : Word;
    Total   : LongInt;
    St      : String[5];
    InFile  : File;
    Buff    : Pointer;

  begin
    GetMem(Buff, $FFF0);  {Get max buffer size of 64K}

    if (Buff = nil) then
    begin
      Load := bOutOfMemory;
      EXIT;
    end;

    {$I-}
    Assign(InFile, InputFilePath);
    System.Reset(InFile, 1);
    Err   := IoResult;
    X     := 0;
    Total := 0;

    While (Status = bOkay) and (Err = 0) and not EOF(InFile) do
    begin
      BlockRead(InFile, Ch, 1);
      Err := IoResult;
      St := '';

      While (Ch <> ',') and (Ch <> ' ') and (Ch <> #26) and (Err = 0) do
      begin
        St := St + Ch;
        BlockRead(InFile, Ch, 1);
        Err := IoResult;
      end;

      if (Err = 0) and (Ch <> #26) then
      begin
        Val(St, Size, Err);

        if (Err <> 0) then
        begin
          Load := bLoadInputErr;
          EXIT;
        end

        else
        begin
          BlockRead(InFile, Buff^, Size);
          Err := IoResult;

          if (Err = 0) then
          begin
            BlockRead(InFile, St, 2);
            Err := IoResult;
          end;

          if not VariableLen and (Size > DataSize) then
            Size := DataSize;

          Move(Buff^, Data^, Size);
          SetOutputSize(Size);
          Insert;
          Inc(X);
          Inc(Total);

          if (X = 10) then
          begin
            if (DisplayObj <> nil) then
              DisplayObj^.Display(Total);

            X := 0;
          end;
        end;
      end;
    end; {WHILE}

    if (DisplayObj <> nil) then
      DisplayObj^.Display(Total);

    if (Status <> bOkay) then
      Load := Status
    else if (Err <> 0) then
      Load := Err
    else
      Load := 0;

    System.Close(InFile);
    {$I+}
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Clone                                                       |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Clone a file from an existing file.                         |}
{| Parameters : NewFilePath - File path name new file                       |}
{|              Mode        - indicates overwrite or warn mode              |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Clone(NewFilePath : PathStr;
                            Mode        : Integer);

  var
    FName : Array[0..SizeOf(PathStr) - 1] of Char;
    FData : FileSpec;
    PBlock: Array[1..PosBlockSize] of Byte;

  begin
    if (Path = NewFilePath) then
    begin
      Status := bDuplicateFilename;
      EXIT;
    end;

    Stat(FData);
    { turn pathname into an ascii zero terminated string }
    Move(NewFilePath[1], FName[0], Length(NewFilePath));
    FName[Length(NewFilePath)] := Chr(0);

    Repeat
      Status := Btrv(bCreate, PBlock, FData, BytesRead, FName, Mode);
    Until (not Error(Status, bCreate, NewFilePath));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : AddSupplKeySegment                                          |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Define the next key segment for a supplemental index.       |}
{| Parameters : Position - where it starts in the key                       |}
{|              Size     - number of bytes in this segment                  |}
{|              Flags    - btrieve file flags                               |}
{|              KeyType  - btrieve key type                                 |}
{|              NullValue- null value for this segment                      |}
{|              Justify  - Applies to lStrings only.                        |}
{|                         0 for the string to be left as is.               |}
{|                         1 for the string to be right justified.          |}
{|                         2 for the string to be left justified.           |}
{| Returns    : none                                                        |}
{| Notes      : Segments must be defined in order.                          |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.AddSupplKeySegment(Position  : Word;
                                         Size      : Word;
                                         Flags     : Word;
                                         KeyType   : Byte;
                                         NullValue : Byte;
                                         Justify   : Byte);
  begin
    { if more segments are allowed  }
    if (SegmentCnt + SISegments < MaxSegments) then
    begin
      { increase the current key size by the size of this segment }
      CurrentKeySize := CurrentKeySize + Size;

      Inc(SISegments);

      { if this is the first segment in the current key
        then add to list of key starting segments
      }
      if (KeyStart[IndexCnt] = 0) then
        KeyStart[IndexCnt] := SegmentCnt + 1;

      { add it to the list of key definitions }
      KeyList[SegmentCnt + SISegments].KeyPos    := Position;
      KeyList[SegmentCnt + SISegments].KeyLen    := Size;
      KeyList[SegmentCnt + SISegments].KeyFlags  := Flags;
      KeyList[SegmentCnt + SISegments].KeyType   := KeyType;
      KeyList[SegmentCnt + SISegments].NullValue := NullValue;
      KeyList[SegmentCnt + SISegments].Justify   := Justify;
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : CreateIndex                                                 |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Create a supplemental index for the file.                   |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.CreateIndex;

  var
    i       : Integer;
    BufSize : Word;
    Buff    : KeySpecArray;
    Temp    : Array[1..1024] of Byte Absolute Buff;
    AltFile : File;

  begin
    { move all the key defs to the data buffer  }
    for i := 1 to SISegments do
    begin
      Buff[i].KeyPos    := KeyList[i + SegmentCnt].KeyPos;
      Buff[i].KeyLen    := KeyList[i + SegmentCnt].KeyLen;
      Buff[i].KeyFlags  := KeyList[i + SegmentCnt].KeyFlags;
      Buff[i].KeyType   := KeyList[i + SegmentCnt].KeyType;
      Buff[i].NullValue := KeyList[i + SegmentCnt].NullValue;
    end;

    { calculate the buffer size so far                    }
    {       Segments * Segment data size + file data size }
    BufSize := SISegments * SizeOf(KeySpec);

    { read the alternate collating sequence if any        }
    {$I-}
    if (AltPath <> '') then
    begin
      System.Assign(AltFile, AltPath);
      System.Reset(AltFile, 1);

      if (IoResult = 0) then
      begin
        System.BlockRead(AltFile, Temp[BufSize+1], 265);{ Read file   }
        System.Close(AltFile);
        BufSize := BufSize + 265;
        i := IoResult;
      end;
    end;
    {$I+}

    Repeat
      Status := Btrv(bCreateIndex, PosBlock, Buff, BufSize, i, i);
    Until (not Error(Status, bCreateIndex, Path));

    if (Status = bOkay) then
    begin
      { bump the number of keys and segments }
      Inc(IndexCnt);
      Inc(SegmentCnt, SISegments);

      { resize the key buffer }
      if (CurrentKeySize > KeySize) then
      begin
        FreeMem(Key, KeySize);
        KeySize := CurrentKeySize;
        CurrentKeySize := 0;
        GetMem(Key, KeySize);

        if ((Key = nil) and (KeySize > 0)) then
        begin
          Status := bOutOfMemory;
          Error(Status, bCreateIndex, Path);
        end;
      end;
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : DropIndex                                                   |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Drop a supplemental index from the file.                    |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.DropIndex(Index : Integer);

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bDropIndex, PosBlock, I, W, I, Index);
    Until (not Error(Status, bDropIndex, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ChangeBufferSize                                            |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Change the size of the data buffer.                         |}
{| Parameters : Size  - new buffer size                                     |}
{| Returns    : none                                                        |}
{| Notes      : ONLY valid for objects that allocated buffer memory.        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.ChangeBufferSize(Size : Word);
  begin
    if (Size = DataSize) then EXIT;

    if (Size > MaxAvail) then
      Size := MaxAvail;

    if (Data <> nil) then
      FreeMem(Data, DataSize);

    DataSize := Size;
    GetMem(Data, DataSize);

    if ((Data = nil) and (DataSize > 0)) then
    begin
      Status := bOutOfMemory;
      Error(Status, 0, Path);
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetOwner                                                    |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Set the owner name and access mode for the file.            |}
{| Parameters : Owner - up to 8 character owner name                        |}
{|              Mode  - Access mode for file                                |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.SetOwner(Owner : String;
                               Mode  : Integer);

  var
    BufSize : Word;
    Buff    : Array[1..9] of Char;

  begin
    Trim(Owner);

    if (Owner = '') then EXIT;

    FillChar(Buff, SizeOf(Buff), 0);
    BufSize := Length(Owner);

    if (BufSize > 8) then
      BufSize := 8;

    Move(Owner[1], Buff[1], BufSize);

    Repeat
      Status := Btrv(bSetOwner, PosBlock, Buff, BufSize, Buff, Mode);
    Until (not Error(Status, bSetOwner, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ClearOwner                                                  |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Clear the owner name and access mode for the file.          |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.ClearOwner;

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bClearOwner, PosBlock, I, W, I, I);
    Until (not Error(Status, bClearOwner, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Close                                                       |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Close a btrieve file                                        |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Call Done to destroy the object and free memory.            |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Close;

  var
    I : Integer;
    W : Word;

  begin
    if FileOpen then
    begin
      Repeat
        Status := Btrv(bClose, PosBlock, I, W, I, 0);
      Until (not Error(Status, bClose, Path));

      FileOpen := not (Status = bOkay);
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Error                                                       |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Call the error handler object.                              |}
{| Parameters : Status    - the last btrieve status code                    |}
{|              OpCode    - btrieve operation that generate error           |}
{|              FileName  - file the error occured with                     |}
{| Returns    : TRUE as long as there is still an error.                    |}
{| Notes      : If an error handler object has not been assigned this will  |}
{|              always return FALSE.                                        |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.Error(ErrStatus: Integer;
                           OpCode   : Byte;
                           FileName : PathStr
                           ): Boolean;
  begin
    if (ErrHandler <> nil) then
      Error := ErrHandler^.Error(ErrStatus, OpCode, FileName)
    else
      Error := False;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Get                                                         |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Read a record                                               |}
{| Parameters : Op   - type of read operation                               |}
{|              Lock - type of lock                                         |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Get(Op   : Word;
                          Lock : Word);
  begin
    BytesRead := DataSize;

    Repeat
      Status := Btrv(Op + Lock, PosBlock, Data^, BytesRead, Key^, CurIndex);
    Until (not Error(Status, Op, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : GetDirect                                                   |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Read a record at a speific file position                    |}
{| Parameters : Lock - type of lock                                         |}
{|              Position - record position in the file as returned by       |}
{|                         a call to GetPosition.                           |}
{| Returns    : none                                                        |}
{| Notes      : Establishes index position for current key path.            |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.GetDirect(Lock     : Word;
                                Position : LongInt);

  begin
    BytesRead := DataSize;
    Move(Position, Data^, 4);

    Repeat
      Status := Btrv(bGetDirect + Lock, PosBlock, Data^, BytesRead, Key^, CurIndex);
    Until (not Error(Status, bGetDirect, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Insert                                                      |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Add a new record to the file                                |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Automatically pads or right justifies key strings.          |}
{|              When writing variable length records make sure to set the   |}
{|              output buffer size.                                         |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Insert;
  begin
    FixKeyStrings;

    Repeat
      Status := Btrv(bInsert, PosBlock, Data^, BytesToWrite, Key^, CurIndex);
    Until (not Error(Status, bInsert, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Update                                                      |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Update an existing record in the file                       |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Updates the last record retrieved.                          |}
{|              Automatically pads or right justifies key strings.          |}
{|              When writing variable length records make sure to set the   |}
{|              output buffer size.                                         |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Update;
  begin
    FixKeyStrings;

    Repeat
      Status := Btrv(bUpdate, PosBlock, Data^, BytesToWrite, Key^, CurIndex);
    Until (not Error(Status, bUpdate, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Delete                                                      |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Delete a record                                             |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Deletes the current record, i.e. last record retrieved.     |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Delete;

  var
    I : Integer;

  begin
    BytesRead := DataSize;

    Repeat
      Status := Btrv(bDelete, PosBlock, I, BytesRead, I, 0);
    Until (not Error(Status, bDelete, Path));

    BytesRead := 0;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : GetPosition                                                 |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Get the physical file position of a record                  |}
{| Parameters : none                                                        |}
{| Returns    : Returns the position of the last record retrieved.          |}
{|              Returns a -1 if any error occurs.                           |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.GetPosition: LongInt;

  var
    I       : Integer;
    Pos     : LongInt;
    BufSize : Word;

  begin
    BufSize := 4;

    Repeat
      Status := Btrv(bGetPosition, PosBlock, Pos, BufSize, I, 0);
    Until (not Error(Status, bGetPosition, Path));

    if (Status = bOkay) then
      GetPosition := Pos
    else
      GetPosition := -1;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : UnlockAll                                                   |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Unlock all records in the file.                             |}
{| Parameters : Lock - if <= 200 then single locks are active               |}
{|                     if > 200 then multiple locks are active              |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.UnlockAll(Lock : Word);

  var
    I     : Integer;
    W     : Word;
    KeyNum: Integer;

  begin
    if (Lock <= bSingleNoWait) then
      KeyNum := 1
    else
      KeyNum := -2;

    Repeat
      Status := Btrv(bUnlock, PosBlock, I, W, I, KeyNum);
    Until (not Error(Status, bUnlock, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : AddError                                                    |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Add an error to the trapped error set                       |}
{| Parameters : ErrorCode - btrieve status code to add                      |}
{| Returns    : none                                                        |}
{| Notes      : All errors except bEOF are trapped by default               |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.AddErrors(ErrorCodes : ErrorSet);
  begin
    if (ErrHandler <> nil) then
      ErrHandler^.AddErrors(ErrorCodes);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : RemoveError                                                 |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Remove a error form the trapped errors                      |}
{| Parameters : ErrorCode - btrieve status code to remove                   |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : bOkay will not be removed.                                  |}
{|              All errors except bEOF are trapped by default               |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.RemoveErrors(ErrorCodes : ErrorSet);
  begin
    if (ErrHandler <> nil) then
      ErrHandler^.RemoveErrors(ErrorCodes);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetErrors                                                   |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Make the set of all trapped errors.                         |}
{| Parameters : ErrorCodes - A set of btrieve status codes to become the new|}
{|                           trapped error set.                             |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.SetErrors(ErrorCodes : ErrorSet);
  begin
    if (ErrHandler <> nil) then
      ErrHandler^.SetErrors(ErrorCodes);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : GetErrors                                                   |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Return the set of all trapped errors.                       |}
{| Parameters : ErrorCodes - The set of btrieve status codes currently      |}
{|              trapped.                                                    |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.GetErrors(var ErrorCodes : ErrorSet);
  begin
    if (ErrHandler <> nil) then
      ErrHandler^.GetErrors(ErrorCodes)
    else
      ErrorCodes := [];
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ClearBuffer                                                 |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Fill the file data buffer with zeros.                       |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Use this to clear the buffer before you add new records.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.ClearBuffer;
  begin
    FillChar(Data^, DataSize, 0);
    BytesRead := 0;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetOutputSize                                               |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Set the number of bytes in the output buffer.               |}
{|              This is used to set the buffer size before writing a        |}
{|              variable length record.                                     |}
{| Parameters : Size - number of bytes in the output buffer                 |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.SetOutputSize(Size : Word);
  begin
    BytesToWrite := Size;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ClearKey                                                    |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Fill the file key buffer with zeros.                        |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.ClearKey;
  begin
    FillChar(Key^, KeySize, 0);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : FillKeyBuffer                                               |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Fill the file key buffer with with supplied data.           |}
{| Parameters : Buff - some data to move into the key buffer                |}
{|              Size - how much data to move into the key buffer            |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.FillKeyBuffer(var Buff; Size : Byte);
  begin
    if (Size > KeySize) then
      Size := KeySize;

    ClearKey;
    Move(Buff, Key^, Size);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : MakeKey                                                     |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Build a key for reading a record from the file.             |}
{| Parameters : KeyNumber - Which path are we building for.                 |}
{|              V1..V6    - Pointers to the data to make into a file key.   |}
{| Returns    : none                                                        |}
{| Notes      : Make sure to pass the addresses in the correct order for the|}
{|              specified path. This routine will left or right justify     |}
{|              strings as defined by AddKeySegment. Pass unused pointers as|}
{|              nil.                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.MakeKey(V1 : Pointer;
                              V2 : Pointer;
                              V3 : Pointer;
                              V4 : Pointer;
                              V5 : Pointer;
                              V6 : Pointer);

  var
    ParamPtr  : Pointer;
    Param     : Byte;
    KeyPos    : Byte;
    SegIndex  : Byte;
    Segmented : Word;
    St        : String;
    x         : Byte;

  begin
    { clear the key buffer }
    FillChar(Key^, KeySize, 0);
    { init the key buffer offset, the current parameter number, }
    { and the offset into the list of key segment definitions   }
    KeyPos  := 1;
    Param   := 1;
    SegIndex:= KeyStart[CurIndex];

    Repeat
      { point to the current parameter }
      Case Param of
        1 : ParamPtr := V1;
        2 : ParamPtr := V2;
        3 : ParamPtr := V3;
        4 : ParamPtr := V4;
        5 : ParamPtr := V5;
        6 : ParamPtr := V6;
      end;

      { pascal strings get some special processing }
      Case KeyList[SegIndex].KeyType of
        bLstring :
        begin
          St := String(ParamPtr^);

          Case KeyList[SegIndex].Justify of
            bRJustify :
            begin
              Trim(St);
              LeftPad(St, KeyList[SegIndex].KeyLen - 1)
            end;

            bLJustify :
            begin
              Trim(St);
              Pad(St, KeyList[SegIndex].KeyLen - 1);
            end;
          end; {CASE}

          Move(St[0], PBytes(Key)^[KeyPos], KeyList[SegIndex].KeyLen);
        end;

        { just copy everything else over to the key buffer }
        else
        begin
          Move(ParamPtr^, PBytes(Key)^[KeyPos], KeyList[SegIndex].KeyLen);
        end; {CASE ELSE}
      end; {CASE}

      { get the value of the segment bit from the key def }
      Segmented := KeyList[SegIndex].KeyFlags AND bSegmented;
      { bump the position in the key buffer }
      KeyPos    := KeyPos + KeyList[SegIndex].KeyLen;
      { move to next segment and parameter }
      Inc(SegIndex);
      Inc(Param);
    Until (Segmented = 0);  { we have copied the last segment }
  end;

{+--------------------------------------------------------------------------+}
{| Name       : FixKeyStrings                                               |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Left or right justify all key string fields as needed.      |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.FixKeyStrings;

  var
    i   : Byte;
    St  : String;

  begin
    { proccess all key segments }
    for i := 1 to SegmentCnt do
    begin
      { pascal strings get some special processing }
      Case KeyList[i].KeyType of
        bLstring :
        begin
          { pull it out of the buffer }
          Move(PBytes(Data)^[KeyList[i].KeyPos], St[0], KeyList[i].KeyLen);

          Case KeyList[i].Justify of
            bRJustify :
            begin
              Trim(St);
              LeftPad(St, KeyList[i].KeyLen - 1)
            end;

            bLJustify :
            begin
              Trim(St);
              Pad(St, KeyList[i].KeyLen - 1);
            end;
          end; {CASE}

          { put it back in the buffer }
          Move(St[0], PBytes(Data)^[KeyList[i].KeyPos], KeyList[i].KeyLen);
        end;
      end; {CASE}
    end; {FOR}
  end;

{+--------------------------------------------------------------------------+}
{| Name       : IsOpen                                                      |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Indicate if the file has been opened.                       |}
{| Parameters : none                                                        |}
{| Returns    : Boolean - TRUE if the file is open.                         |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.IsOpen;
  begin
    IsOpen := FileOpen;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : NumberOfRecords                                             |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Get the number of records in the file.                      |}
{| Parameters : none                                                        |}
{| Returns    : LongInt - Number of records in the file.                    |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.NumberOfRecords: LongInt;

  var
    BufSize : Word;
    Buffer1 : Array[1..1024] of Byte;
    Temp    : FileSpec Absolute Buffer1;
    Buffer2 : Array[1..64] of Byte;

  begin
    BufSize := SizeOf(Buffer1);

    Repeat
      Status := Btrv(bStat, PosBlock, Buffer1, BufSize, Buffer2, 0);
    Until (not Error(Status, bStat, Path));

    if (Status = bOkay) then
      NumberOfRecords := Temp.Records
    else
      NumberOfRecords := -1;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : bResult                                                     |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Get the status of the file.                                 |}
{| Parameters : none                                                        |}
{| Returns    : Integer - Last btrieve error code.                          |}
{| Notes      : Error is not cleared, so it can be checked multiple times.  |}
{+--------------------------------------------------------------------------+}
Function BtrieveFile.bResult: Integer;
  begin
    bResult := Status;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Done                                                        |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Destroy the object.                                         |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Destructor BtrieveFile.Done;
  begin
    if (Key <> nil) then
      FreeMem(Key, KeySize);

    if Allocate and (Data <> nil) then
      FreeMem(Data, DataSize);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : StartTransaction                                            |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Begin a btrieve transaction                                 |}
{| Parameters : Lock - Locking state for the transaction. By default a value|}
{|                     of bNoLock will start a transaction that waits on any|}
{|                     other transactions. Pass bSingleNoWait (200) or      |}
{|                     bMultipleNoWait (400) for a no wait file lock.       |}
{| Returns    : none                                                        |}
{| Notes      : Don't actually need an open file to execute this method.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.StartTransaction(Lock : Word);

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bBeginTransaction, I, I, W, I, 0);
    Until (not Error(Status, bBeginTransaction + Lock, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : EndTransaction                                              |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : End a btrieve transaction                                   |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Don't actually need an open file to execute this method.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.EndTransaction;

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bEndTransaction, I, I, W, I, 0);
    Until (not Error(Status, bEndTransaction, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : AbortTransaction                                            |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Abort a btrieve transaction                                 |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Don't actually need an open file to execute this method.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.AbortTransaction;

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bAbortTransaction, I, I, W, I, 0);
    Until (not Error(Status, bAbortTransaction, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Stat                                                        |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Execute the stat operation.                                 |}
{| Parameters : FDATA - will hold the statistics for the file               |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Stat(var FData : FileSpec);

  var
    FName : Array[1..128] of Char;

  begin
    BytesRead := SizeOf(FData);

    Repeat
      Status := Btrv(bStat, PosBlock, FData, BytesRead, FName, 0);
    Until (not Error(Status, bStat, Path));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Version                                                     |}
{| Class      : BtrieveWorkStation                                          |}
{| Purpose    : Get the version of btrieve being used                       |}
{| Parameters : ver - major version number                                  |}
{|              rev - minor version number                                  |}
{|              flag- an "N" indicates a network version                    |}
{| Returns    : none                                                        |}
{| Notes      : Don't actually need an open file to execute this method.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Version(var Ver    : Word;
                              var Rev    : Word;
                              var OSFlag : Char);

  var
    I       : Integer;
    BufSize : Word;
    Buffer  : Array[0..19] of Byte;

  begin
    BufSize := 20;                          { init length }

    Repeat
      Status := Btrv(bVersion, I, Buffer, BufSize, I, 0);
    Until (not Error(Status, bVersion, ''));

    Move(Buffer[0], Ver, 2);                { set version number  }
    Move(Buffer[2], Rev, 2);                { set revision number }
    Move(Buffer[4], OSFlag,1);              { set network flag    }
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Unload                                                      |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Unload btrieve.                                             |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Don't actually need an open file to execute this method.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Unload;

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bStop, I, I, W, I, 0);
    Until (not Error(Status, bStop, ''));
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Reset                                                       |}
{| Class      : BtrieveFile                                                 |}
{| Purpose    : Reset btrieve and release all workstation resources.        |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Don't actually need an open file to execute this method.    |}
{+--------------------------------------------------------------------------+}
Procedure BtrieveFile.Reset;

  var
    I : Integer;
    W : Word;

  begin
    Repeat
      Status := Btrv(bReset, I, I, W, I, 0);
    Until (not Error(Status, bStop, ''));
  end;


{****************************************************************************
                       Error Handler Object
****************************************************************************}
{+--------------------------------------------------------------------------+}
{| Name       : Init                                                        |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Initialize an errror handler object                         |}
{| Parameters : DisplayObject - pointer to user defined error display object|}
{| Returns    : none                                                        |}
{| Notes      : Sets the default error set to all errors except bEOF and    |}
{|              bKeyNotFound.                                               |}
{+--------------------------------------------------------------------------+}
Constructor ErrorHandler.Init(DisplayObject : PErrorDisplay);
  begin
    RetryCount := 0;
    MaxRetry   := 5;
    { turn seconds into milliseconds }
    RetryDelay  := 5000;
    ErrDisplay  := DisplayObject;
    { init Errors handled to all except End Of File }
    TrappedErrors := [bInvalidOp..bLastError] - [bEOF];
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Done                                                        |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Destroy the object                                          |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Destructor ErrorHandler.Done;
  begin
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ErrorMsg                                                    |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Return the message for a btrieve error code                 |}
{| Parameters : ErrorCode - a btrieve status code                           |}
{| Returns    : A message string                                            |}
{+--------------------------------------------------------------------------+}
Function ErrorHandler.ErrorMsg(ErrorCode : Integer): String;
  begin
    Case ErrorCode of
      bOkay               : ErrorMsg := 'No error';
      bInvalidOp          : ErrorMsg := 'Invalid operation';
      bIOerror            : ErrorMsg := 'I/O error';
      bFileNotOpen        : ErrorMsg := 'File not open';
      bKeyNotFound        : ErrorMsg := 'Key value not found';
      bDuplicateKey       : ErrorMsg := 'Duplicate keys not allowed';
      bInvalidKey         : ErrorMsg := 'Invalid key number';
      bDifferentKey       : ErrorMsg := 'Different key number from previous read';
      bInvalidPos         : ErrorMsg := 'Invalid file positioning';
      bEOF                : ErrorMsg := 'End of file';
      bKeyModifyErr       : ErrorMsg := 'Key data may not be modified';
      bInvalidName        : ErrorMsg := 'Invalid file name';
      bFileNotFound       : ErrorMsg := 'File not found';
      bPreImageOpenErr    : ErrorMsg := 'Pre-Image file open error';
      bPreImageIOErr      : ErrorMsg := 'Pre-Image file I/O error';
      bExpansionErr       : ErrorMsg := 'Expansion file error';
      bCloseErr           : ErrorMsg := 'Close error';
      bDiskFull           : ErrorMsg := 'Disk full';
      bUnRecoverableErr   : ErrorMsg := 'Unrecoverable error, File may be corrupt';
      bNotLoaded          : ErrorMsg := 'Record Manager not loaded';
      bKeyBufferShort     : ErrorMsg := 'Key buffer too short';
      bDataBufferShort    : ErrorMsg := 'Data buffer too short';
      bPosBlockShort      : ErrorMsg := 'Position block is not 128 bytes in size';
      bPageSizeErr        : ErrorMsg := 'Page size error';
      bCreateIOErr        : ErrorMsg := 'File creation error';
      bNumberKeys         : ErrorMsg := 'Number of keys is invalid';
      bInvalidKeyPos      : ErrorMsg := 'Invalid key position';
      bRecordLenErr       : ErrorMsg := 'Invalid record length';
      bKeyLenErr          : ErrorMsg := 'Invalid key length';
      bNotBtrieveFile     : ErrorMsg := 'File is not a Btrieve file';
      bTransactionErr     : ErrorMsg := '/T option was not specified';
      bTransactionActive  : ErrorMsg := 'A transaction is already active';
      bTransactionFileErr : ErrorMsg := 'Transaction control file I/O error';
      bTransactionEndErr  : ErrorMsg := 'No begin transaction issued';
      bTransactionMaxFiles: ErrorMsg := 'Maximum number of transaction files (12) exceeded';
      bOpNotAllowed       : ErrorMsg := 'Operation not allowed';
      bAcceleratedErr     : ErrorMsg := 'Incomplete accelerated access, File may be corrupt';
      bInvalidAddress     : ErrorMsg := 'Invalid record address';
      bNullKeypath        : ErrorMsg := 'Null key path';
      bBadKeyFlags        : ErrorMsg := 'Inconsistent key flags';
      bFileAccessDenied   : ErrorMsg := 'Access to file denied';
      bMaxOpenFiles       : ErrorMsg := 'Maximum number of files open';
      bInvalidAltSequence : ErrorMsg := 'Invalid alternate collating sequence definition';
      bKeyTypeErr         : ErrorMsg := 'Key type error';
      bOwnerIsSet         : ErrorMsg := 'Owner is already set';
      bInvalidOwner       : ErrorMsg := 'Invalid owner';
      bCacheWriteErr      : ErrorMsg := 'Error writing cache buffer';
      bInvalidVersion     : ErrorMsg := 'Invalid Btrieve version';
      bVariablePageErr    : ErrorMsg := 'Variable page error';
      bAutoIncrementErr   : ErrorMsg := 'Autoincrement key error';
      bBadIndex           : ErrorMsg := 'A supplemental index is damaged';
      bExpandedMemoryErr  : ErrorMsg := 'Expanded memory error';
      bCompressBuffShort  : ErrorMsg := 'Compression buffer too short';
      bFileExists         : ErrorMsg := 'File already exists';
      bTTSabort           : ErrorMsg := 'Automatic transaction abort';
      bDeadlock           : ErrorMsg := 'Deadlock detected';
      bConflict           : ErrorMsg := 'Record has been changed';
      bLockErr            : ErrorMsg := 'File lock error';
      bLostPosition       : ErrorMsg := 'File positioning lost';
      bOutOfTransaction   : ErrorMsg := 'Read outside of a transaction';
      bRecordInUse        : ErrorMsg := 'Record in use';
      bFileInUse          : ErrorMsg := 'File in use';
      bFileTblFull        : ErrorMsg := 'File table is full';
      bHandleTblFull      : ErrorMsg := 'No file handles available';
      bBadModeErr         : ErrorMsg := 'Incompatible file open mode';
      bDeviceTableFull    : ErrorMsg := 'Redirected device table full';
      bServerErr          : ErrorMsg := 'Server error';
      bTranTableFull      : ErrorMsg := 'Transaction table full';
      bBadLockType        : ErrorMsg := 'Lock types are incompatible';
      bPermissionErr      : ErrorMsg := 'Permission error';
      bSessionInvalid     : ErrorMsg := 'Session no longer valid';
      bCommunicationErr   : ErrorMsg := 'Communications environment error';
      bDataMessageShort   : ErrorMsg := 'Data message to small';
      bInternalTTSerr     : ErrorMsg := 'Internal TTS error';
      bOutOfMemory        : ErrorMsg := 'Out of Memory';
      else
        ErrorMsg := 'Unknown error';
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : OpMsg                                                        |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Return the message for a btrieve error code                 |}
{| Parameters : ErrorCode - a btrieve status code                           |}
{| Returns    : A message string                                            |}
{+--------------------------------------------------------------------------+}
Function ErrorHandler.OpMsg(OpCode : Integer): String;
  begin
    Case OpCode of
      bOpen             : OpMsg := 'Open file';
      bClose            : OpMsg := 'Close file';
      bInsert           : OpMsg := 'Insert new record';
      bUpdate           : OpMsg := 'Update existing record';
      bDelete           : OpMsg := 'Delete record';
      bGetEqual         : OpMsg := 'Read record equal to key';
      bGetGreat         : OpMsg := 'Read record greater than key';
      bGetGreatEqual    : OpMsg := 'Read record greater than or equal to key';
      bGetLess          : OpMsg := 'Read record less than key';
      bGetLessEqual     : OpMsg := 'Read record less than or equal to key';
      bGetNext          : OpMsg := 'Read next record';
      bGetPrev          : OpMsg := 'Read previous record';
      bGetFirst         : OpMsg := 'Read first record';
      bGetLast          : OpMsg := 'Read last record';
      bCreate           : OpMsg := 'Create file';
      bStat             : OpMsg := 'Get file statistics';
      bBeginTransaction : OpMsg := 'Begin transaction';
      bEndTransaction   : OpMsg := 'End transaction';
      bAbortTransaction : OpMsg := 'Abort transaction';
      bGetPosition      : OpMsg := 'Get record position';
      bGetDirect        : OpMsg := 'Read record by position';
      bStepNext         : OpMsg := 'Step to next record';
      bStop             : OpMsg := 'Unload record manager';
      bVersion          : OpMsg := 'Get version number';
      bUnlock           : OpMsg := 'Unlock';
      bReset            : OpMsg := 'Reset record manager';
      bSetOwner         : OpMsg := 'Set file owner';
      bClearOwner       : OpMsg := 'Clear file owner';
      bCreateIndex      : OpMsg := 'Creating supplemental index';
      bDropIndex        : OpMsg := 'Dropping supplemental index';
      bStepFirst        : OpMsg := 'Step to first record';
      bStepLast         : OpMsg := 'Step to last record';
      bStepPrev         : OpMsg := 'Step to previous record';

      else
        OpMsg := 'Unknown operation';
    end;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetMaxRetry                                                 |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Set the maximum number of retries for lock errors           |}
{| Parameters : Retry - max. retries                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.SetMaxRetry(Retry : Word);
  begin
    MaxRetry := Retry;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : GetMaxRetry                                                 |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Get max. number of retries                                   |}
{| Parameters : none                                                        |}
{| Returns    : Maximum number of retries                                    |}
{+--------------------------------------------------------------------------+}
Function ErrorHandler.GetMaxRetry: Word;
  begin
    GetMaxRetry := MaxRetry;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ClearRetry                                                  |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Clear the current number of retries                          |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.ClearRetry;
  begin
    { clear the current retry count }
    RetryCount  := 0;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetDelay                                                    |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Set the delay between lock retries                           |}
{| Parameters : Seconds - how long to wait                                  |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.SetDelay(Seconds : Word);
  begin
    { turn seconds into milliseconds }
    RetryDelay  := Seconds * 1000;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : GetDelay                                                    |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Get the seconds of delay between lock retries                |}
{| Parameters : none                                                        |}
{| Returns    : Seconds delay                                               |}
{+--------------------------------------------------------------------------+}
Function ErrorHandler.GetDelay: Word;
  begin
    { turn milliseconds into seconds }
    GetDelay  := RetryDelay Div 1000;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : AddError                                                    |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Add an error to the trapped error set                       |}
{| Parameters : ErrorCode - btrieve status code to add                      |}
{| Returns    : none                                                        |}
{| Notes      : All errors except bEOF are trapped by default               |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.AddErrors(ErrorCodes : ErrorSet);
  begin
    TrappedErrors := TrappedErrors + ErrorCodes;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : RemoveError                                                 |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Remove a error form the trapped errors                      |}
{| Parameters : ErrorCode - btrieve status code to remove                   |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : bOkay will not be removed.                                  |}
{|              All errors except bEOF are trapped by default               |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.RemoveErrors(ErrorCodes : ErrorSet);
  begin
    TrappedErrors := TrappedErrors - ErrorCodes;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : SetErrors                                                   |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Make the set of all trapped errors.                         |}
{| Parameters : ErrorCodes - A set of btrieve status codes to become the new|}
{|                           trapped error set.                             |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.SetErrors(ErrorCodes : ErrorSet);
  begin
    TrappedErrors := ErrorCodes;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : GetErrors                                                   |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Return the set of all trapped errors.                       |}
{| Parameters : ErrorCodes - The set of btrieve status codes currently      |}
{|              trapped.                                                    |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Procedure ErrorHandler.GetErrors(var ErrorCodes : ErrorSet);
  begin
    ErrorCodes  := TrappedErrors;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : ErrorDispatcher                                             |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : This routine calls the error display object and if the error|}
{|              display object says abort halts the program.                |}
{| Parameters : ErrorCode - btrieve error                                   |}
{|              OpCode    - btrieve operation that generate error           |}
{|              FileName  - file the error occured with                     |}
{| Returns    : If error is not fatal, a flag of type ErrorAction indicating|}
{|              continue or start over.                                     |}
{| Notes      : Assumes there is an exit routine that will Reset btrieve if |}
{|              desired.                                                    |}
{+--------------------------------------------------------------------------+}
Function ErrorHandler.ErrorDispacther(ErrorCode : Integer;
                                      OpCode    : Byte;
                                      FileName  : PathStr
                                     ): ErrorAction;

  var
    Action  : ErrorAction;

  begin
    { call error object to display the error messages }
    { and see if user wants to stop                   }
    if (ErrDisplay <> nil) then
    begin
      Action := ErrDisplay^.Display(ErrorCode,
                                    ErrorMsg(ErrorCode),
                                    OpCode,
                                    OpMsg(OpCode),
                                    FileName);

      { the error is fatal, so abort through the defined exit procedure }
      if (Action = erAbort) then
        Halt(ErrorCode);
    end

    else
    begin
      Action := erDone;
    end;

    { clear retries so we are ready for more looping }
    ClearRetry;
    ErrorDispacther := Action;
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Error                                                       |}
{| Class      : ErrorHandler                                                |}
{| Purpose    : Traps all non-programmer errors                             |}
{| Parameters : Status    - the last btrieve status code                    |}
{|              OpCode    - btrieve operation that generate error           |}
{|              FileName  - file the error occured with                     |}
{| Returns    : TRUE as long as there is still an error.                    |}
{| Notes      : This routine is called by all routines that execute a       |}
{|              btrieve operation. Any errors that are removed by a call to |}
{|              RemoveError will return to the user program,all other errors|}
{|              will be trapped. Lock errors (bRecordInUse, bFileInUse)     |}
{|              enter the retry loop.                                       |}
{+--------------------------------------------------------------------------+}
Function ErrorHandler.Error(Status   : Integer;
                            OpCode   : Byte;
                            FileName : PathStr
                           ): Boolean;
  begin
    { handle all trapped errors }
    if (Status in TrappedErrors) then
    begin
      { these are lock errors }
      if (Status = bRecordInUse) or (Status = bFileInUse) then
      begin
        { if there are retries left }
        if (RetryCount < MaxRetry) then
        begin
          Inc(RetryCount);
          Delay(RetryDelay);
          Error := True;
        end

        { else go see what the user wants to do }
        else
          { error dispatcher returns either a continue or start over }
          Error := (ErrorDispacther(Status, OpCode, FileName) = erRetry);
      end

      { any other error go see what the user wants to do }
      else
        { error dispatcher returns either a continue or start over }
        Error := (ErrorDispacther(Status, OpCode, FileName) = erRetry);
    end {if}

    { else this is a programmer handled error }
    else
    begin
      { return with "No more error"  status }
      Error := False;
      { clear the retry counter so we are ready for more looping }
      ClearRetry;
    end; {else}
  end;

{****************************************************************************
                         ERROR DISPLAY OBJECT
 Note: These are abstract routines and provide no functionality they are
       shells only. For each instance you must override these routines.
****************************************************************************=}
{+--------------------------------------------------------------------------+}
{| Name       : Init                                                        |}
{| Class      : ErrorDisplay                                                |}
{| Purpose    : Initialize the error display object.                        |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Constructor ErrorDisplay.Init;
  begin
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Display                                                     |}
{| Class      : ErrorDisplay                                                |}
{| Purpose    : Display an error passed from the error handler              |}
{| Parameters : ErrorNumber - the btrieve code that caused the call         |}
{|              OpCode      - btrieve operation that generate error         |}
{|              ErrorMsg    - error description                             |}
{|              FileName    - file the error occured with                   |}
{| Returns    : Returns a flag of type ErrorAction indicating whether the   |}
{|              program should Abort, Continue, or Start Over.              |}
{| Notes      : In practice this routine must check the error and decide    |}
{|              what to do. This is where errors will be displayed and any  |}
{|              user response recieved. However the error is handled, this  |}
{|              routine must return some action (erAbort, erDone, erRetry)  |}
{|              to tell the error handler what to do next.                  |}
{+--------------------------------------------------------------------------+}
Function ErrorDisplay.Display(Error     : Integer;
                              ErrorMsg  : String;
                              OpCode    : Byte;
                              OpCodeMsg : String;
                              FileName  : PathStr
                             ): ErrorAction;
  begin
    { this procedure is virtual and must always be overridden }
    { a call here is illegal, so generate a runtime error     }
    RunError(211);
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Done                                                        |}
{| Class      : ErrorDisplay                                                |}
{| Purpose    : Destroy the object                                          |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{+--------------------------------------------------------------------------+}
Destructor ErrorDisplay.Done;
  begin
  end;

{****************************************************************************
                         PROGRESS DISPLAY OBJECT
 Note: These are abstract routines and provide no functionality they are
       shells only. For each instance you must override these routines.
****************************************************************************=}
{+--------------------------------------------------------------------------+}
{| Name       : Init                                                        |}
{| Class      : TProgress                                                   |}
{| Purpose    : Initialize the progress in display object.                  |}
{| Parameters : None                                                        |}
{| Returns    : None                                                        |}
{+--------------------------------------------------------------------------+}
Constructor TProgress.Init;
  begin
  end;

{+--------------------------------------------------------------------------+}
{| Name       : Display                                                     |}
{| Class      : TProgress                                                   |}
{| Purpose    : Display an the progress in during recover, save or load.    |}
{| Parameters : Count - current record count                                |}
{| Returns    : None                                                        |}
{| Notes      : In practice this routine would display some sort of progress|}
{|              update to calm the users fears that her amchine has locked. |}
{+--------------------------------------------------------------------------+}
Procedure TProgress.Display(Count : LongInt);
  begin
  end;


{+--------------------------------------------------------------------------+}
{| Name       : CheckForBtrieve                                             |}
{| Purpose    : See if Btrieve is loaded and abort if it is not.            |}
{| Parameters : none                                                        |}
{| Returns    : none                                                        |}
{| Notes      : Prints a message to the screen and halts with exit code 999 |}
{|              if Btrieve is not found.                                    |}
{+--------------------------------------------------------------------------+}
Procedure CheckForBtrieve;

  var
    I     : Integer;
    W     : Word;
    Regs  : Registers;
    St    : String[80];
    Len   : Byte Absolute St;
    Temp  : Array[0..80] of Char;

  begin
    { try a reset to see if Btrieve is loaded }
    if (Btrv(bReset, I, I, W, I, 0) <> bOkay) then
    begin
      { display a message and halt  }
      St := 'Btrieve Record Manager is not loaded, program aborted!';
      Move(St[1], Temp[0], Len);
      Temp[Len]   := #13;
      Temp[Len+1] := #10;
      Temp[Len+2] := '$';
      Regs.DS := Seg(Temp);
      Regs.DX := Ofs(Temp);
      Regs.AH := $09;
      { call DOS int 21h function 09h to print the string because unlike
        Turbo's Writeln this output will get redirected
      }
      MsDos(Regs);
      { halt with some non-zero error so a parent process can tell
        there was a problem
      }
      Halt(999);
    end;
  end;


{+--------------------------------------------------------------------------+}
{| Name       : HeapFunc                                                    |}
{| Purpose    : Make sure New and GetMem return nil on errors.              |}
{+--------------------------------------------------------------------------+}
Function HeapFunc(Size : Word): Integer;  FAR;
  begin
    HeapFunc := 1;
  end;


BEGIN
  HeapError := @HeapFunc;   { Add a heap function so errors return nil  }

  {$IFDEF BCHECK}
  CheckForBtrieve;
  {$ENDIF}
END.