trunk/runtime/IBBlob.pas

{************************************************************************}
{                                                                        }
{       Borland Delphi Visual Component Library                          }
{       InterBase Express core components                                }
{                                                                        }
{       Copyright (c) 1998-2000 Inprise Corporation                      }
{                                                                        }
{    InterBase Express is based in part on the product                   }
{    Free IB Components, written by Gregory H. Deatz for                 }
{    Hoagland, Longo, Moran, Dunst & Doukas Company.                     }
{    Free IB Components is used under license.                           }
{                                                                        }
{    The contents of this file are subject to the InterBase              }
{    Public License Version 1.0 (the "License"); you may not             }
{    use this file except in compliance with the License. You            }
{    may obtain a copy of the License at http://www.Inprise.com/IPL.html }
{    Software distributed under the License is distributed on            }
{    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either              }
{    express or implied. See the License for the specific language       }
{    governing rights and limitations under the License.                 }
{    The Original Code was created by InterBase Software Corporation     }
{       and its successors.                                              }
{    Portions created by Inprise Corporation are Copyright (C) Inprise   }
{       Corporation. All Rights Reserved.                                }
{    Contributor(s): Jeff Overcash                                       }
{                                                                        }
{    IBX For Lazarus (Firebird Express)                                  }
{    Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
{    Portions created by MWA Software are copyright McCallum Whyman      }
{    Associates Ltd 2011                                                 }
{************************************************************************}

unit IBBlob;

{$mode Delphi}

interface

uses
  SysUtils, Classes, IBHeader, IBErrorCodes, IBExternals, DB, IB, IBDatabase;


const
  DefaultBlobSegmentSize = 16 * 1024;

type
  TIBBlobStates = (bsUninitialised, bsDataPending, bsData, bsModified);

  { TIBBlobStream }
  TIBBlobStream = class(TStream)
  private
    FBase: TIBBase;
    FBlobID: TISC_QUAD;
    FBlobMaxSegmentSize: Int64;
    FBlobNumSegments: Int64;
    FBlobSize: Int64;
    FBlobType: Short;  { 0 = segmented, 1 = streamed }
    FBuffer: PChar;
    FHandle: TISC_BLOB_HANDLE;
    FMode: TBlobStreamMode;
    FPosition: Int64;
    FBlobState: TIBBlobStates;
    function GetModified: Boolean;
  protected
    procedure CloseBlob;
    procedure CreateBlob;
    procedure EnsureBlobInitialized;
    procedure EnsureLoaded;
    procedure GetBlobInfo;
    function  GetSize: Int64; override;
    function GetDatabase: TIBDatabase;
    function GetDBHandle: PISC_DB_HANDLE;
    function GetTransaction: TIBTransaction;
    function GetTRHandle: PISC_TR_HANDLE;
    procedure OpenBlob;
    procedure SetBlobID(Value: TISC_QUAD);
    procedure SetDatabase(Value: TIBDatabase);
    procedure SetMode(Value: TBlobStreamMode);
    procedure SetState(aValue: TIBBlobStates);
    procedure SetTransaction(Value: TIBTransaction);
  public
    constructor Create;
    destructor Destroy; override;
    function Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
    procedure CheckReadable;
    procedure CheckWritable;
    procedure Finalize;
    procedure LoadFromFile(Filename: string);
    procedure LoadFromStream(Stream: TStream);
    function Read(var Buffer; Count: Longint): Longint; override;
    procedure SaveToFile(Filename: string);
    procedure SaveToStream(Stream: TStream);
    function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
    procedure SetSize(const NewSize: Int64); override;
    procedure SetSize(NewSize: Longint); override;
    procedure Truncate;
    function Write(const Buffer; Count: Longint): Longint; override;
    property Handle: TISC_BLOB_HANDLE read FHandle;
    property BlobID: TISC_QUAD read FBlobID write SetBlobID;
    property BlobMaxSegmentSize: Int64 read FBlobMaxSegmentSize;
    property BlobNumSegments: Int64 read FBlobNumSegments;
    property BlobSize: Int64 read GetSize;
    property BlobType: Short read FBlobType;
    property Database: TIBDatabase read GetDatabase write SetDatabase;
    property DBHandle: PISC_DB_HANDLE read GetDBHandle;
    property Mode: TBlobStreamMode read FMode write SetMode;
    property Modified: Boolean read GetModified;
    property Transaction: TIBTransaction read GetTransaction write SetTransaction;
    property TRHandle: PISC_TR_HANDLE read GetTRHandle;
  end;

  procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments: Int64; var MaxSegmentSize,
                      TotalSize: Int64; var BlobType: Short);
  function GetBlobCharSetID(hDB_Handle: TISC_DB_HANDLE; hTR_Handle: TISC_TR_HANDLE;
                      tableName, columnName: PChar): short;
  procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
  procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);

implementation

uses IBIntf;

procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments: Int64; var MaxSegmentSize,
                      TotalSize: Int64; var BlobType: Short);
var
  items: array[0..3] of Char;
  results: array[0..99] of Char;
  i, item_length: Integer;
  item: Integer;
begin
  items[0] := Char(isc_info_blob_num_segments);
  items[1] := Char(isc_info_blob_max_segment);
  items[2] := Char(isc_info_blob_total_length);
  items[3] := Char(isc_info_blob_type);

  if isc_blob_info(StatusVector, hBlobHandle, 4, @items[0], SizeOf(results),
                    @results[0]) > 0 then
    IBDatabaseError;

  i := 0;
  while (i < SizeOf(results)) and (results[i] <> Char(isc_info_end)) do
  begin
    item := Integer(results[i]); Inc(i);
    item_length := isc_vax_integer(@results[i], 2); Inc(i, 2);
    case item of
      isc_info_blob_num_segments:
        NumSegments := isc_portable_integer(@results[i], item_length);
      isc_info_blob_max_segment:
        MaxSegmentSize := isc_portable_integer(@results[i], item_length);
      isc_info_blob_total_length:
        TotalSize := isc_portable_integer(@results[i], item_length);
      isc_info_blob_type:
        BlobType := isc_portable_integer(@results[i], item_length);
    end;
    Inc(i, item_length);
  end;
end;

function GetBlobCharSetID(hDB_Handle: TISC_DB_HANDLE;
  hTR_Handle: TISC_TR_HANDLE; tableName, columnName: PChar): short;
var desc: TISC_BLOB_DESC;
    uGlobal: array [0..31] of char;
begin
  if isc_blob_lookup_desc(StatusVector,@hDB_Handle,@hTR_Handle,
                tableName,columnName,@desc,@uGlobal) > 0 then
    IBDatabaseError;

  Result := desc.blob_desc_charset;
end;

procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
var
  CurPos: Int64;
  BytesRead, SegLen: UShort;
  LocalBuffer: PChar;
begin
  CurPos := 0;
  LocalBuffer := Buffer;
  SegLen := UShort(DefaultBlobSegmentSize);
  while (CurPos < BlobSize) do
  begin
    if (CurPos + SegLen > BlobSize) then
      SegLen := BlobSize - CurPos;
    if not ((isc_get_segment(StatusVector, hBlobHandle, @BytesRead, SegLen,
                             LocalBuffer) = 0) or
            (StatusVectorArray[1] = isc_segment)) then
      IBDatabaseError;
    Inc(LocalBuffer, BytesRead);
    Inc(CurPos, BytesRead);
    BytesRead := 0;
  end;
end;

procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar;
  BlobSize: Int64);
var
  CurPos: Int64;
  SegLen: Long;
begin
  CurPos := 0;
  SegLen := DefaultBlobSegmentSize;
  while (CurPos < BlobSize) do
  begin
    if (CurPos + SegLen > BlobSize) then
      SegLen := BlobSize - CurPos;
    if isc_put_segment(StatusVector, hBlobHandle, SegLen,
         PChar(@Buffer[CurPos])) > 0 then
      IBDatabaseError;
    Inc(CurPos, SegLen);
  end;
end;


{ TIBBlobStream }
constructor TIBBlobStream.Create;
begin
  inherited Create;
  FBase := TIBBase.Create(Self);
  FBuffer := nil;
  FBlobSize := 0;
  FBlobState := bsUninitialised;
end;

destructor TIBBlobStream.Destroy;
begin
  SetState(bsUninitialised);
  FBase.Free;
  SetSize(0);
  inherited Destroy;
end;

function TIBBlobStream.Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
begin
  result := 0;
  if Transaction <> nil then
    result := Transaction.Call(ErrCode, RaiseError)
  else if RaiseError and (ErrCode > 0) then
    IBDataBaseError;
end;

procedure TIBBlobStream.CheckReadable;
begin
  if FMode = bmWrite then IBError(ibxeBlobCannotBeRead, [nil]);
end;

procedure TIBBlobStream.CheckWritable;
begin
  if FMode = bmRead then IBError(ibxeBlobCannotBeWritten, [nil]);
end;

function TIBBlobStream.GetModified: Boolean;
begin
  Result := FBlobState = bsModified;
end;

procedure TIBBlobStream.CloseBlob;
begin
  Finalize;
  SetState(bsUninitialised);
end;

procedure TIBBlobStream.CreateBlob;
begin
  CheckWritable;
  FBlobID.gds_quad_high := 0;
  FBlobID.gds_quad_low := 0;
  SetState(bsData);
  SetSize(0);
end;

procedure TIBBlobStream.EnsureBlobInitialized;
begin
  if FBlobState = bsUninitialised then
    case FMode of
      bmWrite:
        CreateBlob;
      bmReadWrite: begin
        if (FBlobID.gds_quad_high = 0) and
           (FBlobID.gds_quad_low = 0) then
          CreateBlob
        else
          OpenBlob;
      end;
      else
        OpenBlob;
    end;
end;

procedure TIBBlobStream.EnsureLoaded;
begin
  EnsureBlobInitialized;
  if FBlobState = bsDataPending then
  begin
    SetSize(FBlobSize);
    try
      IBBlob.ReadBlob(@FHandle, FBuffer, FBlobSize);
    except
      Call(isc_close_blob(StatusVector, @FHandle), False);
      raise;
    end;
    SetState(bsData);
  end;
end;

procedure TIBBlobStream.Finalize;
begin
  if FBlobState <> bsModified then
    exit;
  if FBlobSize > 0 then
  begin
    { need to start writing to a blob, create one }
    Call(isc_create_blob2(StatusVector, DBHandle, TRHandle, @FHandle, @FBlobID,
                         0, nil), True);
    IBBlob.WriteBlob(@FHandle, FBuffer, FBlobSize);
    Call(isc_close_blob(StatusVector, @FHandle), True);
  end
  else
  begin
    FBlobID.gds_quad_high := 0;
    FBlobID.gds_quad_low := 0;
  end;
  SetState(bsData);
end;

procedure TIBBlobStream.GetBlobInfo;
var
  iBlobSize: Int64;
begin
  IBBlob.GetBlobInfo(@FHandle, FBlobNumSegments, FBlobMaxSegmentSize,
    iBlobSize, FBlobType);
  SetSize(iBlobSize);
end;

function TIBBlobStream.GetSize: Int64;
begin
  EnsureBlobInitialized;
  Result := FBlobSize;
end;

function TIBBlobStream.GetDatabase: TIBDatabase;
begin
  result := FBase.Database;
end;

function TIBBlobStream.GetDBHandle: PISC_DB_HANDLE;
begin
  result := FBase.DBHandle;
end;

function TIBBlobStream.GetTransaction: TIBTransaction;
begin
  result := FBase.Transaction;
end;

function TIBBlobStream.GetTRHandle: PISC_TR_HANDLE;
begin
  result := FBase.TRHandle;
end;

procedure TIBBlobStream.LoadFromFile(Filename: string);
var
  Stream: TStream;
begin
  Stream := TFileStream.Create(FileName, fmOpenRead);
  try
    LoadFromStream(Stream);
  finally
    Stream.Free;
  end;
end;

procedure TIBBlobStream.LoadFromStream(Stream: TStream);
begin
  CheckWritable;
  EnsureBlobInitialized;
  Stream.Position := 0;
  SetSize(Stream.Size);
  if FBlobSize <> 0 then
    Stream.ReadBuffer(FBuffer^, FBlobSize);
  SetState(bsModified);
end;

procedure TIBBlobStream.OpenBlob;
begin
  CheckReadable;
  Call(isc_open_blob2(StatusVector, DBHandle, TRHandle, @FHandle,
                     @FBlobID, 0, nil), True);
  try
    GetBlobInfo;
    {Defer reading in blob until read method called}
  except
    Call(isc_close_blob(StatusVector, @FHandle), False);
    raise;
  end;
  SetState(bsDataPending);
end;

function TIBBlobStream.Read(var Buffer; Count: Longint): Longint;
begin
  CheckReadable;
  EnsureLoaded;
  if (Count <= 0) then
  begin
    result := 0;
    exit;
  end;
  if (FPosition + Count > FBlobSize) then
    result := FBlobSize - FPosition
  else
    result := Count;
  Move(FBuffer[FPosition], Buffer, result);
  Inc(FPosition, Result);
end;

procedure TIBBlobStream.SaveToFile(Filename: string);
var
  Stream: TStream;
begin
  Stream := TFileStream.Create(FileName, fmCreate);
  try
    SaveToStream(Stream);
  finally
    Stream.Free;
  end;
end;

procedure TIBBlobStream.SaveToStream(Stream: TStream);
begin
  CheckReadable;
  EnsureLoaded;
  if FBlobSize <> 0 then
  begin
    Seek(0, soFromBeginning);
    Stream.WriteBuffer(FBuffer^, FBlobSize);
  end;
end;

function TIBBlobStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;
begin
  EnsureBlobInitialized;
  case Origin of
    soBeginning     : FPosition := Offset;
    soCurrent       : Inc(FPosition, Offset);
    soEnd           : FPosition := FBlobSize + Offset;
  end;
  result := FPosition;
end;

procedure TIBBlobStream.SetBlobID(Value: TISC_QUAD);
begin
  System.Move(Value, FBlobID, SizeOf(TISC_QUAD));
  SetState(bsUninitialised);
end;

procedure TIBBlobStream.SetDatabase(Value: TIBDatabase);
begin
  FBase.Database := Value;
  SetState(bsUninitialised);
end;

procedure TIBBlobStream.SetMode(Value: TBlobStreamMode);
begin
  FMode := Value;
  SetState(bsUninitialised);
end;

procedure TIBBlobStream.SetState(aValue: TIBBlobStates);
begin
  if FBlobState = aValue then Exit;

  if FBlobState = bsDataPending then
    Call(isc_close_blob(StatusVector, @FHandle), True);

  FBlobState := aValue;
end;

procedure TIBBlobStream.SetSize(const NewSize: Int64);
begin
  if (NewSize <> FBlobSize) then
  begin
    ReallocMem(FBuffer, NewSize);
    FBlobSize := NewSize;
    if NewSize = 0 then
      FBuffer := nil;
  end;
end;

procedure TIBBlobStream.SetSize(NewSize: Longint);
begin
  SetSize(Int64(NewSize));
end;

procedure TIBBlobStream.SetTransaction(Value: TIBTransaction);
begin
  FBase.Transaction := Value;
  SetState(bsUninitialised);
end;

procedure TIBBlobStream.Truncate;
begin
  SetSize(0);
  SetState(bsModified);
end;

function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
begin
  CheckWritable;
  EnsureLoaded;  {Could be an untruncated bmReadWrite Blob}
  result := Count;
  if Count <= 0 then
    exit;
  if (FPosition + Count > FBlobSize) then
    SetSize(FPosition + Count);
  Move(Buffer, FBuffer[FPosition], Count);
  Inc(FPosition, Count);
  SetState(bsModified);
end;

end.
Revision:	41
Committed:	Sat Jul 16 12:25:48 2016 UTC (7 years, 9 months ago) by tony
Content type:	text/x-pascal
File size:	14766 byte(s)
Log Message:	Committing updates for Release R1-4-2
#	Content
1	{************************************************************************}
2	{ }
3	{ Borland Delphi Visual Component Library }
4	{ InterBase Express core components }
5	{ }
6	{ Copyright (c) 1998-2000 Inprise Corporation }
7	{ }
8	{ InterBase Express is based in part on the product }
9	{ Free IB Components, written by Gregory H. Deatz for }
10	{ Hoagland, Longo, Moran, Dunst & Doukas Company. }
11	{ Free IB Components is used under license. }
12	{ }
13	{ The contents of this file are subject to the InterBase }
14	{ Public License Version 1.0 (the "License"); you may not }
15	{ use this file except in compliance with the License. You }
16	{ may obtain a copy of the License at http://www.Inprise.com/IPL.html }
17	{ Software distributed under the License is distributed on }
18	{ an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either }
19	{ express or implied. See the License for the specific language }
20	{ governing rights and limitations under the License. }
21	{ The Original Code was created by InterBase Software Corporation }
22	{ and its successors. }
23	{ Portions created by Inprise Corporation are Copyright (C) Inprise }
24	{ Corporation. All Rights Reserved. }
25	{ Contributor(s): Jeff Overcash }
26	{ }
27	{ IBX For Lazarus (Firebird Express) }
28	{ Contributor: Tony Whyman, MWA Software http://www.mwasoftware.co.uk }
29	{ Portions created by MWA Software are copyright McCallum Whyman }
30	{ Associates Ltd 2011 }
31	{************************************************************************}
32
33	unit IBBlob;
34
35	{$mode Delphi}
36
37	interface
38
39	uses
40	SysUtils, Classes, IBHeader, IBErrorCodes, IBExternals, DB, IB, IBDatabase;
41
42
43	const
44	DefaultBlobSegmentSize = 16 * 1024;
45
46	type
47	TIBBlobStates = (bsUninitialised, bsDataPending, bsData, bsModified);
48
49	{ TIBBlobStream }
50	TIBBlobStream = class(TStream)
51	private
52	FBase: TIBBase;
53	FBlobID: TISC_QUAD;
54	FBlobMaxSegmentSize: Int64;
55	FBlobNumSegments: Int64;
56	FBlobSize: Int64;
57	FBlobType: Short; { 0 = segmented, 1 = streamed }
58	FBuffer: PChar;
59	FHandle: TISC_BLOB_HANDLE;
60	FMode: TBlobStreamMode;
61	FPosition: Int64;
62	FBlobState: TIBBlobStates;
63	function GetModified: Boolean;
64	protected
65	procedure CloseBlob;
66	procedure CreateBlob;
67	procedure EnsureBlobInitialized;
68	procedure EnsureLoaded;
69	procedure GetBlobInfo;
70	function GetSize: Int64; override;
71	function GetDatabase: TIBDatabase;
72	function GetDBHandle: PISC_DB_HANDLE;
73	function GetTransaction: TIBTransaction;
74	function GetTRHandle: PISC_TR_HANDLE;
75	procedure OpenBlob;
76	procedure SetBlobID(Value: TISC_QUAD);
77	procedure SetDatabase(Value: TIBDatabase);
78	procedure SetMode(Value: TBlobStreamMode);
79	procedure SetState(aValue: TIBBlobStates);
80	procedure SetTransaction(Value: TIBTransaction);
81	public
82	constructor Create;
83	destructor Destroy; override;
84	function Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
85	procedure CheckReadable;
86	procedure CheckWritable;
87	procedure Finalize;
88	procedure LoadFromFile(Filename: string);
89	procedure LoadFromStream(Stream: TStream);
90	function Read(var Buffer; Count: Longint): Longint; override;
91	procedure SaveToFile(Filename: string);
92	procedure SaveToStream(Stream: TStream);
93	function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
94	procedure SetSize(const NewSize: Int64); override;
95	procedure SetSize(NewSize: Longint); override;
96	procedure Truncate;
97	function Write(const Buffer; Count: Longint): Longint; override;
98	property Handle: TISC_BLOB_HANDLE read FHandle;
99	property BlobID: TISC_QUAD read FBlobID write SetBlobID;
100	property BlobMaxSegmentSize: Int64 read FBlobMaxSegmentSize;
101	property BlobNumSegments: Int64 read FBlobNumSegments;
102	property BlobSize: Int64 read GetSize;
103	property BlobType: Short read FBlobType;
104	property Database: TIBDatabase read GetDatabase write SetDatabase;
105	property DBHandle: PISC_DB_HANDLE read GetDBHandle;
106	property Mode: TBlobStreamMode read FMode write SetMode;
107	property Modified: Boolean read GetModified;
108	property Transaction: TIBTransaction read GetTransaction write SetTransaction;
109	property TRHandle: PISC_TR_HANDLE read GetTRHandle;
110	end;
111
112	procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments: Int64; var MaxSegmentSize,
113	TotalSize: Int64; var BlobType: Short);
114	function GetBlobCharSetID(hDB_Handle: TISC_DB_HANDLE; hTR_Handle: TISC_TR_HANDLE;
115	tableName, columnName: PChar): short;
116	procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
117	procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
118
119	implementation
120
121	uses IBIntf;
122
123	procedure GetBlobInfo(hBlobHandle: PISC_BLOB_HANDLE; var NumSegments: Int64; var MaxSegmentSize,
124	TotalSize: Int64; var BlobType: Short);
125	var
126	items: array[0..3] of Char;
127	results: array[0..99] of Char;
128	i, item_length: Integer;
129	item: Integer;
130	begin
131	items[0] := Char(isc_info_blob_num_segments);
132	items[1] := Char(isc_info_blob_max_segment);
133	items[2] := Char(isc_info_blob_total_length);
134	items[3] := Char(isc_info_blob_type);
135
136	if isc_blob_info(StatusVector, hBlobHandle, 4, @items[0], SizeOf(results),
137	@results[0]) > 0 then
138	IBDatabaseError;
139
140	i := 0;
141	while (i < SizeOf(results)) and (results[i] <> Char(isc_info_end)) do
142	begin
143	item := Integer(results[i]); Inc(i);
144	item_length := isc_vax_integer(@results[i], 2); Inc(i, 2);
145	case item of
146	isc_info_blob_num_segments:
147	NumSegments := isc_portable_integer(@results[i], item_length);
148	isc_info_blob_max_segment:
149	MaxSegmentSize := isc_portable_integer(@results[i], item_length);
150	isc_info_blob_total_length:
151	TotalSize := isc_portable_integer(@results[i], item_length);
152	isc_info_blob_type:
153	BlobType := isc_portable_integer(@results[i], item_length);
154	end;
155	Inc(i, item_length);
156	end;
157	end;
158
159	function GetBlobCharSetID(hDB_Handle: TISC_DB_HANDLE;
160	hTR_Handle: TISC_TR_HANDLE; tableName, columnName: PChar): short;
161	var desc: TISC_BLOB_DESC;
162	uGlobal: array [0..31] of char;
163	begin
164	if isc_blob_lookup_desc(StatusVector,@hDB_Handle,@hTR_Handle,
165	tableName,columnName,@desc,@uGlobal) > 0 then
166	IBDatabaseError;
167
168	Result := desc.blob_desc_charset;
169	end;
170
171	procedure ReadBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar; BlobSize: Int64);
172	var
173	CurPos: Int64;
174	BytesRead, SegLen: UShort;
175	LocalBuffer: PChar;
176	begin
177	CurPos := 0;
178	LocalBuffer := Buffer;
179	SegLen := UShort(DefaultBlobSegmentSize);
180	while (CurPos < BlobSize) do
181	begin
182	if (CurPos + SegLen > BlobSize) then
183	SegLen := BlobSize - CurPos;
184	if not ((isc_get_segment(StatusVector, hBlobHandle, @BytesRead, SegLen,
185	LocalBuffer) = 0) or
186	(StatusVectorArray[1] = isc_segment)) then
187	IBDatabaseError;
188	Inc(LocalBuffer, BytesRead);
189	Inc(CurPos, BytesRead);
190	BytesRead := 0;
191	end;
192	end;
193
194	procedure WriteBlob(hBlobHandle: PISC_BLOB_HANDLE; Buffer: PChar;
195	BlobSize: Int64);
196	var
197	CurPos: Int64;
198	SegLen: Long;
199	begin
200	CurPos := 0;
201	SegLen := DefaultBlobSegmentSize;
202	while (CurPos < BlobSize) do
203	begin
204	if (CurPos + SegLen > BlobSize) then
205	SegLen := BlobSize - CurPos;
206	if isc_put_segment(StatusVector, hBlobHandle, SegLen,
207	PChar(@Buffer[CurPos])) > 0 then
208	IBDatabaseError;
209	Inc(CurPos, SegLen);
210	end;
211	end;
212
213
214	{ TIBBlobStream }
215	constructor TIBBlobStream.Create;
216	begin
217	inherited Create;
218	FBase := TIBBase.Create(Self);
219	FBuffer := nil;
220	FBlobSize := 0;
221	FBlobState := bsUninitialised;
222	end;
223
224	destructor TIBBlobStream.Destroy;
225	begin
226	SetState(bsUninitialised);
227	FBase.Free;
228	SetSize(0);
229	inherited Destroy;
230	end;
231
232	function TIBBlobStream.Call(ErrCode: ISC_STATUS; RaiseError: Boolean): ISC_STATUS;
233	begin
234	result := 0;
235	if Transaction <> nil then
236	result := Transaction.Call(ErrCode, RaiseError)
237	else if RaiseError and (ErrCode > 0) then
238	IBDataBaseError;
239	end;
240
241	procedure TIBBlobStream.CheckReadable;
242	begin
243	if FMode = bmWrite then IBError(ibxeBlobCannotBeRead, [nil]);
244	end;
245
246	procedure TIBBlobStream.CheckWritable;
247	begin
248	if FMode = bmRead then IBError(ibxeBlobCannotBeWritten, [nil]);
249	end;
250
251	function TIBBlobStream.GetModified: Boolean;
252	begin
253	Result := FBlobState = bsModified;
254	end;
255
256	procedure TIBBlobStream.CloseBlob;
257	begin
258	Finalize;
259	SetState(bsUninitialised);
260	end;
261
262	procedure TIBBlobStream.CreateBlob;
263	begin
264	CheckWritable;
265	FBlobID.gds_quad_high := 0;
266	FBlobID.gds_quad_low := 0;
267	SetState(bsData);
268	SetSize(0);
269	end;
270
271	procedure TIBBlobStream.EnsureBlobInitialized;
272	begin
273	if FBlobState = bsUninitialised then
274	case FMode of
275	bmWrite:
276	CreateBlob;
277	bmReadWrite: begin
278	if (FBlobID.gds_quad_high = 0) and
279	(FBlobID.gds_quad_low = 0) then
280	CreateBlob
281	else
282	OpenBlob;
283	end;
284	else
285	OpenBlob;
286	end;
287	end;
288
289	procedure TIBBlobStream.EnsureLoaded;
290	begin
291	EnsureBlobInitialized;
292	if FBlobState = bsDataPending then
293	begin
294	SetSize(FBlobSize);
295	try
296	IBBlob.ReadBlob(@FHandle, FBuffer, FBlobSize);
297	except
298	Call(isc_close_blob(StatusVector, @FHandle), False);
299	raise;
300	end;
301	SetState(bsData);
302	end;
303	end;
304
305	procedure TIBBlobStream.Finalize;
306	begin
307	if FBlobState <> bsModified then
308	exit;
309	if FBlobSize > 0 then
310	begin
311	{ need to start writing to a blob, create one }
312	Call(isc_create_blob2(StatusVector, DBHandle, TRHandle, @FHandle, @FBlobID,
313	0, nil), True);
314	IBBlob.WriteBlob(@FHandle, FBuffer, FBlobSize);
315	Call(isc_close_blob(StatusVector, @FHandle), True);
316	end
317	else
318	begin
319	FBlobID.gds_quad_high := 0;
320	FBlobID.gds_quad_low := 0;
321	end;
322	SetState(bsData);
323	end;
324
325	procedure TIBBlobStream.GetBlobInfo;
326	var
327	iBlobSize: Int64;
328	begin
329	IBBlob.GetBlobInfo(@FHandle, FBlobNumSegments, FBlobMaxSegmentSize,
330	iBlobSize, FBlobType);
331	SetSize(iBlobSize);
332	end;
333
334	function TIBBlobStream.GetSize: Int64;
335	begin
336	EnsureBlobInitialized;
337	Result := FBlobSize;
338	end;
339
340	function TIBBlobStream.GetDatabase: TIBDatabase;
341	begin
342	result := FBase.Database;
343	end;
344
345	function TIBBlobStream.GetDBHandle: PISC_DB_HANDLE;
346	begin
347	result := FBase.DBHandle;
348	end;
349
350	function TIBBlobStream.GetTransaction: TIBTransaction;
351	begin
352	result := FBase.Transaction;
353	end;
354
355	function TIBBlobStream.GetTRHandle: PISC_TR_HANDLE;
356	begin
357	result := FBase.TRHandle;
358	end;
359
360	procedure TIBBlobStream.LoadFromFile(Filename: string);
361	var
362	Stream: TStream;
363	begin
364	Stream := TFileStream.Create(FileName, fmOpenRead);
365	try
366	LoadFromStream(Stream);
367	finally
368	Stream.Free;
369	end;
370	end;
371
372	procedure TIBBlobStream.LoadFromStream(Stream: TStream);
373	begin
374	CheckWritable;
375	EnsureBlobInitialized;
376	Stream.Position := 0;
377	SetSize(Stream.Size);
378	if FBlobSize <> 0 then
379	Stream.ReadBuffer(FBuffer^, FBlobSize);
380	SetState(bsModified);
381	end;
382
383	procedure TIBBlobStream.OpenBlob;
384	begin
385	CheckReadable;
386	Call(isc_open_blob2(StatusVector, DBHandle, TRHandle, @FHandle,
387	@FBlobID, 0, nil), True);
388	try
389	GetBlobInfo;
390	{Defer reading in blob until read method called}
391	except
392	Call(isc_close_blob(StatusVector, @FHandle), False);
393	raise;
394	end;
395	SetState(bsDataPending);
396	end;
397
398	function TIBBlobStream.Read(var Buffer; Count: Longint): Longint;
399	begin
400	CheckReadable;
401	EnsureLoaded;
402	if (Count <= 0) then
403	begin
404	result := 0;
405	exit;
406	end;
407	if (FPosition + Count > FBlobSize) then
408	result := FBlobSize - FPosition
409	else
410	result := Count;
411	Move(FBuffer[FPosition], Buffer, result);
412	Inc(FPosition, Result);
413	end;
414
415	procedure TIBBlobStream.SaveToFile(Filename: string);
416	var
417	Stream: TStream;
418	begin
419	Stream := TFileStream.Create(FileName, fmCreate);
420	try
421	SaveToStream(Stream);
422	finally
423	Stream.Free;
424	end;
425	end;
426
427	procedure TIBBlobStream.SaveToStream(Stream: TStream);
428	begin
429	CheckReadable;
430	EnsureLoaded;
431	if FBlobSize <> 0 then
432	begin
433	Seek(0, soFromBeginning);
434	Stream.WriteBuffer(FBuffer^, FBlobSize);
435	end;
436	end;
437
438	function TIBBlobStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;
439	begin
440	EnsureBlobInitialized;
441	case Origin of
442	soBeginning : FPosition := Offset;
443	soCurrent : Inc(FPosition, Offset);
444	soEnd : FPosition := FBlobSize + Offset;
445	end;
446	result := FPosition;
447	end;
448
449	procedure TIBBlobStream.SetBlobID(Value: TISC_QUAD);
450	begin
451	System.Move(Value, FBlobID, SizeOf(TISC_QUAD));
452	SetState(bsUninitialised);
453	end;
454
455	procedure TIBBlobStream.SetDatabase(Value: TIBDatabase);
456	begin
457	FBase.Database := Value;
458	SetState(bsUninitialised);
459	end;
460
461	procedure TIBBlobStream.SetMode(Value: TBlobStreamMode);
462	begin
463	FMode := Value;
464	SetState(bsUninitialised);
465	end;
466
467	procedure TIBBlobStream.SetState(aValue: TIBBlobStates);
468	begin
469	if FBlobState = aValue then Exit;
470
471	if FBlobState = bsDataPending then
472	Call(isc_close_blob(StatusVector, @FHandle), True);
473
474	FBlobState := aValue;
475	end;
476
477	procedure TIBBlobStream.SetSize(const NewSize: Int64);
478	begin
479	if (NewSize <> FBlobSize) then
480	begin
481	ReallocMem(FBuffer, NewSize);
482	FBlobSize := NewSize;
483	if NewSize = 0 then
484	FBuffer := nil;
485	end;
486	end;
487
488	procedure TIBBlobStream.SetSize(NewSize: Longint);
489	begin
490	SetSize(Int64(NewSize));
491	end;
492
493	procedure TIBBlobStream.SetTransaction(Value: TIBTransaction);
494	begin
495	FBase.Transaction := Value;
496	SetState(bsUninitialised);
497	end;
498
499	procedure TIBBlobStream.Truncate;
500	begin
501	SetSize(0);
502	SetState(bsModified);
503	end;
504
505	function TIBBlobStream.Write(const Buffer; Count: Longint): Longint;
506	begin
507	CheckWritable;
508	EnsureLoaded; {Could be an untruncated bmReadWrite Blob}
509	result := Count;
510	if Count <= 0 then
511	exit;
512	if (FPosition + Count > FBlobSize) then
513	SetSize(FPosition + Count);
514	Move(Buffer, FBuffer[FPosition], Count);
515	Inc(FPosition, Count);
516	SetState(bsModified);
517	end;
518
519	end.