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CCR.Exif.TiffUtils.pas
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CCR.Exif.TiffUtils.pas
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{**************************************************************************************}
{ }
{ CCR Exif - Delphi class library for reading and writing image metadata }
{ Version 1.5.3 }
{ }
{ The contents of this file are subject to the Mozilla Public License Version 1.1 }
{ (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.mozilla.org/MPL/ }
{ }
{ 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 is CCR.Exif.TiffUtils.pas. }
{ }
{ The Initial Developer of the Original Code is Chris Rolliston. Portions created by }
{ Chris Rolliston are Copyright (C) 2009-2014 Chris Rolliston. All Rights Reserved. }
{ }
{**************************************************************************************}
{$I CCR.Exif.inc}
unit CCR.Exif.TiffUtils;
interface
uses
Types, SysUtils, Classes, CCR.Exif.BaseUtils, CCR.Exif.StreamHelper;
type
EInvalidTiffData = class(ECCRExifException);
ETagAlreadyExists = class(EInvalidTiffData);
TTiffTagID = type Word;
{$Z2}
TTiffDataType = (tdByte = 1, tdAscii, tdWord, tdLongWord, tdLongWordFraction,
tdShortInt, tdUndefined, tdSmallInt, tdLongInt, tdLongIntFraction, tdSingle,
tdDouble, tdSubDirectory);
{$Z1}
TTiffDataTypes = set of TTiffDataType;
ITiffTag = interface;
TTiffTag = record const
HeaderSize = 12;
OffsetDataTypes = [tdWord, tdLongWord, {tdLongInt, }tdSubDirectory];
class function IsWellFormed(DataType: TTiffDataType; ElementCount: LongInt): Boolean; overload; static; {$IFDEF CanInline}inline;{$ENDIF}
class function IsWellFormed(const Tag: ITiffTag): Boolean; overload; static; {$IFDEF CanInline}inline;{$ENDIF}
class function MatchOffsetToByteCountID(OffsetTagID: TTiffTagID;
var ByteCountID: TTiffTagID): Boolean; static;
end;
PTiffTagInfo = ^TTiffTagInfo;
TTiffTagInfo = record
public
HeaderOffset, DataOffset: LongWord;
ID: TTiffTagID;
DataType: TTiffDataType;
ElementCount: LongInt;
function DataSize: Integer;
function IsWellFormed: Boolean; overload;{$IFDEF CanInline}inline;{$ENDIF}
end;
TTiffTagInfoDynArray = array of TTiffTagInfo;
TiffString = type AnsiString;
TTiffLongWordFraction = packed record
constructor Create(ANumerator: LongWord; ADenominator: LongWord = 1); overload;
constructor Create(const AQuotient: Currency); overload;
constructor CreateFromString(const AString: string);
class function CreateMissingOrInvalid: TTiffLongWordFraction; static;
function AsString: string; deprecated {$IFDEF DepCom}'Use ToString instead'{$ENDIF};
function MissingOrInvalid: Boolean;
function Quotient: Extended;
function ToString: string;
case Integer of
0: (Numerator, Denominator: LongWord);
1: (PackedValue: Int64);
end;
TTiffLongIntFraction = packed record
constructor Create(ANumerator: LongInt; ADenominator: LongInt = 1); overload;
constructor Create(const AQuotient: Currency); overload;
constructor CreateFromString(const AString: string);
class function CreateMissingOrInvalid: TTiffLongIntFraction; static;
function AsString: string; deprecated {$IFDEF DepCom}'Use ToString instead'{$ENDIF};
function MissingOrInvalid: Boolean;
function Quotient: Extended;
function ToString: string;
case Integer of
0: (Numerator, Denominator: LongInt);
1: (PackedValue: Int64);
end;
ITiffParser = interface;
ITiffDirectory = interface;
ITiffTag = interface(IMetadataBlock)
['{DC9C12D5-EFEF-4B59-9B02-89A757896CCA}']
function GetDataType: TTiffDataType;
function GetParent: ITiffDirectory;
function GetElementCount: LongInt;
function GetID: TTiffTagID;
function GetOriginalDataOffset: LongWord;
property DataType: TTiffDataType read GetDataType;
property ElementCount: LongInt read GetElementCount;
property ID: TTiffTagID read GetID;
property OldDataOffset: LongWord read GetOriginalDataOffset;
property Parent: ITiffDirectory read GetParent;
end;
IFoundTiffTag = interface(ITiffTag)
['{8258F43E-38E8-4FD9-A1D7-D3C42B38F043}']
function GetParser: ITiffParser;
property Parser: ITiffParser read GetParser;
end;
ITiffDirectoryEnumerator = interface
['{7E882310-28E7-4AF3-9978-27D1E5F36D09}']
function GetCurrent: ITiffTag;
function MoveNext: Boolean;
property Current: ITiffTag read GetCurrent;
end;
ITiffDirectory = interface //implemented by both the internal TFoundTiffDirectory below and TExifSection in CCR.Exif.pas
['{3DA5B982-CB8C-412A-8E5F-AD3A98CF345E}']
function GetEnumerator: ITiffDirectoryEnumerator;
function GetIndex: Integer;
function GetParent: ITiffDirectory;
function GetTagCount: Integer;
function FindTag(TagID: TTiffTagID; out ParsedTag: ITiffTag): Boolean;
function TagExists(TagID: TTiffTagID; ValidDataTypes: TTiffDataTypes =
[Low(TTiffDataType)..High(TTiffDataType)]; MinElementCount: LongInt = 1;
MaxElementCount: LongInt = MaxLongInt): Boolean;
property Index: Integer read GetIndex;
property Parent: ITiffDirectory read GetParent;
property TagCount: Integer read GetTagCount;
end;
IFoundTiffDirectory = interface(ITiffDirectory)
['{A8B5DB5F-2084-437C-872D-0139DE7C3E54}']
function GetIndex: Integer;
function GetLoadErrors: TMetadataLoadErrors;
function GetParser: ITiffParser;
function GetTagInfo: TTiffTagInfoDynArray;
function IsLastDirectoryInFile: Boolean;
function IsExifThumbailDirectory: Boolean;
function TryLoadExifThumbnail(const Dest: IStreamPersist): Boolean;
property LoadErrors: TMetadataLoadErrors read GetLoadErrors;
property Parser: ITiffParser read GetParser;
property TagInfo: TTiffTagInfoDynArray read GetTagInfo;
end;
TTiffParserEnumerator = {$IFDEF NoRecEnumBug}record{$ELSE}class sealed{$ENDIF}
strict private
FCurrent: IFoundTiffDirectory;
FMaxPossibleOffset: Int64;
FNextIndex: Integer;
FNextOffset: LongInt;
FSource: ITiffParser;
public
constructor Create(const ASource: ITiffParser; const AMaxPossibleOffset: Int64;
const ANextOffset: LongInt);
function MoveNext: Boolean;
property Current: IFoundTiffDirectory read FCurrent;
end;
ITiffParser = interface
function GetBasePosition: Int64;
function GetEndianness: TEndianness;
function GetEnumerator: TTiffParserEnumerator;
function GetStream: TStream;
procedure LoadTagData(const TagInfo: TTiffTagInfo; var Buffer); overload;
function ParseSubDirectory(const OffsetTag: ITiffTag;
out Directory: IFoundTiffDirectory): Boolean; overload;
function ParseSubDirectory(const Parent: ITiffDirectory;
const OffsetTag: TTiffTagInfo; out Directory: IFoundTiffDirectory): Boolean; overload;
property BasePosition: Int64 read GetBasePosition;
property Endianness: TEndianness read GetEndianness;
property Stream: TStream read GetStream;
end;
ITiffRewriteCallback = interface;
TTiffDirectoryRewriter = class sealed
protected type
TTagToWrite = class abstract
strict private
FNewDataOffset: LongWord;
FInfo: TTiffTagInfo;
FParent: TTiffDirectoryRewriter;
protected
property Info: TTiffTagInfo read FInfo;
public
constructor Create(AParent: TTiffDirectoryRewriter; const AInfo: TTiffTagInfo); overload;
constructor Create(AParent: TTiffDirectoryRewriter; AID: TTiffTagID;
ADataType: TTiffDataType; AElementCount: LongInt; AOriginalDataOffset: LongWord = 0); overload;
function DataSize: Integer; inline;
procedure WriteData(Stream: TStream; Endianness: TEndianness); virtual; abstract;
property DataType: TTiffDataType read FInfo.DataType;
property ElementCount: LongInt read FInfo.ElementCount;
property ID: TTiffTagID read FInfo.ID;
property NewDataOffset: LongWord read FNewDataOffset write FNewDataOffset;
property OldDataOffset: LongWord read FInfo.DataOffset;
property Parent: TTiffDirectoryRewriter read FParent;
end;
TImageItem = record
ByteCount: 0..High(LongInt);
OldOffset, NewOffset: LongWord;
end;
TImageInfo = array of TImageItem;
strict private
FDoneInitialization: Boolean;
FImageInfo: TImageInfo;
FNewIFDOffset: LongWord;
FRewriteSource: Boolean;
FSource: ITiffDirectory;
FSourceInfo: TTiffTagInfoDynArray;
FSourceParser: ITiffParser;
FTagsToWrite: TObjectList;
procedure AddTag(Tag: TTagToWrite); overload;
function FindTagIndex(AID: TTiffTagID; out Index: Integer): Boolean;
function GetTag(Index: Integer): TTagToWrite;
function GetTagCount: Integer;
protected
constructor Create(const Source: ITiffDirectory; const Callback: ITiffRewriteCallback);
function FindTagToWrite(ID: TTiffTagID; var Tag: TTagToWrite): Boolean;
function HasImageData: Boolean; inline;
function ProtectMakerNote(var MakerNoteTag: TTagToWrite): Boolean; //looks for the ttExifOffset sub-dir, then ttMakerNote under that, checking the data type and size
procedure InitializeImageInfo(const Offsets, ByteCounts: array of LongWord);
procedure InitializeNewOffsets(var NextOffset: LongWord; ProtectedTag: TTagToWrite);
procedure Write(AStream: TStream; const ABasePosition: Int64;
AEndianness: TEndianness; ANextIFDOffset: LongWord);
property ImageInfo: TImageInfo read FImageInfo;
property NewIFDOffset: LongWord read FNewIFDOffset write FNewIFDOffset;
property RewriteSource: Boolean read FRewriteSource;
property TagCount: Integer read GetTagCount;
property Tags[Index: Integer]: TTagToWrite read GetTag;
public
destructor Destroy; override;
procedure AddTag(ID: TTiffTagID; const DataSource: IStreamPersist;
DataType: TTiffDataType = tdUndefined); overload;
procedure AddTag(const Source: ITiffTag); overload;
procedure AddSubDirectory(OffsetID: TTiffTagID; const SubDirectory: ITiffDirectory;
const Callback: ITiffRewriteCallback = nil);
procedure IgnoreDirectory;
property Source: ITiffDirectory read FSource;
end;
ITiffRewriteCallback = interface
['{55D2E445-1E18-4887-A004-947F16B696D1}']
procedure AddNewTags(Rewriter: TTiffDirectoryRewriter);
procedure RewritingOldTag(const Source: ITiffDirectory; TagID: TTiffTagID;
DataType: TTiffDataType; var Rewrite: Boolean);
end;
TSimpleTiffRewriteCallbackImpl = class(TAggregatedObject, ITiffRewriteCallback)
strict private //Internal helper class for TIPTCData and TXMPPacket that
FMetadataTagID: TTiffTagID; //standardises the implementation of ITiffRewriteCallback.
function GetOwner: IStreamPersistEx; inline;
protected
{ ITiffRewriteCallback }
procedure AddNewTags(Rewriter: TTiffDirectoryRewriter);
procedure RewritingOldTag(const Source: ITiffDirectory; TagID: TTiffTagID;
DataType: TTiffDataType; var Rewrite: Boolean);
public
constructor Create(const AOwner: IStreamPersistEx; AMetadataTagID: TTiffTagID);
property Owner: IStreamPersistEx read GetOwner;
end;
const
TiffElementSizes: array[TTiffDataType] of Integer = (
1, 1, 2, 4, 8, 1, 1, 2, 4, 8, 4, 8, 4);
function HasTiffHeader(Stream: TStream; var Endianness: TEndianness;
MoveOnSuccess: Boolean = False): Boolean; overload;
function HasTiffHeader(Stream: TStream; MoveOnSuccess: Boolean = False): Boolean; overload; inline;
function ParseTiff(Stream: TStream; StreamOwnership: TStreamOwnership = soReference): ITiffParser; overload;
function ParseTiff(const FileName: string): ITiffParser; overload; inline;
function ParseTiffDirectory(Stream: TStream; Endianness: TEndianness;
const BasePosition, Offset, InternalOffset: Int64): IFoundTiffDirectory;
procedure RewriteTiff(InStream, OutStream: TStream; const Callback: ITiffRewriteCallback);
procedure WriteTiffHeader(Stream: TStream; Endianness: TEndianness;
FirstDirectoryOffset: LongWord = 8);
implementation
uses Math, RTLConsts, CCR.Exif.Consts, CCR.Exif.TagIDs;
function TryLoadJpegImageFromStream(const AJpegImage: IStreamPersist; AStream: TStream): Boolean;
var
JpegSize: Int64;
Temp: TMemoryStream;
begin
try
JpegSize := GetJPEGDataSize(AStream);
if JpegSize = (AStream.Size - AStream.Position) then
AJpegImage.LoadFromStream(AStream)
else
begin
Temp := TMemoryStream.Create;
try
Temp.Size := JpegSize;
AStream.ReadBuffer(Temp.Memory^, JpegSize);
AJpegImage.LoadFromStream(Temp);
finally
Temp.Free;
end;
end;
Result := True;
except
on Exception do Result := False;
end;
end;
type
TFoundTiffDirectory = class;
TFoundTiffTag = class(TMetadataBlock, ITiffTag)
strict private
FParent: TFoundTiffDirectory;
FParentIntf: ITiffDirectory; //need a 'hard' intf ref to ensure the parent is kept alive
FSourcePtr: ^TTiffTagInfo;
protected
function GetDataType: TTiffDataType;
function GetElementCount: LongInt;
function GetOriginalDataOffset: LongWord;
function GetID: TTiffTagID;
function GetParent: ITiffDirectory;
function HasIPTCBlockID: Boolean; override;
function HasXMPBlockID: Boolean; override;
public
constructor Create(AParent: TFoundTiffDirectory; AIndex: Integer); overload;
constructor Create(AID: TTiffTagID; ADataType: TTiffDataType;
const ADataSource: IStreamPersist); overload;
destructor Destroy; override;
property DataType: TTiffDataType read GetDataType;
property ElementCount: LongInt read GetElementCount;
property ID: TTiffTagID read GetID;
property Parent: TFoundTiffDirectory read FParent;
end;
TFoundTiffDirectoryEnumerator = class(TInterfacedObject, ITiffDirectoryEnumerator)
strict private
FCurrentIndex: Integer;
FSource: TFoundTiffDirectory;
protected
function GetCurrent: ITiffTag;
function MoveNext: Boolean;
public
constructor Create(Source: TFoundTiffDirectory);
end;
TFoundTiffDirectory = class(TInterfacedObject, ITiffDirectory, IFoundTiffDirectory)
strict private
FIndex: Integer;
FLoadErrors: TMetadataLoadErrors;
FParent: ITiffDirectory;
FParser: ITiffParser;
FTags: TTiffTagInfoDynArray;
protected
FMoreToFollow: Boolean;
constructor Create(const AParser: ITiffParser; const AParent: ITiffDirectory; AIndex: Integer;
const Tags: TTiffTagInfoDynArray; const LoadErrors: TMetadataLoadErrors); overload;
function GetEnumerator: ITiffDirectoryEnumerator;
function GetIndex: Integer;
function GetLoadErrors: TMetadataLoadErrors;
function GetParent: ITiffDirectory;
function GetParser: ITiffParser;
function LoadSubDirectory(OffsetTagID: TTiffTagID): ITiffDirectory;
function GetTagCount: Integer;
function GetTagInfo: TTiffTagInfoDynArray;
function FindTag(TagID: TTiffTagID; out Index: Integer): Boolean; overload; inline;
function FindTag(TagID: TTiffTagID; out ParsedTag: ITiffTag): Boolean; overload;
function IndexOfTag(TagID: TTiffTagID): Integer;
function IsExifThumbailDirectory: Boolean;
function IsLastDirectoryInFile: Boolean; inline;
function TagExists(TagID: TTiffTagID; ValidDataTypes: TTiffDataTypes =
[Low(TTiffDataType)..High(TTiffDataType)]; MinElementCount: LongInt = 1;
MaxElementCount: LongInt = MaxLongInt): Boolean;
function TryLoadExifThumbnail(Dest: TStream): Boolean; overload;
function TryLoadExifThumbnail(const Dest: IStreamPersist): Boolean; overload;
public
constructor Create(const AParser: ITiffParser; const AParent: ITiffDirectory;
AIndex: Integer; const AOffset: Int64; const AInternalOffset: Int64 = 0); overload;
class function TryCreate(const AParser: ITiffParser; const AParent: ITiffDirectory;
AIndex: Integer; const AOffset: Int64; out Instance: IFoundTiffDirectory): Boolean; static;
property Parser: ITiffParser read FParser;
property TagInfo: TTiffTagInfoDynArray read FTags;
end;
TTiffParser = class(TInterfacedObject, ITiffParser)
strict private
FBasePosition, FMaxOffsetValue: Int64;
FEndianness: TEndianness;
FFirstDirOffset: LongInt;
FStream: TStream;
FStreamOwnership: TStreamOwnership;
protected
function GetBasePosition: Int64;
function GetEndianness: TEndianness;
function GetEnumerator: TTiffParserEnumerator;
function GetStream: TStream;
procedure LoadTagData(const TagInfo: TTiffTagInfo; var Buffer); overload;
function ParseSubDirectory(const OffsetTag: ITiffTag;
out Directory: IFoundTiffDirectory): Boolean; overload;
function ParseSubDirectory(const Parent: ITiffDirectory; const OffsetTag: TTiffTagInfo;
out Directory: IFoundTiffDirectory): Boolean; overload;
public
constructor Create(AStream: TStream; AStreamOwnership: TStreamOwnership); overload;
constructor Create(AStream: TStream; const ABasePosition: Int64;
AEndianness: TEndianness); overload;
destructor Destroy; override;
property BasePosition: Int64 read FBasePosition;
property Endianness: TEndianness read FEndianness;
property Stream: TStream read FStream;
end;
TInternaTiffTagToWrite = class(TTiffDirectoryRewriter.TTagToWrite)
strict private
FParser: ITiffParser;
strict protected
Kind: (itNormal, itImageOffsets, itImageByteCounts);
public
constructor Create(AParent: TTiffDirectoryRewriter; const AParser: ITiffParser;
const ATagInfo: TTiffTagInfo);
procedure WriteData(Stream: TStream; Endianness: TEndianness); override;
property Info;
property Parser: ITiffParser read FParser;
end;
TExternalTiffTagToWrite = class(TTiffDirectoryRewriter.TTagToWrite)
strict protected
FDataSize: Integer;
FTag: ITiffTag;
public
constructor Create(AOwner: TTiffDirectoryRewriter; const ATag: ITiffTag); overload;
constructor Create(AOwner: TTiffDirectoryRewriter; AID: TTiffTagID;
ADataType: TTiffDataType; const ADataSource: IStreamPersist); overload;
procedure WriteData(Stream: TStream; Endianness: TEndianness); override;
property Source: ITiffTag read FTag;
end;
TTiffSubDirToWrite = class(TTiffDirectoryRewriter.TTagToWrite)
strict private
FDirectory: TTiffDirectoryRewriter;
public
constructor Create(AOwner: TTiffDirectoryRewriter; AOffsetID: TTiffTagID;
ADirectory: TTiffDirectoryRewriter);
destructor Destroy; override;
procedure WriteData(Stream: TStream; Endianness: TEndianness); override;
property Directory: TTiffDirectoryRewriter read FDirectory;
end;
{ TTiffTag }
{$Q-}
class function TTiffTag.IsWellFormed(DataType: TTiffDataType; ElementCount: LongInt): Boolean;
begin
case Ord(DataType) of
Ord(Low(DataType))..Ord(High(DataType)):
Result := (LongInt(ElementCount * TiffElementSizes[DataType]) >= 0);
else Result := False;
end;
end;
{$IFDEF OverflowCheckingOn}{$Q+}{$ENDIF}
class function TTiffTag.IsWellFormed(const Tag: ITiffTag): Boolean;
begin
Result := IsWellFormed(Tag.DataType, Tag.ElementCount);
end;
class function TTiffTag.MatchOffsetToByteCountID(OffsetTagID: TTiffTagID;
var ByteCountID: TTiffTagID): Boolean;
begin
Result := True;
case OffsetTagID of
ttStripOffsets: ByteCountID := ttStripByteCounts;
ttTileOffsets: ByteCountID := ttTileOffsets;
ttThumbnailOffset: ByteCountID := ttThumbnailSize;
else Result := False;
end;
end;
{ TTiffTagInfo }
function TTiffTagInfo.DataSize: Integer;
begin
if IsWellFormed then
Result := ElementCount * TiffElementSizes[DataType]
else
Result := 0;
end;
function TTiffTagInfo.IsWellFormed: Boolean;
begin
Result := TTiffTag.IsWellFormed(DataType, ElementCount);
end;
{ TTiffLongXXXFraction }
function GCD(A, B: Int64): Int64;
var
Temp: Int64;
begin
while B <> 0 do
begin
Temp := B;
B := A mod B;
A := Temp;
end;
Result := A;
end;
procedure CurrencyToFraction(const Source: Currency; var N, D: Int64);
var
Factor: Int64;
begin
N := Trunc(Source * 10000);
D := 10000;
Factor := GCD(N, D);
N := N div Factor;
D := D div Factor;
end;
constructor TTiffLongIntFraction.Create(ANumerator, ADenominator: LongInt);
begin
Numerator := ANumerator;
Denominator := ADenominator;
end;
constructor TTiffLongIntFraction.Create(const AQuotient: Currency);
var
N, D: Int64;
begin
CurrencyToFraction(AQuotient, N, D);
{$RANGECHECKS ON}
Numerator := N;
Denominator := D;
{$IFDEF RangeCheckingOff}{$RANGECHECKS OFF}{$ENDIF}
end;
constructor TTiffLongIntFraction.CreateFromString(const AString: string);
var
DivSignPos: Integer;
Quotient: Currency;
Valid: Boolean;
begin
DivSignPos := Pos('/', AString);
if DivSignPos <> 0 then
Valid := TryStrToInt(Copy(AString, 1, DivSignPos - 1), Numerator) and
TryStrToInt(Copy(AString, DivSignPos + 1, MaxInt), Denominator)
else
begin
Valid := TryStrToCurr(AString, Quotient);
if Valid then
try
Create(Quotient);
except
on ERangeError do Valid := False;
end;
end;
if not Valid then
PackedValue := 0;
end;
class function TTiffLongIntFraction.CreateMissingOrInvalid: TTiffLongIntFraction;
begin
Result.Numerator := 0;
Result.Denominator := 0;
end;
function TTiffLongIntFraction.AsString: string;
begin
Result := ToString;
end;
function TTiffLongIntFraction.MissingOrInvalid: Boolean;
begin
Result := (Denominator = 0);
end;
function TTiffLongIntFraction.Quotient: Extended;
begin
if MissingOrInvalid then
Result := 0
else
Result := Numerator / Denominator
end;
function TTiffLongIntFraction.ToString: string;
begin
if MissingOrInvalid then
Result := ''
else if Denominator = 1 then
Result := IntToStr(Numerator)
else
FmtStr(Result, '%d/%d', [Numerator, Denominator]);
end;
function TryStrToLongWord(const S: string; var Value: LongWord): Boolean;
var
Int64Value: Int64;
begin
Result := TryStrToInt64(S, Int64Value) and (Int64Value >= 0) and
(Int64Value <= High(Value));
if Result then Value := LongWord(Int64Value);
end;
constructor TTiffLongWordFraction.Create(ANumerator: LongWord; ADenominator: LongWord);
begin
Numerator := ANumerator;
Denominator := ADenominator;
end;
constructor TTiffLongWordFraction.Create(const AQuotient: Currency);
var
N, D: Int64;
begin
CurrencyToFraction(AQuotient, N, D);
{$RANGECHECKS ON}
Numerator := N;
Denominator := D;
{$IFDEF RangeCheckingOff}{$RANGECHECKS OFF}{$ENDIF}
end;
constructor TTiffLongWordFraction.CreateFromString(const AString: string);
var
DivSignPos: Integer;
Quotient: Currency;
Valid: Boolean;
begin
DivSignPos := Pos('/', AString);
if DivSignPos <> 0 then
Valid := TryStrToLongWord(Copy(AString, 1, DivSignPos - 1), Numerator) and
TryStrToLongWord(Copy(AString, DivSignPos + 1, MaxInt), Denominator)
else
begin
Valid := TryStrToCurr(AString, Quotient);
if Valid then
try
Create(Quotient);
except
on ERangeError do Valid := False;
end;
end;
if not Valid then
PackedValue := 0;
end;
class function TTiffLongWordFraction.CreateMissingOrInvalid: TTiffLongWordFraction;
begin
Result.Numerator := 0;
Result.Denominator := 0;
end;
function TTiffLongWordFraction.AsString: string;
begin
Result := ToString;
end;
function TTiffLongWordFraction.MissingOrInvalid: Boolean;
begin
Result := (Denominator = 0);
end;
function TTiffLongWordFraction.Quotient: Extended;
begin
if MissingOrInvalid then
Result := 0
else
Result := Numerator / Denominator
end;
function TTiffLongWordFraction.ToString: string;
begin
if MissingOrInvalid then
Result := ''
else if Denominator = 1 then
Result := IntToStr(Numerator)
else
FmtStr(Result, '%d/%d', [Numerator, Denominator]);
end;
{ TIFF parsing routines }
function HasTiffHeader(Stream: TStream; var Endianness: TEndianness;
MoveOnSuccess: Boolean = False): Boolean; overload;
var
Buffer: array[0..1] of Word;
BytesRead: Integer;
begin
Result := False;
BytesRead := Stream.Read(Buffer, SizeOf(Buffer));
if BytesRead = SizeOf(Buffer) then
case Buffer[0] of
TiffSmallEndianCode, TiffBigEndianCode: //accept small endian marker when meant big endian and vice versa
case Buffer[1] of
TiffMagicNum:
begin
Endianness := SmallEndian;
Result := True;
end;
TiffMagicNumBigEndian:
begin
Endianness := BigEndian;
Result := True;
end;
end;
end;
if not Result or not MoveOnSuccess then
Stream.Seek(-BytesRead, soCurrent);
end;
function HasTiffHeader(Stream: TStream; MoveOnSuccess: Boolean = False): Boolean; overload;
var
Endianness: TEndianness;
begin
Result := HasTiffHeader(Stream, Endianness, MoveOnSuccess)
end;
{
LoadTiffDirectory - sanity checking:
- We check the reported tag count is theoretically possible up front.
- Data offsets are validated.
- Two bad tag headers in a row, and any further parsing is aborted.
- General aim is to avoid an exception being raised. This is because it becomes
annoying in general use otherwise, Exif data in the wild frequently being badly
formed in some fashion...
}
function LoadTiffDirectory(Stream: TStream; Endianness: TEndianness;
const BasePosition, Offset, InternalOffset: Int64;
out LoadErrors: TMetadataLoadErrors): TTiffTagInfoDynArray; overload;
var
I, TagCount: Integer;
MaxTagCount, StartPos, StreamSize, Offset64: Int64;
begin
LoadErrors := [];
Result := nil;
StartPos := BasePosition + Offset;
StreamSize := Stream.Seek(0, soEnd);
if (StartPos < 0) or (StartPos + 2 > StreamSize) then
begin
LoadErrors := [leBadOffset];
Exit;
end;
MaxTagCount := (StreamSize - StartPos - 2) div TTiffTag.HeaderSize;
Stream.Position := StartPos;
TagCount := Stream.ReadWord(Endianness);
if TagCount > MaxTagCount then
begin
TagCount := MaxTagCount;
Include(LoadErrors, leBadTagCount);
end;
SetLength(Result, TagCount);
for I := 0 to TagCount - 1 do
begin
Result[I].HeaderOffset := Stream.Position - BasePosition;
Result[I].ID := Stream.ReadWord(Endianness);
Word(Result[I].DataType) := Stream.ReadWord(Endianness);
Result[I].ElementCount := Stream.ReadLongInt(Endianness);
if Result[I].DataSize > 4 then //DataSize will validate DataType for us
begin
Offset64 := Stream.ReadLongWord(Endianness) + InternalOffset;
if (Offset64 < 8) or (Offset64 + BasePosition < 0) or
(Offset64 + Result[I].DataSize + BasePosition > StreamSize) then
Result[I].ElementCount := -1
else
Result[I].DataOffset := Offset64;
end
else
begin
Result[I].DataOffset := Result[I].HeaderOffset + 8;
Stream.Seek(4, soCurrent);
end;
if not Result[I].IsWellFormed then
if (I = 0) or Result[I - 1].IsWellFormed then
begin
Include(LoadErrors, leBadTagHeader);
if (I = 0) and (leBadTagCount in LoadErrors) then
begin
Result := nil;
Exit;
end;
end
else
begin
Include(LoadErrors, leBadTagCount);
SetLength(Result, I);
Exit;
end;
end;
end;
function LoadTiffDirectory(const Parser: ITiffParser; const Offset: Int64;
out LoadErrors: TMetadataLoadErrors): TTiffTagInfoDynArray; overload; inline;
begin
Result := LoadTiffDirectory(Parser.Stream, Parser.Endianness, Parser.BasePosition,
Offset, 0, LoadErrors);
end;
function InitLoadOffsetArray(DataType: TTiffDataType; ElementCount: LongInt;
out ArrayResult: TLongWordDynArray): Boolean; inline;
begin
Assert((ElementCount >= 0) and (DataType in TTiffTag.OffsetDataTypes));
SetLength(ArrayResult, ElementCount);
Result := (ArrayResult <> nil);
end;
function LoadOffsetArray(const Source: ITiffParser;
const TagInfo: TTiffTagInfo): TLongWordDynArray; overload;
var
WordArray: TWordDynArray;
I: Integer;
begin
if not InitLoadOffsetArray(TagInfo.DataType, TagInfo.ElementCount, Result) then Exit;
if TagInfo.DataType = tdWord then
begin
SetLength(WordArray, TagInfo.ElementCount);
Source.LoadTagData(TagInfo, WordArray[0]);
for I := 0 to TagInfo.ElementCount - 1 do
Result[I] := WordArray[I];
end
else
Source.LoadTagData(TagInfo, Result[0]);
end;
function LoadOffsetArray(const Tag: ITiffTag): TLongWordDynArray; overload;
var
DataPtr: PWordArray;
I: LongInt;
begin
if not InitLoadOffsetArray(Tag.DataType, Tag.ElementCount, Result) then Exit;
DataPtr := Tag.Data.Memory;
if Tag.DataType = tdWord then
for I := 0 to High(Result) do
Result[I] := DataPtr[I]
else
Move(DataPtr[0], Result[0], Length(Result) * 4);
end;
function SeekToExifThumbnail(const Parser: ITiffParser;
const OffsetTag: TTiffTagInfo): Boolean;
begin
Result := False;
if not (OffsetTag.DataType in TTiffTag.OffsetDataTypes) or
(OffsetTag.ElementCount <> 1) then Exit;
Parser.Stream.Position := Parser.BasePosition + LoadOffsetArray(Parser, OffsetTag)[0];
if HasJPEGHeader(Parser.Stream) then Result := True;
end;
procedure WriteTiffTagData(DataType: TTiffDataType; ElementCount: Longint;
DataPtr: Pointer; Dest: TStream; Endianness: TEndianness);
var
I, DataSize: Integer;
begin
DataSize := TiffElementSizes[DataType] * ElementCount;
if DataType = tdDouble then
for I := 0 to ElementCount - 1 do
Dest.WriteDouble(PDoubleArray(DataPtr)[I], Endianness)
else
case TiffElementSizes[DataType] of
1: Dest.WriteBuffer(DataPtr^, ElementCount);
2: for I := 0 to ElementCount - 1 do
Dest.WriteWord(PWordArray(DataPtr)[I], Endianness);
else
for I := 0 to DataSize div 4 - 1 do
Dest.WriteLongWord(PLongWordArray(DataPtr)[I], Endianness)
end;
for I := 3 downto DataSize do
Dest.WriteByte(0);
end;
{ TFoundTiffTag }
constructor TFoundTiffTag.Create(AParent: TFoundTiffDirectory; AIndex: Integer);
begin
Assert((AParent <> nil) and (AIndex >= 0));
inherited Create;
FParent := AParent;
FParentIntf := AParent;
FSourcePtr := @AParent.TagInfo[AIndex];
Data.SetSize(FSourcePtr.DataSize);
AParent.Parser.LoadTagData(FSourcePtr^, Data.Memory^);
Data.DisableChanges := True;
end;
constructor TFoundTiffTag.Create(AID: TTiffTagID; ADataType: TTiffDataType;
const ADataSource: IStreamPersist);
begin
inherited Create;
New(FSourcePtr);
FSourcePtr.ID := AID;
FSourcePtr.DataType := ADataType;
if ADataSource <> nil then
begin
ADataSource.SaveToStream(Data);
FSourcePtr.ElementCount := LongInt(Data.Size div TiffElementSizes[ADataType]);
end
else
begin
FSourcePtr.ElementCount := 1;
Data.Size := TiffElementSizes[ADataType];
FillChar(Data.Memory^, TiffElementSizes[ADataType], 0);
end;
end;
destructor TFoundTiffTag.Destroy;
begin
if (FParent = nil) and (FSourcePtr <> nil) then Dispose(FSourcePtr);
inherited;
end;
function TFoundTiffTag.GetDataType: TTiffDataType;
begin
Result := FSourcePtr.DataType;
end;
function TFoundTiffTag.GetElementCount: LongInt;
begin
Result := FSourcePtr.ElementCount;
end;
function TFoundTiffTag.GetID: TTiffTagID;
begin
Result := FSourcePtr.ID;
end;
function TFoundTiffTag.GetOriginalDataOffset: LongWord;
begin
Result := FSourcePtr.DataOffset;
end;
function TFoundTiffTag.HasIPTCBlockID: Boolean;
begin
Result := (FSourcePtr.ID = ttIPTC);
end;
function TFoundTiffTag.HasXMPBlockID: Boolean;
begin
Result := (FSourcePtr.ID = ttXMP);
end;
function TFoundTiffTag.GetParent: ITiffDirectory;
begin
Result := FParentIntf;
end;
{ TFoundTiffDirectoryEnumerator }
constructor TFoundTiffDirectoryEnumerator.Create(Source: TFoundTiffDirectory);
begin
FCurrentIndex := -1;
FSource := Source;
end;
function TFoundTiffDirectoryEnumerator.GetCurrent: ITiffTag;
begin
Result := TFoundTiffTag.Create(FSource, FCurrentIndex);
end;
function TFoundTiffDirectoryEnumerator.MoveNext: Boolean;
begin
Result := (FCurrentIndex < High(FSource.TagInfo));
if Result then Inc(FCurrentIndex);
end;
{ TFoundTiffDirectory }
constructor TFoundTiffDirectory.Create(const AParser: ITiffParser; const AParent: ITiffDirectory;
AIndex: Integer; const AOffset: Int64; const AInternalOffset: Int64 = 0);
begin
inherited Create;
FTags := LoadTiffDirectory(AParser.Stream, AParser.Endianness,
AParser.BasePosition, AOffset, AInternalOffset, FLoadErrors);
FIndex := AIndex;
FParser := AParser;
FParent := AParent;
end;
constructor TFoundTiffDirectory.Create(const AParser: ITiffParser; const AParent: ITiffDirectory;
AIndex: Integer; const Tags: TTiffTagInfoDynArray; const LoadErrors: TMetadataLoadErrors);
begin
inherited Create;
FLoadErrors := LoadErrors;
FTags := Tags;
FIndex := AIndex;
FParser := AParser;
FParent := AParent;
end;
class function TFoundTiffDirectory.TryCreate(const AParser: ITiffParser;