1 // Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.eclipse.org/legal/epl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 //

    15 

    16 #ifndef __EXIFGENERALCONSTS_H__

    17 #define __EXIFGENERALCONSTS_H__

    18 

    19 #include <gdi.h>

    20 #include <iclexif.h>

    21 

    22 // Header file containing general constants used by the Exif Encoder and Decoder.

    23 

    24 // Constants for size.

    25 const TUint K32BitIntegerByteCount = 4;

    26 const TUint K16BitIntegerByteCount = 2;

    27 const TUint K8BitIntegerByteCount = 1;

    28 

    29 const TUint16 KApp1Marker = 0xE1FF; // The Application 1 marker (APP1).

    30 const TUint16 KApp1MarkerByteCount = K16BitIntegerByteCount; // Number of bytes in the APP1 marker.

    31 const TUint16 KBlockEndMarker = 0xD9FF; // The Application 1 marker (APP1).

    32 const TUint16 KBlockEndMarkerByteCount = K16BitIntegerByteCount; // Number of bytes in the APP1 marker.

    33 

    34 const TUint KOffsetToApp1Size = K16BitIntegerByteCount; // Two bytes in from the start of the Exif header.

    35 const TUint16 KApp1SizeLength = K16BitIntegerByteCount; // The byte count of the APP1 header length field.

    36 

    37 const TUint KExifMarker = 0x66697845; // 'Exif' string.

    38 const TUint16 KExifMarkerByteCount = K32BitIntegerByteCount; // i.e. number of bytes of 'Exif'

    39 const TUint16 KExifMarkerEnd = 0x0000; // Always follows 'Exif'.

    40 const TUint16 KExifMarkerEndByteCount = K16BitIntegerByteCount;

    41 const TInt KExifHeaderLength = K32BitIntegerByteCount + K16BitIntegerByteCount;

    42 

    43 const TUint16 KIntelByteAlignment = 0x4949; // Indicates little-endian byte alignment.

    44 const TUint16 KMotorolaByteAlignment = 0x4D4D;

    45 const TUint16 KByteAlignmentByteCount = K16BitIntegerByteCount;

    46 const TUint KByteCountToByteAlignment = KApp1MarkerByteCount +

    47 										KApp1SizeLength +

    48 										KExifHeaderLength; // Number of bytes from KApp1Marker through to KIntel.

    49 const TInt KOffsetFromExifHeaderToByteAlignment = KExifHeaderLength;

    50 

    51 const TUint16 KFortyTwo = 0x002A;

    52 const TUint16 KFortyTwoByteCount = K16BitIntegerByteCount;

    53 

    54 const TUint KIfdOffset = 0x00000008; // Offset to 0th IFD.

    55 const TUint16 KIfdOffsetByteCount = K32BitIntegerByteCount;

    56 const TUint KOffsetToFirstIfdSize = K32BitIntegerByteCount; // A 4 byte field containing an offset to the 1st Ifd.

    57 

    58 const TUint16 KMaxApp1Size = 0xFFFF; // Maximum size of the APP1 header.

    59 

    60 const TUint KSizeOfEntryCount = K16BitIntegerByteCount; // Each Ifd has an entry count of 2 bytes.

    61 

    62 const TInt KJPEGEncodedThumbnail = 6; //

    63 

    64 // External user will call functions using either of these two constants as the Ifd argument.

    65 const TInt16 KExternalZerothIfd = 0;

    66 const TInt16 KExternalFirstIfd = 1;

    67 

    68 const TInt KOffsetToZerothOffset = 	KByteAlignmentByteCount +

    69 									KFortyTwoByteCount +

    70 									KIfdOffsetByteCount +

    71 									KSizeOfEntryCount; // Number of bytes from byte alignment to the offset to the 0th Ifd.

    72 

    73 const TUint16 KExifFileHeaderLength = 	KApp1MarkerByteCount +

    74 										KApp1SizeLength +

    75 										KExifMarkerByteCount +

    76 										KExifMarkerEndByteCount +

    77 										KByteAlignmentByteCount + 

    78 										KFortyTwoByteCount + 

    79 										KIfdOffsetByteCount; // Length of the standard Exif Header.

    80 

    81 // Literals used in the encoder/decoder.										

    82 _LIT8(KUnicode, "UNICODE\0"); // The first 8 bytes of the User Comment tag, if using Unicode.

    83 _LIT8(KExifHeader, "Exif\0\0");

    84 

    85 const TInt KThumbnailHeight = 120;

    86 const TInt KThumbnailWidth = 160;

    87 const TDisplayMode KThumbnailDisplayMode= EColor256;

    88 const TInt KIOBlockSize=4096;	// size of blocks used for IO operations

    89 

    90 enum TIfd

    91 	{

    92 	EZeroth, // Main image.	

    93 	EExifSub, // Main image.

    94 	EInterop, // Main image.

    95 	EFirst, // Thumbnail.

    96 	EGpsSub = KExifGpsIfd >> 16 // (==4) Main image.		

    97 	};

    98 

    99 enum TTagValueIndexes

   100 	{

   101 	ETagValue,

   102 	EFormatValue,

   103 	EComponentCountValue,

   104 	EValueOffsetValue,

   105 	EIfdValue,

   106 	ESupportLevelValue

   107 	};

   108 	

   109 // Is the tag Mandatory, Optional or 

   110 enum TSupportLevel

   111 	{

   112 	EOptional,

   113 	EConditionallyMandatory,

   114 	EMandatory

   115 	};

   116 	

   117 // The format field in the Ifd entry is a two byte field, with an identifying short.

   118 enum TFormat

   119 	{

   120 	EByte = 1,

   121 	EAscii = 2,

   122 	EUnsignedShort = 3,

   123 	EUnsignedLong = 4,

   124 	EUnsignedRational = 5,

   125 	EUndefined = 7,

   126 	ESignedLong = 9,

   127 	ESignedRational = 10

   128 	};

   129 	

   130 // Related to TFormat. Stores size (in bytes) of each enumeration, i.e. EByte size is 1 byte, 

   131 // EUnsignedRational size is 8 bytes etc etc.

   132 const TInt KDataFormatSize[] = {0,1,1,2,4,8, 0,1, 0,4,8};

   133 const TUint KDataFormatSizeLength = sizeof(KDataFormatSize)/sizeof(KDataFormatSize[0]); // The length of the KDataFormatsize array.

   134 

   135 // Used by Ifd entry

   136 const TUint KMinimumIfdEntrySize = 12; // The number of bytes in a standard ifd entry.

   137 const TInt KSizeOfTagField = 2; // The number of bytes in the tag field.

   138 const TInt KSizeOfFormatField = 2; // The number of bytes in format field.

   139 const TInt KSizeOfComponentCountField = 4; // The number of bytes in the component count field.

   140 const TUint KSizeOfValueOffsetField = 4; // The number of bytes in the value/offset field.

   141 const TInt KSizeOfRational = 8; // The number of bytes in a rational number.

   142 const TInt KTagFieldPosition = 0;

   143 const TInt KFormatFieldPosition = 2; // The start position of the format field.

   144 const TInt KComponentCountFieldPosition = 4; // The start position of the component count field.

   145 const TInt KValueOffsetFieldPosition = 8; // The start position of the value/offset field.

   146 const TUint8 KThreeBytes = 3;

   147 

   148 #endif // __EXIFGENERALCONSTS_H__