imagingmodules/exiflib/src/ExifCommon.cpp
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     1 /*
       
     2 * Copyright (c) 2003, 2004 Nokia Corporation and/or its subsidiary(-ies).
       
     3 * All rights reserved.
       
     4 * This component and the accompanying materials are made available
       
     5 * under the terms of "Eclipse Public License v1.0"
       
     6 * which accompanies this distribution, and is available
       
     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
       
     8 *
       
     9 * Initial Contributors:
       
    10 * Nokia Corporation - initial contribution.
       
    11 *
       
    12 * Contributors:
       
    13 *
       
    14 * Description:  An internal service class including some utility functions.
       
    15 *
       
    16 */
       
    17 
       
    18 
       
    19 // INCLUDE FILES
       
    20 #include "ExifCommon.h"
       
    21 
       
    22 // ============================ MEMBER FUNCTIONS ===============================
       
    23 
       
    24 // -----------------------------------------------------------------------------
       
    25 // TExifCommon::SetUint32
       
    26 // Puts the given 32-bit unsigned integer to the 4-byte location, whose start 
       
    27 // point is specified with the given 8-bit unsigned integer pointer. 
       
    28 // -----------------------------------------------------------------------------
       
    29 //
       
    30 TInt TExifCommon::SetUint32( TUint8* aPtr, TUint32 aUint32 )
       
    31     {
       
    32     if ( !aPtr )
       
    33         {
       
    34         return KErrGeneral;
       
    35         }
       
    36     *( aPtr + 3 ) = STATIC_CAST( TUint8, ( aUint32 >> 24 ) & KOneByteMask );
       
    37     *( aPtr + 2 ) = STATIC_CAST( TUint8, ( aUint32 >> 16 ) & KOneByteMask );
       
    38     *( aPtr + 1 ) = STATIC_CAST( TUint8, ( aUint32 >> 8 ) & KOneByteMask );
       
    39     *aPtr = STATIC_CAST( TUint8, aUint32 & KOneByteMask );
       
    40     return KErrNone;
       
    41     }
       
    42 
       
    43 // -----------------------------------------------------------------------------
       
    44 // TExifCommon::SetUint16
       
    45 // Puts the given 16-bit unsigned integer to the 2-byte location, whose start 
       
    46 // point is specified with the given 8-bit unsigned integer pointer. 
       
    47 // -----------------------------------------------------------------------------
       
    48 //
       
    49 TInt TExifCommon::SetUint16( TUint8* aPtr, TUint16 aUint16 )
       
    50     {
       
    51     if ( !aPtr )
       
    52         {
       
    53         return KErrGeneral;
       
    54         }
       
    55     *( aPtr + 1 ) = STATIC_CAST( TUint8, ( aUint16 >> 8 ) & KOneByteMask );
       
    56     *aPtr = STATIC_CAST( TUint8, aUint16 & KOneByteMask );
       
    57     return KErrNone;
       
    58     }
       
    59 
       
    60 // -----------------------------------------------------------------------------
       
    61 // TExifCommon::Uint32
       
    62 // Returns a 32-bit unsigned integer from the location, whose start point is 
       
    63 // specified with the given 8-bit unsigned integer pointer. 
       
    64 // -----------------------------------------------------------------------------
       
    65 //
       
    66 TUint32 TExifCommon::Uint32L( TUint8* aPtr )
       
    67     {
       
    68     if ( !aPtr )
       
    69         {
       
    70         User::Leave( KErrGeneral );
       
    71         }
       
    72     TUint32 ret = 0;
       
    73     ret = *( aPtr + 3 );
       
    74     ret = ( ret << 8 ) + *( aPtr + 2 );
       
    75     ret = ( ret << 8 ) + *( aPtr + 1 );
       
    76     ret = ( ret << 8 ) + *aPtr;
       
    77     return ret;
       
    78     }
       
    79 
       
    80 // -----------------------------------------------------------------------------
       
    81 // TExifCommon::Int32
       
    82 // Returns a 32-bit integer from the location, whose start point is specified  
       
    83 // with the given 8-bit integer pointer. 
       
    84 // -----------------------------------------------------------------------------
       
    85 //
       
    86 TInt32 TExifCommon::Int32L( TUint8* aPtr )
       
    87     {
       
    88     if ( !aPtr )
       
    89         {
       
    90         User::Leave( KErrGeneral );
       
    91         }
       
    92     TUint32 ret = 0;
       
    93     ret = *( aPtr + 3 );
       
    94     ret = ( ret << 8 ) + *( aPtr + 2 );
       
    95     ret = ( ret << 8 ) + *( aPtr + 1 );
       
    96     ret = ( ret << 8 ) + *aPtr;
       
    97     return STATIC_CAST( TInt32, ret );
       
    98     }
       
    99 
       
   100 // -----------------------------------------------------------------------------
       
   101 // TExifCommon::Uint16
       
   102 // Returns a 16-bit unsigned integer from the location, whose start point is 
       
   103 // specified with the given 8-bit unsigned integer pointer. 
       
   104 // -----------------------------------------------------------------------------
       
   105 //
       
   106 TUint16 TExifCommon::Uint16L( TUint8* aPtr )
       
   107     {
       
   108     if ( !aPtr )
       
   109         {
       
   110         User::Leave( KErrGeneral );
       
   111         }
       
   112     TUint16 ret = 0;
       
   113     ret = *( aPtr + 1 );
       
   114     ret = STATIC_CAST( TUint16, ( ret << 8 ) + *aPtr );
       
   115     return ret;
       
   116     }
       
   117 
       
   118 // -----------------------------------------------------------------------------
       
   119 // TExifCommon::IsValidTagId
       
   120 // Checks if the given 16-bit unsigned integer is one of the defined tag IDs.
       
   121 // -----------------------------------------------------------------------------
       
   122 //
       
   123 TBool TExifCommon::IsValidTagId( TUint16 aTagId )
       
   124     {
       
   125     TInt i = 0;
       
   126     for ( i = 0; i < KNoIfd0Tags; ++i )
       
   127         {
       
   128         if ( aTagId == ifd0Tags[i].iId )
       
   129             {
       
   130             return ETrue;
       
   131             }
       
   132         }
       
   133     for ( i = 0; i < KNoIfdExifTags; ++i )
       
   134         {
       
   135         if ( aTagId == ifdExifTags[i].iId )
       
   136             {
       
   137             return ETrue;
       
   138             }
       
   139         }
       
   140     for ( i = 0; i < KNoIfd1Tags; ++i )
       
   141         {
       
   142         if ( aTagId == ifd1Tags[i].iId )
       
   143             {
       
   144             return ETrue;
       
   145             }
       
   146         }
       
   147     for ( i = 0; i < KNoIfdGpsTags; ++i )
       
   148         {
       
   149         if ( aTagId == ifdGpsTags[i].iId )
       
   150             {
       
   151             return ETrue;
       
   152             }
       
   153         }
       
   154     for ( i = 0; i < KNoIfdIntOpTags; ++i )
       
   155         {
       
   156         if ( aTagId == ifdIntOpTags[i].iId )
       
   157             {
       
   158             return ETrue;
       
   159             }
       
   160         }
       
   161     LOGTEXT2( _L( "ExifLib: TExifCommon::IsValidTagId() returning EFalse: aTagId=0x%x" ), aTagId );
       
   162     return EFalse;
       
   163     }
       
   164 
       
   165 // -----------------------------------------------------------------------------
       
   166 // TExifCommon::LocateJpegMarkerPtr
       
   167 // Locates the pointer to the first specified Jpeg Marker from the begining
       
   168 // inside the given interval.
       
   169 // -----------------------------------------------------------------------------
       
   170 //
       
   171 TUint8* TExifCommon::LocateJpegMarkerPtr( 
       
   172     TUint16 aMarker, 
       
   173     TUint8* aStartPtr,
       
   174     TUint8* aEndPtr)
       
   175     {
       
   176     if ( ( !aStartPtr ) || ( !aEndPtr ) || ( !aMarker ) )
       
   177         {
       
   178         return NULL;
       
   179         }
       
   180 
       
   181     TUint16 revMarker = 
       
   182         STATIC_CAST( TUint16, ( aMarker << 8 ) + ( aMarker >> 8 ) );
       
   183     --aStartPtr;
       
   184     TUint16 atHand = 0;
       
   185     TInt error = KErrNone;
       
   186     do
       
   187         {
       
   188         if ( aStartPtr >= aEndPtr )
       
   189             {
       
   190             return NULL;
       
   191             }
       
   192         if ( *( ++aStartPtr ) == KMarkerStart )
       
   193             {
       
   194             TRAP( error, atHand = TExifCommon::Uint16L( aStartPtr ) );
       
   195             }
       
   196         } 
       
   197     while ( (atHand != revMarker ) && ( error == KErrNone) );
       
   198     if ( error )
       
   199         {
       
   200         return NULL;
       
   201         }
       
   202     return aStartPtr;
       
   203     }
       
   204 
       
   205 // -----------------------------------------------------------------------------
       
   206 // TExifCommon::LocateJpegMarkerPtrFromEnd
       
   207 // Locates the pointer to the first specified Jpeg Marker from the end
       
   208 // inside the given interval.
       
   209 // -----------------------------------------------------------------------------
       
   210 //
       
   211 TUint8* TExifCommon::LocateJpegMarkerPtrFromEnd( 
       
   212     TUint16 aMarker, 
       
   213     TUint8* aStartPtr,
       
   214     TUint8* aEndPtr)
       
   215     {
       
   216     if ( ( !aStartPtr ) || ( !aEndPtr ) || ( !aMarker ) )
       
   217         {
       
   218         return NULL;
       
   219         }
       
   220 
       
   221     TUint16 revMarker = 
       
   222         STATIC_CAST( TUint16, ( aMarker << 8 ) + ( aMarker >> 8 ) );
       
   223     --aEndPtr;
       
   224     TUint16 atHand = 0;
       
   225     TInt error = KErrNone;
       
   226     do
       
   227         {
       
   228         if ( aEndPtr <= aStartPtr )
       
   229             {
       
   230             return NULL;
       
   231             }
       
   232         if ( *( --aEndPtr ) == KMarkerStart )
       
   233             {
       
   234             TRAP( error, atHand = TExifCommon::Uint16L( aEndPtr ) );
       
   235             }
       
   236         } 
       
   237     while ( (atHand != revMarker ) && ( error == KErrNone) );
       
   238     if ( error )
       
   239         {
       
   240         return NULL;
       
   241         }
       
   242     return aEndPtr;
       
   243     }