1 // Copyright (c) 1996-2009 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 the License "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 // f32\sfat32\inc\sl_cache.inl

    15 // 

    16 //

    17 

    18 /**

    19  @file

    20  @internalTechnology

    21 */

    22 

    23 #ifndef SL_CACHE_INL

    24 #define SL_CACHE_INL

    25 

    26 

    27 /**

    28     @param  aPos media linear position

    29     @return ETrue if the aPos belongs to this page

    30 */

    31 TBool CWTCachePage::PosCached(TInt64 aPos) const

    32     {

    33     return (iValid && aPos >= iStartPos && aPos < iStartPos+PageSize());

    34     }

    35 

    36 

    37 /**

    38     Calculate data position within cache page relatively to the page beginning.

    39     @param  aPos media linear position

    40     @return data offset from the beginning of the page

    41 */

    42 TUint32 CWTCachePage::PosInCachePage(TInt64 aPos) const 

    43     { 

    44     return ((TUint32)aPos - (TUint32)iStartPos) & (PageSize()-1);

    45     }

    46 

    47 /**

    48     Obtain pointer to the data in the cache page by media inear position

    49     @param  aPos media linear position

    50     @return pointer to the data in page buffer

    51 */

    52 TUint8* CWTCachePage::PtrInCachePage(TInt64 aPos) const 

    53     { 

    54     return (TUint8*)iData.Ptr() + PosInCachePage(aPos);

    55     }

    56 

    57 /**

    58     @return cache page size in bytes

    59 */

    60 TUint32 CWTCachePage::PageSize() const 

    61     {

    62     return iData.Size();

    63     }  

    64 

    65 //---------------------------------------------------------------------------------------------------------------------------------

    66 

    67 

    68 /**

    69     Just helper method to calculate cache page start position by given media pos.

    70     @param  aPos media linear position

    71     @return rounded-down and aligned position that is the beginning of the cache page

    72 */

    73 TInt64  CMediaWTCache::CalcPageStartPos(TInt64 aPos) const 

    74     { 

    75     ASSERT(aPos >= iCacheBasePos);

    76     return (((aPos - iCacheBasePos) >> iPageSizeLog2) << iPageSizeLog2) + iCacheBasePos;

    77     }

    78 

    79 /**

    80     @return cache page size

    81 */

    82 TUint32 CMediaWTCache::PageSize() const 

    83     {

    84     return 1<<iPageSizeLog2;

    85     }

    86 

    87 

    88 /**

    89     Set cache base position at aBasePos

    90     @param  aBasePos  base position of the cache pages. Affects pages alignment.

    91 */

    92 void CMediaWTCache::SetCacheBasePos(TInt64 aBasePos)

    93     {

    94     iCacheBasePos = aBasePos;

    95     }

    96 

    97 

    98 

    99 //---------------------------------------------------------------------------------------------------------------------------------

   100 

   101 

   102 #endif //SL_CACHE_INL

   103 

   104 

   105 

   106