| author | sl |
| Tue, 10 Jun 2014 14:32:02 +0200 | |
| changeset 1 | 260cb5ec6c19 |
| permissions | -rw-r--r-- |
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// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies). |
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// All rights reserved. |
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// This component and the accompanying materials are made available |
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// under the terms of "Eclipse Public License v1.0" |
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// which accompanies this distribution, and is available |
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// at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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// |
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// Initial Contributors: |
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// Nokia Corporation - initial contribution. |
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// |
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// Contributors: |
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// |
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// Description: |
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// |
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|
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#include "readers.h" |
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|
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// |
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// |
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// |
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CFileReader::CFileReader(RFile* aFile) |
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: CBufferReader(iFileBuffer, CReader::EFile), |
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iFile(aFile) |
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{
|
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} |
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|
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|
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// |
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// |
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// |
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CFileReader::~CFileReader() |
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{
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} |
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|
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|
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// |
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// |
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// |
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CFileReader* CFileReader::NewLC(RFile* aFile) |
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{
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CFileReader* self = new(ELeave) CFileReader(aFile); |
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CleanupStack::PushL(self); |
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self->ConstructL(); |
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return self; |
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} |
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|
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|
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// |
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// |
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// |
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void CFileReader::ConstructL() |
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{
|
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TInt pos = 0; |
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User::LeaveIfError(iFile->Seek(ESeekStart, pos)); |
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User::LeaveIfError(iFile->Read(iFileBuffer)); |
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} |
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|
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|
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// |
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// Checks if there is aAmount of data left in the buffer. |
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// It is important to call the base-class implementation first |
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// to ensure correct operation. |
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// |
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TBool CFileReader::CheckEnoughData(TInt aAmount) |
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{
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if (CBufferReader::CheckEnoughData(aAmount)) |
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{
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return ETrue; |
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} |
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|
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// Try to read more data. |
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TInt bufPos = CBufferReader::Position(); |
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TInt err = PhysicallySeekAndRead(bufPos - iFileBuffer.Length()); |
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if (err == KErrNone) |
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{
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// The read may have succeeded but that |
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// still doesn't mean we have enough data. |
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return (aAmount <= iFileBuffer.Length()); |
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} |
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|
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return EFalse; |
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} |
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|
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|
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// |
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// |
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// |
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void CFileReader::Reset() |
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{
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CBufferReader::Reset(); // This will reset iBufPos. |
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|
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if (iFilePos != 0) |
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{
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// We need to seek to the start and fill the buffer. |
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iFilePos = 0; |
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TInt filepos = 0; |
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TInt err = iFile->Seek(ESeekStart, filepos); |
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if (err == KErrNone) |
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{
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err = iFile->Read(iFileBuffer); |
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} |
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|
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if (err != KErrNone) |
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{
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iFileBuffer.Zero(); |
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} |
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} |
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else |
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{
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// There's no need to seek and read. |
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iFilePos = 0; |
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} |
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} |
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|
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|
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// |
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// |
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// |
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void CFileReader::SeekL(TInt aOffset) |
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{
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TInt err = CReader::Seek(aOffset); |
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if (err == KErrUnderflow) |
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{
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TInt bufPos = CBufferReader::Position(); |
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aOffset += bufPos - iFileBuffer.Length(); |
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User::LeaveIfError(PhysicallySeekAndRead(aOffset)); |
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} |
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} |
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|
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|
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// |
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// It could be possible for a 64-bit field in formats such as MPEG4 |
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// to have values that would fit in a 32-bit variable. In this case |
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// we can use it for seeking. This function checks if a 64-bit value |
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// is compatible with RFile's 32-bit operations. |
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// |
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void CFileReader::SeekL(TInt64 aOffset) |
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{
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if (aOffset < KMinTInt64) |
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{
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User::Leave(KErrNotSupported); |
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} |
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|
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if (aOffset > KMaxTInt64) |
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{
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User::Leave(KErrNotSupported); |
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} |
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|
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if (aOffset < (TInt64)KMaxTInt) |
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{
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TInt low = (TInt)I64LOW(aOffset); |
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SeekL(low); |
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} |
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else |
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{
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TInt err = CReader::Seek(aOffset); |
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if (err == KErrUnderflow) |
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{
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TInt64 bufPos = CBufferReader::Position(); |
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aOffset += bufPos - iFileBuffer.Length(); |
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User::LeaveIfError(PhysicallySeekAndRead(aOffset)); |
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} |
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} |
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} |
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|
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// |
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// This function seeks forward/backward aOffset bytes |
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// and fills the buffer from that point. |
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// |
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TInt CFileReader::PhysicallySeekAndRead(TInt aOffset) |
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{
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TInt err; |
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|
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// New buffer contents so read from the start of it. |
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CBufferReader::Reset(); |
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|
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iFilePos = aOffset; |
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err = iFile->Seek(ESeekCurrent, aOffset); |
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|
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if (err != KErrNone) |
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{
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return err; |
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} |
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|
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err = iFile->Read(iFileBuffer); |
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if (err != KErrNone) |
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{
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return err; |
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} |
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return (iFileBuffer.Length() == 0 ? KErrEof : KErrNone); |
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} |
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TInt CFileReader::PhysicallySeekAndRead(TInt64 aOffset) |
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{
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TInt err; |
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// New buffer contents so read from the start of it. |
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CBufferReader::Reset(); |
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|
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iFilePos = aOffset; |
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RFile64* tempfile; |
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tempfile = static_cast<RFile64*> (iFile); |
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|
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err = tempfile->Seek(ESeekCurrent, iFilePos); |
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if (err != KErrNone) |
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{
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return err; |
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} |
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|
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err = iFile->Read(iFileBuffer); |
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if (err != KErrNone) |
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{
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return err; |
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} |
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|
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return (iFileBuffer.Length() == 0 ? KErrEof : KErrNone); |
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} |
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