1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/mm/mmlibs/mmfw/Recogniser/src/reader.cpp Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,191 @@
1.4 +// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
1.5 +// All rights reserved.
1.6 +// This component and the accompanying materials are made available
1.7 +// under the terms of "Eclipse Public License v1.0"
1.8 +// which accompanies this distribution, and is available
1.9 +// at the URL "http://www.eclipse.org/legal/epl-v10.html".
1.10 +//
1.11 +// Initial Contributors:
1.12 +// Nokia Corporation - initial contribution.
1.13 +//
1.14 +// Contributors:
1.15 +//
1.16 +// Description:
1.17 +//
1.18 +
1.19 +#include "readers.h"
1.20 +
1.21 +//
1.22 +// Creates a new CReader object.
1.23 +//
1.24 +CReader::CReader(const TDesC8& aBuffer, TReaderType aType)
1.25 + : iBuffer(aBuffer),
1.26 + iType(aType)
1.27 + {
1.28 + }
1.29 +
1.30 +//
1.31 +// Returns ETrue is aPattern is in the buffer, EFalse otherwise.
1.32 +//
1.33 +TBool CReader::Match(const TDesC8& aPattern)
1.34 + {
1.35 + return (iBuffer.Match(aPattern) != KErrNotFound);
1.36 + }
1.37 +
1.38 +
1.39 +//
1.40 +// Reads aBuf.Length() bytes into a descriptor.
1.41 +//
1.42 +void CReader::ReadBytesL(TDes8& aBuf)
1.43 + {
1.44 + TInt bufLen = aBuf.Length();
1.45 +
1.46 + if (!CheckEnoughData(bufLen))
1.47 + {
1.48 + User::Leave(KErrEof);
1.49 + }
1.50 +
1.51 + for (TInt i = 0; i < bufLen; i++)
1.52 + {
1.53 + aBuf[i] = iBuffer[iBufPos++];
1.54 + }
1.55 + }
1.56 +
1.57 +
1.58 +//
1.59 +// Reads a byte from the buffer.
1.60 +//
1.61 +void CReader::ReadByteL(TUint8& aData)
1.62 + {
1.63 + if (!CheckEnoughData(sizeof(TUint8)))
1.64 + {
1.65 + User::Leave(KErrEof);
1.66 + }
1.67 +
1.68 + aData = iBuffer[iBufPos++];
1.69 + }
1.70 +
1.71 +//
1.72 +// Reads 16 bits of data at the current reader position.
1.73 +// Some formats (mainly those developed by Microsoft) still use little-endian
1.74 +// encoding of fields. The file format specifications will specify which
1.75 +// byte-ordering scheme is used.
1.76 +//
1.77 +void CReader::Read16L(TUint16& aData, TBool aLittleEndian)
1.78 + {
1.79 + if (!CheckEnoughData(sizeof(TUint16)))
1.80 + {
1.81 + User::Leave(KErrEof);
1.82 + }
1.83 +
1.84 + TUint8 a = iBuffer[iBufPos++];
1.85 + TUint8 b = iBuffer[iBufPos++];
1.86 +
1.87 + if (aLittleEndian)
1.88 + {
1.89 + aData = (b << 8) | a;
1.90 + }
1.91 + else
1.92 + {
1.93 + aData = (a << 8) | b;
1.94 + }
1.95 + }
1.96 +
1.97 +
1.98 +//
1.99 +// Reads 32 bits of data at the current reader position.
1.100 +// Some formats (mainly those developed by Microsoft) still use little-endian
1.101 +// encoding of fields. The file format specifications will specify which
1.102 +// byte-ordering scheme is used.
1.103 +//
1.104 +void CReader::Read32L(TUint32& aData, TBool aLittleEndian)
1.105 + {
1.106 + if (!CheckEnoughData(sizeof(TUint32)))
1.107 + {
1.108 + User::Leave(KErrEof);
1.109 + }
1.110 +
1.111 + TUint8 a = iBuffer[iBufPos++];
1.112 + TUint8 b = iBuffer[iBufPos++];
1.113 + TUint8 c = iBuffer[iBufPos++];
1.114 + TUint8 d = iBuffer[iBufPos++];
1.115 +
1.116 + if (aLittleEndian)
1.117 + {
1.118 + aData = MAKE_INT32(d, c, b, a);
1.119 + }
1.120 + else
1.121 + {
1.122 + aData = MAKE_INT32(a, b, c, d);
1.123 + }
1.124 + }
1.125 +
1.126 +
1.127 +//
1.128 +// Reads 64 bits of data at the current reader position.
1.129 +// Some formats (mainly those developed by Microsoft) still use little-endian
1.130 +// encoding of fields. The file format specifications will specify which
1.131 +// byte-ordering scheme is used.
1.132 +//
1.133 +void CReader::Read64L(TInt64& aData, TBool aLittleEndian)
1.134 + {
1.135 + TUint32 high;
1.136 + TUint32 low;
1.137 +
1.138 + Read32L(high, aLittleEndian);
1.139 + Read32L(low, aLittleEndian);
1.140 +
1.141 + if (aLittleEndian)
1.142 + {
1.143 + aData = MAKE_TINT64(low, high);
1.144 + }
1.145 + else
1.146 + {
1.147 + aData = MAKE_TINT64(high, low);
1.148 + }
1.149 + }
1.150 +
1.151 +
1.152 +//
1.153 +//
1.154 +//
1.155 +TBool CReader::CheckEnoughData(TInt aNeeded)
1.156 + {
1.157 + return ((iBufPos + aNeeded) <= iBuffer.Length());
1.158 + }
1.159 +
1.160 +
1.161 +//
1.162 +// Skips forwards or backwards aOffset number of bytes.
1.163 +//
1.164 +TInt CReader::Seek(TInt aOffset)
1.165 + {
1.166 + TInt newBufPos = iBufPos + aOffset;
1.167 +
1.168 + if ((newBufPos < 0) || (newBufPos >= iBuffer.Length()))
1.169 + {
1.170 + // Trying to seek past the bounds of the buffer.
1.171 + return KErrUnderflow;
1.172 + }
1.173 +
1.174 + iBufPos += aOffset;
1.175 + return KErrNone;
1.176 + }
1.177 +
1.178 +//
1.179 +// Skips forwards or backwards aOffset number of bytes.
1.180 +//
1.181 +TInt CReader::Seek(TInt64 aOffset)
1.182 + {
1.183 + TInt64 newBufPos = iBufPos + aOffset;
1.184 +
1.185 + if ((newBufPos < 0) || (newBufPos >= iBuffer.Length()))
1.186 + {
1.187 + // Trying to seek past the bounds of the buffer.
1.188 + return KErrUnderflow;
1.189 + }
1.190 +
1.191 + iBufPos += aOffset;
1.192 + return KErrNone;
1.193 + }
1.194 +