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 #include "T_rndutils.h"

    17 

    18 const TInt KMaxWordLength =  64 ;

    19 const TInt KMaxNgramSize = 8;

    20 

    21 void CWordNgrams::ConstructL(const TDesC& aFilename, const TInt  aN, TBool aUseNarrowChar)

    22 	{

    23 	ASSERT(aN<KMaxNgramSize && aN>0);

    24 	

    25 	RFs fsSession;

    26 	RFileReadStream fileStream;

    27 	User::LeaveIfError(fsSession.Connect());

    28 	CleanupClosePushL(fsSession);

    29 	User::LeaveIfError(fileStream.Open(fsSession, aFilename, EFileRead));

    30 	CleanupClosePushL(fileStream);

    31 	TUint number = 0;

    32 	TBuf8<KMaxNgramSize> ngram8;

    33 #ifdef _UNICODE

    34 	TBuf<KMaxNgramSize> ngram;

    35 #else

    36 #define  ngram ngram8;

    37 #endif

    38 	TInt err=KErrNone; 

    39 	while(err==KErrNone)

    40 		{

    41 		TRAP(err, number = fileStream.ReadUint8L()); 

    42 		if(err==KErrNone)

    43 			{

    44 			if(aUseNarrowChar)

    45 				{

    46 				fileStream.ReadL(ngram8,aN);

    47 				SetNgram(ngram8, number);

    48 				}

    49 			else

    50 				{

    51 				fileStream.ReadL(ngram,aN);

    52 				SetNgram(ngram, number);

    53 				}

    54 			}

    55 		}

    56 	CleanupStack::PopAndDestroy(2);

    57 	}

    58 

    59 	

    60 HBufC*  CWordNgrams::WordLC()

    61 	{

    62 	HBufC* buffer = HBufC::NewLC(KMaxWordLength);

    63 	TPtr word = buffer->Des();

    64 	while(AddLetter(word))

    65 		{}

    66 	return buffer;

    67 	}

    68 

    69 

    70 /** Return false if done*/

    71 TBool CWordNgrams::AddLetter(TDes& aWord)

    72 	{

    73 	if(aWord.Length()==aWord.MaxLength())

    74 		{

    75 		return EFalse;

    76 		}

    77 	TChar c = NextLetter(aWord);

    78 	if(c==0)

    79 		{

    80 		return EFalse;

    81 		}

    82 	aWord.Append(c);

    83 	return ETrue;

    84 	}

    85 

    86 //

    87 // CWordDigrams.

    88 //

    89 

    90 

    91 CWordDigrams::CWordDigrams(TInt64& aRandSeed) : iRandSeed(aRandSeed)

    92 	{}

    93 

    94 

    95 CWordDigrams* CWordDigrams::NewLC(const TDesC& aFilename, TInt64& aRandSeed)

    96 	{

    97 	CWordDigrams* self = new(ELeave) CWordDigrams(aRandSeed);

    98 	CleanupStack::PushL(self);

    99 	self->ConstructL(aFilename);

   100 	return self;

   101 	}

   102 

   103 void CWordDigrams::SetNgram(const TDesC8& aNgram, TUint aNumber)

   104 	{

   105 	iDigrams[Index(aNgram[0])][Index(aNgram[1])] = (TUint8) aNumber;

   106 	}

   107 

   108 void CWordDigrams::SetNgram(const TDesC16& /*aNgram*/, TUint /*aNumber*/)

   109 	{}

   110 

   111 void CWordDigrams::ConstructL(const TDesC& aFilename)

   112 	{

   113 	CWordNgrams::ConstructL(aFilename);

   114 	for(TInt i=0;i<KDigramNumberOfChars;i++)

   115 		{

   116 		TUint max =0;

   117 		for(TInt j=0;j<KDigramNumberOfChars;j++)

   118 			{

   119 			max += iDigrams[i][j];

   120 			}

   121 		iSizes[i] = (TUint16)max;

   122 		}

   123 	}

   124 

   125 

   126 

   127 TChar CWordDigrams::NextLetter(const TDesC& aWord)

   128 	{

   129 	TInt len = aWord.Length();

   130 	TInt index = 0;

   131 	if(len!=0)

   132 		{

   133 		index = Index(aWord[len-1]);

   134 		}

   135 

   136 	if(iSizes[index]==0)

   137 		{

   138 		return 0;

   139 		}

   140 	TInt x = Math::Rand(iRandSeed) % iSizes[index];

   141 	for(TInt i=0;i<KDigramNumberOfChars;i++)

   142 		{

   143 		if(x<iDigrams[index][i])

   144 			{

   145 			return Char(i);

   146 			}

   147 		x-=iDigrams[index][i];

   148 		if(x<=0) 

   149 			{

   150 			x=1;

   151 			}

   152 		}

   153 	return 0;

   154 	}

   155 

   156 

   157 

   158 TInt CWordDigrams::Index(TChar c)

   159 	{

   160 	

   161 	if(c.IsSpace())

   162 		return 1;

   163 	if(c=='-')

   164 		return 2;

   165 	if(c.IsUpper())

   166 		return ((TUint)c)-'A'+KDigramNumberOfNonLetters;

   167 	if(c.IsLower())

   168 		return ((TUint) c)-'a'+KDigramNumberOfLetters+KDigramNumberOfNonLetters;

   169 	return 0;

   170 	}

   171 

   172 

   173 TChar CWordDigrams::Char(TInt i)

   174 	{

   175 	if(i==0)

   176 		return 0;

   177 	if(i==1)

   178 		return ' ';

   179 	if(i==2)

   180 		return '-';

   181 	if(i<KDigramNumberOfNonLetters+KDigramNumberOfLetters)

   182 		return TChar('A'+i-KDigramNumberOfNonLetters);

   183 	return TChar('a'+i-KDigramNumberOfNonLetters-KDigramNumberOfLetters);

   184 	}

   185 

   186 

   187 CWordDigrams::~CWordDigrams()

   188 	{}