1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/persistentdata/persistentstorage/dbms/ustor/US_COMP.CPP Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,1259 @@
1.4 +// Copyright (c) 1998-2009 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 +// Store database compression code
1.18 +//
1.19 +//
1.20 +
1.21 +#include "US_STD.H"
1.22 +#include <s32mem.h>
1.23 +
1.24 +#ifdef __WINS__
1.25 +#define __EXTRA_DEFLATE
1.26 +#endif
1.27 +
1.28 +// deflation constants
1.29 +const TInt KDeflateMinLength=3;
1.30 +const TInt KDeflateMaxLength=258;
1.31 +const TInt KDeflateMaxDistance=4096;
1.32 +const TInt KDeflateDistCodeBase=0x200;
1.33 +// huffman coding/decoding
1.34 +const TInt KHuffMaxCodeLength=25;
1.35 +const TInt KHuffTerminate=1;
1.36 +const TUint KBitsEmpty=0x80000000u;
1.37 +const TUint KBitsInit=KBitsEmpty>>1;
1.38 +const TUint KBitsFull=KBitsEmpty>>8;
1.39 +const TUint KBitsEOF=KBitsEmpty>>9;
1.40 +const TUint KBitsNext=0x80u;
1.41 +// encoding storage
1.42 +const TInt KDeflateMetaCodes=26;
1.43 +// hashing
1.44 +const TUint KDeflateHashMultiplier=0xAC4B9B19u;
1.45 +const TInt KDeflateHashShift=24;
1.46 +
1.47 +class Huffman
1.48 + {
1.49 +public:
1.50 + static void EncodingL(TUint32* aEncoding,TInt aCodes);
1.51 + static void Decoding(TUint32* aDecoding,TInt aCodes,TInt aBase=0);
1.52 +private:
1.53 + typedef TUint16 THuff;
1.54 + enum {KLeaf=0x8000};
1.55 + struct TNode
1.56 + {
1.57 + THuff iLeft;
1.58 + THuff iRight;
1.59 + };
1.60 + struct TLeaf
1.61 + {
1.62 + TUint iCount;
1.63 + THuff iVal;
1.64 + };
1.65 +private:
1.66 + static void Lengths(TUint32* aLengths,const TNode* aNodes,TInt aNode,TInt aLen);
1.67 + static TUint32* SubTree(TUint32* aPtr,const TUint32* aValue,TUint32** aLevel);
1.68 + };
1.69 +
1.70 +class THuffEncoder
1.71 + {
1.72 +public:
1.73 + THuffEncoder(RWriteStream& aStream);
1.74 +//
1.75 + void EncodeL(TUint aCode,TInt aLength);
1.76 + void EncodeL(TUint32 aHuffCode);
1.77 + void CompleteL();
1.78 +private:
1.79 + enum {EBufSize=0x100};
1.80 +private:
1.81 + TUint8 iBuf[EBufSize];
1.82 + RWriteStream& iStream;
1.83 + TUint32 iCode; // code in production
1.84 + TInt iBits;
1.85 + TUint8* iWrite;
1.86 + };
1.87 +
1.88 +class HDeflateHash
1.89 + {
1.90 +public:
1.91 + inline static HDeflateHash& NewLC(TInt aLinks);
1.92 +//
1.93 + inline TInt First(const TUint8* aPtr,TInt aPos);
1.94 + inline TInt Next(TInt aPos,TInt aOffset) const;
1.95 +private:
1.96 + inline HDeflateHash();
1.97 + inline static TInt Hash(const TUint8* aPtr);
1.98 +private:
1.99 + typedef TUint16 TOffset;
1.100 +private:
1.101 + TInt iHash[256];
1.102 + TOffset iOffset[1]; // or more
1.103 + };
1.104 +
1.105 +class MDeflater
1.106 + {
1.107 +public:
1.108 + void DeflateL(const TUint8* aBase,TInt aLength);
1.109 +private:
1.110 + const TUint8* DoDeflateL(const TUint8* aBase,const TUint8* aEnd,HDeflateHash& aHash);
1.111 + static TInt Match(const TUint8* aPtr,const TUint8* aEnd,TInt aPos,HDeflateHash& aHas);
1.112 + void SegmentL(TInt aLength,TInt aDistance);
1.113 + virtual void LitLenL(TInt aCode) =0;
1.114 + virtual void OffsetL(TInt aCode) =0;
1.115 + virtual void ExtraL(TInt aLen,TUint aBits) =0;
1.116 + };
1.117 +
1.118 +class TInflater
1.119 + {
1.120 +public:
1.121 + TInflater(const TUint8* aIn,const CDbStoreCompression::TEncoding& aDecoding);
1.122 + TInt Inflate();
1.123 + inline const TUint8* Ptr() const;
1.124 + inline static TInt BufferSize();
1.125 +private:
1.126 + const TUint8* iIn;
1.127 + TUint iBits;
1.128 + const TUint8* iRptr; // partial segment
1.129 + TInt iLen;
1.130 + const TUint32* iLitLenTree;
1.131 + const TUint32* iDistTree;
1.132 + TUint8 iOut[KDeflateMaxDistance]; // circular buffer for distance matches
1.133 + };
1.134 +
1.135 +NONSHARABLE_CLASS(TDeflateStats) : public MDeflater
1.136 + {
1.137 +public:
1.138 + inline TDeflateStats(CDbStoreCompression::TEncoding& aEncoding);
1.139 +private:
1.140 +// from MDeflater
1.141 + void LitLenL(TInt aCode);
1.142 + void OffsetL(TInt aCode);
1.143 + void ExtraL(TInt aLen,TUint aBits);
1.144 +private:
1.145 + CDbStoreCompression::TEncoding& iEncoding;
1.146 + };
1.147 +
1.148 +NONSHARABLE_CLASS(TDeflater) : public MDeflater
1.149 + {
1.150 +public:
1.151 + inline TDeflater(THuffEncoder& aEncoder,const CDbStoreCompression::TEncoding& aEncoding);
1.152 +private:
1.153 +// from MDeflater
1.154 + void LitLenL(TInt aCode);
1.155 + void OffsetL(TInt aCode);
1.156 + void ExtraL(TInt aLen,TUint aBits);
1.157 +private:
1.158 + THuffEncoder& iEncoder;
1.159 + const CDbStoreCompression::TEncoding& iEncoding;
1.160 + };
1.161 +
1.162 +NONSHARABLE_CLASS(HDeflateBuf) : public TBufBuf
1.163 + {
1.164 +public:
1.165 + enum TMode {EAnalysis,EDeflate}; // mirror CDbStoreCompression enum
1.166 +public:
1.167 + static HDeflateBuf* NewL(MStreamBuf* aHost,CDbStoreCompression::TEncoding& aEncoding,TMode aMode);
1.168 +private:
1.169 + inline HDeflateBuf(MStreamBuf* aHost,CDbStoreCompression::TEncoding& aEncoding,CBufBase* aBuf,TMode aMode);
1.170 + virtual inline ~HDeflateBuf();
1.171 +// from MStreamBuf
1.172 + void DoSynchL();
1.173 + void DoRelease();
1.174 +private:
1.175 + RWriteStream iHost;
1.176 + CDbStoreCompression::TEncoding& iEncoding;
1.177 + CBufBase* iBuf;
1.178 + TMode iMode;
1.179 + };
1.180 +
1.181 +NONSHARABLE_CLASS(HInflateBuf) : public TBufBuf
1.182 + {
1.183 +public:
1.184 + static HInflateBuf* NewL(MStreamBuf* aHost,const CDbStoreCompression::TEncoding& aEncoding);
1.185 +private:
1.186 + inline HInflateBuf(CBufBase* aBuf);
1.187 + virtual inline ~HInflateBuf();
1.188 +// from MStreamBuf
1.189 + void DoRelease();
1.190 +private:
1.191 + CBufBase* iBuf;
1.192 + };
1.193 +
1.194 +NONSHARABLE_CLASS(CDbStoreTable::CCompressor) : public CBase, public CCluster::MAlter
1.195 + {
1.196 +public:
1.197 + inline CCompressor();
1.198 + ~CCompressor();
1.199 + void ProcessL(CDbStoreTable* aTable);
1.200 +private:
1.201 + TUint8* AlterRecordL(TUint8* aWPtr,const TUint8* aRPtr,TInt aLength);
1.202 +private:
1.203 + CDbStoreTable* iTable;
1.204 + RDbRow iRow;
1.205 + };
1.206 +
1.207 +// Class Huffman
1.208 +//
1.209 +// This class builds a huffman encoding from a frequency table and builds
1.210 +// a decoding tree from a code-lengths table
1.211 +//
1.212 +// the encoding generated is based on the rule that given two symbols s1 and s2, with
1.213 +// code length l1 and l2, and huffman codes h1 and h2:
1.214 +//
1.215 +// if l1<l2 then h1<h2 when compared lexicographically
1.216 +// if l1==l2 and s1<s2 then h1<h2 ditto
1.217 +//
1.218 +// This allows the encoding to be stored compactly as a table of code lengths
1.219 +
1.220 +//
1.221 +// recursive function to calculate the code lengths from the node tree
1.222 +//
1.223 +void Huffman::Lengths(TUint32* aLengths,const TNode* aNodes,TInt aNode,TInt aLen)
1.224 + {
1.225 + __ASSERT(aLen<KHuffMaxCodeLength);
1.226 + ++aLen;
1.227 + const TNode& node=aNodes[aNode];
1.228 + if (node.iLeft&KLeaf)
1.229 + aLengths[node.iLeft&~KLeaf]=aLen;
1.230 + else
1.231 + Lengths(aLengths,aNodes,node.iLeft,aLen);
1.232 + if (node.iRight&KLeaf)
1.233 + aLengths[node.iRight&~KLeaf]=aLen;
1.234 + else
1.235 + Lengths(aLengths,aNodes,node.iRight,aLen);
1.236 + }
1.237 +
1.238 +//
1.239 +// write the subtree below aPtr and return the head
1.240 +//
1.241 +TUint32* Huffman::SubTree(TUint32* aPtr,const TUint32* aValue,TUint32** aLevel)
1.242 + {
1.243 + TUint32* l=*aLevel++;
1.244 + if (l>aValue)
1.245 + {
1.246 + TUint32* sub1=SubTree(aPtr,aValue,aLevel); // 0-tree first
1.247 + aPtr=SubTree(sub1,aValue-(aPtr-sub1)-1,aLevel); // 1-tree
1.248 + TInt branch=(TUint8*)sub1-(TUint8*)aPtr;
1.249 + *--aPtr=branch;
1.250 + }
1.251 + else if (l==aValue)
1.252 + {
1.253 + TUint term0=*aValue--; // 0-term
1.254 + aPtr=SubTree(aPtr,aValue,aLevel); // 1-tree
1.255 + *--aPtr=term0>>16;
1.256 + }
1.257 + else // l<iNext
1.258 + {
1.259 + TUint term0=*aValue--; // 0-term
1.260 + TUint term1=*aValue--;
1.261 + *--aPtr=(term1>>16<<16)|(term0>>16);
1.262 + }
1.263 + return aPtr;
1.264 + }
1.265 +
1.266 +//
1.267 +// Build a huffman encoding table from a symbol frequency table
1.268 +// aTable contains frequency data on input for aCodes symbols
1.269 +// aTable contains the huffman encoding on output
1.270 +//
1.271 +void Huffman::EncodingL(TUint32* aTable,TInt aCodes)
1.272 + {
1.273 +//
1.274 +// step 1. Sort the values into decreasing order of frequency
1.275 +//
1.276 + TLeaf* leaves=new(ELeave) TLeaf[aCodes];
1.277 + CleanupArrayDeletePushL(leaves);
1.278 + TInt lCount=0;
1.279 + TInt ii;
1.280 + for (ii=0;ii<aCodes;++ii)
1.281 + {
1.282 + TUint c=aTable[ii];
1.283 + if (c==0)
1.284 + continue; // no coding for ii
1.285 + TInt jj;
1.286 + for (jj=0;jj<lCount;++jj)
1.287 + {
1.288 + if (leaves[jj].iCount<=c)
1.289 + break;
1.290 + }
1.291 + Mem::Move(leaves+jj+1,leaves+jj,sizeof(TLeaf)*(lCount-jj));
1.292 + leaves[jj].iCount=c;
1.293 + leaves[jj].iVal=THuff(ii|KLeaf);
1.294 + lCount++;
1.295 + }
1.296 +//
1.297 +// Huffman algorithm: pair off least frequent nodes and reorder
1.298 +// result is the code lengths in aTable[]
1.299 +//
1.300 + if (lCount==1) // special case for a single value (always encode as "0")
1.301 + aTable[leaves[0].iVal&~KLeaf]=1;
1.302 + else if (lCount>1)
1.303 + { // don't encode for empty coding: leaves in order now
1.304 + TInt max=0;
1.305 + TNode* nodes=new(ELeave) TNode[lCount-1];
1.306 + while (--lCount>0)
1.307 + {
1.308 + TNode& node=nodes[max];
1.309 + node.iLeft=leaves[lCount-1].iVal;
1.310 + node.iRight=leaves[lCount].iVal;
1.311 + // re-order the leaves now to reflect new combined frequency
1.312 + TUint c=leaves[lCount-1].iCount+leaves[lCount].iCount;
1.313 + TInt jj=lCount;
1.314 + while (--jj>0)
1.315 + {
1.316 + if (leaves[jj-1].iCount>=c)
1.317 + break;
1.318 + }
1.319 + Mem::Move(leaves+jj+1,leaves+jj,sizeof(TLeaf)*(lCount-1-jj));
1.320 + // update new leaf
1.321 + leaves[jj].iCount=c;
1.322 + leaves[jj].iVal=THuff(max);
1.323 + max++;
1.324 + }
1.325 + Lengths(aTable,nodes,leaves[0].iVal,0);
1.326 + delete[] nodes;
1.327 + }
1.328 + CleanupStack::PopAndDestroy(); // leaves
1.329 +//
1.330 +// step 3: Generate the coding based on the code lengths
1.331 +//
1.332 + TInt lenCount[KHuffMaxCodeLength];
1.333 + Mem::FillZ(lenCount,sizeof(lenCount));
1.334 +
1.335 + for (ii=aCodes;--ii>=0;)
1.336 + {
1.337 + TInt len=aTable[ii]-1;
1.338 + if (len>=0)
1.339 + ++lenCount[len];
1.340 + }
1.341 +
1.342 + TUint nextCode[KHuffMaxCodeLength];
1.343 + TUint code=0;
1.344 + for (ii=0;ii<KHuffMaxCodeLength;++ii)
1.345 + {
1.346 + nextCode[ii]=code;
1.347 + code=(code+lenCount[ii])<<1;
1.348 + }
1.349 +
1.350 + for (ii=0;ii<aCodes;++ii)
1.351 + {
1.352 + TInt len=aTable[ii];
1.353 + if (len)
1.354 + {
1.355 + aTable[ii] = (nextCode[len-1]<<(KHuffMaxCodeLength-len))|(len<<KHuffMaxCodeLength);
1.356 + ++nextCode[len-1];
1.357 + }
1.358 + }
1.359 + }
1.360 +
1.361 +//
1.362 +// generate the decoding tree from the huffman code length data
1.363 +// output alphabet is [aBase,aBase+aCodes)
1.364 +//
1.365 +void Huffman::Decoding(TUint32* aDecoding,TInt aCodes,TInt aBase)
1.366 + {
1.367 + TInt counts[KHuffMaxCodeLength];
1.368 + Mem::FillZ(counts,sizeof(counts));
1.369 + TInt codes=0;
1.370 + TInt ii=aCodes;
1.371 + while (--ii>=0)
1.372 + {
1.373 + TUint len=aDecoding[ii];
1.374 + __ASSERT(len<=(TUint)KHuffMaxCodeLength);
1.375 + if (len)
1.376 + {
1.377 + ++counts[len-1];
1.378 + ++codes;
1.379 + }
1.380 + }
1.381 +//
1.382 + TUint32* level[KHuffMaxCodeLength];
1.383 + TUint32* lit=aDecoding+codes;
1.384 + for (ii=0;ii<KHuffMaxCodeLength;++ii)
1.385 + {
1.386 + level[ii]=lit;
1.387 + lit-=counts[ii];
1.388 + }
1.389 + aBase=(aBase<<17)+(KHuffTerminate<<16);
1.390 + for (ii=0;ii<aCodes;++ii)
1.391 + {
1.392 + TUint len=TUint8(aDecoding[ii]);
1.393 + if (len)
1.394 + *--level[len-1]|=(ii<<17)+aBase;
1.395 + }
1.396 + if (codes==1) // codes==1 special case: tree is not complete
1.397 + *aDecoding>>=16; // 0-terminate at root
1.398 + else if (codes>1)
1.399 + {
1.400 + __DEBUG(TUint32* p=) SubTree(aDecoding+codes-1,aDecoding+codes-1,level);
1.401 + __ASSERT(p==aDecoding);
1.402 + }
1.403 + }
1.404 +
1.405 +// Class HDeflateHash
1.406 +
1.407 +inline HDeflateHash::HDeflateHash()
1.408 + {TInt* p=iHash+256;do *--p=-KDeflateMaxDistance-1; while (p>iHash);}
1.409 +
1.410 +inline HDeflateHash& HDeflateHash::NewLC(TInt aLinks)
1.411 + {
1.412 + __ASSERT(!(KDeflateMaxDistance&(KDeflateMaxDistance-1))); // ensure power of two
1.413 + return *new(User::AllocLC(_FOFF(HDeflateHash,iOffset[Min(aLinks,KDeflateMaxDistance)]))) HDeflateHash;
1.414 + }
1.415 +
1.416 +inline TInt HDeflateHash::Hash(const TUint8* aPtr)
1.417 + {
1.418 + TUint x=aPtr[0]|(aPtr[1]<<8)|(aPtr[2]<<16);
1.419 + return (x*KDeflateHashMultiplier)>>KDeflateHashShift;
1.420 + }
1.421 +
1.422 +inline TInt HDeflateHash::First(const TUint8* aPtr,TInt aPos)
1.423 + {
1.424 + TInt h=Hash(aPtr);
1.425 + TInt offset=Min(aPos-iHash[h],KDeflateMaxDistance<<1);
1.426 + iHash[h]=aPos;
1.427 + iOffset[aPos&(KDeflateMaxDistance-1)]=TOffset(offset);
1.428 + return offset;
1.429 + }
1.430 +
1.431 +inline TInt HDeflateHash::Next(TInt aPos,TInt aOffset) const
1.432 + {return aOffset+iOffset[(aPos-aOffset)&(KDeflateMaxDistance-1)];}
1.433 +
1.434 +
1.435 +// Class TDeflater
1.436 +//
1.437 +// generic deflation algorithm, can do either statistics and the encoder
1.438 +
1.439 +TInt MDeflater::Match(const TUint8* aPtr,const TUint8* aEnd,TInt aPos,HDeflateHash& aHash)
1.440 + {
1.441 + TInt offset=aHash.First(aPtr,aPos);
1.442 + if (offset>KDeflateMaxDistance)
1.443 + return 0;
1.444 + TInt match=0;
1.445 + aEnd=Min(aEnd,aPtr+KDeflateMaxLength);
1.446 + TUint8 c=*aPtr;
1.447 + do
1.448 + {
1.449 + const TUint8* p=aPtr-offset;
1.450 + if (p[match>>16]==c)
1.451 + { // might be a better match
1.452 + const TUint8* m=aPtr;
1.453 + for (;;)
1.454 + {
1.455 + if (*p++!=*m++)
1.456 + break;
1.457 + if (m<aEnd)
1.458 + continue;
1.459 + return ((m-aPtr)<<16)|offset;
1.460 + }
1.461 + TInt l=m-aPtr-1;
1.462 + if (l>match>>16)
1.463 + {
1.464 + match=(l<<16)|offset;
1.465 + c=m[-1];
1.466 + }
1.467 + }
1.468 + offset=aHash.Next(aPos,offset);
1.469 + } while (offset<=KDeflateMaxDistance);
1.470 + return match;
1.471 + }
1.472 +
1.473 +//
1.474 +// Apply the deflation algorithm to the data [aBase,aEnd)
1.475 +// Return a pointer after the last byte that was deflated (which may not be aEnd)
1.476 +//
1.477 +const TUint8* MDeflater::DoDeflateL(const TUint8* aBase,const TUint8* aEnd,HDeflateHash& aHash)
1.478 + {
1.479 + __ASSERT(aEnd-aBase>KDeflateMinLength);
1.480 +//
1.481 + const TUint8* ptr=aBase;
1.482 +#ifdef __EXTRA_DEFLATE
1.483 + TInt prev=0; // the previous deflation match
1.484 +#endif
1.485 + do
1.486 + {
1.487 + TInt match=Match(ptr,aEnd,ptr-aBase,aHash);
1.488 +#ifdef __EXTRA_DEFLATE
1.489 +// Extra deflation applies two optimisations which double the time taken
1.490 +// 1. If we have a match at p, then test for a better match at p+1 before using it
1.491 +// 2. When we have a match, add the hash links for all the data which will be skipped
1.492 + if (match>>16 < prev>>16)
1.493 + { // use the previous match--it was better
1.494 + TInt len=prev>>16;
1.495 + SegmentL(len,prev-(len<<16));
1.496 + // fill in missing hash entries for better compression
1.497 + const TUint8* e=ptr+len-2;
1.498 + do
1.499 + {
1.500 + ++ptr;
1.501 + aHash.First(ptr,ptr-aBase);
1.502 + } while (ptr<e);
1.503 + prev=0;
1.504 + }
1.505 + else if (match<=(KDeflateMinLength<<16))
1.506 + LitLenL(*ptr); // no deflation match here
1.507 + else
1.508 + { // save this match and test the next position
1.509 + if (prev) // we had a match at ptr-1, but this is better
1.510 + LitLenL(ptr[-1]);
1.511 + prev=match;
1.512 + }
1.513 + ++ptr;
1.514 +#else
1.515 +// Basic deflation will store any match found, and not update the hash links for the
1.516 +// data which is skipped
1.517 + if (match<=(KDeflateMinLength<<16)) // no match
1.518 + LitLenL(*ptr++);
1.519 + else
1.520 + { // store the match
1.521 + TInt len=match>>16;
1.522 + SegmentL(len,match-(len<<16));
1.523 + ptr+=len;
1.524 + }
1.525 +#endif
1.526 + } while (ptr+KDeflateMinLength-1<aEnd);
1.527 +#ifdef __EXTRA_DEFLATE
1.528 + if (prev)
1.529 + { // emit the stored match
1.530 + TInt len=prev>>16;
1.531 + SegmentL(len,prev-(len<<16));
1.532 + ptr+=len-1;
1.533 + }
1.534 +#endif
1.535 + return ptr;
1.536 + }
1.537 +
1.538 +//
1.539 +// The generic deflation algorithm
1.540 +//
1.541 +void MDeflater::DeflateL(const TUint8* aBase,TInt aLength)
1.542 + {
1.543 + const TUint8* end=aBase+aLength;
1.544 + if (aLength>KDeflateMinLength)
1.545 + { // deflation kicks in if there is enough data
1.546 + HDeflateHash& hash=HDeflateHash::NewLC(aLength);
1.547 + aBase=DoDeflateL(aBase,end,hash);
1.548 + CleanupStack::PopAndDestroy();
1.549 + }
1.550 + while (aBase<end) // emit remaining bytes
1.551 + LitLenL(*aBase++);
1.552 + LitLenL(CDbStoreCompression::TEncoding::EEos); // eos marker
1.553 + }
1.554 +
1.555 +//
1.556 +// Turn a (length,offset) pair into the deflation codes+extra bits before calling
1.557 +// the specific LitLen(), Offset() and Extra() functions.
1.558 +//
1.559 +void MDeflater::SegmentL(TInt aLength,TInt aDistance)
1.560 + {
1.561 + __ASSERT(aLength>=KDeflateMinLength && aLength<=KDeflateMaxLength);
1.562 + aLength-=KDeflateMinLength;
1.563 + TInt extralen=0;
1.564 + TUint len=aLength;
1.565 + while (len>=8)
1.566 + {
1.567 + ++extralen;
1.568 + len>>=1;
1.569 + }
1.570 + __ASSERT((extralen<<2)+len<CDbStoreCompression::TEncoding::ELengths);
1.571 + LitLenL((extralen<<2)+len+CDbStoreCompression::TEncoding::ELiterals);
1.572 + if (extralen)
1.573 + ExtraL(extralen,TUint(aLength)<<(32-extralen));
1.574 +//
1.575 + __ASSERT(aDistance>0 && aDistance<=KDeflateMaxDistance);
1.576 + aDistance--;
1.577 + extralen=0;
1.578 + TUint dist=aDistance;
1.579 + while (dist>=8)
1.580 + {
1.581 + ++extralen;
1.582 + dist>>=1;
1.583 + }
1.584 + __ASSERT((extralen<<2)+dist<CDbStoreCompression::TEncoding::EDistances);
1.585 + OffsetL((extralen<<2)+dist);
1.586 + if (extralen)
1.587 + ExtraL(extralen,TUint(aDistance)<<(32-extralen));
1.588 + }
1.589 +
1.590 +// Class TDeflateStats
1.591 +//
1.592 +// This class analyses the data stream to generate the frequency tables
1.593 +// for the deflation algorithm
1.594 +
1.595 +inline TDeflateStats::TDeflateStats(CDbStoreCompression::TEncoding& aEncoding)
1.596 + :iEncoding(aEncoding)
1.597 + {}
1.598 +
1.599 +void TDeflateStats::LitLenL(TInt aCode)
1.600 + {
1.601 + ++iEncoding.iLitLen[aCode];
1.602 + }
1.603 +
1.604 +void TDeflateStats::OffsetL(TInt aCode)
1.605 + {
1.606 + ++iEncoding.iDistance[aCode];
1.607 + }
1.608 +
1.609 +void TDeflateStats::ExtraL(TInt,TUint)
1.610 + {}
1.611 +
1.612 +// Class THuffEncoder
1.613 +//
1.614 +// This class generates the byte stream of huffman codes, writing them out to the stream
1.615 +
1.616 +THuffEncoder::THuffEncoder(RWriteStream& aStream)
1.617 + :iStream(aStream),iCode(0),iBits(-8),iWrite(iBuf)
1.618 + {}
1.619 +
1.620 +//
1.621 +// Store a huffman code generated by Huffman::EncodingL()
1.622 +//
1.623 +void THuffEncoder::EncodeL(TUint32 aHuffCode)
1.624 + {
1.625 + EncodeL(aHuffCode<<(32-KHuffMaxCodeLength),aHuffCode>>KHuffMaxCodeLength);
1.626 + }
1.627 +
1.628 +//
1.629 +// Store aLength bits from the most significant bits of aCode
1.630 +//
1.631 +void THuffEncoder::EncodeL(TUint aCode,TInt aLength)
1.632 + {
1.633 + TInt bits=iBits;
1.634 + TUint code=iCode|(aCode>>(bits+8));
1.635 + bits+=aLength;
1.636 + if (bits>=0)
1.637 + {
1.638 + TUint8* write=iWrite;
1.639 + do
1.640 + {
1.641 + if (write-EBufSize==iBuf)
1.642 + {
1.643 + iStream.WriteL(iBuf,EBufSize);
1.644 + write=iBuf;
1.645 + }
1.646 + *write++=TUint8(code>>24);
1.647 + code<<=8;
1.648 + bits-=8;
1.649 + } while (bits>=0);
1.650 + iWrite=write;
1.651 + }
1.652 + iCode=code;
1.653 + iBits=bits;
1.654 + }
1.655 +
1.656 +//
1.657 +// Terminate the huffman coding. The longest code is always 1111111111
1.658 +//
1.659 +void THuffEncoder::CompleteL()
1.660 + {
1.661 + if (iBits>-8)
1.662 + EncodeL(0xffffffffu,-iBits);
1.663 + if (iWrite>iBuf)
1.664 + iStream.WriteL(iBuf,iWrite-iBuf);
1.665 + }
1.666 +
1.667 +// Class TDeflater
1.668 +//
1.669 +// Extends MDeflater to provide huffman encoding of the output
1.670 +
1.671 +//
1.672 +// construct for encoding
1.673 +//
1.674 +inline TDeflater::TDeflater(THuffEncoder& aEncoder,const CDbStoreCompression::TEncoding& aEncoding)
1.675 + :iEncoder(aEncoder),iEncoding(aEncoding)
1.676 + {}
1.677 +
1.678 +void TDeflater::LitLenL(TInt aCode)
1.679 + {
1.680 + iEncoder.EncodeL(iEncoding.iLitLen[aCode]);
1.681 + }
1.682 +
1.683 +void TDeflater::OffsetL(TInt aCode)
1.684 + {
1.685 + iEncoder.EncodeL(iEncoding.iDistance[aCode]);
1.686 + }
1.687 +
1.688 +void TDeflater::ExtraL(TInt aLen,TUint aBits)
1.689 + {
1.690 + iEncoder.EncodeL(aBits,aLen);
1.691 + }
1.692 +
1.693 +// Class TInflater
1.694 +//
1.695 +// The inflation algorithm, complete with huffman decoding
1.696 +
1.697 +TInflater::TInflater(const TUint8* aIn,const CDbStoreCompression::TEncoding& aEncoding)
1.698 + :iIn(aIn),iBits(KBitsInit),iLen(0),iLitLenTree(aEncoding.iLitLen),iDistTree(aEncoding.iDistance)
1.699 + {}
1.700 +
1.701 +//
1.702 +// consume all data lag in the history buffer, then decode to fill up the output buffer
1.703 +//
1.704 +TInt TInflater::Inflate()
1.705 + {
1.706 +// empty the history buffer into the output
1.707 + const TUint8* data=iIn;
1.708 + TUint bits=iBits;
1.709 + const TUint8* from=iRptr;
1.710 + TInt len=iLen;
1.711 + TUint8* out=iOut;
1.712 + TUint8* const end=out+KDeflateMaxDistance;
1.713 + const TUint32* node;
1.714 + if (len)
1.715 + goto useHistory;
1.716 +//
1.717 + if (bits&KBitsEOF)
1.718 + return 0;
1.719 +//
1.720 + node=iLitLenTree;
1.721 + while (out<end)
1.722 + {
1.723 + // get a huffman code
1.724 + {
1.725 + TUint huff;
1.726 + for (;;)
1.727 + {
1.728 + huff=*node++;
1.729 + if ((bits<<=1)&KBitsEmpty)
1.730 + bits=*data++|KBitsFull;
1.731 + if (bits&KBitsNext)
1.732 + {
1.733 + if (huff&(KHuffTerminate<<16))
1.734 + break;
1.735 + }
1.736 + else
1.737 + {
1.738 + if (huff&KHuffTerminate)
1.739 + {
1.740 + huff<<=16;
1.741 + break;
1.742 + }
1.743 + else
1.744 + node=PtrAdd(node,huff);
1.745 + }
1.746 + }
1.747 + TInt val=TInt(huff>>17)-CDbStoreCompression::TEncoding::ELiterals;
1.748 + if (val<0)
1.749 + {
1.750 + *out++=TUint8(val);
1.751 + node=iLitLenTree;
1.752 + continue; // another literal/length combo
1.753 + }
1.754 + if (val==CDbStoreCompression::TEncoding::EEos-CDbStoreCompression::TEncoding::ELiterals)
1.755 + { // eos marker. we're done
1.756 + bits=KBitsEOF;
1.757 + break;
1.758 + }
1.759 + // get the extra bits for the code
1.760 + TInt code=val&0xff;
1.761 + if (code>=8)
1.762 + { // xtra bits
1.763 + TInt xtra=(code>>2)-1;
1.764 + code-=xtra<<2;
1.765 + do
1.766 + {
1.767 + if ((bits<<=1)&KBitsEmpty)
1.768 + bits=*data++|KBitsFull;
1.769 + code<<=1;
1.770 + if (bits&KBitsNext)
1.771 + code|=1;
1.772 + } while (--xtra!=0);
1.773 + }
1.774 + if (val<KDeflateDistCodeBase-CDbStoreCompression::TEncoding::ELiterals)
1.775 + { // length code... get the code
1.776 + len=code+KDeflateMinLength;
1.777 + __ASSERT(len<=KDeflateMaxLength);
1.778 + node=iDistTree;
1.779 + continue; // read the huffman code
1.780 + }
1.781 + // distance code
1.782 + __ASSERT(code<KDeflateMaxDistance);
1.783 + from=out-(code+1);
1.784 + if (from+KDeflateMaxDistance<end)
1.785 + from+=KDeflateMaxDistance;
1.786 + }
1.787 +useHistory:
1.788 + TInt tfr=Min(end-out,len);
1.789 + len-=tfr;
1.790 + do
1.791 + {
1.792 + *out++=*from++;
1.793 + if (from==end)
1.794 + from-=KDeflateMaxDistance;
1.795 + } while (--tfr!=0);
1.796 + node=iLitLenTree;
1.797 + };
1.798 + iIn=data;
1.799 + iBits=bits;
1.800 + iRptr=from;
1.801 + iLen=len;
1.802 + return out-iOut;
1.803 + }
1.804 +
1.805 +inline const TUint8* TInflater::Ptr() const
1.806 + {return iOut;}
1.807 +inline TInt TInflater::BufferSize()
1.808 + {return KDeflateMaxDistance;}
1.809 +
1.810 +// Class HDeflateBuf
1.811 +//
1.812 +// This stream buffer applies the analysis or deflation and huffman coding
1.813 +// on the entire stream data when it is committed
1.814 +
1.815 +inline HDeflateBuf::HDeflateBuf(MStreamBuf* aHost,CDbStoreCompression::TEncoding& aEncoding,CBufBase* aBuf,TMode aMode)
1.816 + :iHost(aHost),iEncoding(aEncoding),iBuf(aBuf),iMode(aMode)
1.817 + {Set(*aBuf,0);}
1.818 +
1.819 +HDeflateBuf* HDeflateBuf::NewL(MStreamBuf* aHost,CDbStoreCompression::TEncoding& aEncoding,TMode aMode)
1.820 + {
1.821 + CBufBase* buf=CBufFlat::NewL(512);
1.822 + CleanupStack::PushL(buf);
1.823 + HDeflateBuf* self=new(ELeave) HDeflateBuf(aHost,aEncoding,buf,aMode);
1.824 + CleanupStack::Pop();
1.825 + return self;
1.826 + }
1.827 +
1.828 +inline HDeflateBuf::~HDeflateBuf()
1.829 + {delete iBuf;iHost.Release();}
1.830 +
1.831 +void HDeflateBuf::DoRelease()
1.832 + {
1.833 + delete this;
1.834 + }
1.835 +
1.836 +//
1.837 +// This is where it all happens
1.838 +//
1.839 +void HDeflateBuf::DoSynchL()
1.840 + {
1.841 + if (iMode==EAnalysis)
1.842 + {
1.843 + TDeflateStats deflater(iEncoding);
1.844 + deflater.DeflateL(iBuf->Ptr(0).Ptr(),iBuf->Size());
1.845 + }
1.846 + else
1.847 + {
1.848 + THuffEncoder encoder(iHost);
1.849 + TDeflater deflater(encoder,iEncoding);
1.850 + deflater.DeflateL(iBuf->Ptr(0).Ptr(),iBuf->Size());
1.851 + encoder.CompleteL();
1.852 + iHost.CommitL();
1.853 + }
1.854 + }
1.855 +
1.856 +// Class HInflateBuf
1.857 +//
1.858 +// Inflate the input stream. This is not a filter, it reads all the input, inflates it and
1.859 +// keeps it in a memory buffer.
1.860 +
1.861 +const TInt KInflateBufSize=0x800; // 2K
1.862 +
1.863 +HInflateBuf::HInflateBuf(CBufBase* aBuf)
1.864 + :iBuf(aBuf)
1.865 + {
1.866 + Set(*aBuf,0,ERead);
1.867 + }
1.868 +
1.869 +inline HInflateBuf::~HInflateBuf()
1.870 + {delete iBuf;}
1.871 +
1.872 +void HInflateBuf::DoRelease()
1.873 + {
1.874 + delete this;
1.875 + }
1.876 +
1.877 +HInflateBuf* HInflateBuf::NewL(MStreamBuf* aHost,const CDbStoreCompression::TEncoding& aEncoding)
1.878 + {
1.879 + CBufFlat* host=CBufFlat::NewL(256);
1.880 + CleanupStack::PushL(host);
1.881 + TUint8 buffer[KInflateBufSize];
1.882 + for (;;)
1.883 + {
1.884 + TInt len=aHost->ReadL(buffer,KInflateBufSize);
1.885 + if (len)
1.886 + host->InsertL(host->Size(),buffer,len);
1.887 + if (len<KInflateBufSize)
1.888 + break;
1.889 + }
1.890 + CBufSeg* out=CBufSeg::NewL(256);
1.891 + CleanupStack::PushL(out);
1.892 + TInflater* inflater=new(ELeave) TInflater(host->Ptr(0).Ptr(),aEncoding);
1.893 + CleanupStack::PushL(inflater);
1.894 + for (;;)
1.895 + {
1.896 + TInt len=inflater->Inflate();
1.897 + if (len)
1.898 + out->InsertL(out->Size(),inflater->Ptr(),len);
1.899 + if (len<inflater->BufferSize())
1.900 + break;
1.901 + }
1.902 + HInflateBuf* buf=new(ELeave) HInflateBuf(out);
1.903 + CleanupStack::PopAndDestroy(); // inflater
1.904 + CleanupStack::Pop(); // out
1.905 + CleanupStack::PopAndDestroy(); // host
1.906 + aHost->Release(); // don't need this anymore
1.907 + return buf;
1.908 + }
1.909 +
1.910 +// Class CDbStoreTable::Compressor
1.911 +//
1.912 +// This class processes an entire table for analysis or compression, using the
1.913 +// CDbStoreRecords::AlterL() functionality and call back to ensure that all clusters
1.914 +// and BLOBs are read and written.
1.915 +
1.916 +inline CDbStoreTable::CCompressor::CCompressor()
1.917 + {}
1.918 +
1.919 +CDbStoreTable::CCompressor::~CCompressor()
1.920 + {
1.921 + if (iTable)
1.922 + iTable->Close();
1.923 + iRow.Close();
1.924 + }
1.925 +
1.926 +//
1.927 +// Walk through every cluster in the table
1.928 +//
1.929 +void CDbStoreTable::CCompressor::ProcessL(CDbStoreTable* aTable)
1.930 + {
1.931 + iTable=aTable;
1.932 + CDbStoreRecords& rec=aTable->StoreRecordsL();
1.933 + for (TClusterId cluster=rec.Head();cluster!=KNullClusterId;cluster=rec.AlterL(cluster,*this))
1.934 + ;
1.935 + }
1.936 +
1.937 +//
1.938 +// Compress every blob, and transfer the record from aRPtr to aWPtr
1.939 +//
1.940 +TUint8* CDbStoreTable::CCompressor::AlterRecordL(TUint8* aWPtr,const TUint8* aRPtr,TInt aLength)
1.941 + {
1.942 + if (iTable->Def().Columns().HasLongColumns())
1.943 + {
1.944 + iTable->CopyToRowL(iRow,TPtrC8(aRPtr,aLength));
1.945 + CDbBlobSpace* blobs=iTable->BlobsL();
1.946 + TDbColNo col=1;
1.947 + HDbColumnSet::TIteratorC iter=iTable->Def().Columns().Begin();
1.948 + const HDbColumnSet::TIteratorC end=iTable->Def().Columns().End();
1.949 + do
1.950 + {
1.951 + if (!TDbCol::IsLong(iter->Type()))
1.952 + continue;
1.953 + TDbBlob& blob=CONST_CAST(TDbBlob&,TDbColumnC(iRow,col).Blob());
1.954 + if (blob.IsInline())
1.955 + continue;
1.956 + // do what has to be done...?
1.957 + TUint8* data=(TUint8*)User::AllocLC(blob.Size());
1.958 + blobs->ReadLC(blob.Id(),iter->Type())->ReadL(data,blob.Size());
1.959 + CleanupStack::PopAndDestroy(); // stream buffer
1.960 + // re-write the Blob to compress it
1.961 + blobs->DeleteL(blob.Id());
1.962 + blob.SetId(blobs->CreateL(iter->Type(),data,blob.Size()));
1.963 + CleanupStack::PopAndDestroy(); // data
1.964 + } while (++col,++iter<end);
1.965 + iTable->CopyFromRow(aWPtr,iRow);
1.966 + }
1.967 + else
1.968 + Mem::Copy(aWPtr,aRPtr,aLength);
1.969 + return aWPtr+aLength;
1.970 + }
1.971 +
1.972 +// Class CDbStoreCompression
1.973 +//
1.974 +// This class manages the compression for the database, applying filters as appropriate
1.975 +// It also defines the extrenalisation format for the huffman trees
1.976 +
1.977 +const TInt KDeflationCodes=3*(CDbStoreCompression::TEncoding::ELitLens+CDbStoreCompression::TEncoding::EDistances);
1.978 +
1.979 +inline CDbStoreCompression::CDbStoreCompression()
1.980 +// :iState(EAnalysis)
1.981 + {}
1.982 +
1.983 +CDbStoreCompression* CDbStoreCompression::NewL()
1.984 + {
1.985 + return new(ELeave) CDbStoreCompression;
1.986 + }
1.987 +
1.988 +//
1.989 +// Build huffman codings from the freqeuncy tables
1.990 +//
1.991 +void CDbStoreCompression::EncodeL()
1.992 + {
1.993 + //Check the comments in CDbStoreCompression::InternalizeL().
1.994 + //The implementation there is very similar to this one and is commented why the "array overrun"
1.995 + //case is impossible.
1.996 + __ASSERT(iState==EAnalysis);
1.997 + TUint32* p=iEncoding[0].iLitLen;
1.998 + TUint32* end=p+KDeflationCodes;
1.999 + do
1.1000 + {
1.1001 + Huffman::EncodingL(p,TEncoding::ELitLens);
1.1002 + p+=TEncoding::ELitLens;
1.1003 + //coverity[overrun-local]
1.1004 + Huffman::EncodingL(p,TEncoding::EDistances);
1.1005 + //coverity[overrun-local]
1.1006 + p+=TEncoding::EDistances;
1.1007 + } while (p<end);
1.1008 + iState=EEncoding;
1.1009 + }
1.1010 +
1.1011 +//
1.1012 +// Store the encoding tables as a sequence of code lengths
1.1013 +// The code lengths (0-25) are themselves huffman coded, and the meta coding is stored first
1.1014 +//
1.1015 +void CDbStoreCompression::ExternalizeL(RWriteStream& aStream) const
1.1016 + {
1.1017 + __ASSERT(iState==EEncoding);
1.1018 + const TUint32* base=iEncoding[0].iLitLen;
1.1019 + const TUint32* end=base+KDeflationCodes;
1.1020 + TUint32 codes[KDeflateMetaCodes];
1.1021 + Mem::FillZ(codes,sizeof(codes));
1.1022 + const TUint32* p=base;
1.1023 + do ++codes[*p++>>KHuffMaxCodeLength]; while (p<end);
1.1024 + Huffman::EncodingL(codes,KDeflateMetaCodes);
1.1025 +// save the meta encoding
1.1026 + p=codes+KDeflateMetaCodes;
1.1027 + do
1.1028 + {
1.1029 + TUint c0=*--p;
1.1030 + TUint c1=*--p;
1.1031 + c0>>=KHuffMaxCodeLength;
1.1032 + c1>>=KHuffMaxCodeLength;
1.1033 + aStream.WriteUint8L((c0<<4)|c1);
1.1034 + } while (p>codes);
1.1035 +// write the encoding
1.1036 + THuffEncoder encoder(aStream);
1.1037 + p=base;
1.1038 + do encoder.EncodeL(codes[*p++>>KHuffMaxCodeLength]); while (p<end);
1.1039 + encoder.CompleteL();
1.1040 + }
1.1041 +
1.1042 +//
1.1043 +// Internalize a previous saved encoding
1.1044 +//
1.1045 +void CDbStoreCompression::InternalizeL(RReadStream& aStream)
1.1046 + {
1.1047 + __ASSERT(iState!=EEncoding);
1.1048 +//
1.1049 +// read the meta encoding
1.1050 + TUint32 decode[KDeflateMetaCodes];
1.1051 + TUint32* p=decode+KDeflateMetaCodes;
1.1052 + do
1.1053 + {
1.1054 + TUint8 c=aStream.ReadUint8L();
1.1055 + *--p=c>>4;
1.1056 + *--p=c&0xf;
1.1057 + } while (p>decode);
1.1058 + Huffman::Decoding(decode,KDeflateMetaCodes);
1.1059 +// decode the encoding
1.1060 + p=iEncoding[0].iLitLen;
1.1061 + TUint32* end=p+KDeflationCodes;
1.1062 + TUint bits=KBitsInit;
1.1063 + do
1.1064 + {
1.1065 + const TUint32* node=decode;
1.1066 + TUint huff;
1.1067 + for (;;)
1.1068 + {
1.1069 + huff=*node++;
1.1070 + if ((bits<<=1)&KBitsEmpty)
1.1071 + bits=aStream.ReadUint8L()|KBitsFull;
1.1072 + if (bits&KBitsNext)
1.1073 + {
1.1074 + if (huff&(KHuffTerminate<<16))
1.1075 + break;
1.1076 + }
1.1077 + else
1.1078 + {
1.1079 + if (huff&KHuffTerminate)
1.1080 + {
1.1081 + huff<<=16;
1.1082 + break;
1.1083 + }
1.1084 + else
1.1085 + node=PtrAdd(node,huff);
1.1086 + }
1.1087 + }
1.1088 + *p++=huff>>17;
1.1089 + } while (p<end);
1.1090 +// convert the length tables into huffman decoding trees
1.1091 + //The iEncoding data member is an array of 3 elements of TEncoding type.
1.1092 + //The TEncoding layout is: TUint32 iLitLen[ELitLens], TUint32 iDistance[EDistances].
1.1093 + //Then the in-memory presentation of iEncoding is:
1.1094 + // ELitLens EDistances
1.1095 + //iEncoding[0] ........ ........
1.1096 + //iEncoding[1] ........ ........
1.1097 + //iEncoding[2] ........ ........
1.1098 + //
1.1099 + //Bellow, in the loop:
1.1100 + // p+=TEncoding::ELitLens; - moves the pointer to the beginning of iDistance data
1.1101 + // p+=TEncoding::EDistances; - moves the pointer to the beginning of iLitLen data of the next element of iEncoding.
1.1102 + //The loop will process the data until "p<end", and "end" is defined as:
1.1103 + // p=iEncoding[0].iLitLen;
1.1104 + // TUint32* end=p+KDeflationCodes;
1.1105 + //KDeflationCodes value is: 3*(CDbStoreCompression::TEncoding::ELitLens+CDbStoreCompression::TEncoding::EDistances),
1.1106 + //so that is the end of the iEncoding array.
1.1107 + //Conclusion: the code incrementing the "p" pointer in the loop bellow won't cause array overrun.
1.1108 + p=iEncoding[0].iLitLen;
1.1109 + do
1.1110 + {
1.1111 + Huffman::Decoding(p,TEncoding::ELitLens);
1.1112 + p+=TEncoding::ELitLens;
1.1113 + //coverity[overrun-local]
1.1114 + Huffman::Decoding(p,TEncoding::EDistances,KDeflateDistCodeBase);
1.1115 + //coverity[overrun-local]
1.1116 + p+=TEncoding::EDistances;
1.1117 + } while (p<end);
1.1118 + if (iState==EAnalysis)
1.1119 + iState=EDecoding;
1.1120 + }
1.1121 +
1.1122 +//
1.1123 +// Apply an inflation filter to a read stream
1.1124 +//
1.1125 +MStreamBuf* CDbStoreCompression::FilterL(MStreamBuf* aHost,TUint32,RDbStoreReadStream::TType aType)
1.1126 + {
1.1127 + if (iState==EDecoding || iState==EInflating)
1.1128 + return HInflateBuf::NewL(aHost,iEncoding[aType]);
1.1129 + return aHost;
1.1130 + }
1.1131 +
1.1132 +//
1.1133 +// Apply a statistics or inflation filter to a write stream
1.1134 +//
1.1135 +MStreamBuf* CDbStoreCompression::FilterL(MStreamBuf* aHost,TUint32,RDbStoreWriteStream::TType aType)
1.1136 + {
1.1137 + TState s=iState;
1.1138 + if (s==EDecoding)
1.1139 + __LEAVE(KErrWrite); // read-only database
1.1140 + else if (s!=EInflating)
1.1141 + {
1.1142 + __ASSERT(TInt(EAnalysis)==TInt(HDeflateBuf::EAnalysis));
1.1143 + __ASSERT(TInt(EEncoding)==TInt(HDeflateBuf::EDeflate));
1.1144 + return HDeflateBuf::NewL(aHost,iEncoding[aType],HDeflateBuf::TMode(s));
1.1145 + }
1.1146 + return aHost;
1.1147 + }
1.1148 +
1.1149 +// Class CDbStoreDatabase
1.1150 +//
1.1151 +// Compression related code is maintained in this source file
1.1152 +
1.1153 +//
1.1154 +// Iterate across all tables applying analysis or compression to them
1.1155 +//
1.1156 +void CDbStoreDatabase::CompressTablesL()
1.1157 + {
1.1158 + TSglQueIterC<CDbStoreDef> iter(SchemaL());
1.1159 + const CDbStoreDef* def;
1.1160 + while ((def=iter++)!=0)
1.1161 + {
1.1162 + CDbStoreTable::CCompressor* comp=new(ELeave) CDbStoreTable::CCompressor;
1.1163 + CleanupStack::PushL(comp);
1.1164 + comp->ProcessL(STATIC_CAST(CDbStoreTable*,TableL(*def)));
1.1165 + CleanupStack::PopAndDestroy(); // comp
1.1166 + }
1.1167 + }
1.1168 +
1.1169 +//
1.1170 +// Compress or decompress the whole database
1.1171 +//
1.1172 +void CDbStoreDatabase::CompressL(TStreamId aStreamId,TZipType aZip)
1.1173 + {
1.1174 + __ASSERT(iStore);
1.1175 + iSchemaId=aStreamId;
1.1176 +// read the databse header for encryption information
1.1177 + RStoreReadStream strm;
1.1178 + strm.OpenLC(Store(),aStreamId);
1.1179 + ReadHeaderL(strm);
1.1180 + CleanupStack::PopAndDestroy(); // strm
1.1181 + InitPagePoolL();
1.1182 +//
1.1183 + if (iVersion==EDbStoreCompressed)
1.1184 + {
1.1185 + iCompression->Inflate();
1.1186 + if (aZip==EDeflate)
1.1187 + __LEAVE(KErrArgument); // already compressed
1.1188 + }
1.1189 + else if (aZip==EInflate)
1.1190 + __LEAVE(KErrArgument); // not compressed
1.1191 + else
1.1192 + { // deflate pass #1: analyse the database
1.1193 + CompressionL(); // construct the compression filter
1.1194 + Transaction().DDLBeginLC();
1.1195 + CompressTablesL();
1.1196 + iClusterCache->FlushL(); // force through the stats buffer
1.1197 + ReplaceSchemaL(); // force through the stats buffer
1.1198 + CleanupStack::PopAndDestroy(); // rollback after analysis!
1.1199 + iCompression->EncodeL();
1.1200 + }
1.1201 +// now inflate or deflate the data
1.1202 + Transaction().DDLBeginLC();
1.1203 + CompressTablesL();
1.1204 + iVersion=TUint8(aZip==EDeflate ? EDbStoreCompressed : EDbStoreVersion2);
1.1205 + Transaction().DDLCommitL();
1.1206 + CleanupStack::Pop(); // rollback not required
1.1207 + }
1.1208 +
1.1209 +void CDbStoreDatabase::CompressL(CStreamStore* aStore,TStreamId aStreamId,TZipType aZip)
1.1210 + {
1.1211 + //It looks like there is a potential memory leak in the next 4 lines of code, because:
1.1212 + //1) CDbStoreDatabase* self=NewLC(aStore) - new CDbStoreDatabase object is created on the heap
1.1213 + //2) CDbObject* db=self->InterfaceL() - new CDbObject is created on the heap
1.1214 + //3) CleanupStack::Pop() - the CDbStoreDatabase object from (1) - out from the cleanup stack
1.1215 + //4) db->PushL() - the CDbObject from (2) - in the cleanup stack
1.1216 + //If one of the DDLPrepareL() or CompressL() leaves, looks like the CDbStoreDatabase object from (1) will be leaked.
1.1217 + //This is not a correct guess, becuse:
1.1218 + // - CDbObject* db=self->InterfaceL() - this call creates a new CInterface object
1.1219 + // on the heap. The CInterface() constructor will store the "this" pointer
1.1220 + // passed from the InterfaceL() (so the "self" pointer),
1.1221 + // into its "iDatabase" private data member.
1.1222 + // In which case, the returned CDbObject, of CInterface type, will have
1.1223 + // its "iDatabase" data member initialized.
1.1224 + // The inheritance tree is:
1.1225 + // CBase <-- CDbObject <-- CDbDatabase <-- CInterface
1.1226 + // - db->PushL() - this call puts on the cleanup stack CDbObject::Destroy().
1.1227 + // The "db" object which real type is CInterface with "iDatabase" data member
1.1228 + // initialized with "self", is on the cleanup stack.
1.1229 + // - If one of the next "L" functions leaves, then CDbObject::Destroy() will be executed.
1.1230 + // - CDbObject::Destroy() will call CInterface::~CInterface() - CBase is at the root of the inheritance tree, with
1.1231 + // virtual ~CBase() destructor.
1.1232 + // - CInterface::~CInterface() implementation calls Database().Close(), so that is CDbStoreDatabase::Close() called on
1.1233 + // the "self" pointer.
1.1234 + // - The CDbStoreDatabase::Close() will call "delete this" when its reference count reaches 0.
1.1235 + // The reference counter is increased by 1 in the InterfaceL() chain of calls.
1.1236 + // -------- Conclusion ---------
1.1237 + // No memory leak will occur in the next lines of code. Coverity errors - disabled.
1.1238 + CDbStoreDatabase* self=NewLC(aStore);
1.1239 + //coverity[alloc_fn]
1.1240 + //coverity[var_assign]
1.1241 + CDbObject* db=self->InterfaceL(); // a reference to the database is required
1.1242 + CleanupStack::Pop(); // self
1.1243 + //coverity[noescape]
1.1244 + db->PushL();
1.1245 + //coverity[noescape]
1.1246 + self->Transaction().DDLPrepareL(*db);
1.1247 + self->CompressL(aStreamId,aZip);
1.1248 + CleanupStack::PopAndDestroy(); // db
1.1249 + //coverity[leaked_storage]
1.1250 + }
1.1251 +
1.1252 +// Class RDbStoreDatabase
1.1253 +
1.1254 +EXPORT_C void RDbStoreDatabase::CompressL(CStreamStore& aStore,TStreamId aId)
1.1255 + {
1.1256 + CDbStoreDatabase::CompressL(&aStore,aId,CDbStoreDatabase::EDeflate);
1.1257 + }
1.1258 +
1.1259 +EXPORT_C void RDbStoreDatabase::DecompressL(CStreamStore& aStore,TStreamId aId)
1.1260 + {
1.1261 + CDbStoreDatabase::CompressL(&aStore,aId,CDbStoreDatabase::EInflate);
1.1262 + }