--- a/e32tools/e32lib/e32image/deflate/deflate.cpp Thu Nov 04 09:25:46 2010 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,325 +0,0 @@
-// Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
-// All rights reserved.
-// This component and the accompanying materials are made available
-// under the terms of "Eclipse Public License v1.0"
-// which accompanies this distribution, and is available
-// at the URL "http://www.eclipse.org/legal/epl-v10.html".
-//
-// Initial Contributors:
-// Nokia Corporation - initial contribution.
-//
-// Contributors:
-//
-// Description:
-// e32tools\petran\Szip\deflate.cpp
-//
-//
-
-#include "deflate.h"
-#include "h_utl.h"
-#include "panic.h"
-
-class HDeflateHash
- {
-public:
- inline static HDeflateHash* NewLC(TInt aLinks);
-//
- inline TInt First(const TUint8* aPtr,TInt aPos);
- inline TInt Next(TInt aPos,TInt aOffset) const;
-private:
- inline HDeflateHash();
- inline static TInt Hash(const TUint8* aPtr);
-private:
- typedef TUint16 TOffset;
-private:
- TInt iHash[256];
- TOffset iOffset[1]; // or more
- };
-
-class MDeflater
- {
-public:
- void DeflateL(const TUint8* aBase,TInt aLength);
- inline virtual ~MDeflater() { };
-private:
- const TUint8* DoDeflateL(const TUint8* aBase,const TUint8* aEnd,HDeflateHash& aHash);
- static TInt Match(const TUint8* aPtr,const TUint8* aEnd,TInt aPos,HDeflateHash& aHas);
- void SegmentL(TInt aLength,TInt aDistance);
- virtual void LitLenL(TInt aCode) =0;
- virtual void OffsetL(TInt aCode) =0;
- virtual void ExtraL(TInt aLen,TUint aBits) =0;
- };
-
-class TDeflateStats : public MDeflater
- {
-public:
- inline TDeflateStats(TEncoding& aEncoding);
- inline virtual ~TDeflateStats() { }
-private:
-// from MDeflater
- void LitLenL(TInt aCode);
- void OffsetL(TInt aCode);
- void ExtraL(TInt aLen,TUint aBits);
-private:
- TEncoding& iEncoding;
- };
-
-class TDeflater : public MDeflater
- {
-public:
- inline TDeflater(TBitOutput& aOutput,const TEncoding& aEncoding);
- inline virtual ~TDeflater() { };
-private:
-// from MDeflater
- void LitLenL(TInt aCode);
- void OffsetL(TInt aCode);
- void ExtraL(TInt aLen,TUint aBits);
-private:
- TBitOutput& iOutput;
- const TEncoding& iEncoding;
- };
-
-
-// Class HDeflateHash
-
-inline HDeflateHash::HDeflateHash()
- {TInt* p=iHash+256;do *--p=-KDeflateMaxDistance-1; while (p>iHash);}
-
-inline HDeflateHash* HDeflateHash::NewLC(TInt aLinks)
- {
- return new(HMem::Alloc(0,_FOFF(HDeflateHash,iOffset[0]) + (sizeof(TOffset) * Min(aLinks,KDeflateMaxDistance)))) HDeflateHash;
- }
-
-inline TInt HDeflateHash::Hash(const TUint8* aPtr)
- {
- TUint x=aPtr[0]|(aPtr[1]<<8)|(aPtr[2]<<16);
- return (x*KDeflateHashMultiplier)>>KDeflateHashShift;
- }
-
-inline TInt HDeflateHash::First(const TUint8* aPtr,TInt aPos)
- {
- TInt h=Hash(aPtr);
- TInt offset=Min(aPos-iHash[h],KDeflateMaxDistance<<1);
- iHash[h]=aPos;
- iOffset[aPos&(KDeflateMaxDistance-1)]=TOffset(offset);
- return offset;
- }
-
-inline TInt HDeflateHash::Next(TInt aPos,TInt aOffset) const
- {return aOffset+iOffset[(aPos-aOffset)&(KDeflateMaxDistance-1)];}
-
-
-// Class TDeflater
-//
-// generic deflation algorithm, can do either statistics and the encoder
-
-TInt MDeflater::Match(const TUint8* aPtr,const TUint8* aEnd,TInt aPos,HDeflateHash& aHash)
- {
- TInt offset=aHash.First(aPtr,aPos);
- if (offset>KDeflateMaxDistance)
- return 0;
- TInt match=0;
- aEnd=Min(aEnd,aPtr+KDeflateMaxLength);
- TUint8 c=*aPtr;
- do
- {
- const TUint8* p=aPtr-offset;
- if (p[match>>16]==c)
- { // might be a better match
- const TUint8* m=aPtr;
- for (;;)
- {
- if (*p++!=*m++)
- break;
- if (m<aEnd)
- continue;
- return ((m-aPtr)<<16)|offset;
- }
- TInt l=m-aPtr-1;
- if (l>match>>16)
- {
- match=(l<<16)|offset;
- c=m[-1];
- }
- }
- offset=aHash.Next(aPos,offset);
- } while (offset<=KDeflateMaxDistance);
- return match;
- }
-
-const TUint8* MDeflater::DoDeflateL(const TUint8* aBase,const TUint8* aEnd,HDeflateHash& aHash)
-//
-// Apply the deflation algorithm to the data [aBase,aEnd)
-// Return a pointer after the last byte that was deflated (which may not be aEnd)
-//
- {
- const TUint8* ptr=aBase;
- TInt prev=0; // the previous deflation match
- do
- {
- TInt match=Match(ptr,aEnd,ptr-aBase,aHash);
-// Extra deflation applies two optimisations which double the time taken
-// 1. If we have a match at p, then test for a better match at p+1 before using it
-// 2. When we have a match, add the hash links for all the data which will be skipped
- if (match>>16 < prev>>16)
- { // use the previous match--it was better
- TInt len=prev>>16;
- SegmentL(len,prev-(len<<16));
- // fill in missing hash entries for better compression
- const TUint8* e=ptr+len-2;
- do
- {
- ++ptr;
- if (ptr + 2 < aEnd)
- aHash.First(ptr,ptr-aBase);
- } while (ptr<e);
- prev=0;
- }
- else if (match<=(KDeflateMinLength<<16))
- LitLenL(*ptr); // no deflation match here
- else
- { // save this match and test the next position
- if (prev) // we had a match at ptr-1, but this is better
- LitLenL(ptr[-1]);
- prev=match;
- }
- ++ptr;
- } while (ptr+KDeflateMinLength-1<aEnd);
- if (prev)
- { // emit the stored match
- TInt len=prev>>16;
- SegmentL(len,prev-(len<<16));
- ptr+=len-1;
- }
- return ptr;
- }
-
-void MDeflater::DeflateL(const TUint8* aBase,TInt aLength)
-//
-// The generic deflation algorithm
-//
- {
- const TUint8* end=aBase+aLength;
- if (aLength>KDeflateMinLength)
- { // deflation kicks in if there is enough data
- HDeflateHash* hash=HDeflateHash::NewLC(aLength);
- if(hash==NULL)
- Panic(EHuffmanOutOfMemory);
-
- aBase=DoDeflateL(aBase,end,*hash);
- delete hash;
- }
- while (aBase<end) // emit remaining bytes
- LitLenL(*aBase++);
- LitLenL(TEncoding::EEos); // eos marker
- }
-
-void MDeflater::SegmentL(TInt aLength,TInt aDistance)
-//
-// Turn a (length,offset) pair into the deflation codes+extra bits before calling
-// the specific LitLen(), Offset() and Extra() functions.
-//
- {
- aLength-=KDeflateMinLength;
- TInt extralen=0;
- TUint len=aLength;
- while (len>=8)
- {
- ++extralen;
- len>>=1;
- }
- LitLenL((extralen<<2)+len+TEncoding::ELiterals);
- if (extralen)
- ExtraL(extralen,aLength);
-//
- aDistance--;
- extralen=0;
- TUint dist=aDistance;
- while (dist>=8)
- {
- ++extralen;
- dist>>=1;
- }
- OffsetL((extralen<<2)+dist);
- if (extralen)
- ExtraL(extralen,aDistance);
- }
-
-// Class TDeflateStats
-//
-// This class analyses the data stream to generate the frequency tables
-// for the deflation algorithm
-
-inline TDeflateStats::TDeflateStats(TEncoding& aEncoding)
- :iEncoding(aEncoding)
- {}
-
-void TDeflateStats::LitLenL(TInt aCode)
- {
- ++iEncoding.iLitLen[aCode];
- }
-
-void TDeflateStats::OffsetL(TInt aCode)
- {
- ++iEncoding.iDistance[aCode];
- }
-
-void TDeflateStats::ExtraL(TInt,TUint)
- {}
-
-// Class TDeflater
-//
-// Extends MDeflater to provide huffman encoding of the output
-
-inline TDeflater::TDeflater(TBitOutput& aOutput,const TEncoding& aEncoding)
-//
-// construct for encoding
-//
- :iOutput(aOutput),iEncoding(aEncoding)
- {}
-
-void TDeflater::LitLenL(TInt aCode)
- {
- iOutput.HuffmanL(iEncoding.iLitLen[aCode]);
- }
-
-void TDeflater::OffsetL(TInt aCode)
- {
- iOutput.HuffmanL(iEncoding.iDistance[aCode]);
- }
-
-void TDeflater::ExtraL(TInt aLen,TUint aBits)
- {
- iOutput.WriteL(aBits,aLen);
- }
-
-void DoDeflateL(const TUint8* aBuf,TInt aLength,TBitOutput& aOutput,TEncoding& aEncoding)
- {
-// analyse the data for symbol frequency
- TDeflateStats analyser(aEncoding);
- analyser.DeflateL(aBuf,aLength);
-
-// generate the required huffman encodings
- Huffman::HuffmanL(aEncoding.iLitLen,TEncoding::ELitLens,aEncoding.iLitLen);
- Huffman::HuffmanL(aEncoding.iDistance,TEncoding::EDistances,aEncoding.iDistance);
-
-// Store the encoding table
- Huffman::ExternalizeL(aOutput,aEncoding.iLitLen,KDeflationCodes);
-
-// generate the tables
- Huffman::Encoding(aEncoding.iLitLen,TEncoding::ELitLens,aEncoding.iLitLen);
- Huffman::Encoding(aEncoding.iDistance,TEncoding::EDistances,aEncoding.iDistance);
-
-// now finally deflate the data with the generated encoding
- TDeflater deflater(aOutput,aEncoding);
- deflater.DeflateL(aBuf,aLength);
- aOutput.PadL(1);
- }
-
-void DeflateL(const TUint8* aBuf, TInt aLength, TBitOutput& aOutput)
- {
- TEncoding* encoding=new TEncoding;
- HMem::FillZ(encoding,sizeof(TEncoding));
- DoDeflateL(aBuf,aLength,aOutput,*encoding);
- }
-