patch.c

//
//  patch.cpp
//  HPatch
//
/*
 This is the HPatch copyright.
 
 Copyright (c) 2012-2013 HouSisong All Rights Reserved.
 
 Permission is hereby granted, free of charge, to any person
 obtaining a copy of this software and associated documentation
 files (the "Software"), to deal in the Software without
 restriction, including without limitation the rights to use,
 copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the
 Software is furnished to do so, subject to the following
 conditions:
 
 The above copyright notice and this permission notice shall be
 included in all copies of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 OTHER DEALINGS IN THE SOFTWARE.
*/
#include "patch.h"
#include "string.h" //memcpy memset
#include "assert.h" //assert
#include "patch_base.h"

static hpatch_BOOL _bytesRle_load(TByte* out_data,TByte* out_dataEnd,const TByte* rle_code,const TByte* rle_code_end);
static void addData(TByte* dst,const TByte* src,TUInt32 length);

hpatch_BOOL patch(TByte* newData,TByte* newData_end,
            const TByte* oldData,const TByte* oldData_end,
            const TByte* serializedDiff,const TByte* serializedDiff_end){
    TUInt32 ctrlCount,lengthSize,inc_newPosSize,inc_oldPosSize,newDataDiffSize;
    const TByte *code_length,*code_length_end, *code_inc_newPos,*code_inc_newPos_end,
                *code_inc_oldPos,*code_inc_oldPos_end, *code_newDataDiff,*code_newDataDiff_end;
    TUInt32 i,oldPosBack,newPos_end,inc_newPos,newPos,addLength,copyLength,oldPos,inc_oldPos,newDataSize;
    int     inc_oldPos_sign;
    
    ctrlCount=unpack32Bit(&serializedDiff, serializedDiff_end);
    lengthSize=unpack32Bit(&serializedDiff, serializedDiff_end);
    inc_newPosSize=unpack32Bit(&serializedDiff, serializedDiff_end);
    inc_oldPosSize=unpack32Bit(&serializedDiff, serializedDiff_end);
    newDataDiffSize=unpack32Bit(&serializedDiff, serializedDiff_end);
#ifdef PATCH_RUN_MEM_SAFE_CHECK
    if (lengthSize>(TUInt32)(serializedDiff_end-serializedDiff)) return hpatch_FALSE;
#endif
    code_length=serializedDiff;     serializedDiff+=lengthSize;
    code_length_end=serializedDiff;
#ifdef PATCH_RUN_MEM_SAFE_CHECK
    if (inc_newPosSize>(TUInt32)(serializedDiff_end-serializedDiff)) return hpatch_FALSE;
#endif
    code_inc_newPos=serializedDiff; serializedDiff+=inc_newPosSize;
    code_inc_newPos_end=serializedDiff;
#ifdef PATCH_RUN_MEM_SAFE_CHECK
    if (inc_oldPosSize>(TUInt32)(serializedDiff_end-serializedDiff)) return hpatch_FALSE;
#endif
    code_inc_oldPos=serializedDiff; serializedDiff+=inc_oldPosSize;
    code_inc_oldPos_end=serializedDiff;
#ifdef PATCH_RUN_MEM_SAFE_CHECK
    if (newDataDiffSize>(TUInt32)(serializedDiff_end-serializedDiff)) return hpatch_FALSE;
#endif
    code_newDataDiff=serializedDiff; serializedDiff+=newDataDiffSize;
    code_newDataDiff_end=serializedDiff;
    
    //rle data begin==serializedDiff;
    if (!_bytesRle_load(newData, newData_end, serializedDiff, serializedDiff_end))
        return hpatch_FALSE;

    oldPosBack=0;
    newPos_end=0;
    for (i=0; i<ctrlCount; ++i){
        inc_newPos=unpack32Bit(&code_inc_newPos, code_inc_newPos_end);
        newPos=newPos_end+inc_newPos;
        addLength=unpack32Bit(&code_length, code_length_end);
        inc_oldPos_sign=(*code_inc_oldPos)>>(8-1);
        inc_oldPos=unpack32BitWithTag(&code_inc_oldPos, code_inc_oldPos_end, 1);
        if (inc_oldPos_sign==0)
            oldPos=oldPosBack+inc_oldPos;
        else
            oldPos=oldPosBack-inc_oldPos;
#ifdef PATCH_RUN_MEM_SAFE_CHECK
        if ((oldPos>(TUInt32)(oldData_end-oldData))||(addLength>(TUInt32)(oldData_end-oldData-oldPos))) return hpatch_FALSE;
        if ((newPos>(TUInt32)(newData_end-newData))||(addLength>(TUInt32)(newData_end-newData-newPos))) return hpatch_FALSE;
#endif
        if (newPos>newPos_end){
            copyLength=newPos-newPos_end;
#ifdef PATCH_RUN_MEM_SAFE_CHECK
            if (copyLength>(TUInt32)(code_newDataDiff_end-code_newDataDiff)) return hpatch_FALSE;
#endif
            memcpy(newData+newPos_end,code_newDataDiff,copyLength);
            code_newDataDiff+=copyLength;
        }
        addData(newData+newPos,oldData+oldPos,addLength);
        oldPosBack=oldPos;
        newPos_end=newPos+addLength;
    }
    
    newDataSize=(TUInt32)(newData_end-newData);
    if (newPos_end<newDataSize){
        copyLength=newDataSize-newPos_end;
#ifdef PATCH_RUN_MEM_SAFE_CHECK
        if (copyLength>(TUInt32)(code_newDataDiff_end-code_newDataDiff)) return hpatch_FALSE;
#endif
        memcpy(newData+newPos_end,code_newDataDiff,copyLength);
        code_newDataDiff+=copyLength;
        newPos_end=newDataSize;
    }
    return (code_length==code_length_end)&&(code_inc_newPos==code_inc_newPos_end)
            &&(code_inc_oldPos==code_inc_oldPos_end)&&(code_newDataDiff==code_newDataDiff_end);
}

//变长32bit正整数编码方案(x bit额外类型标志位,x<=3),从高位开始输出1-5byte:
// x0*  7-x bit
// x1* 0*  7+7-x bit
// x1* 1* 0*  7+7+7-x bit
// x1* 1* 1* 0*  7+7+7+7-x bit
// x1* 1* 1* 1* 0*  7+7+7+7+7-x bit
TUInt32 unpack32BitWithTag(const TByte** src_code,const TByte* src_code_end,const int kTagBit){//读出整数并前进指针.
    const TByte* pcode;
    TUInt32 value;
    TByte   code;
    pcode=*src_code;
    
#ifdef PATCH_RUN_MEM_SAFE_CHECK
    if (src_code_end-pcode<=0) return 0;
#endif
    code=*pcode; ++pcode;
    value=code&((1<<(7-kTagBit))-1);
    if ((code&(1<<(7-kTagBit)))!=0){
        do {
#ifdef PATCH_RUN_MEM_SAFE_CHECK
            assert((value>>(sizeof(value)*8-7))==0);
            if (src_code_end==pcode) break;
#endif
            code=*pcode; ++pcode;
            value=(value<<7) | (code&((1<<7)-1));
        } while ((code&(1<<7))!=0);
    }
    (*src_code)=pcode;
    return value;
}

static void addData(TByte* dst,const TByte* src,TUInt32 length){
    TUInt32 length_fast,i;
    
    length_fast=length&(~7);
    for (i=0;i<length_fast;i+=8){
        dst[i  ]+=src[i  ];
        dst[i+1]+=src[i+1];
        dst[i+2]+=src[i+2];
        dst[i+3]+=src[i+3];
        dst[i+4]+=src[i+4];
        dst[i+5]+=src[i+5];
        dst[i+6]+=src[i+6];
        dst[i+7]+=src[i+7];
    }
    for (;i<length;++i)
        dst[i]+=src[i];
}

static hpatch_BOOL _bytesRle_load(TByte* out_data,TByte* out_dataEnd,const TByte* rle_code,const TByte* rle_code_end){
    TUInt32 ctrlSize,length;
    const TByte* ctrlBuf,*ctrlBuf_end;
    enum TByteRleType type;
    
    ctrlSize= unpack32Bit(&rle_code,rle_code_end);
#ifdef PATCH_RUN_MEM_SAFE_CHECK
    if (ctrlSize>(TUInt32)(rle_code_end-rle_code)) return hpatch_FALSE;
#endif
    ctrlBuf=rle_code;
    rle_code+=ctrlSize;
    ctrlBuf_end=rle_code;
    while (ctrlBuf_end-ctrlBuf>0){
        type=(enum TByteRleType)((*ctrlBuf)>>(8-kByteRleType_bit));
        length= 1 + unpack32BitWithTag(&ctrlBuf,ctrlBuf_end,kByteRleType_bit);
#ifdef PATCH_RUN_MEM_SAFE_CHECK
        if (length>(TUInt32)(out_dataEnd-out_data)) return hpatch_FALSE;
#endif
        switch (type){
            case kByteRleType_rle0:{
                memset(out_data,0,length);
                out_data+=length;
            }break;
            case kByteRleType_rle255:{
                memset(out_data,255,length);
                out_data+=length;
            }break;
            case kByteRleType_rle:{
#ifdef PATCH_RUN_MEM_SAFE_CHECK
                if (rle_code_end-rle_code<1) return hpatch_FALSE;
#endif
                memset(out_data,*rle_code,length);
                ++rle_code;
                out_data+=length;
            }break;
            case kByteRleType_unrle:{
#ifdef PATCH_RUN_MEM_SAFE_CHECK
                if (length>(TUInt32)(rle_code_end-rle_code)) return hpatch_FALSE;
#endif
                memcpy(out_data,rle_code,length);
                rle_code+=length;
                out_data+=length;
            }break;
        }
    }
    return (ctrlBuf==ctrlBuf_end)&&(rle_code==rle_code_end)&&(out_data==out_dataEnd);
}