FILTER.CPP

#include "CkyPch.h" 
 
#include "filter.h" 
#include "keyword.h" 
#include "utils.h" 
#include "globals.h" 
 
 
 
// 
// First pass through the data: count how many extra bytes we're going to 
// need to allocate to hold the modified data, if any. 
// 
 
int 
CountExtraBytes( 
    LPCTSTR ptszStart, 
    UINT    cch) 
{ 
    ASSERT(ptszStart != NULL); 
     
    LPCTSTR ptszEnd = ptszStart + cch; 
    CStateStack ss; 
    int cb = 0; 
     
    for (LPCTSTR ptsz = ptszStart;  ptsz < ptszEnd; ) 
    { 
        int cLen; 
        const CToken* ptok = g_trie.Search(ptsz, &cLen, ptszEnd - ptsz); 
 
        if (ptok == NULL) 
            ++ptsz; 
        else 
        { 
            cb += ptok->CountBytes(ss, ptsz, ptszEnd - ptsz); 
            ptsz += ptok->m_str.length(); 
        } 
    } 
 
    return cb; 
} 
 
 
 
// 
// Second pass: munge the data 
// 
 
void 
DoFilter( 
    LPCTSTR ptszStart, 
    UINT    cch, 
    LPCTSTR ptszSessionID, 
    LPTSTR  ptszOutBuf) 
{ 
    ASSERT(ptszStart != NULL  &&  cch > 0); 
    ASSERT(ptszSessionID != NULL  &&  _tcslen(ptszSessionID) > 0); 
    ASSERT(ptszOutBuf != NULL); 
     
    LPCTSTR ptszEnd = ptszStart + cch; 
    // const int cchUrl = _tcslen(ptszSessionID); 
    // const int cchUrlNameValue = _tcslen(s_szUrlNameValue); 
    CStateStack ss(ptszSessionID); 
     
    for (LPCTSTR ptsz = ptszStart;  ptsz < ptszEnd; ) 
    { 
        int cLen; 
        const CToken* ptok = g_trie.Search(ptsz, &cLen, ptszEnd - ptsz); 
 
        if (ptok == NULL) 
        { 
            // TRACE("%c", *ptsz); 
            *ptszOutBuf++ = *ptsz++; 
        } 
        else 
        { 
            // DoFilter is supposed to copy itself, if appropriate, 
            // and adjust ptsz and ptszOutBuf 
            ptok->DoFilter(ss, ptsz, ptszEnd - ptsz, ptszOutBuf); 
        } 
    } 
} 
 
 
 
int 
Filter( 
    PHTTP_FILTER_CONTEXT  pfc, 
    PHTTP_FILTER_RAW_DATA pRawData, 
    LPCSTR                pszStart, 
    UINT                  cch, 
    int                   iStart, 
    LPCSTR                pszSessionID) 
{ 
    ASSERT(pszSessionID != NULL); 
 
    // If empty SessionID (typically happens on plain HTML pages), nothing 
    // useful can be done 
    if (strlen(pszSessionID) == 0) 
        return 0; 
 
    const int nExtra = CountExtraBytes(pszStart + iStart, cch - iStart); 
 
    if (nExtra > 0) 
    { 
        TRACE("Filtering `%s', found %d extra bytes\n", pszSessionID, nExtra); 
        const int nNewSize = nExtra + cch; 
        TRACE("FilterNew: "); 
        LPSTR pchNew = (LPSTR) AllocMem(pfc, nNewSize); 
         
        memcpy(pchNew, pszStart, iStart); 
        DoFilter(pszStart + iStart, cch - iStart, 
                 pszSessionID, pchNew + iStart); 
        pRawData->pvInData = pchNew; 
        pRawData->cbInData = pRawData->cbInBuffer = nNewSize; 
    } 
 
    return nExtra; 
}