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/* 
 * Copyright (c) 2015-2019, Intel Corporation
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met: 
 * 
 *  * Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer. 
 *  * Redistributions in binary form must reproduce the above copyright 
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the distribution. 
 *  * Neither the name of Intel Corporation nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE. 
 */ 
 
/** \file 
 * \brief Hamster Wheel Literal Matcher: literal representation at build time. 
 */ 
#include "hwlm_literal.h" 
#include "util/bitutils.h" // for CASE_BIT 
#include "util/compare.h" // for ourisalpha 
#include "util/ue2string.h" // for escapeString 
 
#include <algorithm>
#include <iomanip> 
#include <sstream> 
 
using namespace std; 
 
namespace ue2 { 
 
#ifdef DEBUG 
static UNUSED 
std::string dumpMask(const vector<u8> &v) { 
    ostringstream oss; 
    vector<u8>::const_iterator it, ite; 
    for (it = v.begin(), ite = v.end(); it != ite; ++it) { 
        oss << setfill('0') << setw(2) << hex << (unsigned int)*it; 
    } 
    return oss.str(); 
} 
#endif 
 
bool maskIsConsistent(const std::string &s, bool nocase, const vector<u8> &msk, 
                      const vector<u8> &cmp) { 
    string::const_reverse_iterator si = s.rbegin(); 
    vector<u8>::const_reverse_iterator mi = msk.rbegin(), ci = cmp.rbegin(); 
 
    for (; si != s.rend() && mi != msk.rend(); ++si, ++mi, ++ci) { 
        u8 c = *si, m = *mi, v = *ci; 
        if (nocase && ourisalpha(c)) { 
            m &= ~CASE_BIT; 
            v &= ~CASE_BIT; 
        } 
 
        assert(ci != cmp.rend()); 
        if ((c & m) != v) { 
            DEBUG_PRINTF("c = %02hhx; *ci = %02hhx m =%02hhx\n", c, *ci, m); 
            DEBUG_PRINTF("s = %s; dist = %zd\n", s.c_str(), si - s.rbegin()); 
            return false; 
        } 
    } 
 
    return true; 
} 
 
/** \brief Complete constructor, takes group information and msk/cmp. 
 * 
 * This constructor takes a msk/cmp pair. Both must be vectors of length <= 
 * \ref HWLM_MASKLEN. */ 
hwlmLiteral::hwlmLiteral(const std::string &s_in, bool nocase_in, 
                         bool noruns_in, u32 id_in, hwlm_group_t groups_in, 
                         const vector<u8> &msk_in, const vector<u8> &cmp_in) 
    : s(s_in), id(id_in), nocase(nocase_in), noruns(noruns_in), 
      groups(groups_in), msk(msk_in), cmp(cmp_in) { 
    assert(s.size() <= HWLM_LITERAL_MAX_LEN);
    assert(msk.size() <= HWLM_MASKLEN); 
    assert(msk.size() == cmp.size()); 
 
    // If we've been handled a nocase literal, all letter characters must be
    // upper-case.
    if (nocase) {
        upperString(s);
    }

    DEBUG_PRINTF("literal '%s'%s, msk=%s, cmp=%s\n", escapeString(s).c_str(),
                 nocase ? " (nocase)" : "", dumpMask(msk).c_str(),
                 dumpMask(cmp).c_str()); 
 

    // Mask and compare vectors MUST be the same size. 
    assert(msk.size() == cmp.size()); 
 
    // We must have been passed a msk/cmp that can be applied to s. 
    assert(maskIsConsistent(s, nocase, msk, cmp)); 
 
    // In the name of good hygiene, zap msk/cmp if msk is all zeroes. 
    if (all_of(begin(msk), end(msk), [](u8 val) { return val == 0; })) {
        msk.clear(); 
        cmp.clear(); 
    } 
} 
 
} // namespace ue2