diff options
Diffstat (limited to 'modules/policy/lua-aho-corasick/ac_slow.cxx')
| -rw-r--r-- | modules/policy/lua-aho-corasick/ac_slow.cxx | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/modules/policy/lua-aho-corasick/ac_slow.cxx b/modules/policy/lua-aho-corasick/ac_slow.cxx new file mode 100644 index 0000000..cb3957a --- /dev/null +++ b/modules/policy/lua-aho-corasick/ac_slow.cxx @@ -0,0 +1,318 @@ +#include <ctype.h> +#include <strings.h> // for bzero +#include <algorithm> +#include "ac_slow.hpp" +#include "ac.h" + +////////////////////////////////////////////////////////////////////////// +// +// Implementation of AhoCorasick_Slow +// +////////////////////////////////////////////////////////////////////////// +// +ACS_Constructor::ACS_Constructor() : _next_node_id(1) { + _root = new_state(); + _root_char = new InputTy[256]; + bzero((void*)_root_char, 256); + +#ifdef VERIFY + _pattern_buf = 0; +#endif +} + +ACS_Constructor::~ACS_Constructor() { + for (std::vector<ACS_State* >::iterator i = _all_states.begin(), + e = _all_states.end(); i != e; i++) { + delete *i; + } + _all_states.clear(); + delete[] _root_char; + +#ifdef VERIFY + delete[] _pattern_buf; +#endif +} + +ACS_State* +ACS_Constructor::new_state() { + ACS_State* t = new ACS_State(_next_node_id++); + _all_states.push_back(t); + return t; +} + +void +ACS_Constructor::Add_Pattern(const char* str, unsigned int str_len, + int pattern_idx) { + ACS_State* state = _root; + for (unsigned int i = 0; i < str_len; i++) { + const char c = str[i]; + ACS_State* new_s = state->Get_Goto(c); + if (!new_s) { + new_s = new_state(); + new_s->_depth = state->_depth + 1; + state->Set_Goto(c, new_s); + } + state = new_s; + } + state->_is_terminal = true; + state->set_Pattern_Idx(pattern_idx); +} + +void +ACS_Constructor::Propagate_faillink() { + ACS_State* r = _root; + std::vector<ACS_State*> wl; + + const ACS_Goto_Map& m = r->Get_Goto_Map(); + for (ACS_Goto_Map::const_iterator i = m.begin(), e = m.end(); i != e; i++) { + ACS_State* s = i->second; + s->_fail_link = r; + wl.push_back(s); + } + + // For any input c, make sure "goto(root, c)" is valid, which make the + // fail-link propagation lot easier. + ACS_Goto_Map goto_save = r->_goto_map; + for (uint32 i = 0; i <= 255; i++) { + ACS_State* s = r->Get_Goto(i); + if (!s) r->Set_Goto(i, r); + } + + for (uint32 i = 0; i < wl.size(); i++) { + ACS_State* s = wl[i]; + ACS_State* fl = s->_fail_link; + + const ACS_Goto_Map& tran_map = s->Get_Goto_Map(); + + for (ACS_Goto_Map::const_iterator ii = tran_map.begin(), + ee = tran_map.end(); ii != ee; ii++) { + InputTy c = ii->first; + ACS_State *tran = ii->second; + + ACS_State* tran_fl = 0; + for (ACS_State* fl_walk = fl; ;) { + if (ACS_State* t = fl_walk->Get_Goto(c)) { + tran_fl = t; + break; + } else { + fl_walk = fl_walk->Get_FailLink(); + } + } + + tran->_fail_link = tran_fl; + wl.push_back(tran); + } + } + + // Remove "goto(root, c) == root" transitions + r->_goto_map = goto_save; +} + +void +ACS_Constructor::Construct(const char** strv, unsigned int* strlenv, + uint32 strnum) { + Save_Patterns(strv, strlenv, strnum); + + for (uint32 i = 0; i < strnum; i++) { + Add_Pattern(strv[i], strlenv[i], i); + } + + Propagate_faillink(); + unsigned char* p = _root_char; + + const ACS_Goto_Map& m = _root->Get_Goto_Map(); + for (ACS_Goto_Map::const_iterator i = m.begin(), e = m.end(); + i != e; i++) { + p[i->first] = 1; + } +} + +Match_Result +ACS_Constructor::MatchHelper(const char *str, uint32 len) const { + const ACS_State* root = _root; + const ACS_State* state = root; + + uint32 idx = 0; + while (idx < len) { + InputTy c = str[idx]; + idx++; + if (_root_char[c]) { + state = root->Get_Goto(c); + break; + } + } + + if (unlikely(state->is_Terminal())) { + // This could happen if the one of the pattern has only one char! + uint32 pos = idx - 1; + Match_Result r(pos - state->Get_Depth() + 1, pos, + state->get_Pattern_Idx()); + return r; + } + + while (idx < len) { + InputTy c = str[idx]; + ACS_State* gs = state->Get_Goto(c); + + if (!gs) { + ACS_State* fl = state->Get_FailLink(); + if (fl == root) { + while (idx < len) { + InputTy c = str[idx]; + idx++; + if (_root_char[c]) { + state = root->Get_Goto(c); + break; + } + } + } else { + state = fl; + } + } else { + idx ++; + state = gs; + } + + if (state->is_Terminal()) { + uint32 pos = idx - 1; + Match_Result r = Match_Result(pos - state->Get_Depth() + 1, pos, + state->get_Pattern_Idx()); + return r; + } + } + + return Match_Result(-1, -1, -1); +} + +#ifdef DEBUG +void +ACS_Constructor::dump_text(const char* txtfile) const { + FILE* f = fopen(txtfile, "w+"); + for (std::vector<ACS_State*>::const_iterator i = _all_states.begin(), + e = _all_states.end(); i != e; i++) { + ACS_State* s = *i; + + fprintf(f, "S%d goto:{", s->Get_ID()); + const ACS_Goto_Map& goto_func = s->Get_Goto_Map(); + + for (ACS_Goto_Map::const_iterator i = goto_func.begin(), e = goto_func.end(); + i != e; i++) { + InputTy input = i->first; + ACS_State* tran = i->second; + if (isprint(input)) + fprintf(f, "'%c' -> S:%d,", input, tran->Get_ID()); + else + fprintf(f, "%#x -> S:%d,", input, tran->Get_ID()); + } + fprintf(f, "} "); + + if (s->_fail_link) { + fprintf(f, ", fail=S:%d", s->_fail_link->Get_ID()); + } + + if (s->_is_terminal) { + fprintf(f, ", terminal"); + } + + fprintf(f, "\n"); + } + fclose(f); +} + +void +ACS_Constructor::dump_dot(const char *dotfile) const { + FILE* f = fopen(dotfile, "w+"); + const char* indent = " "; + + fprintf(f, "digraph G {\n"); + + // Emit node information + fprintf(f, "%s%d [style=filled];\n", indent, _root->Get_ID()); + for (std::vector<ACS_State*>::const_iterator i = _all_states.begin(), + e = _all_states.end(); i != e; i++) { + ACS_State *s = *i; + if (s->_is_terminal) { + fprintf(f, "%s%d [shape=doublecircle];\n", indent, s->Get_ID()); + } + } + fprintf(f, "\n"); + + // Emit edge information + for (std::vector<ACS_State*>::const_iterator i = _all_states.begin(), + e = _all_states.end(); i != e; i++) { + ACS_State* s = *i; + uint32 id = s->Get_ID(); + + const ACS_Goto_Map& m = s->Get_Goto_Map(); + for (ACS_Goto_Map::const_iterator ii = m.begin(), ee = m.end(); + ii != ee; ii++) { + InputTy input = ii->first; + ACS_State* tran = ii->second; + if (isalnum(input)) + fprintf(f, "%s%d -> %d [label=%c];\n", + indent, id, tran->Get_ID(), input); + else + fprintf(f, "%s%d -> %d [label=\"%#x\"];\n", + indent, id, tran->Get_ID(), input); + + } + + // Emit fail-link + ACS_State* fl = s->Get_FailLink(); + if (fl && fl != _root) { + fprintf(f, "%s%d -> %d [style=dotted, color=red]; \n", + indent, id, fl->Get_ID()); + } + } + fprintf(f, "}\n"); + fclose(f); +} +#endif + +#ifdef VERIFY +void +ACS_Constructor::Verify_Result(const char* subject, const Match_Result* r) + const { + if (r->begin >= 0) { + unsigned len = r->end - r->begin + 1; + int ptn_idx = r->pattern_idx; + + ASSERT(ptn_idx >= 0 && + len == get_ith_Pattern_Len(ptn_idx) && + memcmp(subject + r->begin, get_ith_Pattern(ptn_idx), len) == 0); + } +} + +void +ACS_Constructor::Save_Patterns(const char** strv, unsigned int* strlenv, + int pattern_num) { + // calculate the total size needed to save all patterns. + // + int buf_size = 0; + for (int i = 0; i < pattern_num; i++) { buf_size += strlenv[i]; } + + // HINT: patterns are delimited by '\0' in order to ease debugging. + buf_size += pattern_num; + ASSERT(_pattern_buf == 0); + _pattern_buf = new char[buf_size + 1]; + #define MAGIC_NUM 0x5a + _pattern_buf[buf_size] = MAGIC_NUM; + + int ofst = 0; + _pattern_lens.resize(pattern_num); + _pattern_vect.resize(pattern_num); + for (int i = 0; i < pattern_num; i++) { + int l = strlenv[i]; + _pattern_lens[i] = l; + _pattern_vect[i] = _pattern_buf + ofst; + + memcpy(_pattern_buf + ofst, strv[i], l); + ofst += l; + _pattern_buf[ofst++] = '\0'; + } + + ASSERT(_pattern_buf[buf_size] == MAGIC_NUM); + #undef MAGIC_NUM +} + +#endif |