1 files changed, 173 insertions, 0 deletions
diff --git a/modules/policy/lua-aho-corasick/ac_lua.cxx b/modules/policy/lua-aho-corasick/ac_lua.cxx
new file mode 100644
index 0000000..ad7307e
--- /dev/null
+++ b/modules/policy/lua-aho-corasick/ac_lua.cxx
@@ -0,0 +1,173 @@
+// Interface functions for libac.so
+//
+#include <vector>
+#include <string>
+#include "ac_slow.hpp"
+#include "ac_fast.hpp"
+#include "ac.h" // for the definition of ac_result_t
+#include "ac_util.hpp"
+
+extern "C" {
+    #include <lua.h>
+    #include <lauxlib.h>
+}
+
+#if defined(USE_SLOW_VER)
+#error "Not going to implement it"
+#endif
+
+using namespace std;
+static const char* tname = "aho-corasick";
+
+class BufAlloc : public Buf_Allocator {
+public:
+    BufAlloc(lua_State* L) : _L(L) {}
+    virtual AC_Buffer* alloc(int sz) {
+        return (AC_Buffer*)lua_newuserdata (_L, sz);
+    }
+
+    // Let GC to take care.
+    virtual void free() {}
+
+private:
+    lua_State* _L;
+};
+
+static bool
+_create_helper(lua_State* L, const vector<const char*>& str_v,
+               const vector<unsigned int>& strlen_v) {
+    ASSERT(str_v.size() == strlen_v.size());
+
+    ACS_Constructor acc;
+    BufAlloc ba(L);
+
+    // Step 1: construt the slow version.
+    unsigned int strnum = str_v.size();
+    const char** str_vect = new const char*[strnum];
+    unsigned int* strlen_vect = new unsigned int[strnum];
+
+    int idx = 0;
+    for (vector<const char*>::const_iterator i = str_v.begin(), e = str_v.end();
+         i != e; i++) {
+        str_vect[idx++] = *i;
+    }
+
+    idx = 0;
+    for (vector<unsigned int>::const_iterator i = strlen_v.begin(),
+            e = strlen_v.end(); i != e; i++) {
+        strlen_vect[idx++] = *i;
+    }
+
+    acc.Construct(str_vect, strlen_vect, idx);
+    delete[] str_vect;
+    delete[] strlen_vect;
+
+    // Step 2: convert to fast version
+    AC_Converter cvt(acc, ba);
+    return cvt.Convert() != 0;
+}
+
+static ac_result_t
+_match_helper(buf_header_t* ac, const char *str, unsigned int len) {
+    AC_Buffer* buf = (AC_Buffer*)(void*)ac;
+    ASSERT(ac->magic_num == AC_MAGIC_NUM);
+
+    ac_result_t r = Match(buf, str, len);
+    return r;
+}
+
+// LUA sematic:
+//  input: array of strings
+//  output: userdata containing the AC-graph (i.e. the AC_Buffer).
+//
+static int
+lac_create(lua_State* L) {
+    // The table of the array must be the 1st argument.
+    int input_tab = 1;
+
+    luaL_checktype(L, input_tab, LUA_TTABLE);
+
+    // Init the "iteartor".
+    lua_pushnil(L);
+
+    vector<const char*> str_v;
+    vector<unsigned int> strlen_v;
+
+    // Loop over the elements
+    while (lua_next(L, input_tab)) {
+        size_t str_len;
+        const char* s = luaL_checklstring(L, -1, &str_len);
+        str_v.push_back(s);
+        strlen_v.push_back(str_len);
+
+        // remove the value, but keep the key as the iterator.
+        lua_pop(L, 1);
+    }
+
+    // pop the nil value
+    lua_pop(L, 1);
+
+    if (_create_helper(L, str_v, strlen_v)) {
+        // The AC graph, as a userdata is already pushed to the stack, hence 1.
+        return 1;
+    }
+
+    return 0;
+}
+
+// LUA input:
+//    arg1: the userdata, representing the AC graph, returned from l_create().
+//    arg2: the string to be matched.
+//
+// LUA return:
+//    if match, return index range of the match; otherwise nil is returned.
+//
+static int
+lac_match(lua_State* L) {
+    buf_header_t* ac = (buf_header_t*)lua_touserdata(L, 1);
+    if (!ac) {
+        luaL_checkudata(L, 1, tname);
+        return 0;
+    }
+
+    size_t len;
+    const char* str;
+    #if LUA_VERSION_NUM >= 502
+        str = luaL_tolstring(L, 2, &len);
+    #else
+        str = lua_tolstring(L, 2, &len);
+    #endif
+    if (!str) {
+        luaL_checkstring(L, 2);
+        return 0;
+    }
+
+    ac_result_t r = _match_helper(ac, str, len);
+    if (r.match_begin != -1) {
+        lua_pushinteger(L, r.match_begin);
+        lua_pushinteger(L, r.match_end);
+        return 2;
+    }
+
+    return 0;
+}
+
+static const struct luaL_Reg lib_funcs[] = {
+    { "create", lac_create },
+    { "match",  lac_match },
+    {0, 0}
+};
+
+extern "C" int AC_EXPORT
+luaopen_ahocorasick(lua_State* L) {
+    luaL_newmetatable(L, tname);
+
+#if LUA_VERSION_NUM == 501
+    luaL_register(L, tname, lib_funcs);
+#elif LUA_VERSION_NUM >= 502
+    luaL_newlib(L, lib_funcs);
+#else
+    #error "Don't know how to do it right"
+#endif
+    return 1;
+}