vectorscan/src/hwlm/noodle_build.cpp
2015-10-20 09:13:35 +11:00

111 lines
3.5 KiB
C++

/*
* Copyright (c) 2015, 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 Noodle literal matcher: build code.
*/
#include <cstring> // for memcpy
#include "noodle_build.h"
#include "noodle_internal.h"
#include "ue2common.h"
#include "util/alloc.h"
#include "util/compare.h"
#include "util/verify_types.h"
namespace ue2 {
static
size_t findNoodFragOffset(const u8 *lit, size_t len, bool nocase) {
size_t offset = 0;
for (size_t i = 0; i + 1 < len; i++) {
int diff = 0;
const char c = lit[i];
const char d = lit[i + 1];
if (nocase && ourisalpha(c)) {
diff = (mytoupper(c) != mytoupper(d));
} else {
diff = (c != d);
}
offset = i;
if (diff) {
break;
}
}
return offset;
}
/** \brief Construct a Noodle matcher for the given literal. */
aligned_unique_ptr<noodTable> noodBuildTable(const u8 *lit, size_t len,
bool nocase, u32 id) {
size_t noodle_len = sizeof(noodTable) + len;
aligned_unique_ptr<noodTable> n =
aligned_zmalloc_unique<noodTable>(noodle_len);
assert(n);
size_t key_offset = findNoodFragOffset(lit, len, nocase);
n->id = id;
n->len = verify_u32(len);
n->key_offset = verify_u32(key_offset);
n->nocase = nocase ? 1 : 0;
memcpy(n->str, lit, len);
return n;
}
size_t noodSize(const noodTable *n) {
assert(n); // shouldn't call with null
return sizeof(*n) + n->len;
}
} // namespace ue2
#ifdef DUMP_SUPPORT
#include <cctype>
namespace ue2 {
void noodPrintStats(const noodTable *n, FILE *f) {
fprintf(f, "Noodle table\n");
fprintf(f, "Len: %u Key Offset: %u\n", n->len, n->key_offset);
fprintf(f, "String: ");
for (u32 i = 0; i < n->len; i++) {
if (isgraph(n->str[i]) && n->str[i] != '\\') {
fprintf(f, "%c", n->str[i]);
} else {
fprintf(f, "\\x%02hhx", n->str[i]);
}
}
fprintf(f, "\n");
}
} // namespace ue2
#endif