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// Copyright 2013, Google Inc.
// All rights reserved.
//
// 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 Google Inc. 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.
%module fast_masking
%include "cstring.i"
%{
#include <cstring>
#ifdef __SSE2__
#include <emmintrin.h>
#endif
%}
%apply (char *STRING, int LENGTH) {
(const char* payload, int payload_length),
(const char* masking_key, int masking_key_length) };
%cstring_output_allocate_size(
char** result, int* result_length, delete [] *$1);
%inline %{
void mask(
const char* payload, int payload_length,
const char* masking_key, int masking_key_length,
int masking_key_index,
char** result, int* result_length) {
*result = new char[payload_length];
*result_length = payload_length;
memcpy(*result, payload, payload_length);
char* cursor = *result;
char* cursor_end = *result + *result_length;
#ifdef __SSE2__
while ((cursor < cursor_end) &&
(reinterpret_cast<size_t>(cursor) & 0xf)) {
*cursor ^= masking_key[masking_key_index];
++cursor;
masking_key_index = (masking_key_index + 1) % masking_key_length;
}
if (cursor == cursor_end) {
return;
}
const int kBlockSize = 16;
__m128i masking_key_block;
for (int i = 0; i < kBlockSize; ++i) {
*(reinterpret_cast<char*>(&masking_key_block) + i) =
masking_key[masking_key_index];
masking_key_index = (masking_key_index + 1) % masking_key_length;
}
while (cursor + kBlockSize <= cursor_end) {
__m128i payload_block =
_mm_load_si128(reinterpret_cast<__m128i*>(cursor));
_mm_stream_si128(reinterpret_cast<__m128i*>(cursor),
_mm_xor_si128(payload_block, masking_key_block));
cursor += kBlockSize;
}
#endif
while (cursor < cursor_end) {
*cursor ^= masking_key[masking_key_index];
++cursor;
masking_key_index = (masking_key_index + 1) % masking_key_length;
}
}
%}