fast_masking.i (3312B)
1 // Copyright 2013, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 31 %module fast_masking 32 33 %include "cstring.i" 34 35 %{ 36 #include <cstring> 37 38 #ifdef __SSE2__ 39 #include <emmintrin.h> 40 #endif 41 %} 42 43 %apply (char *STRING, int LENGTH) { 44 (const char* payload, int payload_length), 45 (const char* masking_key, int masking_key_length) }; 46 %cstring_output_allocate_size( 47 char** result, int* result_length, delete [] *$1); 48 49 %inline %{ 50 51 void mask( 52 const char* payload, int payload_length, 53 const char* masking_key, int masking_key_length, 54 int masking_key_index, 55 char** result, int* result_length) { 56 *result = new char[payload_length]; 57 *result_length = payload_length; 58 memcpy(*result, payload, payload_length); 59 60 char* cursor = *result; 61 char* cursor_end = *result + *result_length; 62 63 #ifdef __SSE2__ 64 while ((cursor < cursor_end) && 65 (reinterpret_cast<size_t>(cursor) & 0xf)) { 66 *cursor ^= masking_key[masking_key_index]; 67 ++cursor; 68 masking_key_index = (masking_key_index + 1) % masking_key_length; 69 } 70 if (cursor == cursor_end) { 71 return; 72 } 73 74 const int kBlockSize = 16; 75 __m128i masking_key_block; 76 for (int i = 0; i < kBlockSize; ++i) { 77 *(reinterpret_cast<char*>(&masking_key_block) + i) = 78 masking_key[masking_key_index]; 79 masking_key_index = (masking_key_index + 1) % masking_key_length; 80 } 81 82 while (cursor + kBlockSize <= cursor_end) { 83 __m128i payload_block = 84 _mm_load_si128(reinterpret_cast<__m128i*>(cursor)); 85 _mm_stream_si128(reinterpret_cast<__m128i*>(cursor), 86 _mm_xor_si128(payload_block, masking_key_block)); 87 cursor += kBlockSize; 88 } 89 #endif 90 91 while (cursor < cursor_end) { 92 *cursor ^= masking_key[masking_key_index]; 93 ++cursor; 94 masking_key_index = (masking_key_index + 1) % masking_key_length; 95 } 96 } 97 98 %}