#ifndef SIMDUTF8CHECK_H #define SIMDUTF8CHECK_H #include #include #include #include #include /* * legal utf-8 byte sequence * http://www.unicode.org/versions/Unicode6.0.0/ch03.pdf - page 94 * * Code Points 1st 2s 3s 4s * U+0000..U+007F 00..7F * U+0080..U+07FF C2..DF 80..BF * U+0800..U+0FFF E0 A0..BF 80..BF * U+1000..U+CFFF E1..EC 80..BF 80..BF * U+D000..U+D7FF ED 80..9F 80..BF * U+E000..U+FFFF EE..EF 80..BF 80..BF * U+10000..U+3FFFF F0 90..BF 80..BF 80..BF * U+40000..U+FFFFF F1..F3 80..BF 80..BF 80..BF * U+100000..U+10FFFF F4 80..8F 80..BF 80..BF * */ // all byte values must be no larger than 0xF4 static inline void checkSmallerThan0xF4(__m128i current_bytes, __m128i *has_error) { // unsigned, saturates to 0 below max *has_error = _mm_or_si128(*has_error, _mm_subs_epu8(current_bytes, _mm_set1_epi8(0xF4))); } static inline __m128i continuationLengths(__m128i high_nibbles) { return _mm_shuffle_epi8( _mm_setr_epi8(1, 1, 1, 1, 1, 1, 1, 1, // 0xxx (ASCII) 0, 0, 0, 0, // 10xx (continuation) 2, 2, // 110x 3, // 1110 4), // 1111, next should be 0 (not checked here) high_nibbles); } static inline __m128i carryContinuations(__m128i initial_lengths, __m128i previous_carries) { __m128i right1 = _mm_subs_epu8(_mm_alignr_epi8(initial_lengths, previous_carries, 16 - 1), _mm_set1_epi8(1)); __m128i sum = _mm_add_epi8(initial_lengths, right1); __m128i right2 = _mm_subs_epu8(_mm_alignr_epi8(sum, previous_carries, 16 - 2), _mm_set1_epi8(2)); return _mm_add_epi8(sum, right2); } static inline void checkContinuations(__m128i initial_lengths, __m128i carries, __m128i *has_error) { // overlap || underlap // carry > length && length > 0 || !(carry > length) && !(length > 0) // (carries > length) == (lengths > 0) __m128i overunder = _mm_cmpeq_epi8(_mm_cmpgt_epi8(carries, initial_lengths), _mm_cmpgt_epi8(initial_lengths, _mm_setzero_si128())); *has_error = _mm_or_si128(*has_error, overunder); } // when 0xED is found, next byte must be no larger than 0x9F // when 0xF4 is found, next byte must be no larger than 0x8F // next byte must be continuation, ie sign bit is set, so signed < is ok static inline void checkFirstContinuationMax(__m128i current_bytes, __m128i off1_current_bytes, __m128i *has_error) { __m128i maskED = _mm_cmpeq_epi8(off1_current_bytes, _mm_set1_epi8(0xED)); __m128i maskF4 = _mm_cmpeq_epi8(off1_current_bytes, _mm_set1_epi8(0xF4)); __m128i badfollowED = _mm_and_si128(_mm_cmpgt_epi8(current_bytes, _mm_set1_epi8(0x9F)), maskED); __m128i badfollowF4 = _mm_and_si128(_mm_cmpgt_epi8(current_bytes, _mm_set1_epi8(0x8F)), maskF4); *has_error = _mm_or_si128(*has_error, _mm_or_si128(badfollowED, badfollowF4)); } // map off1_hibits => error condition // hibits off1 cur // C => < C2 && true // E => < E1 && < A0 // F => < F1 && < 90 // else false && false static inline void checkOverlong(__m128i current_bytes, __m128i off1_current_bytes, __m128i hibits, __m128i previous_hibits, __m128i *has_error) { __m128i off1_hibits = _mm_alignr_epi8(hibits, previous_hibits, 16 - 1); __m128i initial_mins = _mm_shuffle_epi8( _mm_setr_epi8(-128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, // 10xx => false 0xC2, -128, // 110x 0xE1, // 1110 0xF1), off1_hibits); __m128i initial_under = _mm_cmpgt_epi8(initial_mins, off1_current_bytes); __m128i second_mins = _mm_shuffle_epi8( _mm_setr_epi8(-128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, // 10xx => false 127, 127, // 110x => true 0xA0, // 1110 0x90), off1_hibits); __m128i second_under = _mm_cmpgt_epi8(second_mins, current_bytes); *has_error = _mm_or_si128(*has_error, _mm_and_si128(initial_under, second_under)); } struct processed_utf_bytes { __m128i rawbytes; __m128i high_nibbles; __m128i carried_continuations; }; static inline void count_nibbles(__m128i bytes, struct processed_utf_bytes *answer) { answer->rawbytes = bytes; answer->high_nibbles = _mm_and_si128(_mm_srli_epi16(bytes, 4), _mm_set1_epi8(0x0F)); } // check whether the current bytes are valid UTF-8 // at the end of the function, previous gets updated static struct processed_utf_bytes checkUTF8Bytes(__m128i current_bytes, struct processed_utf_bytes *previous, __m128i *has_error) { struct processed_utf_bytes pb; count_nibbles(current_bytes, &pb); checkSmallerThan0xF4(current_bytes, has_error); __m128i initial_lengths = continuationLengths(pb.high_nibbles); pb.carried_continuations = carryContinuations(initial_lengths, previous->carried_continuations); checkContinuations(initial_lengths, pb.carried_continuations, has_error); __m128i off1_current_bytes = _mm_alignr_epi8(pb.rawbytes, previous->rawbytes, 16 - 1); checkFirstContinuationMax(current_bytes, off1_current_bytes, has_error); checkOverlong(current_bytes, off1_current_bytes, pb.high_nibbles, previous->high_nibbles, has_error); return pb; } static bool validate_utf8_fast(const char *src, size_t len) { size_t i = 0; __m128i has_error = _mm_setzero_si128(); struct processed_utf_bytes previous = {.rawbytes = _mm_setzero_si128(), .high_nibbles = _mm_setzero_si128(), .carried_continuations = _mm_setzero_si128()}; if (len >= 16) { for (; i <= len - 16; i += 16) { __m128i current_bytes = _mm_loadu_si128((const __m128i *)(src + i)); previous = checkUTF8Bytes(current_bytes, &previous, &has_error); } } // last part if (i < len) { char buffer[16]; memset(buffer, 0, 16); memcpy(buffer, src + i, len - i); __m128i current_bytes = _mm_loadu_si128((const __m128i *)(buffer)); previous = checkUTF8Bytes(current_bytes, &previous, &has_error); } else { has_error = _mm_or_si128(_mm_cmpgt_epi8(previous.carried_continuations, _mm_setr_epi8(9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1)), has_error); } return _mm_testz_si128(has_error, has_error); } #ifdef __AVX2__ /*****************************/ static inline __m256i push_last_byte_of_a_to_b(__m256i a, __m256i b) { return _mm256_alignr_epi8(b, _mm256_permute2x128_si256(a, b, 0x21), 15); } static inline __m256i push_last_2bytes_of_a_to_b(__m256i a, __m256i b) { return _mm256_alignr_epi8(b, _mm256_permute2x128_si256(a, b, 0x21), 14); } // all byte values must be no larger than 0xF4 static inline void avxcheckSmallerThan0xF4(__m256i current_bytes, __m256i *has_error) { // unsigned, saturates to 0 below max *has_error = _mm256_or_si256( *has_error, _mm256_subs_epu8(current_bytes, _mm256_set1_epi8(0xF4))); } static inline __m256i avxcontinuationLengths(__m256i high_nibbles) { return _mm256_shuffle_epi8( _mm256_setr_epi8(1, 1, 1, 1, 1, 1, 1, 1, // 0xxx (ASCII) 0, 0, 0, 0, // 10xx (continuation) 2, 2, // 110x 3, // 1110 4, // 1111, next should be 0 (not checked here) 1, 1, 1, 1, 1, 1, 1, 1, // 0xxx (ASCII) 0, 0, 0, 0, // 10xx (continuation) 2, 2, // 110x 3, // 1110 4 // 1111, next should be 0 (not checked here) ), high_nibbles); } static inline __m256i avxcarryContinuations(__m256i initial_lengths, __m256i previous_carries) { __m256i right1 = _mm256_subs_epu8( push_last_byte_of_a_to_b(previous_carries, initial_lengths), _mm256_set1_epi8(1)); __m256i sum = _mm256_add_epi8(initial_lengths, right1); __m256i right2 = _mm256_subs_epu8( push_last_2bytes_of_a_to_b(previous_carries, sum), _mm256_set1_epi8(2)); return _mm256_add_epi8(sum, right2); } static inline void avxcheckContinuations(__m256i initial_lengths, __m256i carries, __m256i *has_error) { // overlap || underlap // carry > length && length > 0 || !(carry > length) && !(length > 0) // (carries > length) == (lengths > 0) __m256i overunder = _mm256_cmpeq_epi8( _mm256_cmpgt_epi8(carries, initial_lengths), _mm256_cmpgt_epi8(initial_lengths, _mm256_setzero_si256())); *has_error = _mm256_or_si256(*has_error, overunder); } // when 0xED is found, next byte must be no larger than 0x9F // when 0xF4 is found, next byte must be no larger than 0x8F // next byte must be continuation, ie sign bit is set, so signed < is ok static inline void avxcheckFirstContinuationMax(__m256i current_bytes, __m256i off1_current_bytes, __m256i *has_error) { __m256i maskED = _mm256_cmpeq_epi8(off1_current_bytes, _mm256_set1_epi8(0xED)); __m256i maskF4 = _mm256_cmpeq_epi8(off1_current_bytes, _mm256_set1_epi8(0xF4)); __m256i badfollowED = _mm256_and_si256( _mm256_cmpgt_epi8(current_bytes, _mm256_set1_epi8(0x9F)), maskED); __m256i badfollowF4 = _mm256_and_si256( _mm256_cmpgt_epi8(current_bytes, _mm256_set1_epi8(0x8F)), maskF4); *has_error = _mm256_or_si256(*has_error, _mm256_or_si256(badfollowED, badfollowF4)); } // map off1_hibits => error condition // hibits off1 cur // C => < C2 && true // E => < E1 && < A0 // F => < F1 && < 90 // else false && false static inline void avxcheckOverlong(__m256i current_bytes, __m256i off1_current_bytes, __m256i hibits, __m256i previous_hibits, __m256i *has_error) { __m256i off1_hibits = push_last_byte_of_a_to_b(previous_hibits, hibits); __m256i initial_mins = _mm256_shuffle_epi8( _mm256_setr_epi8(-128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, // 10xx => false 0xC2, -128, // 110x 0xE1, // 1110 0xF1, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, // 10xx => false 0xC2, -128, // 110x 0xE1, // 1110 0xF1), off1_hibits); __m256i initial_under = _mm256_cmpgt_epi8(initial_mins, off1_current_bytes); __m256i second_mins = _mm256_shuffle_epi8( _mm256_setr_epi8(-128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, // 10xx => false 127, 127, // 110x => true 0xA0, // 1110 0x90, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, -128, // 10xx => false 127, 127, // 110x => true 0xA0, // 1110 0x90), off1_hibits); __m256i second_under = _mm256_cmpgt_epi8(second_mins, current_bytes); *has_error = _mm256_or_si256(*has_error, _mm256_and_si256(initial_under, second_under)); } struct avx_processed_utf_bytes { __m256i rawbytes; __m256i high_nibbles; __m256i carried_continuations; }; static inline void avx_count_nibbles(__m256i bytes, struct avx_processed_utf_bytes *answer) { answer->rawbytes = bytes; answer->high_nibbles = _mm256_and_si256(_mm256_srli_epi16(bytes, 4), _mm256_set1_epi8(0x0F)); } // check whether the current bytes are valid UTF-8 // at the end of the function, previous gets updated static struct avx_processed_utf_bytes avxcheckUTF8Bytes(__m256i current_bytes, struct avx_processed_utf_bytes *previous, __m256i *has_error) { struct avx_processed_utf_bytes pb; avx_count_nibbles(current_bytes, &pb); avxcheckSmallerThan0xF4(current_bytes, has_error); __m256i initial_lengths = avxcontinuationLengths(pb.high_nibbles); pb.carried_continuations = avxcarryContinuations(initial_lengths, previous->carried_continuations); avxcheckContinuations(initial_lengths, pb.carried_continuations, has_error); __m256i off1_current_bytes = push_last_byte_of_a_to_b(previous->rawbytes, pb.rawbytes); avxcheckFirstContinuationMax(current_bytes, off1_current_bytes, has_error); avxcheckOverlong(current_bytes, off1_current_bytes, pb.high_nibbles, previous->high_nibbles, has_error); return pb; } // check whether the current bytes are valid UTF-8 // at the end of the function, previous gets updated static struct avx_processed_utf_bytes avxcheckUTF8Bytes_asciipath(__m256i current_bytes, struct avx_processed_utf_bytes *previous, __m256i *has_error) { if (_mm256_testz_si256(current_bytes, _mm256_set1_epi8(0x80))) { // fast ascii path *has_error = _mm256_or_si256( _mm256_cmpgt_epi8(previous->carried_continuations, _mm256_setr_epi8(9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1)), *has_error); return *previous; } struct avx_processed_utf_bytes pb; avx_count_nibbles(current_bytes, &pb); avxcheckSmallerThan0xF4(current_bytes, has_error); __m256i initial_lengths = avxcontinuationLengths(pb.high_nibbles); pb.carried_continuations = avxcarryContinuations(initial_lengths, previous->carried_continuations); avxcheckContinuations(initial_lengths, pb.carried_continuations, has_error); __m256i off1_current_bytes = push_last_byte_of_a_to_b(previous->rawbytes, pb.rawbytes); avxcheckFirstContinuationMax(current_bytes, off1_current_bytes, has_error); avxcheckOverlong(current_bytes, off1_current_bytes, pb.high_nibbles, previous->high_nibbles, has_error); return pb; } static bool validate_utf8_fast_avx_asciipath(const char *src, size_t len) { size_t i = 0; __m256i has_error = _mm256_setzero_si256(); struct avx_processed_utf_bytes previous = { .rawbytes = _mm256_setzero_si256(), .high_nibbles = _mm256_setzero_si256(), .carried_continuations = _mm256_setzero_si256()}; if (len >= 32) { for (; i <= len - 32; i += 32) { __m256i current_bytes = _mm256_loadu_si256((const __m256i *)(src + i)); previous = avxcheckUTF8Bytes_asciipath(current_bytes, &previous, &has_error); } } // last part if (i < len) { char buffer[32]; memset(buffer, 0, 32); memcpy(buffer, src + i, len - i); __m256i current_bytes = _mm256_loadu_si256((const __m256i *)(buffer)); previous = avxcheckUTF8Bytes(current_bytes, &previous, &has_error); } else { has_error = _mm256_or_si256( _mm256_cmpgt_epi8(previous.carried_continuations, _mm256_setr_epi8(9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1)), has_error); } return _mm256_testz_si256(has_error, has_error); } static bool validate_utf8_fast_avx(const char *src, size_t len) { size_t i = 0; __m256i has_error = _mm256_setzero_si256(); struct avx_processed_utf_bytes previous = { .rawbytes = _mm256_setzero_si256(), .high_nibbles = _mm256_setzero_si256(), .carried_continuations = _mm256_setzero_si256()}; if (len >= 32) { for (; i <= len - 32; i += 32) { __m256i current_bytes = _mm256_loadu_si256((const __m256i *)(src + i)); previous = avxcheckUTF8Bytes(current_bytes, &previous, &has_error); } } // last part if (i < len) { char buffer[32]; memset(buffer, 0, 32); memcpy(buffer, src + i, len - i); __m256i current_bytes = _mm256_loadu_si256((const __m256i *)(buffer)); previous = avxcheckUTF8Bytes(current_bytes, &previous, &has_error); } else { has_error = _mm256_or_si256( _mm256_cmpgt_epi8(previous.carried_continuations, _mm256_setr_epi8(9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 1)), has_error); } return _mm256_testz_si256(has_error, has_error); } #endif // __AVX2__ #endif