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- #ifndef SIMDUTF8CHECK_H
- #define SIMDUTF8CHECK_H
- #include <stdbool.h>
- #include <stddef.h>
- #include <stdint.h>
- #include <string.h>
- #include <x86intrin.h>
- /*
- * 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
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