#ifdef __AVX2__ #include #include #include int utf8_naive(const unsigned char *data, int len); #if 0 static void print256(const char *s, const __m256i v256) { const unsigned char *v8 = (const unsigned char *)&v256; if (s) printf("%s:\t", s); for (int i = 0; i < 32; i++) printf("%02x ", v8[i]); printf("\n"); } #endif /* * Map high nibble of "First Byte" to legal character length minus 1 * 0x00 ~ 0xBF --> 0 * 0xC0 ~ 0xDF --> 1 * 0xE0 ~ 0xEF --> 2 * 0xF0 ~ 0xFF --> 3 */ static const int8_t _first_len_tbl[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, }; /* Map "First Byte" to 8-th item of range table (0xC2 ~ 0xF4) */ static const int8_t _first_range_tbl[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 8, 8, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 8, 8, 8, }; /* * Range table, map range index to min and max values * Index 0 : 00 ~ 7F (First Byte, ascii) * Index 1,2,3: 80 ~ BF (Second, Third, Fourth Byte) * Index 4 : A0 ~ BF (Second Byte after E0) * Index 5 : 80 ~ 9F (Second Byte after ED) * Index 6 : 90 ~ BF (Second Byte after F0) * Index 7 : 80 ~ 8F (Second Byte after F4) * Index 8 : C2 ~ F4 (First Byte, non ascii) * Index 9~15 : illegal: i >= 127 && i <= -128 */ static const int8_t _range_min_tbl[] = { 0x00, 0x80, 0x80, 0x80, 0xA0, 0x80, 0x90, 0x80, 0xC2, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x00, 0x80, 0x80, 0x80, 0xA0, 0x80, 0x90, 0x80, 0xC2, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, }; static const int8_t _range_max_tbl[] = { 0x7F, 0xBF, 0xBF, 0xBF, 0xBF, 0x9F, 0xBF, 0x8F, 0xF4, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x7F, 0xBF, 0xBF, 0xBF, 0xBF, 0x9F, 0xBF, 0x8F, 0xF4, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, }; /* * Tables for fast handling of four special First Bytes(E0,ED,F0,F4), after * which the Second Byte are not 80~BF. It contains "range index adjustment". * +------------+---------------+------------------+----------------+ * | First Byte | original range| range adjustment | adjusted range | * +------------+---------------+------------------+----------------+ * | E0 | 2 | 2 | 4 | * +------------+---------------+------------------+----------------+ * | ED | 2 | 3 | 5 | * +------------+---------------+------------------+----------------+ * | F0 | 3 | 3 | 6 | * +------------+---------------+------------------+----------------+ * | F4 | 4 | 4 | 8 | * +------------+---------------+------------------+----------------+ */ /* index1 -> E0, index14 -> ED */ static const int8_t _df_ee_tbl[] = { 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, }; /* index1 -> F0, index5 -> F4 */ static const int8_t _ef_fe_tbl[] = { 0, 3, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, }; #define RET_ERR_IDX 0 /* Define 1 to return index of first error char */ 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); } static inline __m256i push_last_3bytes_of_a_to_b(__m256i a, __m256i b) { return _mm256_alignr_epi8(b, _mm256_permute2x128_si256(a, b, 0x21), 13); } /* 5x faster than naive method */ /* Return 0 - success, -1 - error, >0 - first error char(if RET_ERR_IDX = 1) */ int utf8_range_avx2(const unsigned char *data, int len) { #if RET_ERR_IDX int err_pos = 1; #endif if (len >= 32) { __m256i prev_input = _mm256_set1_epi8(0); __m256i prev_first_len = _mm256_set1_epi8(0); /* Cached tables */ const __m256i first_len_tbl = _mm256_loadu_si256((const __m256i *)_first_len_tbl); const __m256i first_range_tbl = _mm256_loadu_si256((const __m256i *)_first_range_tbl); const __m256i range_min_tbl = _mm256_loadu_si256((const __m256i *)_range_min_tbl); const __m256i range_max_tbl = _mm256_loadu_si256((const __m256i *)_range_max_tbl); const __m256i df_ee_tbl = _mm256_loadu_si256((const __m256i *)_df_ee_tbl); const __m256i ef_fe_tbl = _mm256_loadu_si256((const __m256i *)_ef_fe_tbl); #if !RET_ERR_IDX __m256i error1 = _mm256_set1_epi8(0); __m256i error2 = _mm256_set1_epi8(0); #endif while (len >= 32) { const __m256i input = _mm256_loadu_si256((const __m256i *)data); /* high_nibbles = input >> 4 */ const __m256i high_nibbles = _mm256_and_si256(_mm256_srli_epi16(input, 4), _mm256_set1_epi8(0x0F)); /* first_len = legal character length minus 1 */ /* 0 for 00~7F, 1 for C0~DF, 2 for E0~EF, 3 for F0~FF */ /* first_len = first_len_tbl[high_nibbles] */ __m256i first_len = _mm256_shuffle_epi8(first_len_tbl, high_nibbles); /* First Byte: set range index to 8 for bytes within 0xC0 ~ 0xFF */ /* range = first_range_tbl[high_nibbles] */ __m256i range = _mm256_shuffle_epi8(first_range_tbl, high_nibbles); /* Second Byte: set range index to first_len */ /* 0 for 00~7F, 1 for C0~DF, 2 for E0~EF, 3 for F0~FF */ /* range |= (first_len, prev_first_len) << 1 byte */ range = _mm256_or_si256( range, push_last_byte_of_a_to_b(prev_first_len, first_len)); /* Third Byte: set range index to saturate_sub(first_len, 1) */ /* 0 for 00~7F, 0 for C0~DF, 1 for E0~EF, 2 for F0~FF */ __m256i tmp1, tmp2; /* tmp1 = (first_len, prev_first_len) << 2 bytes */ tmp1 = push_last_2bytes_of_a_to_b(prev_first_len, first_len); /* tmp2 = saturate_sub(tmp1, 1) */ tmp2 = _mm256_subs_epu8(tmp1, _mm256_set1_epi8(1)); /* range |= tmp2 */ range = _mm256_or_si256(range, tmp2); /* Fourth Byte: set range index to saturate_sub(first_len, 2) */ /* 0 for 00~7F, 0 for C0~DF, 0 for E0~EF, 1 for F0~FF */ /* tmp1 = (first_len, prev_first_len) << 3 bytes */ tmp1 = push_last_3bytes_of_a_to_b(prev_first_len, first_len); /* tmp2 = saturate_sub(tmp1, 2) */ tmp2 = _mm256_subs_epu8(tmp1, _mm256_set1_epi8(2)); /* range |= tmp2 */ range = _mm256_or_si256(range, tmp2); /* * Now we have below range indices caluclated * Correct cases: * - 8 for C0~FF * - 3 for 1st byte after F0~FF * - 2 for 1st byte after E0~EF or 2nd byte after F0~FF * - 1 for 1st byte after C0~DF or 2nd byte after E0~EF or * 3rd byte after F0~FF * - 0 for others * Error cases: * 9,10,11 if non ascii First Byte overlaps * E.g., F1 80 C2 90 --> 8 3 10 2, where 10 indicates error */ /* Adjust Second Byte range for special First Bytes(E0,ED,F0,F4) */ /* Overlaps lead to index 9~15, which are illegal in range table */ __m256i shift1, pos, range2; /* shift1 = (input, prev_input) << 1 byte */ shift1 = push_last_byte_of_a_to_b(prev_input, input); pos = _mm256_sub_epi8(shift1, _mm256_set1_epi8(0xEF)); /* * shift1: | EF F0 ... FE | FF 00 ... ... DE | DF E0 ... EE | * pos: | 0 1 15 | 16 17 239| 240 241 255| * pos-240: | 0 0 0 | 0 0 0 | 0 1 15 | * pos+112: | 112 113 127| >= 128 | >= 128 | */ tmp1 = _mm256_subs_epu8(pos, _mm256_set1_epi8(240)); range2 = _mm256_shuffle_epi8(df_ee_tbl, tmp1); tmp2 = _mm256_adds_epu8(pos, _mm256_set1_epi8(112)); range2 = _mm256_add_epi8(range2, _mm256_shuffle_epi8(ef_fe_tbl, tmp2)); range = _mm256_add_epi8(range, range2); /* Load min and max values per calculated range index */ __m256i minv = _mm256_shuffle_epi8(range_min_tbl, range); __m256i maxv = _mm256_shuffle_epi8(range_max_tbl, range); /* Check value range */ #if RET_ERR_IDX __m256i error = _mm256_cmpgt_epi8(minv, input); error = _mm256_or_si256(error, _mm256_cmpgt_epi8(input, maxv)); /* 5% performance drop from this conditional branch */ if (!_mm256_testz_si256(error, error)) break; #else error1 = _mm256_or_si256(error1, _mm256_cmpgt_epi8(minv, input)); error2 = _mm256_or_si256(error2, _mm256_cmpgt_epi8(input, maxv)); #endif prev_input = input; prev_first_len = first_len; data += 32; len -= 32; #if RET_ERR_IDX err_pos += 32; #endif } #if RET_ERR_IDX /* Error in first 16 bytes */ if (err_pos == 1) goto do_naive; #else __m256i error = _mm256_or_si256(error1, error2); if (!_mm256_testz_si256(error, error)) return -1; #endif /* Find previous token (not 80~BF) */ int32_t token4 = _mm256_extract_epi32(prev_input, 7); const int8_t *token = (const int8_t *)&token4; int lookahead = 0; if (token[3] > (int8_t)0xBF) lookahead = 1; else if (token[2] > (int8_t)0xBF) lookahead = 2; else if (token[1] > (int8_t)0xBF) lookahead = 3; data -= lookahead; len += lookahead; #if RET_ERR_IDX err_pos -= lookahead; #endif } /* Check remaining bytes with naive method */ #if RET_ERR_IDX int err_pos2; do_naive: err_pos2 = utf8_naive(data, len); if (err_pos2) return err_pos + err_pos2 - 1; return 0; #else return utf8_naive(data, len); #endif } #endif