Protocol Buffers - Google's data interchange format (grpc依赖)
https://developers.google.com/protocol-buffers/
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255 lines
9.1 KiB
255 lines
9.1 KiB
#ifdef __x86_64__ |
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#include <stdio.h> |
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#include <stdint.h> |
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#include <x86intrin.h> |
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int utf8_naive(const unsigned char *data, int len); |
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#if 0 |
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static void print128(const char *s, const __m128i v128) |
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{ |
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const unsigned char *v8 = (const unsigned char *)&v128; |
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if (s) |
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printf("%s:\t", s); |
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for (int i = 0; i < 16; i++) |
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printf("%02x ", v8[i]); |
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printf("\n"); |
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} |
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#endif |
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/* |
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* Map high nibble of "First Byte" to legal character length minus 1 |
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* 0x00 ~ 0xBF --> 0 |
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* 0xC0 ~ 0xDF --> 1 |
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* 0xE0 ~ 0xEF --> 2 |
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* 0xF0 ~ 0xFF --> 3 |
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*/ |
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static const int8_t _first_len_tbl[] = { |
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, |
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}; |
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/* Map "First Byte" to 8-th item of range table (0xC2 ~ 0xF4) */ |
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static const int8_t _first_range_tbl[] = { |
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 8, 8, 8, |
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}; |
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/* |
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* Range table, map range index to min and max values |
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* Index 0 : 00 ~ 7F (First Byte, ascii) |
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* Index 1,2,3: 80 ~ BF (Second, Third, Fourth Byte) |
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* Index 4 : A0 ~ BF (Second Byte after E0) |
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* Index 5 : 80 ~ 9F (Second Byte after ED) |
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* Index 6 : 90 ~ BF (Second Byte after F0) |
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* Index 7 : 80 ~ 8F (Second Byte after F4) |
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* Index 8 : C2 ~ F4 (First Byte, non ascii) |
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* Index 9~15 : illegal: i >= 127 && i <= -128 |
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*/ |
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static const int8_t _range_min_tbl[] = { |
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0x00, 0x80, 0x80, 0x80, 0xA0, 0x80, 0x90, 0x80, |
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0xC2, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, 0x7F, |
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}; |
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static const int8_t _range_max_tbl[] = { |
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0x7F, 0xBF, 0xBF, 0xBF, 0xBF, 0x9F, 0xBF, 0x8F, |
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0xF4, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, |
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}; |
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/* |
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* Tables for fast handling of four special First Bytes(E0,ED,F0,F4), after |
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* which the Second Byte are not 80~BF. It contains "range index adjustment". |
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* +------------+---------------+------------------+----------------+ |
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* | First Byte | original range| range adjustment | adjusted range | |
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* +------------+---------------+------------------+----------------+ |
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* | E0 | 2 | 2 | 4 | |
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* +------------+---------------+------------------+----------------+ |
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* | ED | 2 | 3 | 5 | |
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* +------------+---------------+------------------+----------------+ |
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* | F0 | 3 | 3 | 6 | |
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* +------------+---------------+------------------+----------------+ |
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* | F4 | 4 | 4 | 8 | |
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* +------------+---------------+------------------+----------------+ |
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*/ |
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/* index1 -> E0, index14 -> ED */ |
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static const int8_t _df_ee_tbl[] = { |
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0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, |
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}; |
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/* index1 -> F0, index5 -> F4 */ |
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static const int8_t _ef_fe_tbl[] = { |
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0, 3, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
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}; |
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#define RET_ERR_IDX 0 /* Define 1 to return index of first error char */ |
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/* 5x faster than naive method */ |
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/* Return 0 - success, -1 - error, >0 - first error char(if RET_ERR_IDX = 1) */ |
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int utf8_range(const unsigned char *data, int len) |
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{ |
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#if RET_ERR_IDX |
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int err_pos = 1; |
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#endif |
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if (len >= 16) { |
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__m128i prev_input = _mm_set1_epi8(0); |
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__m128i prev_first_len = _mm_set1_epi8(0); |
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/* Cached tables */ |
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const __m128i first_len_tbl = |
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_mm_loadu_si128((const __m128i *)_first_len_tbl); |
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const __m128i first_range_tbl = |
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_mm_loadu_si128((const __m128i *)_first_range_tbl); |
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const __m128i range_min_tbl = |
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_mm_loadu_si128((const __m128i *)_range_min_tbl); |
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const __m128i range_max_tbl = |
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_mm_loadu_si128((const __m128i *)_range_max_tbl); |
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const __m128i df_ee_tbl = |
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_mm_loadu_si128((const __m128i *)_df_ee_tbl); |
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const __m128i ef_fe_tbl = |
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_mm_loadu_si128((const __m128i *)_ef_fe_tbl); |
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__m128i error = _mm_set1_epi8(0); |
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while (len >= 16) { |
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const __m128i input = _mm_loadu_si128((const __m128i *)data); |
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/* high_nibbles = input >> 4 */ |
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const __m128i high_nibbles = |
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_mm_and_si128(_mm_srli_epi16(input, 4), _mm_set1_epi8(0x0F)); |
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/* first_len = legal character length minus 1 */ |
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/* 0 for 00~7F, 1 for C0~DF, 2 for E0~EF, 3 for F0~FF */ |
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/* first_len = first_len_tbl[high_nibbles] */ |
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__m128i first_len = _mm_shuffle_epi8(first_len_tbl, high_nibbles); |
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/* First Byte: set range index to 8 for bytes within 0xC0 ~ 0xFF */ |
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/* range = first_range_tbl[high_nibbles] */ |
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__m128i range = _mm_shuffle_epi8(first_range_tbl, high_nibbles); |
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/* Second Byte: set range index to first_len */ |
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/* 0 for 00~7F, 1 for C0~DF, 2 for E0~EF, 3 for F0~FF */ |
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/* range |= (first_len, prev_first_len) << 1 byte */ |
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range = _mm_or_si128( |
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range, _mm_alignr_epi8(first_len, prev_first_len, 15)); |
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/* Third Byte: set range index to saturate_sub(first_len, 1) */ |
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/* 0 for 00~7F, 0 for C0~DF, 1 for E0~EF, 2 for F0~FF */ |
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__m128i tmp; |
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/* tmp = (first_len, prev_first_len) << 2 bytes */ |
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tmp = _mm_alignr_epi8(first_len, prev_first_len, 14); |
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/* tmp = saturate_sub(tmp, 1) */ |
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tmp = _mm_subs_epu8(tmp, _mm_set1_epi8(1)); |
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/* range |= tmp */ |
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range = _mm_or_si128(range, tmp); |
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/* Fourth Byte: set range index to saturate_sub(first_len, 2) */ |
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/* 0 for 00~7F, 0 for C0~DF, 0 for E0~EF, 1 for F0~FF */ |
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/* tmp = (first_len, prev_first_len) << 3 bytes */ |
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tmp = _mm_alignr_epi8(first_len, prev_first_len, 13); |
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/* tmp = saturate_sub(tmp, 2) */ |
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tmp = _mm_subs_epu8(tmp, _mm_set1_epi8(2)); |
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/* range |= tmp */ |
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range = _mm_or_si128(range, tmp); |
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/* |
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* Now we have below range indices calculated |
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* Correct cases: |
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* - 8 for C0~FF |
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* - 3 for 1st byte after F0~FF |
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* - 2 for 1st byte after E0~EF or 2nd byte after F0~FF |
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* - 1 for 1st byte after C0~DF or 2nd byte after E0~EF or |
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* 3rd byte after F0~FF |
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* - 0 for others |
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* Error cases: |
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* 9,10,11 if non ascii First Byte overlaps |
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* E.g., F1 80 C2 90 --> 8 3 10 2, where 10 indicates error |
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*/ |
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/* Adjust Second Byte range for special First Bytes(E0,ED,F0,F4) */ |
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/* Overlaps lead to index 9~15, which are illegal in range table */ |
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__m128i shift1, pos, range2; |
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/* shift1 = (input, prev_input) << 1 byte */ |
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shift1 = _mm_alignr_epi8(input, prev_input, 15); |
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pos = _mm_sub_epi8(shift1, _mm_set1_epi8(0xEF)); |
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/* |
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* shift1: | EF F0 ... FE | FF 00 ... ... DE | DF E0 ... EE | |
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* pos: | 0 1 15 | 16 17 239| 240 241 255| |
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* pos-240: | 0 0 0 | 0 0 0 | 0 1 15 | |
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* pos+112: | 112 113 127| >= 128 | >= 128 | |
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*/ |
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tmp = _mm_subs_epu8(pos, _mm_set1_epi8(0xF0)); |
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range2 = _mm_shuffle_epi8(df_ee_tbl, tmp); |
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tmp = _mm_adds_epu8(pos, _mm_set1_epi8(0x70)); |
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range2 = _mm_add_epi8(range2, _mm_shuffle_epi8(ef_fe_tbl, tmp)); |
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range = _mm_add_epi8(range, range2); |
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/* Load min and max values per calculated range index */ |
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__m128i minv = _mm_shuffle_epi8(range_min_tbl, range); |
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__m128i maxv = _mm_shuffle_epi8(range_max_tbl, range); |
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/* Check value range */ |
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#if RET_ERR_IDX |
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error = _mm_cmplt_epi8(input, minv); |
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error = _mm_or_si128(error, _mm_cmpgt_epi8(input, maxv)); |
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/* 5% performance drop from this conditional branch */ |
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if (!_mm_testz_si128(error, error)) |
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break; |
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#else |
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/* error |= (input < minv) | (input > maxv) */ |
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tmp = _mm_or_si128( |
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_mm_cmplt_epi8(input, minv), |
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_mm_cmpgt_epi8(input, maxv) |
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); |
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error = _mm_or_si128(error, tmp); |
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#endif |
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prev_input = input; |
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prev_first_len = first_len; |
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data += 16; |
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len -= 16; |
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#if RET_ERR_IDX |
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err_pos += 16; |
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#endif |
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} |
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#if RET_ERR_IDX |
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/* Error in first 16 bytes */ |
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if (err_pos == 1) |
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goto do_naive; |
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#else |
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if (!_mm_testz_si128(error, error)) |
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return -1; |
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#endif |
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/* Find previous token (not 80~BF) */ |
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int32_t token4 = _mm_extract_epi32(prev_input, 3); |
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const int8_t *token = (const int8_t *)&token4; |
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int lookahead = 0; |
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if (token[3] > (int8_t)0xBF) |
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lookahead = 1; |
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else if (token[2] > (int8_t)0xBF) |
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lookahead = 2; |
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else if (token[1] > (int8_t)0xBF) |
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lookahead = 3; |
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data -= lookahead; |
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len += lookahead; |
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#if RET_ERR_IDX |
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err_pos -= lookahead; |
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#endif |
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} |
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/* Check remaining bytes with naive method */ |
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#if RET_ERR_IDX |
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int err_pos2; |
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do_naive: |
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err_pos2 = utf8_naive(data, len); |
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if (err_pos2) |
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return err_pos + err_pos2 - 1; |
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return 0; |
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#else |
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return utf8_naive(data, len); |
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#endif |
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} |
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#endif
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