mirror of
https://github.com/ii64/sonic.git
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62 lines
No EOL
1.8 KiB
C
62 lines
No EOL
1.8 KiB
C
/*
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* Copyright 2021 ByteDance Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "native.h"
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size_t lspace(const char *sp, size_t nb, size_t p) {
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const char * ss = sp;
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/* seek to `p` */
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sp += p;
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nb -= p;
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/* likely to run into non-spaces within a few characters, try scalar code first */
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#if USE_AVX2
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__m256i space_tab = _mm256_setr_epi8(
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'\x20', 0, 0, 0, 0, 0, 0, 0,
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0, '\x09', '\x0A', 0, 0, '\x0D', 0, 0,
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'\x20', 0, 0, 0, 0, 0, 0, 0,
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0, '\x09', '\x0A', 0, 0, '\x0D', 0, 0
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);
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/* 32-byte loop */
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while (likely(nb >= 32)) {
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__m256i input = _mm256_loadu_si256((__m256i*)sp);
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__m256i shuffle = _mm256_shuffle_epi8(space_tab, input);
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__m256i result = _mm256_cmpeq_epi8(input, shuffle);
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int32_t mask = _mm256_movemask_epi8(result);
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if (mask != -1) {
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return sp - ss + __builtin_ctzll(~(uint64_t)mask);
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}
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sp += 32;
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nb -= 32;
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}
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#endif
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/* remaining bytes, do with scalar code */
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while (nb-- > 0) {
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switch (*sp++) {
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case ' ' : break;
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case '\r' : break;
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case '\n' : break;
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case '\t' : break;
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default : return sp - ss - 1;
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}
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}
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/* all the characters are spaces */
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return sp - ss;
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} |