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6c8338c252
We are also avoiding potential cache-misses, by avoiding load. name old speed new speed delta BM_Searchcase 3.09GB/s ±13% 3.20GB/s ±16% +3.69% (p=0.039 n=20+17) BM_SearchcaseMedium 1.08GB/s ± 7% 1.04GB/s ±14% ~ (p=0.814 n=16+20) BM_SearchcasePathological 618kB/s ±13% 652kB/s ± 6% +5.55% (p=0.043 n=20+16) BM_Memcasematch 2.43GB/s ± 3% 2.45GB/s ± 3% ~ (p=0.488 n=17+16) BM_MemcasematchMedium 230MB/s ± 8% 261MB/s ±14% +13.77% (p=0.000 n=16+20) BM_MemcasematchPathological 624kB/s ±14% 619kB/s ±14% ~ (p=0.836 n=20+20) PiperOrigin-RevId: 577919033 Change-Id: I31324e04b6a577c582ad630d171d3b41d826f1e4
49 lines
1.6 KiB
C++
49 lines
1.6 KiB
C++
// Copyright 2017 The Abseil Authors.
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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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// https://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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#include "absl/strings/internal/memutil.h"
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#include <cstdlib>
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#include "absl/strings/ascii.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace strings_internal {
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int memcasecmp(const char* s1, const char* s2, size_t len) {
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const unsigned char* us1 = reinterpret_cast<const unsigned char*>(s1);
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const unsigned char* us2 = reinterpret_cast<const unsigned char*>(s2);
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for (size_t i = 0; i < len; i++) {
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unsigned char c1 = us1[i];
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unsigned char c2 = us2[i];
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// If bytes are the same, they will be the same when converted to lower.
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// So we only need to convert if bytes are not equal.
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// NOTE(b/308193381): We do not use `absl::ascii_tolower` here in order
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// to avoid its lookup table and improve performance.
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if (c1 != c2) {
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c1 = c1 >= 'A' && c1 <= 'Z' ? c1 - 'A' + 'a' : c1;
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c2 = c2 >= 'A' && c2 <= 'Z' ? c2 - 'A' + 'a' : c2;
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const int diff = int{c1} - int{c2};
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if (diff != 0) return diff;
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}
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}
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return 0;
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}
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} // namespace strings_internal
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ABSL_NAMESPACE_END
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} // namespace absl
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