Abseil Common Libraries (C++) (grcp 依赖)
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112 lines
3.2 KiB
112 lines
3.2 KiB
// 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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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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const int diff = |
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int{static_cast<unsigned char>(absl::ascii_tolower(us1[i]))} - |
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int{static_cast<unsigned char>(absl::ascii_tolower(us2[i]))}; |
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if (diff != 0) return diff; |
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} |
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return 0; |
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} |
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char* memdup(const char* s, size_t slen) { |
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void* copy; |
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if ((copy = malloc(slen)) == nullptr) return nullptr; |
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memcpy(copy, s, slen); |
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return reinterpret_cast<char*>(copy); |
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} |
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char* memrchr(const char* s, int c, size_t slen) { |
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for (const char* e = s + slen - 1; e >= s; e--) { |
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if (*e == c) return const_cast<char*>(e); |
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} |
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return nullptr; |
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} |
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size_t memspn(const char* s, size_t slen, const char* accept) { |
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const char* p = s; |
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const char* spanp; |
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char c, sc; |
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cont: |
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c = *p++; |
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if (slen-- == 0) return p - 1 - s; |
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for (spanp = accept; (sc = *spanp++) != '\0';) |
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if (sc == c) goto cont; |
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return p - 1 - s; |
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} |
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size_t memcspn(const char* s, size_t slen, const char* reject) { |
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const char* p = s; |
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const char* spanp; |
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char c, sc; |
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while (slen-- != 0) { |
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c = *p++; |
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for (spanp = reject; (sc = *spanp++) != '\0';) |
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if (sc == c) return p - 1 - s; |
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} |
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return p - s; |
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} |
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char* mempbrk(const char* s, size_t slen, const char* accept) { |
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const char* scanp; |
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int sc; |
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for (; slen; ++s, --slen) { |
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for (scanp = accept; (sc = *scanp++) != '\0';) |
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if (sc == *s) return const_cast<char*>(s); |
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} |
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return nullptr; |
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} |
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// This is significantly faster for case-sensitive matches with very |
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// few possible matches. See unit test for benchmarks. |
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const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle, |
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size_t neelen) { |
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if (0 == neelen) { |
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return phaystack; // even if haylen is 0 |
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} |
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if (haylen < neelen) return nullptr; |
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const char* match; |
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const char* hayend = phaystack + haylen - neelen + 1; |
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// A static cast is used here to work around the fact that memchr returns |
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// a void* on Posix-compliant systems and const void* on Windows. |
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while ((match = static_cast<const char*>( |
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memchr(phaystack, pneedle[0], hayend - phaystack)))) { |
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if (memcmp(match, pneedle, neelen) == 0) |
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return match; |
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else |
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phaystack = match + 1; |
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} |
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return nullptr; |
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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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