113 lines
3.2 KiB
C++
113 lines
3.2 KiB
C++
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// 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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