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// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/strings/internal/memutil.h"
#include <cstdlib>
namespace absl {
namespace strings_internal {
int memcasecmp(const char* s1, const char* s2, size_t len) {
const unsigned char* us1 = reinterpret_cast<const unsigned char*>(s1);
const unsigned char* us2 = reinterpret_cast<const unsigned char*>(s2);
for (size_t i = 0; i < len; i++) {
const int diff =
int{static_cast<unsigned char>(absl::ascii_tolower(us1[i]))} -
int{static_cast<unsigned char>(absl::ascii_tolower(us2[i]))};
if (diff != 0) return diff;
}
return 0;
}
char* memdup(const char* s, size_t slen) {
void* copy;
if ((copy = malloc(slen)) == nullptr) return nullptr;
memcpy(copy, s, slen);
return reinterpret_cast<char*>(copy);
}
char* memrchr(const char* s, int c, size_t slen) {
for (const char* e = s + slen - 1; e >= s; e--) {
if (*e == c) return const_cast<char*>(e);
}
return nullptr;
}
size_t memspn(const char* s, size_t slen, const char* accept) {
const char* p = s;
const char* spanp;
char c, sc;
cont:
c = *p++;
if (slen-- == 0) return p - 1 - s;
for (spanp = accept; (sc = *spanp++) != '\0';)
if (sc == c) goto cont;
return p - 1 - s;
}
size_t memcspn(const char* s, size_t slen, const char* reject) {
const char* p = s;
const char* spanp;
char c, sc;
while (slen-- != 0) {
c = *p++;
for (spanp = reject; (sc = *spanp++) != '\0';)
if (sc == c) return p - 1 - s;
}
return p - s;
}
char* mempbrk(const char* s, size_t slen, const char* accept) {
const char* scanp;
int sc;
for (; slen; ++s, --slen) {
for (scanp = accept; (sc = *scanp++) != '\0';)
if (sc == *s) return const_cast<char*>(s);
}
return nullptr;
}
// This is significantly faster for case-sensitive matches with very
// few possible matches. See unit test for benchmarks.
const char* memmatch(const char* phaystack, size_t haylen, const char* pneedle,
size_t neelen) {
if (0 == neelen) {
return phaystack; // even if haylen is 0
}
if (haylen < neelen) return nullptr;
const char* match;
const char* hayend = phaystack + haylen - neelen + 1;
// A static cast is used here to work around the fact that memchr returns
// a void* on Posix-compliant systems and const void* on Windows.
while ((match = static_cast<const char*>(
memchr(phaystack, pneedle[0], hayend - phaystack)))) {
if (memcmp(match, pneedle, neelen) == 0)
return match;
else
phaystack = match + 1;
}
return nullptr;
}
} // namespace strings_internal
} // namespace absl
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