tvl-depot/absl/strings/internal/memutil.h
Abseil Team 12bc53e031 Export of internal Abseil changes
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c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>:

Remove a floating point division by zero test.

This isn't testing behavior related to the library, and MSVC warns
about it in opt mode.

PiperOrigin-RevId: 285220804

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68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>:

This CL introduces following changes to the class FlagImpl:
* We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately.
* CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now.
* Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call.
* We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced.

PiperOrigin-RevId: 285132636

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ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>:

Change null-term* (and nul-term*) to NUL-term* in comments

PiperOrigin-RevId: 285036610

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729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>:

Use the Posix implementation of thread identity on MinGW.
Some versions of MinGW suffer from thread_local bugs.

PiperOrigin-RevId: 285022920

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39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>:

Implementation detail change.

Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil.

PiperOrigin-RevId: 285012012
GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c
Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
2019-12-12 15:37:13 -05:00

148 lines
5.6 KiB
C++

//
// 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
//
// https://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.
//
// These routines provide mem versions of standard C string routines,
// such as strpbrk. They function exactly the same as the str versions,
// so if you wonder what they are, replace the word "mem" by
// "str" and check out the man page. I could return void*, as the
// strutil.h mem*() routines tend to do, but I return char* instead
// since this is by far the most common way these functions are called.
//
// The difference between the mem and str versions is the mem version
// takes a pointer and a length, rather than a '\0'-terminated string.
// The memcase* routines defined here assume the locale is "C"
// (they use absl::ascii_tolower instead of tolower).
//
// These routines are based on the BSD library.
//
// Here's a list of routines from string.h, and their mem analogues.
// Functions in lowercase are defined in string.h; those in UPPERCASE
// are defined here:
//
// strlen --
// strcat strncat MEMCAT
// strcpy strncpy memcpy
// -- memccpy (very cool function, btw)
// -- memmove
// -- memset
// strcmp strncmp memcmp
// strcasecmp strncasecmp MEMCASECMP
// strchr memchr
// strcoll --
// strxfrm --
// strdup strndup MEMDUP
// strrchr MEMRCHR
// strspn MEMSPN
// strcspn MEMCSPN
// strpbrk MEMPBRK
// strstr MEMSTR MEMMEM
// (g)strcasestr MEMCASESTR MEMCASEMEM
// strtok --
// strprefix MEMPREFIX (strprefix is from strutil.h)
// strcaseprefix MEMCASEPREFIX (strcaseprefix is from strutil.h)
// strsuffix MEMSUFFIX (strsuffix is from strutil.h)
// strcasesuffix MEMCASESUFFIX (strcasesuffix is from strutil.h)
// -- MEMIS
// -- MEMCASEIS
// strcount MEMCOUNT (strcount is from strutil.h)
#ifndef ABSL_STRINGS_INTERNAL_MEMUTIL_H_
#define ABSL_STRINGS_INTERNAL_MEMUTIL_H_
#include <cstddef>
#include <cstring>
#include "absl/base/port.h" // disable some warnings on Windows
#include "absl/strings/ascii.h" // for absl::ascii_tolower
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace strings_internal {
inline char* memcat(char* dest, size_t destlen, const char* src,
size_t srclen) {
return reinterpret_cast<char*>(memcpy(dest + destlen, src, srclen));
}
int memcasecmp(const char* s1, const char* s2, size_t len);
char* memdup(const char* s, size_t slen);
char* memrchr(const char* s, int c, size_t slen);
size_t memspn(const char* s, size_t slen, const char* accept);
size_t memcspn(const char* s, size_t slen, const char* reject);
char* mempbrk(const char* s, size_t slen, const char* accept);
// This is for internal use only. Don't call this directly
template <bool case_sensitive>
const char* int_memmatch(const char* haystack, size_t haylen,
const char* needle, size_t neelen) {
if (0 == neelen) {
return haystack; // even if haylen is 0
}
const char* hayend = haystack + haylen;
const char* needlestart = needle;
const char* needleend = needlestart + neelen;
for (; haystack < hayend; ++haystack) {
char hay = case_sensitive
? *haystack
: absl::ascii_tolower(static_cast<unsigned char>(*haystack));
char nee = case_sensitive
? *needle
: absl::ascii_tolower(static_cast<unsigned char>(*needle));
if (hay == nee) {
if (++needle == needleend) {
return haystack + 1 - neelen;
}
} else if (needle != needlestart) {
// must back up haystack in case a prefix matched (find "aab" in "aaab")
haystack -= needle - needlestart; // for loop will advance one more
needle = needlestart;
}
}
return nullptr;
}
// These are the guys you can call directly
inline const char* memstr(const char* phaystack, size_t haylen,
const char* pneedle) {
return int_memmatch<true>(phaystack, haylen, pneedle, strlen(pneedle));
}
inline const char* memcasestr(const char* phaystack, size_t haylen,
const char* pneedle) {
return int_memmatch<false>(phaystack, haylen, pneedle, strlen(pneedle));
}
inline const char* memmem(const char* phaystack, size_t haylen,
const char* pneedle, size_t needlelen) {
return int_memmatch<true>(phaystack, haylen, pneedle, needlelen);
}
inline const char* memcasemem(const char* phaystack, size_t haylen,
const char* pneedle, size_t needlelen) {
return int_memmatch<false>(phaystack, haylen, pneedle, needlelen);
}
// 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);
} // namespace strings_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_MEMUTIL_H_