FaceAccess/VocieProcess/rtc_base/string_utils.h

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2024-09-05 09:59:28 +08:00
/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_STRING_UTILS_H_
#define RTC_BASE_STRING_UTILS_H_
#include <stdio.h>
#include <string.h>
#include "absl/strings/string_view.h"
#if defined(WEBRTC_WIN)
#include <malloc.h>
#include <wchar.h>
#include <windows.h>
#endif // WEBRTC_WIN
#if defined(WEBRTC_POSIX)
#include <stdlib.h>
#include <strings.h>
#endif // WEBRTC_POSIX
#include <string>
#include "absl/strings/string_view.h"
namespace rtc {
const size_t SIZE_UNKNOWN = static_cast<size_t>(-1);
// An absl::string_view comparator functor for use with container types such as
// std::map that support heterogenous lookup.
//
// Example usage:
// std::map<std::string, int, rtc::AbslStringViewCmp> my_map;
struct AbslStringViewCmp {
using is_transparent = void;
bool operator()(absl::string_view a, absl::string_view b) const {
return a < b;
}
};
// Safe version of strncpy that always nul-terminate.
size_t strcpyn(char* buffer, size_t buflen, absl::string_view source);
///////////////////////////////////////////////////////////////////////////////
// UTF helpers (Windows only)
///////////////////////////////////////////////////////////////////////////////
#if defined(WEBRTC_WIN)
inline std::wstring ToUtf16(const char* utf8, size_t len) {
if (len == 0)
return std::wstring();
int len16 = ::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len),
nullptr, 0);
std::wstring ws(len16, 0);
::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len), &*ws.begin(),
len16);
return ws;
}
inline std::wstring ToUtf16(absl::string_view str) {
return ToUtf16(str.data(), str.length());
}
inline std::string ToUtf8(const wchar_t* wide, size_t len) {
if (len == 0)
return std::string();
int len8 = ::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len),
nullptr, 0, nullptr, nullptr);
std::string ns(len8, 0);
::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len), &*ns.begin(),
len8, nullptr, nullptr);
return ns;
}
inline std::string ToUtf8(const wchar_t* wide) {
return ToUtf8(wide, wcslen(wide));
}
inline std::string ToUtf8(const std::wstring& wstr) {
return ToUtf8(wstr.data(), wstr.length());
}
#endif // WEBRTC_WIN
// TODO(jonasolsson): replace with absl::Hex when that becomes available.
std::string ToHex(int i);
// CompileTimeString comprises of a string-like object which can be used as a
// regular const char* in compile time and supports concatenation. Useful for
// concatenating constexpr strings in for example macro declarations.
namespace rtc_base_string_utils_internal {
template <int NPlus1>
struct CompileTimeString {
char string[NPlus1] = {0};
constexpr CompileTimeString() = default;
template <int MPlus1>
explicit constexpr CompileTimeString(const char (&chars)[MPlus1]) {
char* chars_pointer = string;
for (auto c : chars)
*chars_pointer++ = c;
}
template <int MPlus1>
constexpr auto Concat(CompileTimeString<MPlus1> b) {
CompileTimeString<NPlus1 + MPlus1 - 1> result;
char* chars_pointer = result.string;
for (auto c : string)
*chars_pointer++ = c;
chars_pointer = result.string + NPlus1 - 1;
for (auto c : b.string)
*chars_pointer++ = c;
result.string[NPlus1 + MPlus1 - 2] = 0;
return result;
}
constexpr operator const char*() { return string; }
};
} // namespace rtc_base_string_utils_internal
// Makes a constexpr CompileTimeString<X> without having to specify X
// explicitly.
template <int N>
constexpr auto MakeCompileTimeString(const char (&a)[N]) {
return rtc_base_string_utils_internal::CompileTimeString<N>(a);
}
} // namespace rtc
#endif // RTC_BASE_STRING_UTILS_H_