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/*
* Copyright (C) 2018 The Android Open Source Project
*
* 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.
*/
#ifndef INCLUDE_PERFETTO_EXT_BASE_STRING_VIEW_H_
#define INCLUDE_PERFETTO_EXT_BASE_STRING_VIEW_H_
#include <string.h>
#include <algorithm>
#include <string>
#include "perfetto/base/build_config.h"
#include "perfetto/base/logging.h"
#include "perfetto/ext/base/hash.h"
namespace perfetto {
namespace base {
// A string-like object that refers to a non-owned piece of memory.
// Strings are internally NOT null terminated.
class StringView {
public:
static constexpr size_t npos = static_cast<size_t>(-1);
StringView() : data_(nullptr), size_(0) {}
StringView(const StringView&) = default;
StringView& operator=(const StringView&) = default;
StringView(const char* data, size_t size) : data_(data), size_(size) {
PERFETTO_DCHECK(size == 0 || data != nullptr);
}
// Allow implicit conversion from any class that has a |data| and |size| field
// and has the kConvertibleToStringView trait (e.g., protozero::ConstChars).
template <typename T, typename = std::enable_if<T::kConvertibleToStringView>>
StringView(const T& x) : StringView(x.data, x.size) {
PERFETTO_DCHECK(x.size == 0 || x.data != nullptr);
}
// Creates a StringView from a null-terminated C string.
// Deliberately not "explicit".
StringView(const char* cstr) : data_(cstr), size_(strlen(cstr)) {
PERFETTO_DCHECK(cstr != nullptr);
}
// This instead has to be explicit, as creating a StringView out of a
// std::string can be subtle.
explicit StringView(const std::string& str)
: data_(str.data()), size_(str.size()) {}
bool empty() const { return size_ == 0; }
size_t size() const { return size_; }
const char* data() const { return data_; }
const char* begin() const { return data_; }
const char* end() const { return data_ + size_; }
char at(size_t pos) const {
PERFETTO_DCHECK(pos < size_);
return data_[pos];
}
size_t find(char c, size_t start_pos = 0) const {
for (size_t i = start_pos; i < size_; ++i) {
if (data_[i] == c)
return i;
}
return npos;
}
size_t find(const StringView& str, size_t start_pos = 0) const {
if (start_pos > size())
return npos;
auto it = std::search(begin() + start_pos, end(), str.begin(), str.end());
size_t pos = static_cast<size_t>(it - begin());
return pos + str.size() <= size() ? pos : npos;
}
size_t find(const char* str, size_t start_pos = 0) const {
return find(StringView(str), start_pos);
}
size_t rfind(char c) const {
for (size_t i = size_; i > 0; --i) {
if (data_[i - 1] == c)
return i - 1;
}
return npos;
}
StringView substr(size_t pos, size_t count = npos) const {
if (pos >= size_)
return StringView("", 0);
size_t rcount = std::min(count, size_ - pos);
return StringView(data_ + pos, rcount);
}
bool CaseInsensitiveEq(const StringView& other) {
if (size() != other.size())
return false;
if (size() == 0)
return true;
#if PERFETTO_BUILDFLAG(PERFETTO_OS_WIN)
return _strnicmp(data(), other.data(), size()) == 0;
#else
return strncasecmp(data(), other.data(), size()) == 0;
#endif
}
std::string ToStdString() const {
return data_ == nullptr ? "" : std::string(data_, size_);
}
uint64_t Hash() const {
base::Hash hasher;
hasher.Update(data_, size_);
return hasher.digest();
}
private:
const char* data_ = nullptr;
size_t size_ = 0;
};
inline bool operator==(const StringView& x, const StringView& y) {
if (x.size() != y.size())
return false;
if (x.size() == 0)
return true;
return memcmp(x.data(), y.data(), x.size()) == 0;
}
inline bool operator!=(const StringView& x, const StringView& y) {
return !(x == y);
}
inline bool operator<(const StringView& x, const StringView& y) {
auto size = std::min(x.size(), y.size());
if (size == 0)
return x.size() < y.size();
int result = memcmp(x.data(), y.data(), size);
return result < 0 || (result == 0 && x.size() < y.size());
}
inline bool operator>=(const StringView& x, const StringView& y) {
return !(x < y);
}
inline bool operator>(const StringView& x, const StringView& y) {
return y < x;
}
inline bool operator<=(const StringView& x, const StringView& y) {
return !(y < x);
}
} // namespace base
} // namespace perfetto
namespace std {
template <>
struct hash<::perfetto::base::StringView> {
size_t operator()(const ::perfetto::base::StringView& sv) const {
return static_cast<size_t>(sv.Hash());
}
};
} // namespace std
#endif // INCLUDE_PERFETTO_EXT_BASE_STRING_VIEW_H_
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