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Make string_view a full std::string_view implementation 

Adds the missing pieces plus adds a test script.
This commit is contained in:
Jason Rhinelander 2020-02-22 21:57:32 -04:00
parent 03827ac1f7
commit da96c1ec79
2 changed files with 133 additions and 2 deletions
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134
lokimq/string_view.h
View File

@ -38,26 +38,50 @@ namespace lokimq { using string_view = std::string_view; }
#else
#include <ostream>
#include <limits>
namespace lokimq {
/// Basic implementation of a subset of std::string_view (enough for what we need in lokimq)
/// Basic implementation of std::string_view (except for std::hash support).
class simple_string_view {
const char *data_;
size_t size_;
public:
using traits_type = std::char_traits<char>;
using value_type = char;
using pointer = char*;
using const_pointer = const char*;
using reference = char&;
using const_reference = const char&;
using const_iterator = const_pointer;
using iterator = const_iterator;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using reverse_iterator = const_reverse_iterator;
using size_type = std::size_t;
using different_type = std::ptrdiff_t;
static constexpr auto& npos = std::string::npos;
constexpr simple_string_view() noexcept : data_{nullptr}, size_{0} {}
constexpr simple_string_view(const simple_string_view&) noexcept = default;
simple_string_view(const std::string& str) : data_{str.data()}, size_{str.size()} {}
constexpr simple_string_view(const char* data, size_t size) noexcept : data_{data}, size_{size} {}
simple_string_view(const char* data) : data_{data}, size_{std::char_traits<char>::length(data)} {}
simple_string_view(const char* data) : data_{data}, size_{traits_type::length(data)} {}
simple_string_view& operator=(const simple_string_view&) = default;
constexpr const char* data() const noexcept { return data_; }
constexpr size_t size() const noexcept { return size_; }
constexpr size_t length() const noexcept { return size_; }
constexpr size_t max_size() const noexcept { return std::numeric_limits<size_t>::max(); }
constexpr bool empty() const noexcept { return size_ == 0; }
operator std::string() const { return {data_, size_}; }
const char* begin() const noexcept { return data_; }
const char* cbegin() const noexcept { return data_; }
const char* end() const noexcept { return data_ + size_; }
const char* cend() const noexcept { return data_ + size_; }
reverse_iterator rbegin() const { return reverse_iterator{end()}; }
reverse_iterator crbegin() const { return reverse_iterator{end()}; }
reverse_iterator rend() const { return reverse_iterator{begin()}; }
reverse_iterator crend() const { return reverse_iterator{begin()}; }
constexpr const char& operator[](size_t pos) const { return data_[pos]; }
constexpr const char& front() const { return *data_; }
constexpr const char& back() const { return data_[size_ - 1]; }
@ -65,6 +89,112 @@ public:
constexpr void remove_prefix(size_t n) { data_ += n; size_ -= n; }
constexpr void remove_suffix(size_t n) { size_ -= n; }
void swap(simple_string_view &s) noexcept { std::swap(data_, s.data_); std::swap(size_, s.size_); }
constexpr const char& at(size_t pos) const {
if (pos >= size())
throw std::out_of_range{"invalid string_view index"};
return data_[pos];
};
size_t copy(char* dest, size_t count, size_t pos = 0) const {
if (pos > size()) throw std::out_of_range{"invalid copy pos"};
size_t rcount = std::min(count, size_ - pos);
traits_type::copy(dest, data_ + pos, rcount);
return rcount;
}
constexpr simple_string_view substr(size_t pos = 0, size_t count = npos) const {
if (pos > size()) throw std::out_of_range{"invalid substr range"};
simple_string_view result = *this;
if (pos > 0) result.remove_prefix(pos);
if (count < result.size()) result.remove_suffix(result.size() - count);
return result;
}
constexpr size_t find(simple_string_view v, size_t pos = 0) const noexcept {
if (pos > size_ || v.size_ > size_) return npos;
for (const size_t max_pos = size_ - v.size_; pos <= max_pos; ++pos) {
if (0 == traits_type::compare(v.data_, data_ + pos, v.size_))
return pos;
}
return npos;
}
constexpr size_t find(char c, size_t pos = 0) const noexcept { return find({&c, 1}, pos); }
constexpr size_t find(const char* c, size_t pos, size_t count) const { return find({c, count}, pos); }
size_t find(const char* c, size_t pos = 0) const { return find(simple_string_view(c), pos); }
constexpr size_t rfind(simple_string_view v, size_t pos = npos) const noexcept {
if (v.size_ > size_) return npos;
const size_t max_pos = size_ - v.size_;
for (pos = std::min(pos, max_pos); pos <= max_pos; --pos) {
if (0 == traits_type::compare(v.data_, data_ + pos, v.size_))
return pos;
}
return npos;
}
constexpr size_t rfind(char c, size_t pos = npos) const noexcept { return rfind({&c, 1}, pos); }
constexpr size_t rfind(const char* c, size_t pos, size_t count) const { return rfind({c, count}, pos); }
size_t rfind(const char* c, size_t pos = npos) const { return rfind(simple_string_view(c), pos); }
constexpr size_t find_first_of(simple_string_view v, size_t pos = 0) const noexcept {
for (; pos < size_; ++pos)
for (char c : v)
if (data_[pos] == c)
return pos;
return npos;
}
constexpr size_t find_first_of(char c, size_t pos = 0) const noexcept { return find_first_of({&c, 1}, pos); }
constexpr size_t find_first_of(const char* c, size_t pos, size_t count) const { return find_first_of({c, count}, pos); }
size_t find_first_of(const char* c, size_t pos = 0) const { return find_first_of(simple_string_view(c), pos); }
constexpr size_t find_last_of(simple_string_view v, const size_t pos = npos) const noexcept {
if (size_ == 0) return npos;
const size_t last_pos = std::min(pos, size_-1);
for (size_t i = last_pos; i <= last_pos; --i)
for (char c : v)
if (data_[i] == c)
return i;
return npos;
}
constexpr size_t find_last_of(char c, size_t pos = npos) const noexcept { return find_last_of({&c, 1}, pos); }
constexpr size_t find_last_of(const char* c, size_t pos, size_t count) const { return find_last_of({c, count}, pos); }
size_t find_last_of(const char* c, size_t pos = npos) const { return find_last_of(simple_string_view(c), pos); }
constexpr size_t find_first_not_of(simple_string_view v, size_t pos = 0) const noexcept {
for (; pos < size_; ++pos) {
bool none = true;
for (char c : v) {
if (data_[pos] == c) {
none = false;
break;
}
}
if (none) return pos;
}
return npos;
}
constexpr size_t find_first_not_of(char c, size_t pos = 0) const noexcept { return find_first_not_of({&c, 1}, pos); }
constexpr size_t find_first_not_of(const char* c, size_t pos, size_t count) const { return find_first_not_of({c, count}, pos); }
size_t find_first_not_of(const char* c, size_t pos = 0) const { return find_first_not_of(simple_string_view(c), pos); }
constexpr size_t find_last_not_of(simple_string_view v, const size_t pos = npos) const noexcept {
if (size_ == 0) return npos;
const size_t last_pos = std::min(pos, size_-1);
for (size_t i = last_pos; i <= last_pos; --i) {
bool none = true;
for (char c : v) {
if (data_[i] == c) {
none = false;
break;
}
}
if (none) return i;
}
return npos;
}
constexpr size_t find_last_not_of(char c, size_t pos = npos) const noexcept { return find_last_not_of({&c, 1}, pos); }
constexpr size_t find_last_not_of(const char* c, size_t pos, size_t count) const { return find_last_not_of({c, count}, pos); }
size_t find_last_not_of(const char* c, size_t pos = npos) const { return find_last_not_of(simple_string_view(c), pos); }
};
inline bool operator==(simple_string_view lhs, simple_string_view rhs) {
return lhs.size() == rhs.size() && 0 == std::char_traits<char>::compare(lhs.data(), rhs.data(), lhs.size());

1
tests/CMakeLists.txt
View File

@ -7,6 +7,7 @@ set(LMQ_TEST_SRC
test_connect.cpp
test_commands.cpp
test_requests.cpp
test_string_view.cpp
)
add_executable(tests ${LMQ_TEST_SRC})