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Diffstat (limited to 'ext/protozero/include/protozero/data_view.hpp')
| -rw-r--r-- | ext/protozero/include/protozero/data_view.hpp | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/ext/protozero/include/protozero/data_view.hpp b/ext/protozero/include/protozero/data_view.hpp new file mode 100644 index 0000000..3ec87af --- /dev/null +++ b/ext/protozero/include/protozero/data_view.hpp @@ -0,0 +1,236 @@ +#ifndef PROTOZERO_DATA_VIEW_HPP +#define PROTOZERO_DATA_VIEW_HPP + +/***************************************************************************** + +protozero - Minimalistic protocol buffer decoder and encoder in C++. + +This file is from https://github.com/mapbox/protozero where you can find more +documentation. + +*****************************************************************************/ + +/** + * @file data_view.hpp + * + * @brief Contains the implementation of the data_view class. + */ + +#include "config.hpp" + +#include <algorithm> +#include <cstddef> +#include <cstring> +#include <string> +#include <utility> + +namespace protozero { + +#ifdef PROTOZERO_USE_VIEW +using data_view = PROTOZERO_USE_VIEW; +#else + +/** + * Holds a pointer to some data and a length. + * + * This class is supposed to be compatible with the std::string_view + * that will be available in C++17. + */ +class data_view { + + const char* m_data = nullptr; + std::size_t m_size = 0; + +public: + + /** + * Default constructor. Construct an empty data_view. + */ + constexpr data_view() noexcept = default; + + /** + * Create data_view from pointer and size. + * + * @param ptr Pointer to the data. + * @param length Length of the data. + */ + constexpr data_view(const char* ptr, std::size_t length) noexcept + : m_data{ptr}, + m_size{length} { + } + + /** + * Create data_view from string. + * + * @param str String with the data. + */ + data_view(const std::string& str) noexcept // NOLINT(google-explicit-constructor, hicpp-explicit-conversions) + : m_data{str.data()}, + m_size{str.size()} { + } + + /** + * Create data_view from zero-terminated string. + * + * @param ptr Pointer to the data. + */ + data_view(const char* ptr) noexcept // NOLINT(google-explicit-constructor, hicpp-explicit-conversions) + : m_data{ptr}, + m_size{std::strlen(ptr)} { + } + + /** + * Swap the contents of this object with the other. + * + * @param other Other object to swap data with. + */ + void swap(data_view& other) noexcept { + using std::swap; + swap(m_data, other.m_data); + swap(m_size, other.m_size); + } + + /// Return pointer to data. + constexpr const char* data() const noexcept { + return m_data; + } + + /// Return length of data in bytes. + constexpr std::size_t size() const noexcept { + return m_size; + } + + /// Returns true if size is 0. + constexpr bool empty() const noexcept { + return m_size == 0; + } + +#ifndef PROTOZERO_STRICT_API + /** + * Convert data view to string. + * + * @pre Must not be default constructed data_view. + * + * @deprecated to_string() is not available in C++17 string_view so it + * should not be used to make conversion to that class easier + * in the future. + */ + std::string to_string() const { + protozero_assert(m_data); + return {m_data, m_size}; + } +#endif + + /** + * Convert data view to string. + * + * @pre Must not be default constructed data_view. + */ + explicit operator std::string() const { + protozero_assert(m_data); + return {m_data, m_size}; + } + + /** + * Compares the contents of this object with the given other object. + * + * @returns 0 if they are the same, <0 if this object is smaller than + * the other or >0 if it is larger. If both objects have the + * same size returns <0 if this object is lexicographically + * before the other, >0 otherwise. + * + * @pre Must not be default constructed data_view. + */ + int compare(data_view other) const noexcept { + assert(m_data && other.m_data); + const int cmp = std::memcmp(data(), other.data(), + std::min(size(), other.size())); + if (cmp == 0) { + if (size() == other.size()) { + return 0; + } + return size() < other.size() ? -1 : 1; + } + return cmp; + } + +}; // class data_view + +/** + * Swap two data_view objects. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline void swap(data_view& lhs, data_view& rhs) noexcept { + lhs.swap(rhs); +} + +/** + * Two data_view instances are equal if they have the same size and the + * same content. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline constexpr bool operator==(const data_view lhs, const data_view rhs) noexcept { + return lhs.size() == rhs.size() && + std::equal(lhs.data(), lhs.data() + lhs.size(), rhs.data()); +} + +/** + * Two data_view instances are not equal if they have different sizes or the + * content differs. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline constexpr bool operator!=(const data_view lhs, const data_view rhs) noexcept { + return !(lhs == rhs); +} + +/** + * Returns true if lhs.compare(rhs) < 0. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline bool operator<(const data_view lhs, const data_view rhs) noexcept { + return lhs.compare(rhs) < 0; +} + +/** + * Returns true if lhs.compare(rhs) <= 0. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline bool operator<=(const data_view lhs, const data_view rhs) noexcept { + return lhs.compare(rhs) <= 0; +} + +/** + * Returns true if lhs.compare(rhs) > 0. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline bool operator>(const data_view lhs, const data_view rhs) noexcept { + return lhs.compare(rhs) > 0; +} + +/** + * Returns true if lhs.compare(rhs) >= 0. + * + * @param lhs First object. + * @param rhs Second object. + */ +inline bool operator>=(const data_view lhs, const data_view rhs) noexcept { + return lhs.compare(rhs) >= 0; +} + +#endif + +} // end namespace protozero + +#endif // PROTOZERO_DATA_VIEW_HPP |