mirror of
https://github.com/boostorg/mqtt5.git
synced 2025-10-04 12:50:54 +02:00
2d957cd46f
Summary: resolves T12767 Reviewers: ivica Reviewed By: ivica Subscribers: miljen Tags: #spacetime Maniphest Tasks: T12767 Differential Revision: https://repo.mireo.local/D25970
493 lines
14 KiB
C++
493 lines
14 KiB
C++
#ifndef ASYNC_MQTT5_BASE_ENCODERS_HPP
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#define ASYNC_MQTT5_BASE_ENCODERS_HPP
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#include <cstddef>
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#include <cstdint>
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#include <boost/endian/conversion.hpp>
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#include <async_mqtt5/property_types.hpp>
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#include <async_mqtt5/impl/internal/codecs/traits.hpp>
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namespace async_mqtt5::encoders {
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namespace basic {
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inline void to_variable_bytes(std::string& s, int32_t val) {
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if (val > 0xfffffff) return;
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while (val > 127) {
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s.push_back(char((val & 0b01111111) | 0b10000000));
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val >>= 7;
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}
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s.push_back(val & 0b01111111);
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}
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inline size_t variable_length(int32_t val) {
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if (val > 0xfffffff) return 0;
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size_t rv = 1;
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for (; val > 127; ++rv) val >>= 7;
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return rv;
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}
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struct encoder {};
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template <size_t bits, typename repr = uint8_t>
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class flag_def : public encoder {
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template <size_t num_bits>
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using least_type = std::conditional_t<
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num_bits <= 8, uint8_t,
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std::conditional_t<
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num_bits <= 16, uint16_t,
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std::conditional_t<
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num_bits <= 32, uint32_t,
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std::conditional_t<num_bits <= 64, uint64_t, void>
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>
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>
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>;
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template <size_t oth_bits, typename oth_repr>
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friend class flag_def;
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repr _val { 0 };
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public:
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flag_def(repr val) : _val(val) {}
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flag_def() = default;
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template <class T, typename projection = std::identity>
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requires (is_optional<T>)
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auto operator()(T&& value, projection proj = {}) const {
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if constexpr (std::is_same_v<projection, std::identity>) {
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repr val = value.has_value();
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return flag_def<bits, repr> { val };
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}
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else {
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repr val = value.has_value() ? static_cast<repr>(std::invoke(proj, *value)) : 0;
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return flag_def<bits, repr> { val };
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}
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}
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template <class T, typename projection = std::identity>
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requires (!is_optional<T>)
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auto operator()(T&& value, projection proj = {}) const {
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auto val = static_cast<repr>(std::invoke(proj, value));
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return flag_def<bits, repr> { val };
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}
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uint16_t byte_size() const { return sizeof(repr); }
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template <size_t rhs_bits, typename rhs_repr>
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auto operator|(const flag_def<rhs_bits, rhs_repr>& rhs) const {
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using res_repr = least_type<bits + rhs_bits>;
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auto val = static_cast<res_repr>((_val << rhs_bits) | rhs._val);
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return flag_def<bits + rhs_bits, res_repr> { val };
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}
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std::string& encode(std::string& s) const {
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using namespace boost::endian;
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size_t sz = s.size(); s.resize(sz + sizeof(repr));
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auto p = reinterpret_cast<uint8_t*>(s.data() + sz);
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endian_store<repr, sizeof(repr), order::big>(p, _val);
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return s;
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}
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};
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template <size_t bits, typename repr = uint8_t>
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constexpr auto flag = flag_def<bits, repr>{};
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template <typename T, typename Repr>
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class int_val : public encoder {
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T _val;
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public:
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int_val(T val) : _val(val) {}
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uint16_t byte_size() const {
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if constexpr (is_optional<T>) {
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if (_val) return uint16_t(val_length(*_val));
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return uint16_t(0);
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}
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else
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return uint16_t(val_length(_val));
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}
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std::string& encode(std::string& s) const {
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if constexpr (is_optional<T>) {
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if (_val) return encode_val(s, *_val);
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return s;
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}
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else
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return encode_val(s, _val);
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}
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private:
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template <typename U>
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static size_t val_length(U&& val) {
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if constexpr (std::is_same_v<Repr, intptr_t>)
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return variable_length(int32_t(val));
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else
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return sizeof(Repr);
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}
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template <typename U>
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static std::string& encode_val(std::string& s, U&& val) {
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using namespace boost::endian;
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if constexpr (std::is_same_v<Repr, intptr_t>) {
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to_variable_bytes(s, int32_t(val));
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return s;
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}
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else {
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size_t sz = s.size(); s.resize(sz + sizeof(Repr));
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auto p = reinterpret_cast<uint8_t*>(s.data() + sz);
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endian_store<Repr, sizeof(Repr), order::big>(p, val);
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return s;
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}
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}
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};
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template <typename Repr>
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class int_def {
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public:
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template <typename T>
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auto operator()(T&& val) const {
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return int_val<T, Repr> { std::forward<T>(val) };
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}
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template <typename T, typename projection>
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auto operator()(T&& val, projection proj) const {
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if constexpr (is_optional<T>) {
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using rv_type = std::invoke_result_t<
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projection, typename std::remove_cvref_t<T>::value_type
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>;
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if (val.has_value())
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return (*this)(std::invoke(proj, *val));
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return int_val<rv_type, Repr> { rv_type {} };
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}
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else {
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using rv_type = std::invoke_result_t<projection, T>;
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return int_val<rv_type, Repr> { std::invoke(proj, val) };
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}
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}
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};
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constexpr auto byte_ = int_def<uint8_t>{};
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constexpr auto int16_ = int_def<uint16_t>{};
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constexpr auto int32_ = int_def<uint32_t>{};
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constexpr auto varlen_ = int_def<intptr_t>{};
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template <typename T>
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class array_val : public encoder {
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T _val;
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bool _with_length;
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public:
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array_val(T val, bool with_length) : _val(val), _with_length(with_length) {
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static_assert(std::is_reference_v<T> || std::is_same_v<T, std::string_view>);
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}
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uint16_t byte_size() const {
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if constexpr (is_optional<T>)
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return uint16_t(_val ? _with_length * 2 + val_length(*_val) : 0);
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else
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return uint16_t(_with_length * 2 + val_length(_val));
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}
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std::string& encode(std::string& s) const {
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if constexpr (is_optional<T>) {
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if (_val) return encode_val(s, *_val);
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return s;
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}
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else
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return encode_val(s, _val);
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}
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private:
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template <typename U>
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static size_t val_length(U&& val) {
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if constexpr (std::same_as<std::remove_cvref_t<U>, const char*>)
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return std::strlen(val);
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if constexpr (requires { val.size(); })
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return val.size();
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else // fallback to type const char (&)[N] (substract 1 for trailing 0)
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return sizeof(val) - 1;
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}
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template <typename U>
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std::string& encode_val(std::string& s, U&& u) const {
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using namespace boost::endian;
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int16_t byte_len = int16_t(val_length(std::forward<U>(u)));
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if (byte_len == 0 && !_with_length) return s;
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if (_with_length) {
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size_t sz = s.size(); s.resize(sz + 2);
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auto p = reinterpret_cast<uint8_t*>(s.data() + sz);
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endian_store<int16_t, sizeof(int16_t), order::big>(p, byte_len);
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}
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s.append(std::begin(u), std::begin(u) + byte_len);
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return s;
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}
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};
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template <bool with_length = true>
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class array_def {
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public:
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template <typename T>
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auto operator()(T&& val) const {
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return array_val<T> { std::forward<T>(val), with_length };
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}
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template <typename T, typename projection>
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auto operator()(T&& val, projection proj) const {
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if constexpr (is_optional<T>) {
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using rv_type = std::invoke_result_t<
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projection, typename std::remove_cvref_t<T>::value_type
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>;
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if (val.has_value())
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return (*this)(std::invoke(proj, *val));
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return array_val<rv_type> { rv_type {}, false };
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}
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else {
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const auto& av = std::invoke(proj, val);
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return array_val<T> { av, true };
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}
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}
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};
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using utf8_def = array_def<true>;
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constexpr auto utf8_ = utf8_def{};
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constexpr auto binary_ = array_def<true>{}; // for now
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constexpr auto verbatim_ = array_def<false>{};
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template <class T, class U>
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class composed_val : public encoder {
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T _lhs; U _rhs;
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public:
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composed_val(T lhs, U rhs) :
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_lhs(std::forward<T>(lhs)), _rhs(std::forward<U>(rhs)) {}
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uint16_t byte_size() const {
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return uint16_t(_lhs.byte_size() + _rhs.byte_size());
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}
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std::string& encode(std::string& s) const {
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_lhs.encode(s);
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return _rhs.encode(s);
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}
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};
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template <class T, class U>
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requires (std::derived_from<std::decay_t<T>, encoder> && std::derived_from<std::decay_t<U>, encoder>)
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inline auto operator&(T&& t, U&& u) {
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return composed_val(std::forward<T>(t), std::forward<U>(u));
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}
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template <class T>
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requires (std::derived_from<std::decay_t<T>, encoder>)
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std::string& operator<<(std::string& s, T&& t) {
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return t.encode(s);
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}
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} // end namespace basic
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namespace detail {
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template <std::integral_constant p, std::size_t I, typename Tuple>
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constexpr bool match_v = std::is_same_v<decltype(p), typename std::tuple_element_t<I, Tuple>::key>;
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template <std::integral_constant p, typename Tuple, typename Idxs = std::make_index_sequence<std::tuple_size_v<Tuple>>>
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struct type_index;
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template <std::integral_constant p, template <typename...> typename Tuple, typename... Args, std::size_t... Is>
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struct type_index<p, Tuple<Args...>, std::index_sequence<Is...>>
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: std::integral_constant<std::size_t, ((Is * match_v<p, Is, Tuple<Args...>>)+... + 0)> {
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static_assert(1 == (match_v<p, Is, Tuple<Args...>> + ... + 0), "T doesn't appear once in tuple");
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};
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} // end namespace detail
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namespace prop {
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namespace pp = async_mqtt5::prop;
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template <std::integral_constant p, typename T>
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struct prop_encoder_type { using key = decltype(p); using value = T; };
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using encoder_types = std::tuple<
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prop_encoder_type<pp::shared_subscription_available, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::payload_format_indicator, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::message_expiry_interval, basic::int_def<int32_t>>,
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prop_encoder_type<pp::content_type, basic::utf8_def>,
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prop_encoder_type<pp::response_topic, basic::utf8_def>,
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prop_encoder_type<pp::correlation_data, basic::utf8_def>,
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prop_encoder_type<pp::subscription_identifier, basic::int_def<intptr_t>>,
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prop_encoder_type<pp::session_expiry_interval, basic::int_def<int32_t>>,
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prop_encoder_type<pp::assigned_client_identifier, basic::utf8_def>,
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prop_encoder_type<pp::server_keep_alive, basic::int_def<int16_t>>,
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prop_encoder_type<pp::authentication_method, basic::utf8_def>,
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prop_encoder_type<pp::authentication_data, basic::utf8_def>,
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prop_encoder_type<pp::request_problem_information, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::will_delay_interval, basic::int_def<int32_t>>,
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prop_encoder_type<pp::request_response_information, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::response_information, basic::utf8_def>,
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prop_encoder_type<pp::server_reference, basic::utf8_def>,
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prop_encoder_type<pp::reason_string, basic::utf8_def>,
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prop_encoder_type<pp::receive_maximum, basic::int_def<int16_t>>,
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prop_encoder_type<pp::topic_alias_maximum, basic::int_def<int16_t>>,
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prop_encoder_type<pp::topic_alias, basic::int_def<int16_t>>,
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prop_encoder_type<pp::maximum_qos, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::retain_available, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::user_property, basic::utf8_def>,
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prop_encoder_type<pp::maximum_packet_size, basic::int_def<int32_t>>,
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prop_encoder_type<pp::wildcard_subscription_available, basic::int_def<uint8_t>>,
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prop_encoder_type<pp::subscription_identifier_available, basic::int_def<uint8_t>>
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>;
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template <std::integral_constant p>
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constexpr auto encoder_for_prop = typename std::tuple_element_t<
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detail::type_index<p, encoder_types>::value, encoder_types
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>::value {};
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template <typename T, std::integral_constant p>
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class prop_val;
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template <typename T, std::integral_constant p>
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requires (!is_vector<T> && is_optional<T>)
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class prop_val<T, p> : public basic::encoder {
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// T is always std::optional
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using opt_type = typename std::remove_cvref_t<T>::value_type;
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// allows T to be reference type to std::optional
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static inline std::optional<opt_type> nulltype;
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T _val;
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public:
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prop_val(T val) : _val(val) {
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static_assert(std::is_reference_v<T>);
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}
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prop_val() : _val(nulltype) {}
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size_t byte_size() const {
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if (!_val) return 0;
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auto sval = encoder_for_prop<p>(_val);
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return 1 + sval.byte_size();
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}
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std::string& encode(std::string& s) const {
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if (!_val)
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return s;
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s.push_back(p());
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auto sval = encoder_for_prop<p>(_val);
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return sval.encode(s);
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}
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};
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template <typename T, std::integral_constant p>
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requires (is_vector<T>)
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class prop_val<T, p> : public basic::encoder {
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// allows T to be reference type to std::vector
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static inline std::remove_cvref_t<T> nulltype;
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T _val;
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public:
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prop_val(T val) : _val(val) {
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static_assert(std::is_reference_v<T>);
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}
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prop_val() : _val(nulltype) { }
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size_t byte_size() const {
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if (_val.empty()) return 0;
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size_t total_size = 0;
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for (const auto& pr: _val) {
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auto sval = encoder_for_prop<p>(pr);
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size_t prop_size = sval.byte_size();
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if (prop_size) total_size += 1 + prop_size;
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}
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return total_size;
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}
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std::string& encode(std::string& s) const {
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if (_val.empty())
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return s;
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for (const auto& pr: _val) {
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auto sval = encoder_for_prop<p>(pr);
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s.push_back(p());
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sval.encode(s);
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}
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return s;
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}
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};
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template <typename Props>
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class props_val : public basic::encoder {
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static inline std::decay_t<Props> nulltype;
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template <std::integral_constant P, typename T>
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static auto to_prop_val(const T& val) {
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return prop_val<const T&, P>(val);
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}
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template <std::integral_constant... Ps>
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static auto to_prop_vals(const pp::properties<Ps...>& props) {
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return std::make_tuple(to_prop_val<Ps>(props[Ps])...);
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}
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template <class Func>
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auto apply_each(Func&& func) const {
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return std::apply([&func](const auto&... props) {
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return (std::invoke(func, props), ...);
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}, _prop_vals);
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}
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decltype(to_prop_vals(std::declval<Props>())) _prop_vals;
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bool _may_omit;
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public:
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props_val(Props val, bool may_omit) : _prop_vals(to_prop_vals(val)), _may_omit(may_omit) {
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static_assert(std::is_reference_v<Props>);
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}
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props_val(bool may_omit) : _prop_vals(to_prop_vals(nulltype)), _may_omit(may_omit) { }
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size_t byte_size() const {
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size_t psize = props_size();
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if (_may_omit && psize == 0) return 0;
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return psize + basic::varlen_(psize).byte_size();
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}
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std::string& encode(std::string& s) const {
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size_t psize = props_size();
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if (_may_omit && psize == 0) return s;
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basic::varlen_(psize).encode(s);
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apply_each([&s](const auto& pv) { return pv.encode(s); });
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return s;
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}
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private:
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size_t props_size() const {
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size_t retval = 0;
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apply_each([&retval](const auto& pv) { return retval += pv.byte_size(); });
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return retval;
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}
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};
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template <bool may_omit>
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class props_def {
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public:
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template <typename T>
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auto operator()(T&& prop_container) const {
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if constexpr (is_optional<T>) {
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if (prop_container.has_value())
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return (*this)(*prop_container);
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return props_val<const typename std::remove_cvref_t<T>::value_type&>(true);
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}
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else {
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return props_val<T> { prop_container, may_omit };
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}
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}
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};
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constexpr auto props_ = props_def<false>{};
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constexpr auto props_may_omit_ = props_def<true>{};
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} // end namespace prop
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} // end namespace async_mqtt5::encoders
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#endif // !ASYNC_MQTT5_BASE_ENCODERS_HPP
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