254 lines
8.4 KiB
C++
254 lines
8.4 KiB
C++
#ifndef RFL_CBOR_READER_HPP_
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#define RFL_CBOR_READER_HPP_
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#include <array>
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#include <cbor.h>
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#include <concepts>
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#include <exception>
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#include <map>
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#include <memory>
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#include <source_location>
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#include <sstream>
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#include <stdexcept>
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#include <string>
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#include <string_view>
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#include <type_traits>
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#include <unordered_map>
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#include <vector>
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#include "../Box.hpp"
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#include "../Result.hpp"
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#include "../always_false.hpp"
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namespace rfl {
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namespace cbor {
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/// Please refer to https://intel.github.io/tinycbor/current/index.html
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struct Reader {
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struct CBORInputArray {
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CborValue* val_;
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};
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struct CBORInputObject {
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CborValue* val_;
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};
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struct CBORInputVar {
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CborValue* val_;
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};
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using InputArrayType = CBORInputArray;
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using InputObjectType = CBORInputObject;
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using InputVarType = CBORInputVar;
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template <class T>
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static constexpr bool has_custom_constructor =
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(requires(InputVarType var) { T::from_cbor_obj(var); });
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rfl::Result<InputVarType> get_field(const std::string& _name, const InputObjectType& _obj)
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const noexcept {
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CborValue val;
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auto buffer = std::vector<char>();
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auto err = cbor_value_enter_container(_obj.val_, &val);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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size_t length = 0;
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err = cbor_value_get_map_length(_obj.val_, &length);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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for (size_t i = 0; i < length; ++i) {
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if (!cbor_value_is_text_string(&val)) {
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return Error("Expected the key to be a string value.");
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}
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err = get_string(&val, &buffer);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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err = cbor_value_advance(&val);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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if (_name == buffer.data()) {
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return to_input_var(&val);
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}
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err = cbor_value_advance(&val);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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}
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return Error("No field named '" + _name + "' was found.");
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}
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bool is_empty(const InputVarType& _var) const noexcept {
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return cbor_value_is_null(_var.val_);
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}
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template <class T>
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rfl::Result<T> to_basic_type(const InputVarType& _var) const noexcept {
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if constexpr (std::is_same<std::remove_cvref_t<T>, std::string>()) {
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if (!cbor_value_is_text_string(_var.val_)) {
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return Error("Could not cast to string.");
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}
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std::vector<char> buffer;
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const auto err = get_string(_var.val_, &buffer);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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return std::string(buffer.data());
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} else if constexpr (std::is_same<std::remove_cvref_t<T>, bool>()) {
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if (!cbor_value_is_boolean(_var.val_)) {
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return rfl::Error("Could not cast to boolean.");
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}
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bool result = false;
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const auto err = cbor_value_get_boolean(_var.val_, &result);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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return result;
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} else if constexpr (std::is_floating_point<std::remove_cvref_t<T>>() ||
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std::is_integral<std::remove_cvref_t<T>>()) {
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if (cbor_value_is_integer(_var.val_)) {
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std::int64_t result = 0;
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const auto err = cbor_value_get_int64(_var.val_, &result);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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return static_cast<T>(result);
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} else if (cbor_value_is_float(_var.val_)) {
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float result = 0.0;
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const auto err = cbor_value_get_float(_var.val_, &result);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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return static_cast<T>(result);
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} else if (cbor_value_is_double(_var.val_)) {
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double result = 0.0;
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const auto err = cbor_value_get_double(_var.val_, &result);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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return static_cast<T>(result);
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}
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return rfl::Error(
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"Could not cast to numeric value. The type must be integral, "
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"float "
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"or double."
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);
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} else {
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static_assert(rfl::always_false_v<T>, "Unsupported type.");
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}
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}
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rfl::Result<InputArrayType> to_array(const InputVarType& _var) const noexcept {
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if (!cbor_value_is_array(_var.val_)) {
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return Error("Could not cast to an array.");
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}
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return InputArrayType { _var.val_ };
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}
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rfl::Result<InputObjectType> to_object(const InputVarType& _var) const noexcept {
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if (!cbor_value_is_map(_var.val_)) {
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return Error("Could not cast to an object.");
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}
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return InputObjectType { _var.val_ };
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}
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template <class ArrayReader>
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std::optional<Error> read_array(const ArrayReader& _array_reader, const InputArrayType& _arr)
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const noexcept {
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CborValue val;
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auto buffer = std::vector<char>();
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auto err = cbor_value_enter_container(_arr.val_, &val);
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if (err != CborNoError && err != CborErrorOutOfMemory) {
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return Error(cbor_error_string(err));
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}
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size_t length = 0;
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err = cbor_value_get_array_length(_arr.val_, &length);
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if (err != CborNoError && err != CborErrorOutOfMemory) {
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return Error(cbor_error_string(err));
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}
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for (size_t i = 0; i < length; ++i) {
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const auto err2 = _array_reader.read(to_input_var(&val));
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if (err2) {
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return err2;
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}
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err = cbor_value_advance(&val);
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if (err != CborNoError && err != CborErrorOutOfMemory) {
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return Error(cbor_error_string(err));
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}
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}
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return std::nullopt;
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}
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template <class ObjectReader>
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std::optional<Error>
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read_object(const ObjectReader& _object_reader, const InputObjectType& _obj) const noexcept {
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size_t length = 0;
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auto err = cbor_value_get_map_length(_obj.val_, &length);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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CborValue val;
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err = cbor_value_enter_container(_obj.val_, &val);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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auto buffer = std::vector<char>();
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for (size_t i = 0; i < length; ++i) {
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err = get_string(&val, &buffer);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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err = cbor_value_advance(&val);
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if (err != CborNoError) {
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return Error(cbor_error_string(err));
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}
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const auto name = std::string_view(buffer.data(), buffer.size() - 1);
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_object_reader.read(name, InputVarType { &val });
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cbor_value_advance(&val);
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}
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return std::nullopt;
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}
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template <class T>
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rfl::Result<T> use_custom_constructor(const InputVarType& _var) const noexcept {
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try {
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return T::from_cbor_obj(_var);
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} catch (std::exception& e) { return rfl::Error(e.what()); }
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}
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private:
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CborError get_string(const CborValue* _ptr, std::vector<char>* _buffer) const noexcept {
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size_t length = 0;
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auto err = cbor_value_get_string_length(_ptr, &length);
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if (err != CborNoError && err != CborErrorOutOfMemory) {
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return err;
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}
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_buffer->resize(length + 1);
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(*_buffer)[length] = '\0';
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return cbor_value_copy_text_string(_ptr, _buffer->data(), &length, NULL);
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}
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InputVarType to_input_var(CborValue* _ptr) const noexcept {
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values_->emplace_back(rfl::Box<CborValue>::make(*_ptr));
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auto* last_value = values_->back().get();
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return InputVarType { last_value };
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}
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private:
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/// Contains the values inside the object.
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rfl::Box<std::vector<rfl::Box<CborValue>>> values_;
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};
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} // namespace cbor
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} // namespace rfl
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#endif // JSON_PARSER_HPP_
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