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CLK/Reflection/Struct.cpp
2021-04-05 17:26:18 -04:00

567 lines
15 KiB
C++

//
// Struct.cpp
// Clock Signal
//
// Created by Thomas Harte on 13/03/2020.
// Copyright © 2020 Thomas Harte. All rights reserved.
//
#include "Struct.hpp"
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iterator>
#include <sstream>
#include <type_traits>
// MARK: - Setters
template <> bool Reflection::set(Struct &target, const std::string &name, float value, size_t offset) {
const auto target_type = target.type_of(name);
if(!target_type) return false;
if(*target_type == typeid(float)) {
target.set(name, &value, offset);
return true;
}
return set<double>(target, name, value);
}
template <> bool Reflection::set(Struct &target, const std::string &name, double value, size_t offset) {
const auto target_type = target.type_of(name);
if(!target_type) return false;
if(*target_type == typeid(double)) {
target.set(name, &value, offset);
return true;
}
if(*target_type == typeid(float)) {
const float float_value = float(value);
target.set(name, &float_value, offset);
return true;
}
return false;
}
template <> bool Reflection::set(Struct &target, const std::string &name, int value, size_t offset) {
return set<int64_t>(target, name, value, offset);
}
template <> bool Reflection::set(Struct &target, const std::string &name, int64_t value, size_t offset) {
const auto target_type = target.type_of(name);
if(!target_type) return false;
// No need to convert an int or a registered enum.
if(*target_type == typeid(int) || !Reflection::Enum::name(*target_type).empty()) {
const int value32 = int(value);
target.set(name, &value32, offset);
return true;
}
// Set an int64_t directly.
if(*target_type == typeid(int64_t)) {
target.set(name, &value, offset);
return true;
}
#define SetInt(x) if(*target_type == typeid(x)) { x truncated_value = x(value); target.set(name, &truncated_value, offset); }
ForAllInts(SetInt);
#undef SetInt
return false;
}
template <> bool Reflection::set(Struct &target, const std::string &name, const std::string &value, size_t offset) {
const auto target_type = target.type_of(name);
if(!target_type) return false;
// If the target is a string, assign.
if(*target_type == typeid(std::string)) {
auto child = reinterpret_cast<std::string *>(target.get(name));
*child = value;
return true;
}
// From here on, make an attempt to convert to a named enum.
if(Reflection::Enum::name(*target_type).empty()) {
return false;
}
const int enum_value = Reflection::Enum::from_string(*target_type, value);
if(enum_value < 0) {
return false;
}
target.set(name, &enum_value, offset);
return true;
}
template <> bool Reflection::set(Struct &target, const std::string &name, const char *value, size_t offset) {
const std::string string(value);
return set<const std::string &>(target, name, string, offset);
}
template <> bool Reflection::set(Struct &target, const std::string &name, bool value, size_t offset) {
const auto target_type = target.type_of(name);
if(!target_type) return false;
if(*target_type == typeid(bool)) {
target.set(name, &value, offset);;
}
return false;
}
// MARK: - Fuzzy setter
bool Reflection::fuzzy_set(Struct &target, const std::string &name, const std::string &value) {
const auto target_type = target.type_of(name);
if(!target_type) return false;
// If the target is a registered enum, ttry to convert the value. Failing that,
// try to match without case sensitivity.
if(Reflection::Enum::size(*target_type)) {
const int from_string = Reflection::Enum::from_string(*target_type, value);
if(from_string >= 0) {
target.set(name, &from_string);
return true;
}
const auto all_values = Reflection::Enum::all_values(*target_type);
const auto value_location = std::find_if(all_values.begin(), all_values.end(),
[&value] (const auto &entry) {
if(value.size() != entry.size()) return false;
const char *v = value.c_str();
const char *e = entry.c_str();
while(*v) {
if(tolower(*v) != tolower(*e)) return false;
++v;
++e;
}
return true;
});
if(value_location != all_values.end()) {
const int offset = int(value_location - all_values.begin());
target.set(name, &offset);
return true;
}
return false;
}
return false;
}
// MARK: - Description
void Reflection::Struct::append(std::ostringstream &stream, const std::string &key, const std::type_info *const type, size_t offset) const {
// Output Bools as yes/no.
if(*type == typeid(bool)) {
stream << ::Reflection::get<bool>(*this, key, offset);
return;
}
// Output Ints of all sizes as hex.
#define OutputIntC(int_type, cast_type) if(*type == typeid(int_type)) { stream << std::setfill('0') << std::setw(sizeof(int_type)*2) << std::hex << cast_type(::Reflection::get<int_type>(*this, key, offset)); return; }
#define OutputInt(int_type) OutputIntC(int_type, int_type)
OutputIntC(int8_t, int16_t);
OutputIntC(uint8_t, uint16_t);
OutputInt(int16_t);
OutputInt(uint16_t);
OutputInt(int32_t);
OutputInt(uint32_t);
OutputInt(int64_t);
OutputInt(uint64_t);
#undef OutputInt
#undef OutputIntC
// Output floats and strings natively.
#define OutputNative(val_type) if(*type == typeid(val_type)) { stream << ::Reflection::get<val_type>(*this, key, offset); return; }
OutputNative(float);
OutputNative(double);
OutputNative(char *);
OutputNative(std::string);
#undef OutputNative
// Output the current value of any enums.
if(!Enum::name(*type).empty()) {
const int value = ::Reflection::get<int>(*this, key, offset);
stream << Enum::to_string(*type, value);
return;
}
// Recurse to deal with embedded objects.
if(*type == typeid(Reflection::Struct)) {
const Reflection::Struct *const child = reinterpret_cast<const Reflection::Struct *>(get(key));
stream << child->description();
return;
}
}
std::string Reflection::Struct::description() const {
std::ostringstream stream;
stream << "{";
bool is_first = true;
for(const auto &key: all_keys()) {
if(!is_first) stream << ", ";
is_first = false;
stream << key << ": ";
const auto count = count_of(key);
const auto type = type_of(key);
if(count != 1) {
stream << "[";
}
for(size_t index = 0; index < count; ++index) {
append(stream, key, type, index);
if(index != count-1) stream << ", ";
}
if(count != 1) {
stream << "]";
}
}
stream << "}";
return stream.str();
}
/* Contractually, this serialises as BSON. */
std::vector<uint8_t> Reflection::Struct::serialise() const {
auto push_name = [] (std::vector<uint8_t> &result, const std::string &name) {
std::copy(name.begin(), name.end(), std::back_inserter(result));
result.push_back(0);
};
auto append = [push_name, this] (std::vector<uint8_t> &result, const std::string &key, const std::string &output_name, const std::type_info *type, size_t offset) {
auto push_int = [&result] (auto x) {
for(size_t c = 0; c < sizeof(x); ++c)
result.push_back(uint8_t((x) >> (8 * c)));
};
auto push_named_int = [push_int, push_name, &result, &output_name] (uint8_t type, auto x) {
result.push_back(type);
push_name(result, output_name);
push_int(x);
};
auto push_string = [push_int, push_name, &result, &output_name] (const std::string &text) {
result.push_back(0x02);
push_name(result, output_name);
const uint32_t string_length = uint32_t(text.size() + 1);
push_int(string_length);
std::copy(text.begin(), text.end(), std::back_inserter(result));
result.push_back(0);
};
// Test for an exact match on Booleans.
if(*type == typeid(bool)) {
result.push_back(0x08);
push_name(result, output_name);
result.push_back(uint8_t(Reflection::get<bool>(*this, key, offset)));
return;
}
// Record the string value for enums.
if(!Reflection::Enum::name(*type).empty()) {
int value;
Reflection::get(*this, key, value, offset);
const auto text = Reflection::Enum::to_string(*type, 0);
push_string(text);
return;
}
// Test for ints that will safely convert to an int32.
int32_t int32;
if(Reflection::get(*this, key, int32, offset)) {
push_named_int(0x10, int32);
return;
}
// Test for ints that can be converted to an int64.
int64_t int64;
if(Reflection::get(*this, key, int64, offset)) {
push_named_int(0x12, int64);
return;
}
// There's only one BSON float type: a double.
double float64;
if(Reflection::get(*this, key, float64, offset)) {
result.push_back(0x01);
push_name(result, output_name);
// The following declines to assume an internal representation
// for doubles, constructing IEEE 708 from first principles.
// Which is probably absurd given how often I've assumed
// e.g. two's complement.
int exponent;
const double mantissa = frexp(fabs(float64), &exponent);
exponent += 1022;
const uint64_t integer_mantissa =
static_cast<uint64_t>(mantissa * 9007199254740992.0);
const uint64_t binary64 =
((float64 < 0) ? 0x8000'0000'0000'0000 : 0) |
(integer_mantissa & 0x000f'ffff'ffff'ffff) |
(static_cast<uint64_t>(exponent) << 52);
push_int(binary64);
return;
}
// Strings are written naturally.
if(*type == typeid(std::string)) {
const uint8_t *address = reinterpret_cast<const uint8_t *>(get(key));
const std::string *const text = reinterpret_cast<const std::string *>(address + offset*sizeof(std::string));
push_string(*text);
return;
}
// Store std::vector<uint_8>s as binary data.
if(*type == typeid(std::vector<uint8_t>)) {
result.push_back(0x05);
push_name(result, output_name);
auto source = reinterpret_cast<const std::vector<uint8_t> *>(get(key));
push_int(uint32_t(source->size()));
result.push_back(0x00);
std::copy(source->begin(), source->end(), std::back_inserter(result));
return;
}
// Okay, check for a potential recursion.
// Not currently supported: arrays of structs.
if(*type == typeid(Reflection::Struct)) {
result.push_back(0x03);
push_name(result, output_name);
const Reflection::Struct *const child = reinterpret_cast<const Reflection::Struct *>(get(key));
const auto sub_document = child->serialise();
std::copy(sub_document.begin(), sub_document.end(), std::back_inserter(result));
return;
}
// Should never reach here; that means a type was discovered in a struct which is intended for
// serialisation but which could not be parsed.
assert(false);
};
auto wrap_object = [] (std::vector<uint8_t> &data) {
/*
document ::= int32 e_list "\x00"
The int32 is the total number of bytes comprising the document.
*/
data.push_back(0);
const uint32_t size_with_prefix = uint32_t(data.size()) + 4;
data.insert(data.begin(), uint8_t(size_with_prefix >> 24));
data.insert(data.begin(), uint8_t(size_with_prefix >> 16));
data.insert(data.begin(), uint8_t(size_with_prefix >> 8));
data.insert(data.begin(), uint8_t(size_with_prefix & 0xff));
};
std::vector<uint8_t> result;
for(const auto &key: all_keys()) {
if(!should_serialise(key)) continue;
/* Here: e_list ::= element e_list | "" */
const auto count = count_of(key);
const auto type = type_of(key);
if(count > 1) {
// In BSON, an array is a sub-document with ASCII keys '0', '1', etc.
result.push_back(0x04);
push_name(result, key);
std::vector<uint8_t> array;
for(size_t c = 0; c < count; ++c) {
append(array, key, std::to_string(c), type, c);
}
wrap_object(array);
std::copy(array.begin(), array.end(), std::back_inserter(result));
} else {
append(result, key, key, type, 0);
}
}
wrap_object(result);
return result;
}
bool Reflection::Struct::deserialise(const std::vector<uint8_t> &bson) {
return deserialise(bson.data(), bson.size());
}
namespace {
/*!
Provides a proxy struct that redirects calls to set to another object and property, picking
an offset based on the propety name specified here.
*/
struct ArrayReceiver: public Reflection::Struct {
ArrayReceiver(Reflection::Struct *target, const std::type_info *type, const std::string &key, size_t count) :
target_(target), type_(type), key_(key), count_(count) {}
std::vector<std::string> all_keys() const final { return {}; }
const std::type_info *type_of(const std::string &) const final { return type_; }
size_t count_of(const std::string &) const final { return 0; }
void set(const std::string &name, const void *value, size_t) final {
const auto index = size_t(std::stoi(name));
if(index >= count_) {
return;
}
target_->set(key_, value, index);
}
virtual std::vector<std::string> values_for(const std::string &) const final {
return {};
}
void *get(const std::string &) final {
return nullptr;
}
private:
Reflection::Struct *target_;
const std::type_info *type_;
std::string key_;
size_t count_;
};
}
bool Reflection::Struct::deserialise(const uint8_t *bson, size_t size) {
// Validate the object's declared size.
const auto end = bson + size;
auto read_int = [&bson] (auto &target) {
constexpr auto shift = 8 * (sizeof(target) - 1);
target = 0;
for(size_t c = 0; c < sizeof(target); ++c) {
target >>= 8;
target |= decltype(target)(*bson) << shift;
++bson;
}
};
uint32_t object_size;
read_int(object_size);
if(object_size > size) return false;
while(true) {
const uint8_t next_type = *bson;
++bson;
if(!next_type)
break;
std::string key;
while(*bson) {
key.push_back(char(*bson));
++bson;
}
++bson;
switch(next_type) {
default:
return false;
// 0x03: A subdocument; try to install the inner BSON.
// 0x05: Binary data. Seek to populate a std::vector<uint8_t>.
case 0x03:
case 0x05: {
const auto type = type_of(key);
uint32_t subobject_size;
read_int(subobject_size);
if(next_type == 0x03 && *type == typeid(Reflection::Struct)) {
auto child = reinterpret_cast<Reflection::Struct *>(get(key));
child->deserialise(bson - 4, size_t(end - bson + 4));
bson += subobject_size - 4;
}
if(next_type == 0x05 && *type == typeid(std::vector<uint8_t>)) {
auto child = reinterpret_cast<std::vector<uint8_t> *>(get(key));
*child = std::vector<uint8_t>(bson, bson + subobject_size);
bson += subobject_size;
}
} break;
// Array. BSON's encoding of these is a minor pain, but could be worse;
// they're presented as a subobject with objects serialised in array order
// but given the string keys "0", "1", etc. So: validate the keys, decode
// the objects.
case 0x04: {
ArrayReceiver receiver(this, type_of(key), key, count_of(key));
uint32_t subobject_size;
read_int(subobject_size);
receiver.deserialise(bson - 4, size_t(end - bson + 4));
bson += subobject_size - 4;
} break;
// String.
case 0x02: {
uint32_t length;
read_int(length);
const std::string value(bson, bson + length - 1);
::Reflection::set<const std::string &>(*this, key, value);
bson += length;
} break;
// Boolean.
case 0x08: {
const bool value = *bson;
++bson;
::Reflection::set(*this, key, value);
} break;
// 32-bit int.
case 0x10: {
int32_t value;
read_int(value);
::Reflection::set(*this, key, value);
} break;
// 64-bit int.
case 0x12: {
int64_t value;
read_int(value);
::Reflection::set(*this, key, value);
} break;
// 64-bit double.
case 0x01: {
uint64_t value;
read_int(value);
const double mantissa = 0.5 + double(value & 0x000f'ffff'ffff'ffff) / 9007199254740992.0;
const int exponent = ((value >> 52) & 2047) - 1022;
const double double_value = ldexp(mantissa, exponent);
const double sign = (value & 0x8000'0000'0000'0000) ? -1 : 1;
::Reflection::set(*this, key, double_value * sign);
} break;
}
}
return true;
}