Implement a higher-level API on top of the basics

This commit is contained in:
TennesseeTrash 2025-09-27 03:53:07 +02:00
parent e06b85632a
commit 2e9b507837
7 changed files with 491 additions and 174 deletions

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@ -0,0 +1,74 @@
#ifndef LIBCBOR_CONCEPTS_HPP
#define LIBCBOR_CONCEPTS_HPP
#include "Core.hpp"
#include <concepts>
#include <span>
#include <string_view>
#include <type_traits>
namespace CBOR
{
template <typename T>
concept SimpleType = std::integral<T> ||
std::floating_point<T> ||
std::same_as<std::remove_cvref_t<T>, Special> ||
std::same_as<std::remove_cvref_t<T>, bool>;
template <typename T>
concept StringLike = std::convertible_to<T, std::string_view>;
template <typename T>
concept BinaryLike = std::convertible_to<T, std::span<const std::uint8_t>>;
template <typename T>
concept EncodableContainer = !StringLike<T> && requires(T t) {
{ t.size() } -> std::same_as<std::size_t>;
t.begin();
t.end();
typename T::value_type;
};
template <typename T>
concept MapContainer = EncodableContainer<T> && requires {
typename T::key_type;
typename T::mapped_type;
};
template <typename T>
concept SequenceContainer = EncodableContainer<T> && !MapContainer<T>;
namespace Implementation
{
template <typename... Ts>
struct First;
template <typename T>
struct First<T>
{
using Type = T;
};
template <typename T, typename... Ts>
struct First<T, Ts...>
{
using Type = T;
};
}
template <typename... Ts>
using First = Implementation::First<Ts...>::Type;
template <typename T>
struct MemberTraits;
template <typename T, typename MemberT>
struct MemberTraits<MemberT T:: *>
{
using ContainingType = T;
using MemberType = MemberT;
};
}
#endif // LIBCBOR_CONCEPTS_HPP

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@ -1,10 +1,15 @@
#ifndef LIBCBOR_DECODER_HPP
#define LIBCBOR_DECODER_HPP
#include "Concepts.hpp"
#include "Core.hpp"
#include <concepts>
#include <limits>
#include <string_view>
#include <tuple>
#include <type_traits>
#include <utility>
namespace CBOR
{
@ -59,6 +64,9 @@ namespace CBOR
class Map Map();
class TaggedItem TaggedItem();
template <typename T>
T Decode();
private:
friend class Decoder;
friend class Array;
@ -183,6 +191,8 @@ namespace CBOR
Array &operator=(const Array &) = delete;
public:
static constexpr std::size_t Indefinite = std::numeric_limits<std::size_t>::max();
Array(Array &&other);
Array &operator=(Array &&other);
~Array() = default;
@ -190,6 +200,8 @@ namespace CBOR
bool Done();
Item Next();
std::size_t Size();
private:
friend class Decoder;
@ -210,6 +222,8 @@ namespace CBOR
Map &operator=(const Map &) = delete;
public:
static constexpr std::size_t Indefinite = std::numeric_limits<std::size_t>::max();
Map(Map &&other);
Map &operator=(Map &&other);
~Map() = default;
@ -217,6 +231,8 @@ namespace CBOR
bool Done();
KeyValue Next();
std::size_t Size();
private:
friend class Decoder;
@ -272,6 +288,10 @@ namespace CBOR
class TaggedItem TaggedItem();
class Item AsItem();
template <typename T>
T Decode();
private:
friend class Binary;
friend class String;
@ -282,6 +302,136 @@ namespace CBOR
std::size_t mCurrent;
ConstBuffer mBuffer;
};
template <typename T>
T Item::Decode()
{
return mDecoder->Decode<T>();
}
template <typename T>
T Decoder::Decode()
{
if constexpr (std::same_as<T, bool>) {
return Bool();
}
else if constexpr (std::same_as<T, enum class Special>) {
return Special();
}
else if constexpr (std::signed_integral<T>) {
if constexpr (sizeof(T) == 1) {
return Int8();
}
else if constexpr (sizeof(T) == 2) {
return Int16();
}
else if constexpr (sizeof(T) == 4) {
return Int32();
}
else if constexpr (sizeof(T) == 8) {
return Int64();
}
}
else if constexpr (std::unsigned_integral<T>) {
if constexpr (sizeof(T) == 1) {
return Uint8();
}
else if constexpr (sizeof(T) == 2) {
return Uint16();
}
else if constexpr (sizeof(T) == 4) {
return Uint32();
}
else if constexpr (sizeof(T) == 8) {
return Uint64();
}
}
else if constexpr (std::same_as<T, float>) {
return Float();
}
else if constexpr (std::same_as<T, double>) {
return Double();
}
else if constexpr (std::same_as<T, std::string_view>) {
return String();
}
else if constexpr (std::same_as<T, ConstBuffer>) {
return Binary();
}
else if constexpr (requires (T a) { DecodeHook(*this, a); }) {
T result;
DecodeHook(*this, result);
return result;
}
else {
static_assert(false, "This type is not decodable (needs a custom DecodeHook)");
}
}
template <typename Key, typename ValuePtr>
requires std::is_member_object_pointer_v<ValuePtr>
class StructMember
{
public:
using KeyType = Key;
using MemberPtrType = ValuePtr;
using ContainingType = MemberTraits<ValuePtr>::ContainingType;
using MemberType = MemberTraits<ValuePtr>::MemberType;
StructMember(Key key, ValuePtr ptr)
: mEnabled(true), mKey(key), mValuePtr(ptr)
{}
bool Match(const Key &other) const
{
return mEnabled && other == mKey;
}
void Decode(Item &item, ContainingType &result)
{
result.*mValuePtr = item.Decode<MemberType>();
mEnabled = false;
}
private:
bool mEnabled;
Key mKey;
ValuePtr mValuePtr;
};
template <typename ValuePtr>
StructMember(const char *, ValuePtr) -> StructMember<std::string_view, ValuePtr>;
template <typename Key, typename... ValuePtrs>
class StructHelper
{
public:
using ContainingType = MemberTraits<First<ValuePtrs...>>::ContainingType;
StructHelper(StructMember<Key, ValuePtrs> &&...items)
: mStructItems(std::forward<StructMember<Key, ValuePtrs>>(items)...)
{}
void Decode(Decoder &decoder, ContainingType &result)
{
return Decode(decoder.AsItem(), result);
}
void Decode(Item item, ContainingType &result)
{
CBOR::Map map = item.Map();
while (!map.Done()) {
CBOR::KeyValue kv = map.Next();
Key key = kv.Key().Decode<Key>();
Item value = kv.Value();
std::apply([&key, &value, &result](auto &&...args) {
void(((args.Match(key) ? (args.Decode(value, result), true) : false) || ...));
}, mStructItems);
}
}
private:
std::tuple<StructMember<Key, ValuePtrs>...> mStructItems;
};
}
#endif // LIBCBOR_DECODER_HPP

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@ -0,0 +1,80 @@
#ifndef LIBCBOR_DECODERHOOKS_HPP
#define LIBCBOR_DECODERHOOKS_HPP
#include "Decoder.hpp"
#include <format>
#include <map>
#include <unordered_map>
#include <tuple>
#include <utility>
#include <vector>
namespace CBOR
{
constexpr
void DecodeHook(Decoder &decoder, std::string &value)
{
String string = decoder.IndefiniteString();
while (!string.Done()) {
value.append(string.Next());
}
}
constexpr
void DecodeHook(Decoder &decoder, std::vector<std::uint8_t> &value)
{
Binary binary = decoder.IndefiniteBinary();
while(!binary.Done()) {
value.append_range(binary.Next());
}
}
template <typename T>
constexpr
void DecodeHook(Decoder &decoder, std::vector<T> &value)
{
Array array = decoder.Array();
while (!array.Done()) {
value.push_back(array.Next().Decode<T>());
}
}
template <typename Key, typename Value>
constexpr
void DecodeHook(Decoder &decoder, std::unordered_map<Key, Value> &value)
{
Map map = decoder.Map();
while (!map.Done()) {
KeyValue kv = map.Next();
value.insert(std::make_pair(kv.Key().Decode<Key>(), kv.Value().Decode<Value>()));
}
}
template <typename Key, typename Value>
constexpr
void DecodeHook(Decoder &decoder, std::map<Key, Value> &value)
{
Map map = decoder.Map();
while (!map.Done()) {
KeyValue kv = map.Next();
value.insert(std::make_pair(kv.Key().Decode<Key>(), kv.Value().Decode<Value>()));
}
}
template <typename... Items>
constexpr
void DecodeHook(Decoder &decoder, std::tuple<Items...> &value)
{
Array array = decoder.Array();
if (array.Size() != sizeof...(Items)) {
throw DecodeError(std::format("Expected {} elements to fill tuple, got {} instead",
sizeof...(Items), array.Size()));
}
std::apply([&array] <typename... Args> (Args &...args) {
((array.Done(), args = array.Next().Decode<Args>()), ...);
}, value);
}
}
#endif // LIBCBOR_DECODERHOOKS_HPP

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@ -1,6 +1,7 @@
#ifndef LIBCBOR_ENCODER_HPP
#define LIBCBOR_ENCODER_HPP
#include "Concepts.hpp"
#include "Core.hpp"
#include <array>
@ -39,7 +40,7 @@ namespace CBOR
void Write(std::uint16_t value);
void Write(std::uint32_t value);
void Write(std::uint64_t value);
void Write(Buffer value);
void Write(ConstBuffer value);
void Write(std::string_view value);
std::size_t Size() const;
@ -51,7 +52,7 @@ namespace CBOR
void Write(std::uint16_t value);
void Write(std::uint32_t value);
void Write(std::uint64_t value);
void Write(Buffer value);
void Write(ConstBuffer value);
void Write(std::string_view value);
std::size_t Size() const;
@ -67,7 +68,7 @@ namespace CBOR
void Write(std::uint16_t value);
void Write(std::uint32_t value);
void Write(std::uint64_t value);
void Write(Buffer value);
void Write(ConstBuffer value);
void Write(std::string_view value);
std::size_t Size() const;
@ -108,7 +109,7 @@ namespace CBOR
void Encode(float value);
void Encode(double value);
void Encode(Buffer value);
void Encode(ConstBuffer value);
void Encode(const char *value);
void Encode(std::string_view value);
@ -125,9 +126,91 @@ namespace CBOR
void EncodeTag(std::uint64_t value);
std::size_t Size() const;
private:
EncoderBuffer mBuffer;
};
class Encoder
{
public:
Encoder(EncoderBuffer buffer);
template <typename T>
Encoder &Encode(const T &value)
{
if constexpr (SimpleType<T> || StringLike<T> || BinaryLike<T>) {
mEncoder.Encode(value);
}
else if constexpr (SequenceContainer<T>) {
mEncoder.BeginArray(value.size());
for (const auto &item: value) {
Encode(item);
}
}
else if constexpr (MapContainer<T>) {
mEncoder.BeginMap(value.size());
for (const auto &[key, value]: value) {
Encode(key);
Encode(value);
}
}
else if constexpr (requires { EncodeHook(*this, value); }) {
EncodeHook(*this, value);
}
else if constexpr (requires { EncodeHook(mEncoder, value); }) {
EncodeHook(mEncoder, value);
}
else {
static_assert(false, "This type is not encodable (needs a custom EncodeHook)");
}
return *this;
}
template <typename... Ts>
Encoder &EncodeArray(Ts &&...values)
{
mEncoder.BeginArray(sizeof...(values));
(Encode(std::forward<Ts>(values)), ...);
return *this;
}
template <typename... Ts>
requires (sizeof...(Ts) % 2 == 0)
Encoder &EncodeMap(Ts &&...values)
{
mEncoder.BeginMap(sizeof...(values) / 2);
(Encode(std::forward<Ts>(values)), ...);
return *this;
}
template <typename T>
Encoder &EncodeTagged(std::uint64_t tag, const T &value)
{
mEncoder.EncodeTag(tag);
return Encode(value);
}
template <typename... Ts>
Encoder &EncodeTaggedArray(std::uint64_t tag, Ts &&...values)
{
mEncoder.EncodeTag(tag);
return EncodeArray(std::forward<Ts>(values)...);
}
template <typename... Ts>
requires (sizeof...(Ts) % 2 == 0)
Encoder &EncodeTaggedMap(std::uint64_t tag, Ts &&...values)
{
mEncoder.EncodeTag(tag);
return EncodeMap(std::forward<Ts>(values)...);
}
std::size_t Size() const;
private:
BasicEncoder mEncoder;
};
}
#endif // LIBCBOR_ENCODER_HPP

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@ -55,8 +55,6 @@ namespace CBOR
namespace
{
static constexpr std::size_t Indefinite = std::numeric_limits<std::size_t>::max();
std::size_t SpaceLeft(ConstBuffer buffer, std::size_t offset)
{
if (offset >= buffer.size()) {
@ -851,7 +849,7 @@ namespace CBOR
}
if (!mCheckedDone) {
throw InvalidUsageError("check whether the indefinite string is done first");
throw InvalidUsageError("check whether the array is done first");
}
mCheckedDone = false;
@ -859,6 +857,27 @@ namespace CBOR
return Item(*mDecoder);
}
std::size_t Array::Size()
{
if (!mHeaderParsed) {
std::uint8_t header = Consume1B(mDecoder->mBuffer, mDecoder->mCurrent);
mHeaderParsed = true;
if (GetMajorType(header) != MajorType::Array) {
throw TypeMismatchError("array", ToString(GetMajorType(header)));
}
bool indefinite = GetArgumentPosition(header) == ArgumentPosition::Indefinite;
mSize = indefinite ? Indefinite
: ArgumentValue(header, mDecoder->mBuffer, mDecoder->mCurrent);
if (!mSize) {
mDone = true;
mCheckedDone = true;
}
}
return mSize;
}
Map::Map(Decoder &decoder)
: mHeaderParsed(false)
, mDone(false)
@ -935,7 +954,7 @@ namespace CBOR
}
if (!mCheckedDone) {
throw InvalidUsageError("check whether the indefinite string is done first");
throw InvalidUsageError("check whether the map is done first");
}
mCheckedDone = false;
@ -943,6 +962,27 @@ namespace CBOR
return KeyValue(*mDecoder);
}
std::size_t Map::Size()
{
if (!mHeaderParsed) {
std::uint8_t header = Consume1B(mDecoder->mBuffer, mDecoder->mCurrent);
mHeaderParsed = true;
if (GetMajorType(header) != MajorType::Map) {
throw TypeMismatchError("map", ToString(GetMajorType(header)));
}
bool indefinite = GetArgumentPosition(header) == ArgumentPosition::Indefinite;
mSize = indefinite ? Indefinite
: ArgumentValue(header, mDecoder->mBuffer, mDecoder->mCurrent);
if (!mSize) {
mDone = true;
mCheckedDone = true;
}
}
return mSize;
}
Decoder::Decoder(ConstBuffer buffer)
: mCurrent(0), mBuffer(buffer)
{}

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@ -120,7 +120,7 @@ namespace CBOR
}, mBuffer);
}
void EncoderBuffer::Write(Buffer value)
void EncoderBuffer::Write(ConstBuffer value)
{
std::visit(Overload {
[value] (FixedBuffer &buffer) { buffer.Write(value); },
@ -185,7 +185,7 @@ namespace CBOR
mBuffer[mCurrent++] = static_cast<std::uint8_t>((network >> 56) & mask);
}
void EncoderBuffer::FixedBuffer::Write(Buffer value)
void EncoderBuffer::FixedBuffer::Write(ConstBuffer value)
{
EnsureSpace(value.size());
std::memcpy(mBuffer.data() + mCurrent, value.data(), value.size());
@ -250,7 +250,7 @@ namespace CBOR
mBuffer->push_back(static_cast<std::uint8_t>((network >> 56) & mask));
}
void EncoderBuffer::DynamicBuffer::Write(Buffer value)
void EncoderBuffer::DynamicBuffer::Write(ConstBuffer value)
{
mBuffer->append_range(value);
}
@ -447,7 +447,7 @@ namespace CBOR
mBuffer.Write(std::bit_cast<std::uint64_t>(value));
}
void BasicEncoder::Encode(Buffer value)
void BasicEncoder::Encode(ConstBuffer value)
{
WriteHeader(mBuffer, MajorType::Binary, value.size());
mBuffer.Write(value);
@ -508,4 +508,13 @@ namespace CBOR
{
return mBuffer.Size();
}
Encoder::Encoder(EncoderBuffer buffer)
: mEncoder(std::move(buffer))
{}
std::size_t Encoder::Size() const
{
return mEncoder.Size();
}
}

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@ -1,11 +1,14 @@
#include "CBOR/Decoder.hpp"
#include "CBOR/Encoder.hpp"
#include "CBOR/Printer.hpp"
#include <CBOR/Core.hpp>
#include <CBOR/Decoder.hpp>
#include <CBOR/DecoderHooks.hpp> // IWYU pragma: keep
#include <CBOR/Encoder.hpp>
#include <CBOR/Printer.hpp>
#include <array>
#include <compare> // IWYU pragma: keep
#include <cstdint>
#include <iostream>
#include <print>
#include <ranges>
#include <stdexcept>
#include <vector>
@ -18,166 +21,47 @@ struct SomeStruct
std::int64_t slots;
std::uint32_t times;
std::vector<std::string> tools;
constexpr auto operator<=>(const SomeStruct &) const = default;
};
std::size_t Encode(const SomeStruct &value, auto &buffer)
void EncodeHook(CBOR::Encoder &enc, const SomeStruct &value)
{
CBOR::BasicEncoder enc(buffer);
enc.EncodeTag(15'000);
enc.BeginMap(7);
enc.Encode("name");
enc.Encode(value.name);
enc.Encode("speed");
enc.Encode(value.speed);
enc.Encode("fov");
enc.Encode(value.fov);
enc.Encode("thing");
enc.Encode(value.thing);
enc.Encode("slots");
enc.Encode(value.slots);
enc.Encode("times");
enc.Encode(value.times);
enc.Encode("tools");
enc.BeginIndefiniteArray();
for (std::string_view tool: value.tools) {
enc.Encode(tool);
}
enc.End();
return enc.Size();
enc.EncodeTaggedMap(
15'000,
"name", value.name,
"speed", value.speed,
"fov", value.fov,
"thing", value.thing,
"slots", value.slots,
"times", value.times,
"tools", value.tools
);
}
SomeStruct Decode1(std::span<std::uint8_t> buffer)
void DecodeHook(CBOR::Decoder &dec, SomeStruct &value)
{
SomeStruct result;
CBOR::Decoder dec(buffer);
CBOR::StructHelper helper {
CBOR::StructMember { "name", &SomeStruct::name },
CBOR::StructMember { "speed", &SomeStruct::speed },
CBOR::StructMember { "fov", &SomeStruct::fov },
CBOR::StructMember { "thing", &SomeStruct::thing },
CBOR::StructMember { "slots", &SomeStruct::slots },
CBOR::StructMember { "times", &SomeStruct::times },
CBOR::StructMember { "tools", &SomeStruct::tools },
};
CBOR::TaggedItem tagged = dec.TaggedItem();
if (tagged.Tag() != 15'000) {
throw std::runtime_error("test error: could not extract object tag");
}
CBOR::Map object = tagged.Item().Map();
while (!object.Done()) {
CBOR::KeyValue kv = object.Next();
std::string_view key = kv.Key().String();
CBOR::Item value = kv.Value();
if (key == "name") {
result.name = value.String();
}
else if (key == "speed") {
result.speed = value.Double();
}
else if (key == "fov") {
result.fov = value.Float();
}
else if (key == "thing") {
result.thing = value.Int8();
}
else if (key == "slots") {
result.slots = value.Int64();
}
else if (key == "times") {
result.times = value.Uint32();
}
else if (key == "tools") {
CBOR::Array tools = value.Array();
while(!tools.Done()) {
result.tools.push_back(std::string(tools.Next().String()));
}
}
}
return result;
}
SomeStruct Decode2(std::span<std::uint8_t> buffer)
{
SomeStruct result;
CBOR::Decoder dec(buffer);
CBOR::TaggedItem tagged = dec.TaggedItem();
if (tagged.Tag() != 15'000) {
throw std::runtime_error("test error: could not extract object tag");
}
CBOR::Map object = tagged.Item().Map();
while (!object.Done()) {
CBOR::KeyValue kv = object.Next();
std::string_view key = kv.Key().String();
CBOR::Item value = kv.Value();
if (key == "name") {
result.name = value.String();
}
else if (key == "speed") {
result.speed = value.Double();
}
else if (key == "fov") {
result.fov = value.Float();
}
else if (key == "thing") {
result.thing = value.Int8();
}
else if (key == "slots") {
result.slots = value.Int64();
}
else if (key == "times") {
result.times = value.Uint32();
}
else if (key == "tools") {
CBOR::Array tools = value.Array();
while(!tools.Done()) {
result.tools.push_back("");
CBOR::String tool = tools.Next().IndefiniteString();
while (!tool.Done()) {
result.tools.back().append(tool.Next());
}
}
}
}
return result;
}
void Compare(const SomeStruct &s1, const SomeStruct &s2)
{
if (s1.name != s2.name) {
throw std::runtime_error("test error: names are not the same");
}
if (s1.speed != s2.speed) {
throw std::runtime_error("test error: speed is not the same");
}
if (s1.fov != s2.fov) {
throw std::runtime_error("test error: fovs are not the same");
}
if (s1.thing != s2.thing) {
throw std::runtime_error("test error: things are not the same");
}
if (s1.slots != s2.slots) {
throw std::runtime_error("test error: slots are not the same");
}
if (s1.times != s2.times) {
throw std::runtime_error("test error: times are not the same");
}
for (const auto &[t1, t2]: std::ranges::views::zip(s1.tools, s2.tools)) {
if (t1 != t2) {
throw std::runtime_error("test error: some tools are not the same");
}
throw std::runtime_error("Expected item with tag value 15000");
}
helper.Decode(tagged.Item(), value);
}
int main()
{
using namespace std::string_view_literals;
//std::array<std::uint8_t, 1024> buffer {};
std::vector<std::uint8_t> buffer;
std::array<std::uint8_t, 1024> buffer {};
SomeStruct expected {
.name = "Player1",
@ -196,23 +80,20 @@ int main()
};
try {
std::size_t encodedSize = Encode(expected, buffer);
std::println("Encoded size: {}", encodedSize);
CBOR::Encoder enc(buffer);
enc.Encode(expected);
std::print("Encoded hex: ");
for (std::size_t i = 0; i < encodedSize; ++i) {
std::print("{:02X} ", buffer[i]);
CBOR::ConstBuffer encoded(buffer.data(), enc.Size());
CBOR::Decoder dec(encoded);
SomeStruct res = dec.Decode<SomeStruct>();
if (res != expected) {
throw std::runtime_error("test error: the encode/decode round trip should be lossless");
}
std::println();
SomeStruct result1 = Decode1(std::span<std::uint8_t>(buffer.data(), encodedSize));
SomeStruct result2 = Decode2(std::span<std::uint8_t>(buffer.data(), encodedSize));
CBOR::Print(std::cout, encoded);
std::println("JSON-esque serialization:");
CBOR::Print(std::cout, std::span<std::uint8_t>(buffer.data(), encodedSize));
Compare(expected, result1);
Compare(expected, result2);
std::println("The test has been completed successfully.");
}
catch (const std::exception &e) {