initial

.clang-format

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+BasedOnStyle:  Google
+ColumnLimit : 110
+AllowShortFunctionsOnASingleLine: false
+AllowShortLambdasOnASingleLine: true
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+SortIncludes: false

.github/FUNDING.yml

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+# These are supported funding model platforms
+
+github: [kelbon]
+

.github/workflows/build_and_test.yml

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+name: build_and_test
+
+on: push
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: [ubuntu-22.04]
+        compiler: [g++-12, clang++-14]
+        cpp_standard: [20]
+        build_type: [Debug, Release]
+    runs-on: ${{matrix.os}}
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install ninja-build lld gcc-12 clang-14
+          sudo ln -sf /usr/local/bin/ld /usr/bin/lld
+      - name: Configure CMake
+        run: |
+          cmake . -DHPACK_ENABLE_TESTING=ON              \
+            -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+            -DCMAKE_CXX_COMPILER=${{matrix.compiler}} \
+            -DCMAKE_CXX_STANDARD=${{matrix.cpp_standard}}   \
+            -B build -G "Ninja"
+      - name: Build
+        run:
+          cmake --build build
+
+      - name: Test
+        run: |
+          cd build
+          ctest --output-on-failure -C ${{matrix.build_type}} -V

.gitignore

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+/build*
+/.cache
+/.vscode

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.05)
+project(HPACK LANGUAGES CXX)
+
+### options ###
+
+option(HPACK_ENABLE_TESTING "enables testing" OFF)
+
+### dependecies ###
+
+include(cmake/get_cpm.cmake)
+
+set(BOOST_INCLUDE_LIBRARIES intrusive)
+CPMAddPackage(
+  NAME Boost
+  VERSION 1.84.0
+  URL https://github.com/boostorg/boost/releases/download/boost-1.84.0/boost-1.84.0.tar.xz
+  OPTIONS "BOOST_ENABLE_CMAKE ON"
+)
+unset(BOOST_INCLUDE_LIBRARIES)
+find_package(Boost 1.84 COMPONENTS intrusive REQUIRED)
+
+### hpacklib ###
+
+add_library(hpacklib STATIC
+  "${CMAKE_CURRENT_SOURCE_DIR}/src/decoder.cpp"
+  "${CMAKE_CURRENT_SOURCE_DIR}/src/dynamic_table.cpp"
+  "${CMAKE_CURRENT_SOURCE_DIR}/src/huffman.cpp"
+  "${CMAKE_CURRENT_SOURCE_DIR}/src/static_table.cpp")
+
+target_include_directories(hpacklib PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/include")
+
+target_link_libraries(hpacklib PUBLIC Boost::intrusive)
+
+set_target_properties(hpacklib PROPERTIES
+	CMAKE_CXX_EXTENSIONS OFF
+	LINKER_LANGUAGE CXX
+	CMAKE_CXX_STANDARD_REQUIRED ON
+	CXX_STANDARD 20)
+
+if(HPACK_ENABLE_TESTING)
+	include(CTest)
+	add_subdirectory(tests)
+endif()

cmake/get_cpm.cmake

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+# SPDX-License-Identifier: MIT
+#
+# SPDX-FileCopyrightText: Copyright (c) 2019-2023 Lars Melchior and contributors
+
+set(CPM_DOWNLOAD_VERSION 0.40.2)
+set(CPM_HASH_SUM "c8cdc32c03816538ce22781ed72964dc864b2a34a310d3b7104812a5ca2d835d")
+
+if(CPM_SOURCE_CACHE)
+  set(CPM_DOWNLOAD_LOCATION "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+elseif(DEFINED ENV{CPM_SOURCE_CACHE})
+  set(CPM_DOWNLOAD_LOCATION "$ENV{CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+else()
+  set(CPM_DOWNLOAD_LOCATION "${CMAKE_BINARY_DIR}/cmake/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+endif()
+
+# Expand relative path. This is important if the provided path contains a tilde (~)
+get_filename_component(CPM_DOWNLOAD_LOCATION ${CPM_DOWNLOAD_LOCATION} ABSOLUTE)
+
+file(DOWNLOAD
+     https://github.com/cpm-cmake/CPM.cmake/releases/download/v${CPM_DOWNLOAD_VERSION}/CPM.cmake
+     ${CPM_DOWNLOAD_LOCATION} EXPECTED_HASH SHA256=${CPM_HASH_SUM}
+)
+
+include(${CPM_DOWNLOAD_LOCATION})

include/hpack/basic_types.hpp

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+#pragma once
+
+#include <cstdint>
+#include <iterator>
+#include <string_view>
+
+#ifndef KELBON_HPACK_HANDLE_PROTOCOL_ERROR
+
+#include <exception>
+
+namespace hpack {
+struct protocol_error : std::exception {};
+}  // namespace hpack
+
+#define KELBON_HPACK_HANDLE_PROTOCOL_ERROR \
+  throw ::hpack::protocol_error {          \
+  }
+#endif
+
+namespace hpack {
+
+struct sym_info_t {
+  uint32_t bits;
+  uint8_t bit_count;
+};
+extern const sym_info_t huffman_table[257];
+
+// uint16_t(-1) if not found
+uint16_t huffman_decode_table_find(sym_info_t info);
+
+// integer/string len
+using size_type = uint32_t;
+// header index
+using index_type = uint32_t;
+using byte_t = unsigned char;
+using In = const byte_t*;
+
+template <typename T>
+concept Out = std::output_iterator<T, byte_t>;
+
+[[noreturn]] inline void handle_protocol_error() {
+  KELBON_HPACK_HANDLE_PROTOCOL_ERROR;
+}
+[[noreturn]] inline void handle_size_error() {
+  KELBON_HPACK_HANDLE_PROTOCOL_ERROR;
+}
+
+namespace noexport {
+
+template <typename T>
+struct adapted_output_iterator {
+  T base_it;
+  mutable byte_t byte = 0;
+
+  using iterator_category = std::output_iterator_tag;
+  using value_type = byte_t;
+  using difference_type = std::ptrdiff_t;
+
+  constexpr value_type& operator*() const noexcept {
+    return byte;
+  }
+  constexpr adapted_output_iterator& operator++() {
+    *base_it = byte;
+    ++base_it;
+    return *this;
+  }
+  constexpr adapted_output_iterator operator++(int) {
+    auto cpy = *this;
+    ++(*this);
+    return cpy;
+  }
+};
+
+template <Out O>
+auto adapt_output_iterator(O it) {
+  return adapted_output_iterator<O>(it);
+}
+template <typename T>
+auto adapt_output_iterator(adapted_output_iterator<T> it) {
+  return it;
+}
+
+inline byte_t* adapt_output_iterator(byte_t* ptr) {
+  return ptr;
+}
+inline byte_t* adapt_output_iterator(std::byte* ptr) {
+  return reinterpret_cast<byte_t*>(ptr);
+}
+inline byte_t* adapt_output_iterator(char* ptr) {
+  return reinterpret_cast<byte_t*>(ptr);
+}
+
+template <typename Original, typename T>
+Original unadapt(adapted_output_iterator<T> it) {
+  return Original(std::move(it.base_it));
+}
+
+template <typename Original>
+Original unadapt(byte_t* ptr) {
+  static_assert(std::is_pointer_v<Original>);
+  return reinterpret_cast<Original>(ptr);
+}
+
+}  // namespace noexport
+
+struct table_entry {
+  std::string_view name;   // empty if not found
+  std::string_view value;  // empty if no
+
+  constexpr explicit operator bool() const noexcept {
+    return !name.empty();
+  }
+  auto operator<=>(const table_entry&) const = default;
+};
+
+struct find_result_t {
+  // not found by default
+  index_type header_name_index = 0;
+  bool value_indexed = false;
+
+  constexpr explicit operator bool() const noexcept {
+    return header_name_index != 0;
+  }
+};
+
+}  // namespace hpack