cth

c++26 utility library

built and tested with:

• linux: gcc 16, clang 23
• windows: msvc, clang 23

overview

cth::cth

header only core

data structures & allocators (cth::dt)

• miniram: O(1) offset allocator with defragmentation, fully constexpr (inspired by Sebastian Aaltonen's OffsetAllocator)
• ring_alloc: lock-free ring allocator, contiguous allocations
• poly_vector: struct of arrays in a single allocation
• union_find: disjoint sets on poly_vector
• optional: supports references and void, monadic operations
• pool, thread_pool, string_joiner

concurrency primitives (cth::co)

• atomic_fence: manual reset event on std::atomic wait / notify, atomic_heap_fence as movable variant
• global_switch: thread safe, reference counted on / off switch for global state
• unique_cohandle: owning std::coroutine_handle
• extract_awaiter: the awaiter of any awaitable, member or free operator co_await

metaprogramming (cth::mta)

• concepts as values: CPT(std::integral)
• multi dimensional range traits: md_range_value_t, range2d_over_cpt
• trait packs, tuple & variant helpers

logging & exceptions (cth::log, cth::except)

• CTH_STABLE_* macros always active, CTH_* debug only
• capture std::source_location and std::stacktrace
• trailing block runs only if the condition holds

formatting

• CTH_FORMAT_CLASS, CTH_FORMAT_ALIAS, CTH_FORMAT_CPT: generate std::formatter specializations for classes, wrapper types and all types of a concept

algorithms (cth::alg, cth::views)

• unique_combine / assign: bipartite matching on 2d ranges
• pipeable views: split_into, drop_stride, transform_call, to_ptr_range

hashing (cth::hash)

• combine, range hashing
• hash_aggregate: hashes aggregates member wise

pointers

• not_null, move_ptr

io (cth::io)

• colored console output: col_stream
• file reading: file::chop, file::read

cth::coro

coroutine runtime on asio

• co::scheduler: asio::io_context on its own threads
• co::executor: spawns tasks, moves execution back onto the scheduler after foreign awaitables
• this_coro::executor, this_coro::wait(duration), native handle waits

cth::os

portable waitable handles

• native handles: fd (linux), HANDLE (windows)
• os::fence: eventfd (linux), event (windows)
• os::timer: timerfd (linux), high resolution waitable timer (windows), sub millisecond waits (asio's steady_timer can't)

cth::win

windows only

• win32 wrappers without leaking <Windows.h>
• cth::win::capture: window capture

examples

offset allocation & defragmentation

cth::dt::miniram ram{1024};

auto const a = ram.allocate(256);
auto const b = ram.allocate(256);
ram.free(a);

auto const report = ram.defragment(); // b moves to offset 0
for(auto const& move : report.moves)
    std::memmove(memory + move.dstOffset, memory + move.srcOffset, move.size);

coroutines

cth::co::scheduler scheduler{cth::co::autostart, 2};
cth::co::executor executor{scheduler};

auto task = []() -> cth::co::executor_task<int> {
    co_await cth::co::this_coro::wait(std::chrono::microseconds{200});
    co_return 42;
};

int const result = cth::co::sync(executor.spawn(task()));

logging

from cth/io/file.hpp:

CTH_STABLE_ERR(!file.is_open(), "failed to open file") {
    details->add("file: {0}", path.string());
    throw details->exception();
}

building

requirements

• cmake 4.1+, ninja
• vcpkg with VCPKG_ROOT set
• gcc 16, clang 22+ (libstdc++) or msvc

build & test

git clone --recursive https://github.com/codethinki/cth.git
cd cth
cmake --preset gcc_release
cmake --build out/build/gcc_release
ctest --test-dir out/build/gcc_release

presets

• gcc_debug, gcc_release, clang_debug, clang_release
• windows only: msvc_debug, msvc_release

using cth in another project

building installs the package into out/install/<preset> (target cth_package), point cth_ROOT there:

find_package(cth CONFIG REQUIRED COMPONENTS coro)
target_link_libraries(app PRIVATE cth::coro)

api not stable yet, no versioned releases

components

• cth, os, coro
• windows only: win, win_capture

license

MIT