libflint is a C library of containers and helpers. Handles are caller-owned; payloads are void *. Each module page covers ownership, return codes, and examples.

Modules

Data Structures

• [[linkedlist]]: Doubly-linked list of void *. Foundation for stack, queue, and set
• [[vector]]: Growable array of void *
• [[stack]]: LIFO stack of void *
• [[queue]]: Unbounded FIFO queue
• [[set]]: Small unique collection. Membership is linear
• [[hashset]]: Unique collection with hashed membership
• [[binarytree]]: Binary tree you build by attaching left and right children
• [[bst]]: Ordered binary search tree (insert, find, remove)
• [[ringbuf]]: Fixed-capacity FIFO of void *. No allocation after init
• [[bytering]]: Lock-free byte ring for one producer and one consumer
• [[statemachine]]: Table-driven finite state machine with guards and entry/exit callbacks

Allocators

• [[memory]]: Arena (bump allocation with save/restore) and pool (fixed-size chunks)

Utilities

• [[string]]: lfstr_* helpers and LfStr views
• [[math]]: Integer helpers, LfPoint, and Bresenham
• [[codec]]: Hex and Base64 (encoding, not cryptography)
• [[puzzle]]: Repeating-key XOR, Hamming distance, English scoring
• [[crypto]]: Includes [[codec]] and [[puzzle]]
• [[input]]: Read a regular, seekable file into memory
• [[process]]: lf_capture_system (popen; the command is not sanitized)
• [[bitops]]: Macros to set, clear, toggle, test, extract, and insert bit fields

Platform

• [[network]]: IPv4 lf_listen_tcp, lf_bind_udp, and lf_close
• [[macos]]: Process CPU and memory sampling (Apple only)
• [[compat]]: Overflow-checked lf_reallocarray on every platform

Requirements

A C99 compiler and CMake. Linux needs libbsd (strtonum in the input module). macOS, OpenBSD, and FreeBSD need no extra libraries.

Memory Management

You allocate the handle (List, Vector, and so on). The library allocates internal nodes and buffers. A destroy callback, if you pass one, runs when the container is destroyed or cleared, not when you pop or remove an item.

Why the name 'libflint'?

libflint is named after my dog Flint, who passed away in 2021. I miss you buddy.