HASHCC - Template-based C++ Hash Map Library

Overview

HASHCC is an object-oriented C++ hash map library based on C++ templates. It implements a trie-like hash tree data structure, providing efficient key-value storage with customizable hash functions.

When you push a key/object tuple into the HashMap, it builds a tree structure where:

• Depth equals the length of the hash
• Width equals the variety of hash symbols

The library supports multiple hash functions:

• FNV (Fowler-Noll-Vo) - 24-character decimal hash
• Adler - 24-character decimal hash
• ELF - 10-character decimal hash

This creates a massive address space (e.g., 24^10 = possible combinations) for storing objects with minimal collisions.

Features

• Template-based generic key-value storage
• Multiple hash functions (FNV, Adler, ELF)
• Support for various key types: String, Int16, Int32, Int64, uInt16, uInt32, uInt64
• Trie-like internal tree structure for efficient storage
• Comprehensive unit tests with Catch2
• Performance benchmarking capabilities
• MIT Licensed

Prerequisites

• CMake 3.10+
• Ninja build system
• C++11 compatible compiler (GCC, Clang, MSVC)

Building

Clone the Repository

git clone https://github.com/graetz23/hashcc.git
cd hashcc

Configure and Build

mkdir -p build
cd build
cmake -G Ninja ..
ninja

This will create two executables:

• ./build/hashcc - Main application
• ./build/hashcc-test - Unit and performance tests

Running Tests

All Tests (Unit + Performance)

./build/hashcc-test

Unit Tests Only

./build/hashcc-test "~[perf]"

Performance Tests Only

./build/hashcc-test "[perf]"

Benchmark Results

Tests were run on the following workstation:

Component	Specification
CPU	Intel Xeon E5-2680 v4 @ 2.40GHz
Cores	14 cores / 28 threads
RAM	62 GB
OS	Linux

Unit Test Results

All tests passed (1,000,170 assertions in 36 test cases)

Performance Benchmarks

Operation	Entries	Time (ms)
Insert	1,000,000	~3,400 ms
Insert	2,000,000	~6,300 ms
Insert	4,000,000	~13,000 ms
Insert	8,000,000	~27,000 ms
Retrieve	1,000,000	~2,800 ms
Retrieve	2,000,000	~5,900 ms
Retrieve	4,000,000	~12,000 ms
Retrieve	8,000,000	~25,000 ms

Note: Performance results may vary based on hardware and system load.

Usage Example

#include "hashcc/hashcc.h"

using namespace HASHCC;

int main() {
    // Create a HashMap with FNV hash
    OBJ::HashMapBuilder builder;
    OBJ::HashMap<Int32, String>* map = builder.create<Int32, String>(OBJ::Type::Dec24Fnv);

    // Put values
    map->put(1, "first");
    map->put(2, "second");

    // Get values
    String value = map->get(1);  // returns "first"

    delete map;
    return 0;
}

Author

Christian (graetz23@gmail.com)

License

HASHCC is distributed under the MIT License. See the LICENSE file for full details.

---

Copyright (c) 2008-2026 Christian (graetz23@gmail.com)