Custom Memory Allocation Library

Description

This project re-implements the standard malloc, calloc, realloc and free routines. The implementation lives in src/nu_malloc.c with its public header in include/nu_malloc.h.

Project layout

• src/ ‑ library and example sources
• include/ ‑ public headers
• tests/ ‑ unit tests and helper scripts

Usage

To use the custom memory functions, include nu_malloc.h in your program. The header is C++ friendly and wraps the declarations in extern "C" when included from C++ code. Call the functions just like their standard library counterparts. The function prototypes are as follows:

        void* nu_malloc(size_t);
        void* nu_calloc(size_t, size_t);
        void* nu_realloc(void*, size_t);
        void nu_free(void*);

Example

        #include "nu_malloc.h"

        int main() {
        int* ptr = (int*) nu_malloc(sizeof(int));
        *ptr = 5;
        printf("Value at ptr: %d\n", *ptr);
        nu_free(ptr);
        return 0;
        }

Building

A simple Makefile is included. The project uses mmap and munmap on POSIX systems. When _POSIX_VERSION is undefined the code falls back to the standard malloc family. Both a static library (libnu_malloc.a) and a shared library (libnu_malloc.so) are produced.

POSIX systems

make

This compiles the example program, the test binary and the libnu_malloc.a library into the build/ directory. Run make test to execute the test suite.

Non‑POSIX systems

The same command works because the source automatically switches to malloc/realloc/free. It does so when mmap is unavailable.

make

To compile manually without make on any platform:

gcc -std=c11 src/example.c src/nu_malloc.c -Iinclude -o example

To build just the static library:

make libnu_malloc.a

To build just the shared library:

make libnu_malloc.so

You can install the header and libraries with:

make install

The install location can be customized with PREFIX, INCLUDEDIR and LIBDIR variables. The defaults install into /usr/local.

Using CMake

cmake -B build
cmake --build build

This will place libnu_malloc.a, libnu_malloc.so, example and memory_test inside the build/ directory. To run the tests use:

cd build && ctest

You can remove the installed files with:

make uninstall

Windows (MinGW/MSVC)

gcc src/example.c src/nu_malloc.c -Iinclude -o example.exe

Documentation

A minimal Doxyfile is provided. Run doxygen from the project root to generate HTML documentation in docs/html. The configuration scans the include/ and src/ directories.

Testing

You can either run make test or invoke the helper script directly:

./tests/test_example.sh

The script expects the program to print Value: 42 and requires a POSIX shell. It isn't supported on Windows unless you run it inside such an environment.

Note

This sample code is not recommended for production use. Test it thoroughly before deploying.

Compatibility

The library is written in standard C and uses mmap/munmap from <sys/mman.h> when available. When mmap is unavailable the implementation falls back to the standard memory functions. This allows the library to work on non‑POSIX platforms.

Contributing

If you want to contribute to this project, feel free to open a pull request or issue on GitHub.

License

This project is licensed under the MIT License.