libmsort: Generic Merge Sort Library in C

This library provides a type-agnostic, generic merge sort implementation in C using function pointers and manual memory handling. It demonstrates low-level data manipulation, pointer arithmetic, and functional design — all without relying on qsort.

Features

• Supports sorting arrays of any data type (integers, floats, structs, etc.)
• Requires only a comparison function to sort custom data types
• Replaces memcpy with a custom my_memcpy implementation
• Pure C — portable and dependency-free

How It Works

• merge_sort_generic(arr, n, element_size, cmp)
  Recursively divides the array and merges sorted halves.

• merge_generic(dest, src1, src2, len1, len2, cmp, element_size)
  Merges two sorted subarrays into a destination buffer.

• my_memcpy(dest, src, n)
  Custom byte-wise memory copy function for portability and learning.

Usage Example

#include <stdio.h>
#include "merge_sort_generic.h"

int cmp_int(const void *a, const void *b) {
    return (*(int *)a) - (*(int *)b);
}

int main() {
    int arr[] = {5, 3, 8, 1, 9};
    size_t n = sizeof(arr) / sizeof(arr[0]);

    merge_sort_generic(arr, n, sizeof(int), cmp_int);

    for (size_t i = 0; i < n; ++i) {
        printf("%d ", arr[i]);
    }
    return 0;
}