#ifndef INCLUDED_C_MERGESORT_H
#define INCLUDED_C_MERGESORT_H

#ifndef INCLUDED_C_BASE_H
#include <c_Base.h>
#endif /*INCLUDED_C_BASE_H*/


#ifndef INCLUDED_C_MEMORY_H
#include <c_Memory.h>
#endif /*INCLUDED_C_MEMORY_H*/


/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

void c_MergeSortSub(char* arr, c_size_t left, c_size_t right, c_size_t size, char* aux,
                           int (*compar)(const void*, const void*));

/**
 * Top-Level Custom Framework Entry Point for Top-Down Merge Sort.
 * Time Complexity: O(n log n) | Space Complexity: O(n) | Stable: Yes
 */
C_STATIC_FORCE_INLINE
void c_MergeSort(void* base, c_size_t num, c_size_t size,
                 int (*compar)(const void*, const void*)) {
    if (base == NULL || num < 2 || size == 0) return;

    char* arr = (char*)base;
    c_size_t total_bytes = num * size;

    // Optimization: Fallback to stack buffer allocation if overall payload fits locally
    #define MERGE_STACK_LIMIT 512
    char stack_buf[MERGE_STACK_LIMIT];
    char* aux = NULL;

    if (total_bytes <= MERGE_STACK_LIMIT) {
        aux = stack_buf;
    } else {
        aux = (char*)C_ALLOC(total_bytes);
        if (aux == NULL) return; // Allocation safeguard
    }

    // Execute recursive divide-and-conquer strategy
    c_MergeSortSub(arr, 0, num - 1, size, aux, compar);

    if (total_bytes > MERGE_STACK_LIMIT) {
        C_FREE(aux);
    }
    #undef MERGE_STACK_LIMIT
}


#endif /*INCLUDED_C_MERGESORT_H*/