开始设计

cKit/Sort/c_ShellSort.h

@@ -0,0 +1,71 @@
+#ifndef INCLUDED_C_SHELLSORT_H
+#define INCLUDED_C_SHELLSORT_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*/
+
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+C_STATIC_FORCE_INLINE
+void c_ShellSort(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;
+
+    // Stack optimization for memory swap space
+#define STACK_LIMIT 128
+    char stack_buf[STACK_LIMIT];
+    void* temp = NULL;
+
+    if (size <= STACK_LIMIT) {
+        temp = stack_buf;
+    } else {
+        temp = C_ALLOC(size);
+        if (temp == NULL) return;
+    }
+
+    // Using Knuth's gap sequence: h = h * 3 + 1 (1, 4, 13, 40, 121, ...)
+    c_size_t gap = 1;
+    while (gap < num / 3) {
+        gap = gap * 3 + 1;
+    }
+
+    // Start with the largest gap and work down to a gap of 1
+    while (gap > 0) {
+        for (c_size_t i = gap; i < num; i++) {
+            // temp = arr[i]
+            memcpy(temp, arr + (i * size), size);
+
+            c_size_t j = i;
+
+            // Shift elements of the gap-sorted variant until the correct position is found
+            // Loop guards prevent underflow on unsigned c_size_t subtraction (j >= gap)
+            while (j >= gap && compar(arr + ((j - gap) * size), temp) > 0) {
+                // arr[j] = arr[j - gap]
+                memcpy(arr + (j * size), arr + ((j - gap) * size), size);
+                j -= gap;
+            }
+
+            // arr[j] = temp
+            memcpy(arr + (j * size), temp, size);
+        }
+        // Reduce the gap
+        gap /= 3;
+    }
+
+    if (size > STACK_LIMIT) {
+        C_FREE(temp);
+    }
+#undef STACK_LIMIT
+}
+
+
+#endif /*INCLUDED_C_SHELLSORT_H*/