From 5f92d24de075a56ccdfa47c38a3bd465fe6f7435 Mon Sep 17 00:00:00 2001
From: Seoxi Ryouko <amaterasuseoxi@proton.me>
Date: Fri, 21 Aug 2026 01:01:11 -0500
Subject: [PATCH] Added dependency-injected shuffle function

---
 libkeke_array.c | 11 ++++++++++-
 libkeke_array.h |  4 +++-
 libkeke_utils.c | 24 +++++++++++++++++-------
 libkeke_utils.h |  2 +-
 test_array.c    | 13 +++++++++----
 5 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/libkeke_array.c b/libkeke_array.c
index a4b18b2..418ea22 100644
--- a/libkeke_array.c
+++ b/libkeke_array.c
@@ -22,7 +22,7 @@ typedef struct {
 KekeArray *keke_array_alloc(size_t initial_len, size_t type_size) {
 	KekeArray *array = malloc(sizeof(*array));
 	array->len = initial_len;
-	size_t max_len = next_power_of_two(initial_len);
+	size_t max_len = bit_ceil(initial_len);
 
 	array->type_size = type_size;
 	array->max_len = max_len;
@@ -198,6 +198,15 @@ void keke_array_qsort_header(KekeArray *array, size_t start_header_size) {
 	qsort_r(array->content, array->len, array->type_size, compar, &start_header_size);
 }
 
+typedef int (*Rng_fun)(int);
+
+void keke_array_shuffle(KekeArray *array, Rng_fun rng) {
+	for(size_t i = 0; i < array->len; ++i) {
+		size_t j = rng(i + 1);
+		keke_swap(ARRAY_GET(array, i), ARRAY_GET(array, j), array->type_size);
+	} 
+}
+
 // requires pre-sorted arrays
 KekeArray *keke_array_merge(KekeArray *a, KekeArray *b) {
 	if(a->len == 0) {
diff --git a/libkeke_array.h b/libkeke_array.h
index 51a34bd..2bdf804 100644
--- a/libkeke_array.h
+++ b/libkeke_array.h
@@ -40,13 +40,15 @@ void keke_array_reverse(KekeArray *array);
 void keke_array_qsort(KekeArray *array);
 void keke_array_qsort_header(KekeArray *array, size_t start_header_size);
 KekeArray *keke_array_merge(KekeArray *a, KekeArray *b);
+typedef int (*Rng_fun)(int);
+void keke_array_shuffle(KekeArray *array, Rng_fun rng);
 
 typedef bool (*Test_func)(void *, size_t, KekeArray *);
 bool keke_array_some(KekeArray *array, Test_func test);
 bool keke_array_all(KekeArray *array, Test_func test);
 
-void *keke_array_find_start(KekeArray *array, void *start, size_t size);
 void *keke_array_find(KekeArray *array, Test_func test);
+void *keke_array_find_start(KekeArray *array, void *start, size_t size);
 
 KekeArray *keke_array_filter(KekeArray *array, Test_func test);
 
diff --git a/libkeke_utils.c b/libkeke_utils.c
index 009bd3b..798db44 100644
--- a/libkeke_utils.c
+++ b/libkeke_utils.c
@@ -1,17 +1,27 @@
 #include <stddef.h>
 
 void keke_swap(void *a, void *b, size_t size) {
-	char *aa = a;
-	char *bb = b;
-	for(size_t i = 0; i < size; i++) {
+	if(a == b) return;
+	size_t i = 0;
+	int *ia = a;
+	int *ib = b;
+	for(i = 0; i < (size / sizeof(int)); ++i) {
+		ia[i] ^= ib[i];
+		ib[i] ^= ia[i];
+		ia[i] ^= ib[i];
+	}
+	size %= sizeof(int);
+	char *aa = a + (i * sizeof(int));
+	char *bb = b + (i * sizeof(int));
+	for(i = 0; i < size; i++) {
 		aa[i] ^= bb[i];
 		bb[i] ^= aa[i];
 		aa[i] ^= bb[i];
 	}
 }
 
-size_t next_power_of_two(size_t s) {
-	size_t t = 1;
-	while(t < s) t <<= 1;
-	return t;
+size_t bit_ceil(size_t	s) {
+    size_t t = 1;
+    while(t < s) t <<= 1;
+    return t;
 }
diff --git a/libkeke_utils.h b/libkeke_utils.h
index 05870fd..1eb4929 100644
--- a/libkeke_utils.h
+++ b/libkeke_utils.h
@@ -6,7 +6,7 @@
 #define BOOL_PRETTY(b) (b ? "True" : "False")
 
 void keke_swap(void *, void *, size_t);
-size_t next_power_of_two(size_t s);
+size_t bit_ceil(size_t s);
 
 #endif
 
diff --git a/test_array.c b/test_array.c
index 0f7cb33..4ccfc6e 100644
--- a/test_array.c
+++ b/test_array.c
@@ -33,6 +33,10 @@ void add(void *vx, void *vacc) {
 	*acc += *x;
 }
 
+int rng(int x) {
+	return rand() % x;
+}
+
 int main(void) {
 	KekeArray *array = keke_array_alloc(ARRAY_LEN, sizeof(int));
 
@@ -78,7 +82,7 @@ int main(void) {
 	puts("\n");
 
     keke_array_pop(array2, &j);
-    puts("Expected value:\n7, 7, 6, 5, 6,\t0");
+    puts("Expected value:\n7, 7, 6, 5, 6,\t5");
     keke_array_foreach(array2, output);
     printf("\t%d", j);
 	puts("\n");
@@ -147,9 +151,10 @@ int main(void) {
 	printf("Expected value:\n0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 5, 6, 7, 8, 9,\n");
 	keke_array_foreach(array5, output);
 	puts("\n");
-	keke_array_foreach(array, output);
-	puts("\n");
-	keke_array_foreach(array2, output);
+
+	keke_array_shuffle(array5, rng);
+	printf("Expected value:\n2, 0, 3, 7, 3, 1, 8, 2, 2, 1, 3, 5, 6, 2, 9, 4,\n");
+	keke_array_foreach(array5, output);
 	puts("\n");
 
     keke_array_free(array);