From 967be9e750221ab2ab783f95df79bb26d290a45e Mon Sep 17 00:00:00 2001
From: Martial Simon <msimon_fr@hotmail.com>
Date: Mon, 15 Sep 2025 01:07:58 +0200
Subject: add: added projects

---
 malloc/page_begin/main.c       | 21 +++++++++++++++++++++
 malloc/page_begin/page_begin.c | 10 ++++++++++
 malloc/page_begin/page_begin.h |  8 ++++++++
 3 files changed, 39 insertions(+)
 create mode 100644 malloc/page_begin/main.c
 create mode 100644 malloc/page_begin/page_begin.c
 create mode 100644 malloc/page_begin/page_begin.h

(limited to 'malloc/page_begin')

diff --git a/malloc/page_begin/main.c b/malloc/page_begin/main.c
new file mode 100644
index 0000000..8fc931e
--- /dev/null
+++ b/malloc/page_begin/main.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+#include "page_begin.h"
+
+static void display_result(void *ptr, size_t page_size, void *expected_result)
+{
+    void *res = page_begin(ptr, page_size);
+
+    printf("ptr: %p\n", ptr);
+    printf("page_size: %lu\n", page_size);
+    printf("expected_result: %p\n", expected_result);
+    printf("result: %p\n", res);
+
+    printf(expected_result == res ? "OK\n" : "KO\n");
+}
+
+int main(void)
+{
+    display_result((void *)0x1234ffea, 4096, (void *)0x1234f000);
+    display_result((void *)0x1234ffea, 256, (void *)0x1234ff00);
+}
diff --git a/malloc/page_begin/page_begin.c b/malloc/page_begin/page_begin.c
new file mode 100644
index 0000000..ebb1842
--- /dev/null
+++ b/malloc/page_begin/page_begin.c
@@ -0,0 +1,10 @@
+#include "page_begin.h"
+
+void *page_begin(void *ptr, size_t page_size)
+{
+    char *a = ptr;
+    char *p = NULL;
+    size_t test = a - p;
+    void *res = (void *)(test & ~(page_size - 1));
+    return res;
+}
diff --git a/malloc/page_begin/page_begin.h b/malloc/page_begin/page_begin.h
new file mode 100644
index 0000000..ba467d5
--- /dev/null
+++ b/malloc/page_begin/page_begin.h
@@ -0,0 +1,8 @@
+#ifndef PAGE_BEGIN_H
+#define PAGE_BEGIN_H
+
+#include <stddef.h>
+
+void *page_begin(void *ptr, size_t page_size);
+
+#endif /* !PAGE_BEGIN_H */
-- 
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