From 51169f5f9ab178a4ddfe9dac461405a71c9c0f94 Mon Sep 17 00:00:00 2001
From: Mike Vink <mike@pionative.com>
Date: Wed, 22 May 2024 08:49:29 +0200
Subject: organise

---
 2/homework/implement_calloc.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 2/homework/implement_calloc.c

(limited to '2/homework/implement_calloc.c')

diff --git a/2/homework/implement_calloc.c b/2/homework/implement_calloc.c
new file mode 100644
index 0000000..62c3804
--- /dev/null
+++ b/2/homework/implement_calloc.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+void *my_calloc(size_t nmemb, size_t size) {
+    if (nmemb == 0 || size == 0) {
+        return NULL;
+    }
+    /* Check if invariant of multiplication is broken by overflow */
+    size_t membytes = nmemb * size;
+    if (membytes/nmemb != size) {
+        return NULL;
+    }
+    void *mem_or_null = malloc(membytes);
+    if (mem_or_null == NULL) {
+        return NULL;
+    }
+
+    return memset(mem_or_null, 0, membytes);
+}
+
+int main() {
+    char *buf = my_calloc(10, 15);
+    int i;
+    for (i=0; i<10*15; ++i)
+        printf("%c", 97 + buf[i]);
+    return 0;
+}
-- 
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