From 0f35f48c25608732bb74275ae9da6ed09964298b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zo=C3=ABy=20Noort?= <zoey@sourcedot.nl>
Date: Sat, 31 May 2025 19:37:00 +0200
Subject: [PATCH] feat: added memchr, memcmp, memmv and realloc

---
 srcs/ft_memchr.c  | 35 +++++++++++++++++++++++++++++++++++
 srcs/ft_memcmp.c  | 28 ++++++++++++++++++++++++++++
 srcs/ft_memmv.c   | 44 ++++++++++++++++++++++++++++++++++++++++++++
 srcs/ft_realloc.c | 22 ++++++++++++++++++++++
 4 files changed, 129 insertions(+)
 create mode 100644 srcs/ft_memchr.c
 create mode 100644 srcs/ft_memcmp.c
 create mode 100644 srcs/ft_memmv.c
 create mode 100644 srcs/ft_realloc.c

diff --git a/srcs/ft_memchr.c b/srcs/ft_memchr.c
new file mode 100644
index 0000000..21baf6c
--- /dev/null
+++ b/srcs/ft_memchr.c
@@ -0,0 +1,35 @@
+#include <stddef.h>
+#include <stdint.h>
+
+void *ft_memchr(const void *s, int c, size_t n)
+{
+    const unsigned char *p = s;
+    unsigned char uc = (unsigned char)c;
+
+    while (n && ((uintptr_t)p % sizeof(size_t))) {
+        if (*p == uc)
+            return ((void *)p);
+        ++p;
+        --n;
+    }
+    size_t mask = 0;
+    for (size_t i = 0; i < sizeof(size_t); ++i)
+        mask |= (size_t)uc << (i * 8);
+
+    while (n >= sizeof(size_t)) {
+        size_t word = *(const size_t *)p;
+        size_t cmp = word ^ mask;
+        for (size_t i = 0; i < sizeof(size_t); ++i) {
+            if (((cmp >> (i * 8)) & 0xFF) == 0)
+                return ((void *)(p + i));
+        }
+        p += sizeof(size_t);
+        n -= sizeof(size_t);
+    }
+    while (n--) {
+        if (*p == uc)
+            return ((void *)p);
+        ++p;
+    }
+    return (NULL);
+}
diff --git a/srcs/ft_memcmp.c b/srcs/ft_memcmp.c
new file mode 100644
index 0000000..ab3a0f0
--- /dev/null
+++ b/srcs/ft_memcmp.c
@@ -0,0 +1,28 @@
+#include <stddef.h>
+#include <stdint.h>
+
+int ft_memcmp(const void *s1, const void *s2, size_t n)
+{
+    const unsigned char *p1 = s1, *p2 = s2;
+
+    while (n >= sizeof(size_t)) {
+        size_t w1 = *(const size_t *)p1;
+        size_t w2 = *(const size_t *)p2;
+        if (w1 != w2) {
+            for (size_t i = 0; i < sizeof(size_t); ++i) {
+                if (p1[i] != p2[i])
+                    return (p1[i] - p2[i]);
+            }
+        }
+        p1 += sizeof(size_t);
+        p2 += sizeof(size_t);
+        n  -= sizeof(size_t);
+    }
+    while (n--) {
+        if (*p1 != *p2)
+            return (*p1 - *p2);
+        ++p1;
+        ++p2;
+    }
+    return (0);
+}
diff --git a/srcs/ft_memmv.c b/srcs/ft_memmv.c
new file mode 100644
index 0000000..abd2ccf
--- /dev/null
+++ b/srcs/ft_memmv.c
@@ -0,0 +1,44 @@
+#include <stddef.h>
+#include <stdint.h>
+
+void *ft_memmove(void *dst, const void *src, size_t n)
+{
+    unsigned char *d = dst;
+    const unsigned char *s = src;
+
+    if (d == s || n == 0)
+        return dst;
+
+    if (d < s) {
+        while (((uintptr_t)d % sizeof(size_t)) && n) {
+            *d++ = *s++;
+            n--;
+        }
+        while (n >= sizeof(size_t)) {
+            *(size_t *)d = *(const size_t *)s;
+            d += sizeof(size_t);
+            s += sizeof(size_t);
+            n -= sizeof(size_t);
+        }
+        while (n--) {
+            *d++ = *s++;
+        }
+    } else {
+        d += n;
+        s += n;
+        while (n && ((uintptr_t)d % sizeof(size_t))) {
+            *(--d) = *(--s);
+            n--;
+        }
+        while (n >= sizeof(size_t)) {
+            d -= sizeof(size_t);
+            s -= sizeof(size_t);
+            *(size_t *)d = *(const size_t *)s;
+            n -= sizeof(size_t);
+        }
+        while (n--) {
+            *(--d) = *(--s);
+        }
+    }
+    return (dst);
+}
diff --git a/srcs/ft_realloc.c b/srcs/ft_realloc.c
new file mode 100644
index 0000000..bdd5cf9
--- /dev/null
+++ b/srcs/ft_realloc.c
@@ -0,0 +1,22 @@
+#include "libft.h"
+#include <stdlib.h>
+#include <string.h>
+
+void *ft_realloc(void *ptr, size_t old_size, size_t new_size)
+{
+    if (new_size == 0) {
+        free(ptr);
+        return (NULL);
+    }
+    if (!ptr)
+        return (malloc(new_size));
+
+    void *new_ptr = malloc(new_size);
+    if (!new_ptr)
+        return (NULL);
+
+    size_t copy_size = old_size < new_size ? old_size : new_size;
+    ft_memcpy(new_ptr, ptr, copy_size);
+    free(ptr);
+    return (new_ptr);
+}