From 8108c8f3ab0462c051426639efd4db1a5769b8e4 Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Tue, 20 Nov 2018 17:03:57 +0100
Subject: [PATCH] klibc: add string related func

---
 core/klibc.c | 32 ++++++++++++++++++++++++++++++++
 core/klibc.h |  3 +++
 2 files changed, 35 insertions(+)

diff --git a/core/klibc.c b/core/klibc.c
index 8ba4cef..930409c 100644
--- a/core/klibc.c
+++ b/core/klibc.c
@@ -55,3 +55,35 @@ char * itoa( int value, char * str, int base )
     }
     return rc;
 }
+
+/* K&R */
+void reverse(char s[])
+{
+    int c, i, j;
+    for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
+        c    = s[i];
+        s[i] = s[j];
+        s[j] = c;
+    }
+}
+
+/* K&R */
+int strlen(char s[])
+{
+    int i = 0;
+    while (s[i] != '\0')
+        ++i;
+    return i;
+}
+
+/* K&R
+ * Returns <0 if s1<s2, 0 if s1==s2, >0 if s1>s2 */
+int strcmp(char s1[], char s2[])
+{
+    int i;
+    for (i = 0; s1[i] == s2[i]; i++) {
+        if (s1[i] == '\0')
+            return 0;
+    }
+    return s1[i] - s2[i];
+}
diff --git a/core/klibc.h b/core/klibc.h
index 37fd102..2d3634d 100644
--- a/core/klibc.h
+++ b/core/klibc.h
@@ -4,3 +4,6 @@
 void *memcpy(void *dest, const void *src, size_t n);
 void *memset(void *s, int c, size_t n);
 char *itoa(int value, char *str, int base);
+void reverse(char s[]);
+int strlen(char s[]);
+int strcmp(char s1[], char s2[]);