1 files changed, 138 insertions, 0 deletions
diff --git a/kern/string.c b/kern/string.c
new file mode 100644
index 00000000..82bcd2f1
--- /dev/null
+++ b/kern/string.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2012 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Trivial, portable implementations.
+ */
+
+#include <kern/stddef.h>
+#include <kern/string.h>
+
+void *
+memcpy(void *dest, const void *src, size_t n)
+{
+    const char *src_ptr;
+    char *dest_ptr;
+    size_t i;
+
+    dest_ptr = dest;
+    src_ptr = src;
+
+    for (i = 0; i < n; i++)
+        *dest_ptr++ = *src_ptr++;
+
+    return dest;
+}
+
+void *
+memmove(void *dest, const void *src, size_t n)
+{
+    const char *src_ptr;
+    char *dest_ptr;
+    size_t i;
+
+    if (src == dest)
+        return dest;
+    else if (src < dest) {
+        dest_ptr = (char *)dest + n - 1;
+        src_ptr = (const char *)src + n - 1;
+
+        for (i = 0; i < n; i++)
+            *dest_ptr-- = *src_ptr--;
+    } else if (src > dest) {
+        dest_ptr = dest;
+        src_ptr = src;
+
+        for  (i = 0; i < n; i++)
+            *dest_ptr++ = *src_ptr++;
+    }
+
+    return dest;
+}
+
+void *
+memset(void *s, int c, size_t n)
+{
+    char *buffer;
+    size_t i;
+
+    buffer = s;
+
+    for (i = 0; i < n; i++)
+        buffer[i] = c;
+
+    return s;
+}
+
+int
+memcmp(const void *s1, const void *s2, size_t n)
+{
+    const char *a1, *a2;
+    size_t i;
+
+    a1 = s1;
+    a2 = s2;
+
+    for (i = 0; i < n; i++)
+        if (a1[i] != a2[i])
+            return a2[i] - a1[i];
+
+    return 0;
+}
+
+size_t
+strlen(const char *s)
+{
+    size_t i;
+
+    i = 0;
+
+    while (*s++ != '\0')
+        i++;
+
+    return i;
+}
+
+char *
+strcpy(char *dest, const char *src)
+{
+    char *tmp;
+
+    tmp = dest;
+
+    while ((*dest = *src) != '\0') {
+        dest++;
+        src++;
+    }
+
+    return tmp;
+}
+
+int
+strcmp(const char *s1, const char *s2)
+{
+    char c1, c2;
+
+    while ((c1 = *s1) == (c2 = *s2)) {
+        if (c1 == '\0')
+            return 0;
+
+        s1++;
+        s2++;
+    }
+
+    return (c1 < c2) ? -1 : 1;
+}