1 files changed, 98 insertions, 0 deletions
diff --git a/lib/str.c b/lib/str.c
new file mode 100644
index 0000000..d1ee325
--- /dev/null
+++ b/lib/str.c
@@ -0,0 +1,98 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <def.h>
+#include <mem.h>
+
+u32 strlen(const char *s)
+{
+	const char *ss = s;
+	while (*ss)
+		ss++;
+	return ss - s;
+}
+
+char *strcpy(char *dst, const char *src)
+{
+	char *q = dst;
+	const char *p = src;
+	char ch;
+
+	do {
+		*q++ = ch = *p++;
+	} while (ch);
+
+	return dst;
+}
+
+int strcmp(const char *s1, const char *s2)
+{
+	const u8 *c1 = (const u8 *)s1;
+	const u8 *c2 = (const u8 *)s2;
+	u8 ch;
+	int d = 0;
+
+	while (1) {
+		d = (int)(ch = *c1++) - (int)*c2++;
+		if (d || !ch)
+			break;
+	}
+
+	return d;
+}
+
+int strncmp(const char *s1, const char *s2, u32 n)
+{
+	const u8 *c1 = (const u8 *)s1;
+	const u8 *c2 = (const u8 *)s2;
+	u8 ch;
+	int d = 0;
+
+	while (n--) {
+		d = (int)(ch = *c1++) - (int)*c2++;
+		if (d || !ch)
+			break;
+	}
+
+	return d;
+}
+
+char *strchr(const char *s, int c)
+{
+	while (*s != (char)c) {
+		if (!*s)
+			return NULL;
+		s++;
+	}
+
+	return (char *)s;
+}
+
+char *strcat(char *dst, const char *src)
+{
+	strcpy(strchr(dst, '\0'), src);
+	return dst;
+}
+
+char *strinv(char *s)
+{
+	u32 s_str = strlen(s);
+
+	int iterations = (int)s_str / 2;
+	for (int i = 0; i < iterations; i++) {
+		char aux = s[i];
+		s[i] = s[(s_str - i) - 1];
+		s[(s_str - i) - 1] = aux;
+	}
+	return s;
+}
+
+char *strdup(const char *s)
+{
+	int l = strlen(s) + 1;
+	char *d = malloc(l);
+
+	if (d)
+		memcpy(d, s, l);
+
+	return d;
+}