2 files changed, 135 insertions, 0 deletions
diff --git a/src/libc/string/strerror.c b/src/libc/string/strerror.c
new file mode 100644
index 0000000..c838299
--- /dev/null
+++ b/src/libc/string/strerror.c
@@ -0,0 +1,13 @@
+#include <string.h>
+
+static const char *errstr[] = {
+#	define E(n, str) [n] = str,
+#	include <__errno.h>
+#	undef E
+};
+
+char *strerror(int n) {
+	if (0 <= n && n * sizeof(*errstr) < sizeof(errstr) && errstr[n])
+		return (char*)errstr[n];
+	return "unknown error";
+}
diff --git a/src/libc/string/string.c b/src/libc/string/string.c
new file mode 100644
index 0000000..c65d7c5
--- /dev/null
+++ b/src/libc/string/string.c
@@ -0,0 +1,122 @@
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+char *strchr(const char *s, int c) {
+	for (; *s || c == 0; s++) {
+		if (*s == c) return (char *)s;
+	}
+	return NULL;
+}
+
+char *strrchr(const char *s, int c) {
+	for (int i = strlen(s) + 1; i >= 0; i--) {
+		if (s[i] == c) return (char *)s + i;
+	}
+	return NULL;
+}
+
+size_t strspn(const char *s, const char *accept) {
+	size_t l = 0;
+	for (; s[l] && strchr(accept, s[l]); l++);
+	return l;
+}
+
+size_t strcspn(const char *s, const char *reject) {
+	size_t l = 0;
+	for (; s[l] && !strchr(reject, s[l]); l++);
+	return l;
+}
+
+char *strpbrk(const char *s1, const char *s2) {
+	for (; *s1; s1++) {
+		if (strchr(s2, *s1)) return (char*)s1;
+	}
+	return NULL;
+}
+
+char *strtok(char *restrict s, const char *restrict sep) {
+	static char *state;
+	return strtok_r(s, sep, &state);
+}
+
+char *strtok_r(char *restrict s, const char *restrict sep, char **restrict state) {
+	char *end;
+	if (!s) s = *state;
+	s += strspn(s, sep); /* beginning of token */
+	if (!*s) return NULL;
+
+	end = s + strcspn(s, sep);
+	if (*end) {
+		*end = '\0';
+		*state = end + 1;
+	} else {
+		*state = end;
+	}
+	return s;
+}
+
+int strncmp(const char *s1, const char *s2, size_t n) {
+	for (size_t i = 0; i < n; i++) {
+		if (s1[i] < s2[i]) return -1;
+		if (s1[i] > s2[i]) return  1;
+	}
+	return 0;
+}
+
+int strcoll(const char *s1, const char *s2) {
+	return strcmp(s1, s2);
+}
+
+// TODO implement strstr using Boyer-Moore
+char *strstr(const char *s1, const char *s2) {
+	size_t l1 = strlen(s1), l2 = strlen(s2);
+	for (; l2 <= l1; s1++, l1--) {
+		if (memcmp(s1, s2, l2) == 0) return (char*)s1;
+	}
+	return NULL;
+}
+
+char *strcpy(char *restrict s1, const char *restrict s2) {
+	while (*s2) *s1++ = *s2++;
+	*s1 = *s2;
+	return s1;
+}
+
+char *strncpy(char *restrict dst, const char *restrict src, size_t n) {
+	for (size_t i = 0; i < n; i++) {
+		dst[i] = src[i];
+		if (dst[i] == '\0') return dst + i; // TODO fill with null bytes
+	}
+	return dst;
+}
+
+char *stpncpy(char *restrict dst, const char *restrict src, size_t n) {
+	return stpncpy(dst, src, n) + n;
+}
+
+char *strdup(const char *s) {
+	size_t len = strlen(s) + 1;
+	char *buf = malloc(len);
+	if (buf) memcpy(buf, s, len);
+	return buf;
+}
+
+/* strings.h */
+int strcasecmp(const char *s1, const char *s2) {
+	return strncasecmp(s1, s2, ~0);
+}
+
+int strncasecmp(const char *s1, const char *s2, size_t n) {
+	for (size_t i = 0; i < n; i++) {
+		char c1 = tolower(s1[i]), c2 = tolower(s2[i]);
+		if (c1 == '\0' || c1 != c2) {
+			if (c1 < c2)      return -1;
+			else if (c1 > c2) return 1;
+			else              return 0;
+		}
+	}
+	return 0;
+}