1 files changed, 169 insertions, 0 deletions
diff --git a/src/user/lib/string/string.c b/src/user/lib/string/string.c
new file mode 100644
index 0000000..f141a3d
--- /dev/null
+++ b/src/user/lib/string/string.c
@@ -0,0 +1,169 @@
+#include <ctype.h>
+#include <errno.h>
+#include <string.h>
+#include <strings.h>
+
+long strtol(const char *restrict s, char **restrict end, int base) {
+	long res = 0;
+	int sign = 1;
+
+	while (isspace(*s)) s++;
+
+	if (*s == '+') {
+		s++;
+	} else if (*s == '-') {
+		s++;
+		sign = -1;
+	}
+
+	if (base == 0) {
+		if (*s == '0') {
+			s++;
+			if (*s == 'x' || *s == 'X') {
+				s++;
+				base = 16;
+			} else {
+				base = 8;
+			}
+		} else {
+			base = 10;
+		}
+	}
+
+	for (;;) {
+		unsigned char digit = *s;
+		if      ('0' <= digit && digit <= '9') digit -= '0';
+		else if ('a' <= digit && digit <= 'z') digit -= 'a' - 10;
+		else if ('A' <= digit && digit <= 'Z') digit -= 'A' - 10;
+		else break;
+
+		if (digit >= base) break;
+		// TODO overflow check
+		res *= base;
+		res += digit;
+
+		s++;
+	}
+	if (end) *end = (void*)s;
+	return res * sign;
+}
+
+#include <user/lib/panic.h>
+double strtod(const char *restrict s, char **restrict end) {
+	(void)s; (void)end;
+	__libc_panic("unimplemented");
+}
+
+char *strchr(const char *s, int c) {
+	for (; *s; 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) {
+	while (n-- & *s1 && *s1 == *s2) {
+		s1++; s2++;
+	}
+	if (*s1 == *s2) return  0;
+	if (*s1 <  *s2) return -1;
+	else            return  1;
+}
+
+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 s1, const char *restrict s2, size_t n) {
+	for (size_t i = 0; i < n; i++) {
+		s1[i] = s2[i];
+		if (s1[i] == '\0') return s1 + i; // TODO fill with null bytes
+	}
+	return s1 + 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;
+}