#include "kernel/types.h"
#include "kernel/stat.h"
#include "kernel/fcntl.h"
#include "user/user.h"

//
// wrapper so that it's OK if main() does not call exit().
//
void _main() {
	extern int main();
	main();
	exit(0);
}

char *strcpy(char *s, const char *t) {
	char *os;

	os = s;
	while ((*s++ = *t++) != 0)
		;
	return os;
}

int strcmp(const char *p, const char *q) {
	while (*p && *p == *q)
		p++, q++;
	return (uchar)*p - (uchar)*q;
}

uint strlen(const char *s) {
	int n;

	for (n = 0; s[n]; n++)
		;
	return n;
}

void *memset(void *dst, int c, uint n) {
	char *cdst = (char *)dst;
	int i;
	for (i = 0; i < n; i++) {
		cdst[i] = c;
	}
	return dst;
}

char *strchr(const char *s, char c) {
	for (; *s; s++)
		if (*s == c)
			return (char *)s;
	return 0;
}

char *gets(char *buf, int max) {
	int i, cc;
	char c;

	for (i = 0; i + 1 < max;) {
		cc = read(0, &c, 1);
		if (cc < 1)
			break;
		buf[i++] = c;
		if (c == '\n' || c == '\r')
			break;
	}
	buf[i] = '\0';
	return buf;
}

int stat(const char *n, struct stat *st) {
	int fd;
	int r;

	fd = open(n, O_RDONLY);
	if (fd < 0)
		return -1;
	r = fstat(fd, st);
	close(fd);
	return r;
}

int atoi(const char *s) {
	int n;

	n = 0;
	while ('0' <= *s && *s <= '9')
		n = n * 10 + *s++ - '0';
	return n;
}

void *memmove(void *vdst, const void *vsrc, int n) {
	char *dst;
	const char *src;

	dst = vdst;
	src = vsrc;
	if (src > dst) {
		while (n-- > 0)
			*dst++ = *src++;
	} else {
		dst += n;
		src += n;
		while (n-- > 0)
			*--dst = *--src;
	}
	return vdst;
}

int memcmp(const void *s1, const void *s2, uint n) {
	const char *p1 = s1, *p2 = s2;
	while (n-- > 0) {
		if (*p1 != *p2) {
			return *p1 - *p2;
		}
		p1++;
		p2++;
	}
	return 0;
}

void *memcpy(void *dst, const void *src, uint n) {
	return memmove(dst, src, n);
}