// MIT License, Copyright (c) 2020 Marvin Borner

#include <def.h>
#include <errno.h>
#include <mem.h>
#include <str.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;
}

char *strncpy(char *dst, const char *src, u32 n)
{
	char *q = dst;

	while (n-- && (*dst++ = *src++))
		;

	return q;
}

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(char *s, int c)
{
	while (*s != (char)c) {
		if (!*s)
			return NULL;
		s++;
	}

	return s;
}

char *strrchr(char *s, int c)
{
	char *ret = 0;

	do {
		if (*s == c)
			ret = s;
	} while (*s++);

	return ret;
}

char *strcat(char *dst, const char *src)
{
	strcpy(strchr(dst, '\0'), src);
	return dst;
}

char *strncat(char *dst, const char *src, u32 n)
{
	strncpy(strchr(dst, '\0'), src, n);
	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);

	memcpy(d, s, l);

	return d;
}

static const char *strerrors[EMAX] = {
	"Success",
	"Operation not permitted",
	"No such file or directory",
	"No such process",
	"Interrupted system call",
	"I/O error",
	"No such device or address",
	"Argument list too long",
	"Exec format error",
	"Bad file number",
	"No child processes",
	"Try again",
	"Out of memory",
	"Permission denied",
	"Bad address",
	"Block device required",
	"Device or resource busy",
	"File exists",
	"Cross-device link",
	"No such device",
	"Not a directory",
	"Is a directory",
	"Invalid argument",
	"File table overflow",
	"Too many open files",
	"Not a typewriter",
	"Text file busy",
	"File too large",
	"No space left on device",
	"Illegal seek",
	"Read-only file system",
	"Too many links",
	"Broken pipe",
	"Math argument out of domain of func",
	"Math result not representable",
};

const char *strerror(u32 error)
{
	if (error <= EMAX)
		return strerrors[error];
	return "Unknown error";
}