/**
 * @file ntlibc.c
 * @author CuBeatSystems
 * @author Shinichiro Nakamura
 * @copyright
 * ===============================================================
 * Natural Tiny Shell (NT-Shell) Version 0.3.1
 * ===============================================================
 * Copyright (c) 2010-2016 Shinichiro Nakamura
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include "ntlibc.h"

int ntlibc_strlen(const char *s)
{
	const char *p = s;
	int cnt = 0;
	while (*p) {
		cnt++;
		p++;
	}
	return cnt;
}

char *ntlibc_strcpy(char *des, const char *src)
{
	char *d = des;
	const char *s = src;
	while (*s) {
		*d = *s;
		d++;
		s++;
	}
	*d = '\0';
	return des;
}

int ntlibc_strlcpy(char *des, const char *src, int n)
{
	char *d = des, *e = &des[n];
	const char *s = src;
	while (*s && d < e) {
		*d = *s;
		d++;
		s++;
	}
	*d++ = '\0';
	return (int)d - (int)des;
}

char *ntlibc_strcat(char *des, const char *src)
{
	char *d = des;
	const char *s = src;
	while (*d) {
		d++;
	}
	while (*s) {
		*d = *s;
		d++;
		s++;
	}
	*d = '\0';
	return des;
}

int ntlibc_strlcat(char *des, const char *src, int n)
{
	char *d = des, *e = &des[n];
	const char *s = src;
	while (*d && d < e) {
		d++;
	}
	while (*s && d < e) {
		*d = *s;
		d++;
		s++;
	}
	*d++ = '\0';
	return (int)d - (int)des;
}

int ntlibc_strcmp(const char *s1, const char *s2)
{
	char *p1 = (char *)s1;
	char *p2 = (char *)s2;
	while (*p1 || *p2) {
		if (*p1 != *p2) {
			return (*p1 < *p2) ? -1 : 1;
		}
		p1++;
		p2++;
	}
	if (*p1 == *p2) {
		return 0;
	}
	else {
		return (*p1 < *p2) ? -1 : 1;
	}
}

int ntlibc_stricmp(const char *s1, const char *s2)
{
	char *p1 = (char *)s1;
	char *p2 = (char *)s2;
	while (*p1 || *p2) {
		if (ntlibc_toupper(*p1) != ntlibc_toupper(*p2)) {
			return (*p1 < *p2) ? -1 : 1;
		}
		p1++;
		p2++;
	}
	if (*p1 == *p2) {
		return 0;
	}
	else {
		return (*p1 < *p2) ? -1 : 1;
	}
}

int ntlibc_strncmp(const char *s1, const char *s2, int n)
{
	char *p1 = (char *)s1;
	char *p2 = (char *)s2;
	int len = 0;
	while (*p1 || *p2) {
		if (n <= len) {
			break;
		}
		if (*p1 != *p2) {
			return (*p1 < *p2) ? -1 : 1;
		}
		p1++;
		p2++;
		len++;
	}
	return 0;
}

int ntlibc_isdigit(int c)
{
	if (('0' <= c) && (c <= '9')) {
		return 1;
	}
	return 0;
}

int ntlibc_isalpha(int c)
{
	if (('A' <= c) && (c <= 'Z')) {
		return 1;
	}
	if (('a' <= c) && (c <= 'z')) {
		return 1;
	}
	return 0;
}

int ntlibc_iscntrl(int c)
{
	if (c == 0x07) { return 0; }
	if (c == 0x08) { return 0; }
	if (c == 0x09) { return 0; }
	if (c == 0x0a) { return 0; }
	if (c == 0x0b) { return 0; }
	if (c == 0x0c) { return 0; }
	if (c == 0x0d) { return 0; }
	if ((0x00 <= c) && (c <= 0x1f)) {
		return 1;
	}
	return 0;
}

int ntlibc_toupper(int c)
{
	if (('a' <= c) && (c <= 'z')) {
		int diff = 'a' - 'A';
		return c - diff;
	}
	return c;
}

int ntlibc_tolower(int c)
{
	if (('A' <= c) && (c <= 'Z')) {
		int diff = 'a' - 'A';
		return c + diff;
	}
	return c;
}

int ntlibc_atoi(const char *nptr)
{
	int cnt;
	int num = 0;
	int ofs = 0;
	int sign = 0;
	int scnt = 0;
	char *p = (char *)nptr;
	while (*p != '\0') {
		if (!ntlibc_isdigit(*p)) {
			if (*p == ' ') {
				ofs++;
			}
			if (*p == '+') {
				sign = 0;
				ofs++;
				if (scnt++ > 0) {
					return 0;
				}
			}
			if (*p == '-') {
				sign = 1;
				ofs++;
				if (scnt++ > 0) {
					return 0;
				}
			}
		}
		p++;
	}
	for (cnt = ofs; (nptr[cnt] >= '0') && (nptr[cnt] <= '9'); cnt++) {
		num = 10 * num + (nptr[cnt] - '0');
	}
	if (sign) {
		return -num;
	}
	else {
		return num;
	}
}

unsigned long ntlibc_strtoul(const char *restrict nptr, char **restrict endptr, int base)
{
	int cnt;
	int num = 0;
	int ofs = 0;
	int sign = 0;
	int scnt = 0;
	char *p = (char *)nptr;
	while (*p != '\0') {
		if (!ntlibc_isdigit(*p)) {
			if (*p == ' ') {
				ofs++;
			}
			if (*p == '+') {
				sign = 0;
				ofs++;
				if (scnt++ > 0) {
					*endptr = p;
					break;
				}
			}
			if (*p == '-') {
				sign = 1;
				ofs++;
				if (scnt++ > 0) {
					*endptr = p;
					break;
				}
			}
			*endptr = p;
			break;
		}
		p++;
	}
	for (cnt = ofs; (nptr[cnt] >= '0') && (nptr[cnt] <= '9'); cnt++) {
		num = 10 * num + (nptr[cnt] - '0');
	}
	if (sign) {
		return -num;
	}
	else {
		return num;
	}
}

char *ntlibc_strchr(const char *s, int c)
{
	char *p = (char *)s;
	for (;;) {
		if (*p == c) {
			return p;
		}
		if (!*p)
			break;
		p++;
	}
	return 0;
}

char *ntlibc_utoa(unsigned int value, char *s, int radix)
{
	char *s1 = s;
	char *s2 = s;

	do {
		*s2++ = "0123456789abcdefghijklmnopqrstuvwxyz"[value % radix];
		value /= radix;
	} while (value > 0);

	*s2-- = '\0';

	while (s1 < s2) {
		char c = *s1;
		*s1++ = *s2;
		*s2-- = c;
	}

	return s;
}