#include "stdlib.h"

char buffer[33];
char itoa_chars[] = "0123456789abcdef";

int strlen(char *string) {
	int len;
	for (len = 0; *string; string++, len++)
		;
	return len;
}

void strcat(char *dest, char *source) {
	for (; *dest; dest++)
		;
	for (; *source; dest++, source++) {
		*dest = *source;
	}
}

void strcpy(char *dest, char *source) {
	for (; *source; dest++, source++) {
		*dest = *source;
	}
	*dest = '\0';
}

int strcmp(char *a, char *b) {
	int t;

	for (;; a++, b++) {
//		printf("%c %c\n", *a, *b);
		t = *a - *b;
		if (*a == 0 || *b == 0) {
//			printf("%d %d\n", *a, *b);
			return t;
		}
		if (t != 0) {
			return t;
		}
	}
}

int strncmp(char *a, char *b, int n) {
	int t;

	for (; n > 0; n--, a++, b++) {
		if (*a == 0 || *b == 0) {
			if (*a == 0 && *b == 0) {
				return 0;
			} else {
				return 1;
			}
		}
		t = *a - *b;
		if (t != 0) {
			return t;
		}
	}

	return 0;
}

char *strdup(char *s) {
	char *r = malloc(strlen(s));
	strcpy(r, s);
	return r;
}

void memset(char *dest, unsigned char b, int n) {
	for (; n > 0; n--, dest++) {
		*dest = b;
	}
}

void memcpy(char *dest, char *source, int n) {
	for (; n > 0; n--, dest++, source++) {
		*dest = *source;
	}
}

char *itoa(int i) {
	buffer[32] = '\0';
	char *p = buffer + 32;
	char neg = 0;
	
	if (i == 0) {
		p--;
		*p = '0';
		return p;
	}
	
	if (i < 0) {
		neg = 1;
		i = -i;
	}

	while (i > 0) {
		p--;
		*p = (i % 10) + '0';
		i /= 10;
	}

	if (neg) {
		p--;
		*p = '-';
	}
	
	return p;
}

char *itoa_base(unsigned int i, int base) {
	buffer[32] = '\0';
	char *p = buffer + 32;
	
	if (i == 0) {
		p--;
		*p = '0';
		return p;
	}

	while (i > 0) {
		p--;
		*p = itoa_chars[i % base];
		i /= base;
	}
	
	return p;
}