/dl/string.c

/*
 * Copyright (C) 2011 Nick Johnson <nickbjohnson4224 at gmail.com>
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <string.h>

void *memcpy(void *dst, const void *src, size_t size) {
	size_t i;
	uint8_t *d = dst;
	const uint8_t *s = src;

	for (i = 0; i < size; i++) {
		d[i] = s[i];
	}

	return dst;
}

void *memclr(void *ptr, size_t size) {
	size_t i;
	uint8_t *a = ptr;

	for (i = 0; i < size; i++) {
		a[i] = 0;
	}

	return ptr;
}

char *strcpy(char *dst, const char *src) {
	size_t i;

	for (i = 0; src[i] != '\0'; i++) {
		dst[i] = src[i];
	}

	dst[i] = '\0';

	return dst;
}

int strcmp(const char *s1, const char *s2) {
	size_t i;

	for (i = 0;; i++) {
		if (s1[i] == s2[i]) {
			if (s1[i] == '\0') return 0;
			continue;
		}
		if (s1[i] == '\0') return -1;
		if (s2[i] == '\0') return 1;
		if (s1[i] < s2[i]) return -1;
		else return 1;
	}
}

size_t strlen(const char *str) {
	size_t i;

	for (i = 0; str[i]; i++);

	return i;
}

/*
 * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/****************************************************************************
 * strlcpy
 *
 * Copy src to string dst of size siz.  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz == 0).
 * Returns strlen(src); if retval >= siz, truncation occurred.
 */

size_t strlcpy(char *dst, const char *src, size_t siz) {
	char *d = dst;
	const char *s = src;
	size_t n = siz;

	/* Copy as many bytes as will fit */
	if (n != 0) {
		while (--n != 0) {
			if ((*d++ = *s++) == '\0') {
				break;
			}
		}
	}

	/* Not enough room in dst, add NUL and traverse rest of src */
	if (n == 0) {
		if (siz != 0) {
			*d = '\0';		/* NUL-terminate dst */
		}

		while (*s++);
	}

	return (s - src - 1);	/* count does not include NUL */
}

/****************************************************************************
 * strlcat
 *
 * Appends src to string dst of size siz (unlike strncat, siz is the
 * full size of dst, not space left).  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
 * If retval >= siz, truncation occurred.
 */

size_t strlcat(char *dst, const char *src, size_t siz) {
	char *d = dst;
	const char *s = src;
	size_t n = siz;
	size_t dlen;

	/* Find the end of dst and adjust bytes left but don't go past end */
	while (n-- != 0 && *d != '\0') {
		d++;
	}

	dlen = d - dst;
	n = siz - dlen;

	if (n == 0) {
		return (dlen + strlen(s));
	}
	while (*s != '\0') {
		if (n != 1) {
			*d++ = *s;
			n--;
		}
		s++;
	}
	*d = '\0';

	return (dlen + (s - src));	/* count does not include NUL */
}