#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#include "util.h"

void
copyFile(const char *source, const char *dest)
{
	char buffer[1024];
	ssize_t ret;
	int s, d;

	if ((s = open(source, O_RDONLY)) == -1)
		err(1, "cannot open %s", source);
	if ((d = open(dest, O_WRONLY | O_CREAT, 0644)) == -1)
		err(1, "cannot open %s", dest);

	while ((ret = read(s, &buffer, 1024)) > 0) {
		write(d, buffer, ret);
	}

	if (ret == -1)
		err(1, "cannot read from %s", source);

	close(s);
	close(d);
}

void
changeDirectory(const char *path)
{
	if (chdir(path) == -1)
		err(1, "cd '%s'", path);
}

bool
exists(const char *path)
{
	if (open(path, O_RDONLY) == -1) {
		if (errno == ENOENT)
			return 0;
	}
	return 1;
}

/*
 * Copy string src to buffer dst of size dsize.  At most dsize-1
 * chars will be copied.  Always NUL terminates (unless dsize == 0).
 * Returns strlen(src); if retval >= dsize, truncation occurred.
 */
size_t
strbcpy(char *dst, const char *src, size_t dsize)
{
	const char *osrc = src;
	size_t nleft = dsize;

	/* Copy as many bytes as will fit. */
	if (nleft != 0) {
		while (--nleft != 0) {
			if ((*dst++ = *src++) == '\0')
				break;
		}
	}

	/* Not enough room in dst, add NUL and traverse rest of src. */
	if (nleft == 0) {
		if (dsize != 0)
			*dst = '\0'; /* NUL-terminate dst */
		while (*src++)
			;
	}

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