micro-utils/coreutils/wc.c

#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>

/* cmd arguments l - lines c - bytes w - words */
unsigned int l_flag;
unsigned int c_flag;
unsigned int w_flag;

unsigned int words;
unsigned int bytes;
unsigned int lines;

/* Total */
unsigned int twords;
unsigned int tbytes;
unsigned int tlines;

void count(const int fd) {
	char buf[4096];
	ssize_t n = 0;

	int in_word = 1;
	while ((n = read(fd, buf, sizeof(buf))) > 0) {
		bytes += n;

		for (ssize_t i = 0; i < n; i++) {
			if (buf[i] == '\n')
				lines++;

			if (buf[i] == ' ' || buf[i] - '\t' < 5) {
				if (!in_word) {
					in_word = 1;
					words++;
				}
			}

			else
				in_word = 0;
		}
	}

	tbytes += bytes;
	twords += words;
	tlines += lines;
}

void print_count(const char *path, unsigned int plines, unsigned int pwords, unsigned int pbytes) {
	if (l_flag)
		printf("%u ", plines);

	if (w_flag)
		printf("%u ", pwords);

	if (c_flag)
		printf("%u", pbytes);

	printf(" %s\n", path);
}

int main(int argc, char **argv) {
	int opt;
	while ((opt = getopt(argc, argv, "lcw")) != -1) {
		switch (opt) {
			case 'l':
				l_flag = 1;
				break;

			case 'c':
				c_flag = 1;
				break;

			case 'w':
				w_flag = 1;
				break;

			default:
				printf("wc [file1 file2...]\n\t[-l Lines] [-c Bytes] [-w Words]\n");
				return 0;
		}
	}

	argv += optind;
	argc -= optind;

	if (!w_flag && !l_flag && !c_flag) {
		w_flag = 1;
		l_flag = 1;
		c_flag = 1;
	}

	if (argc == 0 || argv[0][0] == '-') {
		count(STDIN_FILENO);
		print_count("", lines, words, bytes);
		return 0;
	}

	for (int i = 0; i < argc; i++) {
		int fd = open(argv[i], O_RDONLY);
		if (fd < 0) {
			fprintf(stderr, "wc: %s\n", strerror(errno));
			return 1;
		}

		count(fd);
		if (i == argc - 1)
			print_count("total", tlines, twords, tbytes);

		else
			print_count(argv[i], lines, words, bytes);

		close(fd);
		words = bytes = lines = 0;
	}

	return 0;
}