utils

pat.c (1735B)

// Collection of Unix tools, comparable to coreutils
// SPDX-FileCopyrightText: 2017-2023 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 200809L
#include <errno.h>  /* errno */
#include <fcntl.h>  /* open(), O_RDONLY */
#include <stdio.h>  /* fprintf(), fwrite(), BUFSIZ */
#include <string.h> /* strerror(), strncmp() */
#include <unistd.h> /* read(), close() */
int files = 1;
int
concat(int fd, const char *fdname)
{
	ssize_t c;
	char buf[BUFSIZ];
	// File Number as an esccape/containment solution
	printf("\n###	File %d << %s >>	###\n", files++, fdname);
	while((c = read(fd, buf, sizeof(buf))) > 0)
	{
		if(fwrite(buf, (size_t)c, 1, stdout) < 0)
		{
			fprintf(stderr, "pat: Error writing: %s\n", strerror(errno));
			return 1;
		}
	}
	if(c < 0)
	{
		fprintf(stderr, "pat: Error reading ‘%s’: %s\n", fdname, strerror(errno));
		return 1;
	}
	return 0;
}
int
main(int argc, char *argv[])
{
	if(argc <= 1)
	{
		printf("###	1 Files	###");
		return concat(0, "<stdin>");
	}
	// no \n, concat starts with one
	printf("###	%d Files	###", argc - 1);
	for(int argi = 1; argi < argc; argi++)
	{
		if(strncmp(argv[argi], "-", 2) == 0)
		{
			if(concat(0, "<stdin>") != 0)
			{
				return 1;
			}
		}
		else if(strncmp(argv[argi], "--", 3) == 0)
		{
			continue;
		}
		else
		{
			int fd = open(argv[argi], O_RDONLY);
			if(fd < 0)
			{
				fprintf(stderr, "pat: Error opening ‘%s’: %s\n", argv[argi], strerror(errno));
				return 1;
			}
			if(concat(fd, argv[argi]) != 0)
			{
				return 1;
			}
			if(close(fd) < 0)
			{
				fprintf(stderr, "pat: Error closing ‘%s’: %s\n", argv[argi], strerror(errno));
				return 1;
			}
		}
	}
	return 0;
}