utils-std

comm.c (5830B)

// utils-std: Collection of commonly available Unix tools
// SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
// SPDX-License-Identifier: MPL-2.0
#define _POSIX_C_SOURCE 200809L
#include "../libutils/getopt_nolong.h"
#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
enum comm_out
{
	COMM_OUT_NONE = 0,
	COMM_OUT_FILE1 = 1 << 0,
	COMM_OUT_FILE2 = 1 << 1,
	COMM_OUT_COMM = 1 << 2,
	COMM_OUT_ALL = COMM_OUT_FILE1 | COMM_OUT_FILE2 | COMM_OUT_COMM,
};
const char *argv0 = "comm";
enum comm_out c_out = COMM_OUT_ALL;
static void
usage(void)
{
	fprintf(stderr, "Usage: comm [-123] file1 file2\n");
}
static int
drain1(FILE *in, const char *fname, char *buf, size_t *bufsiz)
{
	errno = 0;
	if(!(c_out & COMM_OUT_FILE1))
	{
		fflush(stdout);
		return 0;
	}
	if(buf) printf("%s", buf);
	for(;;)
	{
		size_t nread = fread(buf, 1, *bufsiz, in);
		if(errno != 0)
		{
			fprintf(
			    stderr, "comm: error: Failed reading from file1 \"%s\": %s\n", fname, strerror(errno));
			return 1;
		}
		if(nread == 0) break; // EOF
		fwrite(buf, 1, nread, stdout);
		if(errno != 0)
		{
			fprintf(stderr,
			        "comm: error: Failed writing file1 \"%s\" data to stdout: %s\n",
			        fname,
			        strerror(errno));
			return 1;
		}
	}
	fflush(stdout);
	return 0;
}
static int
drain2(FILE *in, const char *fname, char *buf, size_t *bufsiz)
{
	errno = 0;
	if(!(c_out & COMM_OUT_FILE2))
	{
		fflush(stdout);
		return 0;
	}
	if(buf) printf("\t%s", buf);
	for(;;)
	{
		ssize_t nread = getline(&buf, bufsiz, in);
		if(nread < 0)
		{
			if(errno == 0) break; // EOF
			fprintf(stderr,
			        "comm: error: Failed reading line from file2 \"%s\": %s\n",
			        fname,
			        strerror(errno));
			return 1;
		}
		errno = 0;
		fputc('\t', stdout);
		fwrite(buf, 1, nread, stdout);
		if(errno != 0)
		{
			fprintf(stderr,
			        "comm: error: Failed writing file2 \"%s\" data to stdout: %s\n",
			        fname,
			        strerror(errno));
			return 1;
		}
	}
	fflush(stdout);
	return 0;
}
int
main(int argc, char *argv[])
{
	if(setlocale(LC_ALL, "") == NULL)
	{
		fprintf(stderr,
		        "%s: warning: Failed loading locales. setlocale(LC_ALL, \"\"): %s\n",
		        argv0,
		        strerror(errno));
	}
	errno = 0;
	for(int c = -1; (c = getopt_nolong(argc, argv, ":123")) != -1;)
	{
		switch(c)
		{
		case '1':
			c_out &= ~COMM_OUT_FILE1;
			break;
		case '2':
			c_out &= ~COMM_OUT_FILE2;
			break;
		case '3':
			c_out &= ~COMM_OUT_COMM;
			break;
		case '?':
			GETOPT_UNKNOWN_OPT
			usage();
			return 1;
		default:
			abort();
		}
	}
	argc -= optind;
	argv += optind;
	if(argc != 2)
	{
		fprintf(stderr, "comm: error: Expected 2 arguments, got %d\n", argc);
		usage();
		return 1;
	}
	const char *fname1 = argv[0];
	const char *fname2 = argv[1];
	FILE *file1 = NULL, *file2 = NULL;
	if(fname1[0] == '-' && !fname1[1])
	{
		file1 = stdin;
	}
	else
	{
		file1 = fopen(fname1, "r");
		if(!file1)
		{
			fprintf(stderr, "comm: error: Failed opening file1 \"%s\": %s\n", fname1, strerror(errno));
			return 1;
		}
	}
	if(fname2[0] == '-' && !fname2[1])
	{
		if(fname1[0] == '-' && !fname1[1])
		{
			fprintf(stderr, "comm: error: file1 and file2 cannot be both stdin\n");
			usage();
			return 1;
		}
		file2 = stdin;
	}
	else
	{
		file2 = fopen(fname2, "r");
		if(!file2)
		{
			fprintf(stderr, "comm: error: Failed opening file2 \"%s\": %s\n", fname2, strerror(errno));
			return 1;
		}
	}
	char *f1 = NULL, *f2 = NULL;
	size_t f1n = 0, f2n = 0;
	errno = 0;
	if(getline(&f1, &f1n, file1) < 0)
	{
		if(errno != 0)
		{
			fprintf(stderr,
			        "comm: error: Failed reading line from file1 \"%s\": %s\n",
			        fname1,
			        strerror(errno));
			return 1;
		}
		return drain2(file2, fname2, f2, &f2n);
	}
	errno = 0;
	if(getline(&f2, &f2n, file2) < 0)
	{
		if(errno != 0)
		{
			fprintf(stderr,
			        "comm: error: Failed reading line from file2 \"%s\": %s\n",
			        fname2,
			        strerror(errno));
			return 1;
		}
		return drain1(file1, fname1, f1, &f1n);
	}
	int d = strcoll(f1, f2);
	for(;;)
	{
		// TODO: Compare newly obtained line with it's previous one, to check if the file is sorted
		while(d == 0)
		{
			if(c_out & COMM_OUT_COMM) printf("\t\t%s", f1);
			f1 = NULL;
			f2 = NULL;
			errno = 0;
			if(getline(&f1, &f1n, file1) < 0)
			{
				if(errno != 0)
				{
					fprintf(stderr,
					        "comm: error: Failed reading line from file1 \"%s\": %s\n",
					        fname1,
					        strerror(errno));
					return 1;
				}
				return drain2(file2, fname2, f2, &f2n);
			}
			errno = 0;
			if(getline(&f2, &f2n, file2) < 0)
			{
				if(errno != 0)
				{
					fprintf(stderr,
					        "comm: error: Failed reading line from file2 \"%s\": %s\n",
					        fname2,
					        strerror(errno));
					return 1;
				}
				return drain1(file1, fname1, f1, &f1n);
			}
			d = strcoll(f1, f2);
		}
		while(d > 0)
		{
			if(c_out & COMM_OUT_FILE2) printf("\t%s", f2);
			f2 = NULL;
			errno = 0;
			if(getline(&f2, &f2n, file2) < 0)
			{
				if(errno != 0)
				{
					fprintf(stderr,
					        "comm: error: Failed reading line from file2 \"%s\": %s\n",
					        fname2,
					        strerror(errno));
					return 1;
				}
				return drain1(file1, fname1, f1, &f1n);
			}
			d = strcoll(f1, f2);
		}
		while(d < 0)
		{
			if(c_out & COMM_OUT_FILE1) printf("%s", f1);
			f1 = NULL;
			errno = 0;
			if(getline(&f1, &f1n, file1) < 0)
			{
				if(errno != 0)
				{
					fprintf(stderr,
					        "comm: error: Failed reading line from file1 \"%s\": %s\n",
					        fname1,
					        strerror(errno));
					return 1;
				}
				return drain2(file2, fname2, f2, &f2n);
			}
			d = strcoll(f1, f2);
		}
	}
	return 0;
}