compactor.c

/*
 * compactor.c
 *
 * This file is part of "BoolX"
 * Copyright (c) 2021 Andrea Calligaris
 * Distributed under the MIT License, see "license.txt"
 */

#include <ctype.h> // isprint
#include <getopt.h>
#include <stdbool.h> // bool
#include <stdio.h>   // printf, file stuff
#include <stdlib.h>  // abort

#define LINES_LENGTH_DEFAULT 36

static bool show_usage = false;
static char *source_program_path;
static char *output_program_path;
static long int lines_length = LINES_LENGTH_DEFAULT;
static long long int n_nested_comments = 0;

static int
process_arguments(int argc, char *argv[])
{
	char *lines_length_arg = NULL;
	int c;
	opterr = 0;
	int non_option_argc;

	static struct option long_options[] = {
	    {"lines_length", required_argument, NULL, 'l'}, {NULL, 0, NULL, 0}};

	while ((c = getopt_long(argc, argv, "l:", long_options, NULL)) != -1) {
		switch (c) {
		case 'l': {
			lines_length_arg = optarg;
			break;
		}
		case '?': {
			if (optopt == 'l') {
				fprintf(
				    stderr,
				    "Option -%c requires an argument.\n",
				    optopt);
			} else if (isprint(optopt)) {
				fprintf(
				    stderr, "Unknown option `-%c'.\n", optopt);
			} else {
				fprintf(
				    stderr,
				    "Unknown option character `\\x%x'.\n",
				    optopt);
			}
			return 1;
		}
		default: {
			abort();
		}
		}
	}

	if (lines_length_arg != NULL) {
		lines_length = strtol(lines_length_arg, NULL, 10);
		if (lines_length == 0) {
			fprintf(
			    stderr,
			    "Option '-l' has been given a bad value.\n");
		}
	}

	non_option_argc = argc - optind;

	if (non_option_argc == 0) {
		show_usage = true;
		return 0;
	} else if (non_option_argc == 1) {
		printf("Missing output file.\n");
		return 1;
	} else if (non_option_argc == 2) {
		source_program_path = argv[optind];
		output_program_path = argv[optind + 1];
		return 0;
	} else {
		printf("Too many arguments.\n");
		return 1;
	}
}

static bool
is_instruction_to_be_included(char current_instruction)
{
	switch (current_instruction) {
	case '>':
		return true;
	case '<':
		return true;
	case '|':
		return true;
	case '+':
		return true;
	case '-':
		return true;
	case '=':
		return true;
	case '_':
		return true;
	case '^':
		return true;
	case '*':
		return true;
	case '%':
		return true;
	case ']':
		return true;
	case '[':
		return true;
	case '#':
		return true;
	case '&':
		return true;
	case '?':
		return true;
	case '"':
		return true;
	case '!':
		return true;
	case ';':
		return true;
	case ':':
		return true;
	case '/':
		return true;
	case '\\':
		return true;
	case '$':
		return true;
	case '\'':
		return true;
	case '@':
		return true;
	case '~':
		return true;
	default:
		return false;
	}
}

static void
print_usage()
{
	printf("Usage: compactorx [options] <source_file> <output_file>\n");
	printf("\nA compactor for BoolX code; v1.0."
	       "\nRemove comments and other useless characters from "
	       "<source_file>\n"
	       "and save the result to <output_file>, with the goal of "
	       "creating an\n"
	       "artistic and esoteric source code.\n");
	printf(
	    "  -l N                  set the max number of characters in "
	    "each line to N\n"
	    "                          (default is %d)\n",
	    LINES_LENGTH_DEFAULT);
}

int
main(int argc, char *argv[])
{
	FILE *source_program;
	FILE *output_file;
	char current_instruction;
	bool writing_error = false;
	long int char_line_counter = 0;

	if (process_arguments(argc, argv) != 0) {
		return 1;
	}

	if (show_usage) {
		print_usage();
		return 0;
	}

	source_program = fopen(source_program_path, "r");
	if (source_program == NULL) {
		printf("Can't open the source program file.\n");
		return 1;
	}

	output_file = fopen(output_program_path, "w");
	if (output_file == NULL) {
		printf("Can't open the output file.\n");
		return 1;
	}

	/* Read the instructions one by one. */
	while (fscanf(source_program, "%1c", &current_instruction) == 1) {
		if (current_instruction == '{') {
			n_nested_comments++;
			continue;
		} else if (current_instruction == '}') {
			n_nested_comments--;
			continue;
		}
		if (n_nested_comments > 0) {
			continue;
		}

		if (is_instruction_to_be_included(current_instruction)) {
			if (putc(current_instruction, output_file) == EOF) {
				printf("Error while writing to the output "
				       "file.\n");
				writing_error = true;
				break;
			}
			printf("%c", current_instruction);
			char_line_counter++;
			if (char_line_counter == lines_length) {
				putc('\n', output_file);
				printf("\n");
				char_line_counter = 0;
			}
		}
	}
	if (writing_error == false) {
		printf("\nDone.\n");
	}

	fclose(output_file);
	fclose(source_program);

	return 0;
}