polonius/read/src/main.cpp

#include "includes.h"

#ifndef IOSTREAM
	#define IOSTREAM
	#include <iostream>
#endif

#ifndef GETOPT_H
	#define GETOPT_H
	#include <getopt.h>
#endif

using namespace std;

int main(int argc, char* argv[]) {

	string program_name = "polonius-reader";

	string helpstring = program_name + " " + program_version + "\nCopyright (C) 2023 " + program_author + "\n\nThis is free software (GNU GPL 3), and you are welcome to redistribute it under certain conditions.\n\nUsage: " + program_name + " -i filename\n\nOptions:\n  -i\n  --input\n    Specify input file to read\n\n  -s\n  --start\n    Specify byte number to start reading from\n\n  -l\n  --length\n    Specify how many bytes to read\n\n  -b\n  --block-size\n    Specify the amount of data from the file we're willing to load into memory at any given time\n      Example:\n        -b 10M\n        -b 200K\n      (Default 10 kilobytes)\n\n  -f\n  --find\n  --search\n    Search for a string in the file\n    If -s / --start is specified, the program will only search for matches after that start position\n    If -l / --length is specified, the program will only search for matches within that length from the start\n    Returns nothing (blank) if no matches were found\n\n  -p\n  --output-pos\n    Output the start and end position, rather than the text (in the format \"start,end\", for example 10,15)\n    If used with searches, this will output the start and end position of the search result\n    Outside of searches, it will return the values of -s / --start and the end position (start + length)\n\n  -V\n  --version\n    Print version number\n\n  -h\n  --help\n    Display this message\n\nExamples:\n  " + program_name + " --input ./file.txt --start 50 --length 10\n\n  " + program_name + " -s 50 -l 10 ./file.txt\n\n  " + program_name + " -i ./file.txt --start 75 --search \"hello world\" --length 10\n\n  " + program_name + " ./file.txt -f \"hello world\" --output-pos\n";
	
	/*
	Necessary info for the program to do its job
	The file to read (-i),
	The byte to start from (-s) [0 if unspecified]
	The number of bytes to read (-l) [-1 if unspecified]
		"amount_to_read" == -1 will result in reading from the start position to the end of the file
	*/
	bool received_filename = false;
	string file_to_read = "";
	
	int64_t start_position = 0;
	int64_t amount_to_read = -1;
	
	int block_size = 10240;
	
	reader::job_type job = reader::read_job;
	string searching_for = "";
	
	bool output_position = false;
	
	/*
	GETOPT
	*/
	int c;
	opterr = 0;
	int option_index = 0;
	
	static struct option long_options[] =
	{
		{"input", required_argument, 0, 'i'},
		{"start", required_argument, 0, 's'},
		{"length", required_argument, 0, 'l'},
		{"block-size", required_argument, 0, 'b'},
		{"find", required_argument, 0, 'f'},
		{"search", required_argument, 0, 'f'},
		{"output-pos", no_argument, 0, 'p'},
		{"version", no_argument, 0, 'V'},
		{"help", no_argument, 0, 'h'}
	};
	
	while ((c = getopt_long(argc, argv, "i:s:l:b:f:pVh", long_options, &option_index)) != -1) {
		switch(c) {
			case 'i':
				if (received_filename) {
					cerr << program_name << ": Error: Multiple files specified" << endl;
					return EXIT_BADFILE;
				}
				file_to_read = optarg;
				received_filename = true;
				break;
				
			case 's':
				if (!is_number(optarg)) {
					cerr << program_name << ": '" << optarg << "' is not an integer" << endl << "Use -h for help" << endl;
					return EXIT_BADARG;
				}
				start_position = (int64_t)stoll(optarg);
				break;
				
			case 'l':
				if (!is_number(optarg)) {
					cerr << program_name << ": '" << optarg << "' is not an integer" << endl << "Use -h for help" << endl;
					return EXIT_BADARG;
				}
				amount_to_read = (int64_t)stoll(optarg);
				break;
				
			case 'b':
				block_size = parse_block_units(optarg);
				if (block_size == -1) {
					cerr << program_name << ": Block size '" << optarg << "' is not understood" << endl << "Use -h for help" << endl;
					return EXIT_BADARG;
				}
				break;
			
			case 'f':
				job = reader::search_job;
				searching_for = optarg;
				break;
			
			case 'p':
				output_position = true;
				break;
				
			case 'V':
				cout << program_version << endl;
				return EXIT_SUCCESS;
				break;
				
			case 'h':
				cout << helpstring;
				return EXIT_SUCCESS;
				break;
				
			case '?':
				if (optopt == 'i' || optopt == 's' || optopt == 'l') {
					cerr << program_name << ": Option -" << (char)optopt << " requires an argument" << endl << "Use -h for help" << endl;
					return EXIT_BADOPT;
				}
				break;
		}
	}
	
	for (option_index = optind; option_index < argc; option_index++) {
		if (received_filename) {
			cerr << program_name << ": Error: Multiple files specified" << endl;
			return EXIT_BADFILE;
		}
		file_to_read = argv[option_index];
		received_filename = true;
	}
	
	// Make sure we got an input file
	if (!received_filename) {
		cerr << helpstring;
		return EXIT_BADFILE;
	}
	
	reader::file the_file;
	
	if (!the_file.init(file_to_read)) {
		cerr << program_name << ": " << the_file.get_init_error_message() << endl;
		return EXIT_BADFILE;
	}
	
	// If -l / --length wasn't set, just set it to the full length of the file
	if (amount_to_read == -1) {
		amount_to_read = the_file.get_file_length();
	}
	
	the_file.set_start_position(start_position);
	the_file.set_amount_to_read(amount_to_read);
	
	the_file.set_just_outputting_positions(output_position);
	
	the_file.set_block_size(block_size);
	
	the_file.set_search_query(searching_for);
	
	the_file.set_job_type(job);

	the_file.do_job();

	return EXIT_SUCCESS;
}