ibcm-parse.cpp

/* A program that will quickly check if the file names passed in via
 * command line arguments look like IBCM files.  In particular, it
 * checks if the first four digits on each line are all hexadecimal
 * digits.  It does not program validity checking beyond this.  It is
 * useful to tell the students if, on submission, their programs will
 * parse correctly in an IBCM simulator.
 */

#include <iostream>
#include <fstream>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

using namespace std;

void printHelp(char* name);
bool isEmpty(string& line);

int main (int argc, char *argv[]) {
    string line;
    int linenum = 0;
    bool allowComments = false;
    // make sure they gave some command-line parameters
    if ( argc == 1 ) {
        cout << argv[0] << ": no input files" << endl;
        exit(1);
    }
    for ( int i = 1; i < argc; i++ ) {
        // print the help description
        if ( !strcmp(argv[i], "-help") ) {
            printHelp(argv[0]);
            exit(0);
        }

        // a comment has a '#' as the first character on a line or
        // a comment has a '//' as the first two characters on a line
        if ( !strcmp(argv[i],"-allowcomments") ) {
            allowComments = true;
            continue;
        }

        if ( argv[i][0] == '-' ) {
            cout << argv[0] << ": " << argv[i] << ": no such argument" << endl;
            printHelp(argv[0]);
            exit(1);
        }

        // open the file
        ifstream file(argv[i]);
        if ( !file.is_open() ) {
            cout << argv[0] << ": " << argv[i] << ": no such file" << endl;
            exit(2);
        }
        // read in the entire file...
        while ( file.good() ) {
            // read in a line from the file
            getline (file, line);
            linenum++;
            // is it the last line of the file?
            if ( (line.size() == 0) && (!file.good()) )
                break;
            // is the line empty or all whitespace?
            if ( isEmpty(line) )
                continue;
            // is it a `//` comment?
            else if ( allowComments && (line.size() >= 2) &&
                      (line[0] == '/') && (line[1] == '/') )
                continue;
            // is it a `#` comment?
            else if ( allowComments && (line.size() >= 1) &&
                      (line[0] == '#') )
                continue;
            // is the line too short?
            else if ( line.size() < 4 ) {
                cout << argv[0] << ": " << argv[i] << " has too short a line on line number " << linenum << "(" << line.size() << ")" << endl;
                exit(3);
            }
            // are the first four digits hex characters?
            for ( int j = 0; j < 4; j++ )
                if ( !isxdigit(line[j]) ) {
                    cout << argv[0] << ": " << argv[i] << " invalid hexadecimal digit '" << line[j] << "' on line " << linenum << " character " << (j+1) << endl;
                    exit(3);
                }
        }
        // all done with this file!
        file.close();
    }
    return 0;
}

void printHelp(char *name) {
    static bool helpPrinted; // Static values are initialized to 0 or 0-equivalent
    if(helpPrinted) return;

    helpPrinted = true;

    cout << "Usage: " << name << " [option] <inputfile>" << endl;
    cout << "Options:" << endl;
    cout << "\t[-allowcomments]\tAllows file specified by <inputfile> to contain" << endl
         << "\t\t\t\tlines beginning with `//` and `#`." << endl;
    cout << "\t[-help]\t\t\tPrints this help message." << endl;
}

bool isEmpty(string& line) {
    // is the line empty?
    if ( line.empty() ) {
        return true;
    }

    // does the line contain spaces or carriage returns?
    else if ( line.find_first_not_of(' ') != line.npos &&
              line.find_first_not_of('\n') != line.npos &&
              line.find_first_not_of('\r') != line.npos) {
        return false;
    }

    // otherwise, the line is basically empty
    return true;
}