Question

I’ve written a small utility to open up executables and spit out certain printable strings it finds.

It works fine but I was wondering, is there some way I could remove one of these if statements? I was trying to see how I could arrange my conditionals so I wouldn’t need the 3 different if statements but I don’t see how I can do it with the current structure.

#include <stdio.h>

#define MAX_STR_SIZE 0x666
#define MIN_STR_SIZE 0x5

int main(int argc, char** argv) 
{
    int ch;
    int pos = 0;
    FILE* f;
    char buff[MAX_STR_SIZE];

    if (argc>1 && (f=fopen(argv[1], "rb")))
    {
        while ((ch=getc(f)) != EOF)
        {
            if (ch >= ' ' && ch <= 'z') // is printable char?
            {
                buff[pos++] = ch;
                buff[pos] = '\0';
                if (pos == (MAX_STR_SIZE-1))  // is current string > max length?
                {
                    printf("%08x: %s\n", ftell(f), &buff[0]);
                    pos = 0;
                }
            }
            else // non-printable char, print any string in buffer and start over
            {
                if (pos > (MIN_STR_SIZE - 1)) // is current string > min string?
                {
                    printf("%08x: %s\n", ftell(f), &buff[0]); // print current string
                }
                pos = 0;
            }
        }

        if (pos > (MIN_STR_SIZE - 1)) // any remaining string left to print?
        {
            printf("%08x: %s\n", ftell(f), &buff[0]);
        }

        fclose(f);
    }
}

Answer 1

I believe this version eliminates most of the if statements (or at least collapses them together:

#include <stdio.h>

#define MAX_STR_SIZE 0x666
#define MIN_STR_SIZE 0x5

int main(int argc, char** argv) 
{
    int ch;
    int pos = 0;
    FILE* f;
    char buff[MAX_STR_SIZE];

    if (argc>1 && (f=fopen(argv[1], "rb")))
    {
        while ((ch = getc(f)) != EOF)
        {
            pos = 0;
            while (ch >= ' ' && ch <= 'z' && pos < (MAX_STR_SIZE-1)) {
                buff[pos++] = ch;
                ch = getc(f);
            }
            if (pos > (MIN_STR_SIZE - 1)) // is current string > min string?
            {
                buff[pos] = '\0';
                printf("%08x: %s\n", ftell(f), buff);
            }
        }

        fclose(f);
    }
}