AoC 9 Part 2

#include <stdio.h>
#include <stdlib.h>

int readint(int* dest){
    char c;
    int rv = 0;
    int nread=0;
    while((c=getchar())!=EOF&&(c >= '0')&&(c <= '9')){
        nread++;
        rv *= 10;
        rv += c - '0';
    }
    ungetc(c, stdin);
    if(c==EOF) return -1;
    *dest=rv;
    return nread;
}

unsigned long int psum(int len, int i)
{
    char c;
    unsigned long int rv=0;
    for(;0<len;len--){
        c = getchar();
        if(c == '('){
            int dread = 0;
            int nlen;
            dread += readint(&nlen);
            getchar();dread++;
            int ni;
            dread += readint(&ni);
            getchar();dread++;
            rv += psum(nlen, ni) * i;
            len -= nlen+dread;
        }else{rv += i;}
    }
    return rv;
}

int main(int argc, char** argv)
{
    unsigned long int count = 0;
    char c;
    while((c=getchar())!= EOF){
        if(c=='('){
            int len;
            readint(&len);
            getchar();//discard x
            int i;
            readint(&i);
            getchar();//discard )
            count += psum(len, i);
        }else{count++;}
    }
    printf("%lu", count-1); //don't count eof
    return 0;
}