🚀 go-pugleaf

I need a postscript function that will duplicate the C function below.  It's
an I/O test, what it does is read the standard input for an increasing
sequence of characters.  If a character is out of sequence count it.  Valid
characters are 0x20 to 0x7f, and it wraps around from 0x7f to 0x20.  That
is, look for the sequence 20, 21, 22, 23, ..., 7e, 7f, 20, 21.....

#include <stdio.h>

#define LOW_CHAR 0x20
#define HIGH_CHAR 0x7f

main()
{
    int received = 0, index = LOW_CHAR;
    unsigned char ch;
    int failed = 0;

    while( (ch = getchar()) != EOF){
        received++;
        if(ch != index){
            failed++;

            /*
             *  Assume we dropped a char or two and sync up again.
             */

            if( (ch >= LOW_CHAR) && (ch <= HIGH_CHAR) )
                index = ch;
        }
        if(++index > HIGH_CHAR)
            index = LOW_CHAR;
    }

    printf("Received %d bad chars out of a total of %d\n", failed, received);
}


Thanks in advance ...
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