Files
ioccc/2000/schneiderwent
Landon Curt Noll d981aa2a04 revert non-canonical JSON changes from a previous commit
The PR #2662 introduced TAB characters into entry `.entry.json` files
and mal-formatted `author_handle` JSON members.

To restore canonical JSON formatting, we did:

```sh
find [12][90][89012][0-9] -name .entry.json -print | xargs -n 1 bin/jfmt-wrapper.sh -v 1
```

BTW: We have written a tool, currently untested, to do this.  We plan to also
     add a new fix JSON format rule to the top level `Makefile`.

Performed `make www` to accomplish the above and to test under macOS.
2024-08-29 19:03:28 -07:00
..
2024-08-21 23:42:28 -07:00

To build:

    make

To use:

    ./schneiderwent

Try:

    ./schneiderwent schneiderwent.data
    ./schneiderwent

What's the difference?

If you have a long while to spare (and you're bored enough that you could watch paint dry :-) ) you might also try:

    ./try.sh

Alternatively, you can check on it later on, to see all the entry does. Or if you wish to make it run faster, you can override how long it sleeps per iterations and how many iterations it runs. For instance to make it sleep only 30 seconds and run only twice:

    SLEEP=30 ITERATIONS=2 ./try.sh

Judges' remarks:

Very nice play by the rules and portable text obfuscation. This far surpasses old tricks like adding or subtracting 1 from every character in a C string.

Translating the messages into your language of preference while keeping the program portable between different encodings (Chinese, Japanese, Russian - anyone?) may be an entertaining task.

Author's remarks:

This entry displays the current time to the console, for example:

it's just after ten 'til 6 in the evening

FWIW, none of the compilers with which this entry was tested issued any warnings or errors in compiling the source for this entry. No doubt lint will complain about the goto statements.

The schneiderwent.data file consists of the values used by multiple table lookups. This is simply good program design, separating these values from the source code allows changing the behavior of the application without recompiling.

Having learned COBOL at an early age, the pthreads of my thought processes tend to be translated into code in a verbose manner. Some of the #defines in this entry's code are to mitigate this personal deficiency.

Obfuscation

Obfuscation in this entry consists of:

  • printf(3)ing console messages stored as EBCDIC character values - this is not an attempt at encryption, but rather at cross platform compatibility.
  • ASCII character values are calculated from the EBCDIC in a particularly ugly abuse of the ?: operator. Detection of whether to print the ASCII or EBCDIC values is done by taking the remainder of dividing the character 'J' by 2 - the ASCII value of the character is even, the EBCDIC value is odd.
  • The messages to be printf(3)ed are determined via multiple table lookups and bit-masked values.
  • For minutes, the bit position turned on is multiplied by two to determine the message to be printf(3)ed.
  • For hours, the straight bit position is used.
  • This entry mostly eschews function calls for the often overlooked setjmp(3)/longjmp(3) combination.
  • The trigraphs are not there as obfuscation nor are they there to annoy the judges - it's just the easiest way to get around the absence of square brackets in a normal 3270 environment.