As readers of my blog know, I got interviews (and interview offers) with a lot of great companies (Google, Apple, Amazon, ATG). I even had a company contact me out of the blue recently as well (Quantcast). So, whats the verdict? Where am I with my job hunting progress? Three delightful words: on site interviews. I was given on site interviews with everyone. Google and Quantcast this week, Apple in 2 weeks, Amazon next month. Plane rides, hotels, rental cars, and tour groups here I come! After all, what could be more exciting than visiting a every one of the companies I applied to?

Oh yea, the next step – getting an offer. I was going to write more, but something tells me in a week or two, I will probably have a bit more to say about offers. Talk to you then!

Yea, that feels good!

Resume for Adam Risi

If you are a recruiter, and you were looking for my resume, you might also be interested in the rest of my blog posts, or my open source coding profile on github.com. As always, please feel free to contact me by phone or email at your convenience. My contact information can be found at the top of my resume.

Thank you!

As one of the examples provided with the FSM engine, I provide a date parser for the 3 different valid http date formats: asctime, rfc850, and rfc1123. The HTTP standard provides a great EBNF form description of parsing these dates (section 3.3), so writing the code was actually pretty trivial. After writing the code, and as part of the documentation of the project, I have generated some images to make the parsing process a little clearer.

(Click to enlarge)

The source for this feat of parsing is included in the examples folder of the FSM library. Enjoy!

As part of the FSM examples, I am generating visualizations for the included FSMs via dot, a utility part of the GraphViz collection. It’s a great tool for generating digraphs. I just finished the visualizations for bencode format, so I thought I would share! As always, if you have a question, leave a comment or send me an email: adam@adamrisi.com.

Entry points are always node “0″, and the example’s entry point is the bencode_fsm node 0. Pretty neat, eh? It’s a perfect translation of the bencode standard into a working FSM.

All of the FSM code as well as the different examples (uri parsing, date parsing, etc) are all available at the GitHub project page. Below, you can test the URI parser and take a look at the output. If you notice a bug, please, leave a comment!

This code is memory-leak free (tested via valgrind). I haven’t licensed it yet, so send me an email if you want to use any piece of my FSM project in your own code.

I toyed with ideas like variadic macros (or functions), abusing some sort of global stack of void pointers to various types of structs, and a bunch of other ideas. Finally, I came up with the following code (an example of the technique):

#include <stdio.h>

struct threeint_args {
  int a;
  int b;
  int c;
};

void mult(void *args)
{
  struct threeint_args *ma = (struct threeint_args*)args;
  printf("%d * %d * %d = %d\n",
    ma->a, ma->b, ma->c,
    ma->a * ma->b * ma->c);
}

void add(void *args)
{
  struct threeint_args *aa = (struct threeint_args*)args;
  printf("%d + %d + %d = %d\n",
  aa->a, aa->b, aa->c,
  aa->a + aa->b + aa->c);
}

struct generic_func {
  void(*func)(void*);
  void *args;
};

void run_generics(struct generic_func gfs[])
{
  struct generic_func *gf = gfs;
  while(gf->func != NULL) {
    gf->func(gf->args);
    gf++;
  }
}

int main(int argc, char **argv)
{
  struct generic_func examples[] =
    {
      {mult, (void*)&(struct threeint_args){1, 2, 3}},
      {add, (void*)&(struct threeint_args){1, 2, 3}},

      {mult, (void*)&(struct threeint_args){4, 5, 6}},
      {add, (void*)&(struct threeint_args){4, 5, 6}},

      {mult, (void*)&(struct threeint_args){7, 8, 9}},
      {add, (void*)&(struct threeint_args){7, 8, 9}},

      {NULL}
    };

  run_generics(examples);
}

“Alright”, I thought to myself, “this little program probably will throw a fit if I try to compile it, but lets try anyway.”

$ gcc -ggdb -o test test.c
$

“Now wait a minute – no complaints? Certainly, if I try to run it, there will be some sort of segfault, or bug, or something. This can’t be right…”

$ valgrind ./test
==16546== Memcheck, a memory error detector
==16546== Copyright (C) 2002-2009, and GNU GPLd, by Julian Seward et al.
==16546== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info
==16546== Command: ./test
==16546==
1 * 2 * 3 = 6
1 + 2 + 3 = 6
4 * 5 * 6 = 120
4 + 5 + 6 = 15
7 * 8 * 9 = 504
7 + 8 + 9 = 24
==16546==
==16546== HEAP SUMMARY:
==16546==     in use at exit: 0 bytes in 0 blocks
==16546==   total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==16546==
==16546== All heap blocks were freed -- no leaks are possible
==16546==
==16546== For counts of detected and suppressed errors, rerun with: -v
==16546== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 4 from 4)

Holy s**t. That just worked.

I don’t often get surprised by code that I write. After all, if I am writing it, it means I understand it (most of the time). This example; however, completely flabbergasted me. Being able to store the pointer to a function, and a pointer to the arguments to the function in an array means I can do all sorts of things. I could develop a signals and slots mechanism, I can pass table-local contexts to function pointers, hell, I could rule the world. I couldn’t find anything else like this on the web – so I thought I would share!

First, get this file: Cricket flip-flopper Compile it up (or use the precompiled 32 bit binaries), and install it. Keep the extracted files handy.

Drop in the A600, and wait for it to show up as a CDROM drive. In the previously extracted files, run “sudo ./flipflop.sh”. Let it finish.

Check dmesg to make sure you saw “ttyACM0″ go by at some point. Grep is good for this.

Lastly, install wvdial, and use the following in your /etc/wvdial.conf :

…
Modem = /dev/ttyACM0
Phone = #777
…

Exec sudo wvdial, and off you go!

Not to mention github is awesome.

git clone git://github.com/ajrisi/picodns.git

The purpose of the software is essentially to list the network interfaces, their IP address, and whatever their IP address resolves into. It’s just a single file of delicious C code, and it works like a charm. Check it out!

git clone git://github.com/ajrisi/lsif.git