implementation C hagckure art

Vicky Cristina Barcelona sex stage

vi chiedo di viaggiare con me e fare l amore

si un altro mondo ma poi….

siamo persi nell arte siamo artisti in cerca della 

soluzione a un amore sbagliato mi involo alla ricerca di un viaggio

 

http://www.dogma.net/markn/articles/arith/part1.htm

Arithmetic Coding + Statistical Modeling = Data Compression

Part 1 – Arithmetic Coding

by Mark Nelson

Dr. Dobb’s Journal February, 1991

This page contains my original text and figures for the article that appeared in the February, 1991 DDJ. The article was originally written to be a 2 part feature, but was cut down to 1 part. Links to Part 2 are here and at the end of the article.


Coding for Data Compression", Communications of the ACM, June, pp 520-540.

Listing 1 coder.h Constants, declarations, and prototypes needed to use the arithmetic coding routines. These declarations are for routines that need to interface with the arithmetic coding stuff in coder.c
Listing 2 coder.c This file contains the code needed to accomplish arithmetic coding of a symbol. All the routines in this module need to know in order to accomplish coding is what the probabilities and scales of the symbol counts are. This information is generally passed in a SYMBOL structure.
Listing 3 bitio.h This header file contains the function prototypes needed to use the bitstream i/o routines.
Listing 4 bitio.c This routine contains a set of bit oriented i/o routines used for arithmetic data compression.
Listing 5 bill.c This short demonstration program will use arithmetic data compression to encode and then decode a string that only uses the letters out of the phrase "BILL GATES". It uses a fixed, hardcoded table of probabilities.

esiste un libro del 98 tuto on line simile all arte dell hacking

Modern Compiler Implementation in C

qui la nuova edizione:

https://www.deastore.com/product.asp?productid=BD510000000017370&cookie_test=1

©1998 by Andrew W. Appel with Maia Ginsburg
A preliminary edition of this book appeared in 1997.
Published by Cambridge University Press
(New York, Cambridge).
ISBN 0-521-60765-5 (paperback)
Table of Contents; Preface
Reviews of this book

Also available:

Modern Compiler Implementation in ML
Modern Compiler Implementation in Java

Software

book cover

Tiger compiler modules for programming exercises

http://www.cs.princeton.edu/~appel/modern/c/project.html

  1. Introduction: main.c makefile prog1.c prog1.h slp.c slp.h util.c util.h
  2. Lexical Analysis: driver.c errormsg.c errormsg.h makefile tiger.lex tokens.h util.c util.h
  3. Parsing: errormsg.c errormsg.h lex.yy.c makefile parsetest.c tiger.grm util.c util.h y.output
  4. Abstract Syntax: absyn.c absyn.h lex.yy.c makefile parse.c parse.h prabsyn.c prabsyn.h symbol.c symbol.h table.c table.h tiger.grm
  5. Type Checking: types.c types.h
  6. Activation Records: temp.c temp.h
  7. Translation to Intermediate Representation: printtree.c printtree.h tree.c tree.h
  8. Canonical Trees: canon.c canon.h
  9. Instruction Selection: assem.c assem.h canon.c canon.h main.c
  10. Dataflow Analysis: flowgraph.h graph.c graph.h
  11. Register Allocation:
    How to use precolored nodes color.h regalloc.h
  12. Putting It All Together: runtime.c

Or get the whole Tiger bundle as a tar file, or as a zip file (please preserve directory structure when unzipping).

carino quest articolo in computer grafic

http://answers.google.com/answers/threadview?id=43974

Alcuni sviluppatori software in effetti credono che nel codice possa annidarsi l’arte.

Ovviamente il problema maggiore resta il fatto che una volta compilato il
 codice sorgente viene occultato e, come potete ben immaginare,
un’opera d’arte che nessuno può vedere è un’opera d’arte che non esiste.

Direi che mostrare quello che è nascosto e mostrare il funzionamento

 di codice che normalmente l’industria vuole segretare e rendere

 esclusivo ricade pienamente nella filosofia hacker più pura

http://www.lega-z.com/public/Forum/ipb/index.php?showtopic=4958

http://www.geekissimo.com/2008/08/28/hagackure-lanimo-artistico-dellhacker/
***************************************************************************************
da lista kernel
Example implementation in C:
==============================================================================
TOPIC: markers: bit-field is not thread-safe nor smp-safe
http://groups.google.com/group/fa.linux.kernel/browse_thread/thread/84ad669f17744c5b?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Oct 9 2008 11:46 pm
From: Lai Jiangshan 

 

bit-field is not thread-safe nor smp-safe.

struct marker_entry.rcu_pending is not protected by any lock
in rcu-callback free_old_closure().
so we must turn it into a safe type.

detail:

I suppose rcu_pending and ptype are store in struct marker_entry.tmp1

free_old_closure() side:           change ptype side:

                                |  load struct marker_entry.tmp1
——————————–|——————————–
                                |  change ptype bit in tmp1
load struct marker_entry.tmp1   |
change rcu_pending bit in tmp1  |
store tmp1                      |
——————————–|——————————–
                                |  store tmp1

now this result equals that free_old_closure() do not change rcu_pending
bit, bug! This bug will cause redundant rcu_barrier_sched() called.
not too harmful.

—– corresponding:

free_old_closure() side:           change ptype side:

load struct marker_entry.tmp1   |
——————————–|——————————–
                                |  load struct marker_entry.tmp1
change rcu_pending bit in tmp1  |
                                |  change ptype bit in tmp1
                                |  store tmp1
——————————–|——————————–
store tmp1                      |

now this result equals that change ptype side do not change ptype
bit, bug! this bug cause marker_probe_cb() access to invalid memory.
oops!

see also: http://en.wikipedia.org/wiki/Bit_field

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>

diff –git a/kernel/marker.c b/kernel/marker.c
index 7d1faec..95c62da 100644
— a/kernel/marker.c
+++ b/kernel/marker.c
@@ -62,7 +62,7 @@ struct marker_entry {
  int refcount; /* Number of times armed. 0 if disarmed. */
  struct rcu_head rcu;
  void *oldptr;
– unsigned char rcu_pending:1;
+ int rcu_pending;
  unsigned char ptype:1;
  char name[0]; /* Contains name”format” */
 };

 


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codice C

http://gcc.gnu.org/onlinedocs/gcc/C-Implementation.html

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