The document discusses data compression, focusing on techniques such as Gzip and Deflate, and their applications in various formats like HTTP, PNG, and PDF. It touches on the principles of Huffman coding and other methods of reducing data size while highlighting their effectiveness and efficiency. The text is interspersed with references and examples, illustrating how modern algorithms optimize data compression.

1. H O W G Z I P C O M P R E S S I O N W O R K S
R A U L F R A I L E
J S C O N F E U
B E R L I N

2. • P H P / J S S O F T WA R E D E V E L O P E R
!
• M S ( R E S ) S T U D E N T I N
C O M P U T I N G T E C H N O L O G I E S .
!
• M A D E I N S PA I N .
A B O U T M E

3. D ATA C O M P R E S S I O N

4. N O T A N E X P E R T *

5. D ATA C O M P R E S S I O N I S A N A M A Z I N G T O P I C

6. R E A L LY !

7. M A G I C
I T C A N B E S E E N L I K E …
flickr.com/photos/jeffkrause/6799254170

8. flickr.com/photos/t_e_brown/8677750589
… I T ’ S N O T

9. I N F O R M AT I O N T H E O RY
C L A U D E S H A N N O N

10. E N T R O P Y
flickr.com/photos/95303997@N07/10074330416

11. H = - p ( x ) l o g 2 p ( x )⎲
⎳
AV E R A G E A M O U N T O F I N F O R M AT I O N C O N TA I N E D I N E A C H M E S S A G E
≈ N U M B E R O F B I T S T O R E P R E S E N T T H E M E S S A G E

12. 225 days/year
62 %
17 days/year
6 %
flickr.com/photos/aigle_dore/5952296478flickr.com/photos/mariano-mantel/13955110319

13. H U M A N B R A I N
I S D E S I G N E D T O C O M P R E S S D A TA
flickr.com/photos/birthintobeing/11841180046

14. flickr.com/photos/neolao/3105372669flickr.com/photos/tommiephotography/6840025942
flickr.com/photos/earlysound/2186172726

15. M O R S E C O D E
S H O R T E R S E Q U E N C E S F O R C O M M O N C H A R A C T E R S
flickr.com/photos/amboo213/9044879245

16. D ATA C O M P R E S S I O N I N H T T P

17. GET index.html
Accept-Encoding: gzip, deflate
G Z I P + H T T P

18. G Z I P C O M P R E S S I O N

19. • D E F L A T E A L G O R I T H M
!
• D E S I G N E D B Y P H I L K A T Z
!
• U S E D I N H T T P, P N G A N D P D F
G Z I P

20. D E F L AT E
L Z 7 7
H U F F M A N C O D I N G+

21. L Z 7 7 ( VA R I AT I O N )
T H I S F I L E I S H U G E ! T H AT ' S B E C A U S E T H E F I L E I S N O T C O M P R E S S E D
< 3 3 , 9 >
S E A R C H B U F F E R ( U P T O 3 2 K B ) L O O K - A H E A D

22. T H I S F I L E I S H U G E ! T H AT ' S B E C A U S E T H E F I L E I S N O T C O M P R E S S E D
L Z 7 7 ( VA R I AT I O N )
< 3 3 , 9 >
L I T E R A L S · L E N G T H S · D I S TA N C E S

23. H U F F M A N C O D I N G
0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 1 0 1 0 0 1 1 0 0 0 1 0 0 1 1 0 0
0 1 0 0 1 1 1 1 0 0 1 0 0 0 0 0 0 1 0 1 0 1 1 1 0 1 0 0 1 1 1 1
0 1 0 1 0 0 1 0 0 1 0 0 1 1 0 0 0 1 0 0 0 1 0 0
H 0 0 0
E 0 0 1
L 0 1 0
O 0 1 1
W 1 0 0
R 1 0 1
D 1 1 0
_ 1 1 1
H E L L O W O R L D
8 8
B I T S
F I X E D - L E N G T H C O D E S
0 0 0 0 0 1 0 1 0 0 1 0 0 1 1 1 1 1
1 0 0 0 1 1 1 0 1 0 1 0 1 1 0
3 3
B I T S

24. H U F F M A N C O D I N G
C H A R A C T E R F R E Q U E N C Y:
0 0 0 1 0 0 1 0 0 1 1 0 1 1 1 0 0 0 0
L 3 0
O 2 1
H 1 0 0
E 1 0 1
W 1 1 0
R 1 1 1
D 1 0 0 0
_ 1 0 0 1
H E L L O W O R L D
1 9
B I T S
I T ’ S A M B I G U O U S
H E
L H O
D O
…
VA R I A B L E - L E N G T H C O D E S

25. H U F F M A N C O D I N G
L 3 1 0
O 2 1 1 1
H 1 0 0 1
E 1 1 1 0 0
W 1 0 0 1
R 1 0 0 0
D 1 1 1 0 1
_ 1 0 1 0

26. H U F F M A N C O D I N G
L 3 1 0
O 2 1 1 1
H 1 0 0 1
E 1 1 1 0 0
W 1 0 0 1
R 1 0 0 0
D 1 1 1 0 1
_ 1 0 1 0
0 0 1 1 1 0 0 1 0 1 0 1 1 1 0 1 0 0 0 1
1 1 1 0 0 0 1 0 1 1 0 1
H E L L O W O R L D
3 2
B I T S

27. H U F F M A N C O D I N G
TA B L E 1 : L I T E R A L S + L E N G T H S
TA B L E 2 : D I S TA N C E S

28. B L O C K S
B L O C K 1 B L O C K 2 … B L O C K NM M M M
M O D E 1 : N O C O M P R E S S I O N
M O D E 2 : F I X E D C O D E TA B L E S
M O D E 3 : G E N E R AT E D C O D E TA B L E S

29. flickr.com/photos/functoruser/2436979033

30. G Z I P C O M P R E S S I O N
I M P L E M E N TAT I O N S

31. G N U G Z I P Z O P F L I7 - Z I P
M O D E
FA S T
M O D E
H I G H
C O M P R E S S I O N
M O D E
N O R M A L
G E N E R A L R U L E : M O R E T I M E , B E T T E R C O M P R E S S I O N R AT I O
I M P L E M E N TAT I O N S

32. G Z I P C O M P R E S S I O N
W H Y G Z I P ?

33. • G O O D C O M P R E S S I O N R A T I O .
• FA S T T O ( U N ) C O M P R E S S .
• I N T H E W O R S T C A S E , E X PA N D S
T H E D A TA S L I G H T LY.
• M E M O RY I N D E P E N D E N T.
• F R E E I M P L E M E N TA T I O N S T H A T
A V O I D PA T E N T S .
T R A D E O F F

34. N E W E R A L G O R I T H M S
I S S U E S T RY I N G T O A D D B Z I P 2 S U P P O R T T O C H R O M E

35. G Z I P C O M P R E S S I O N
B E Y O N D G Z I P

36. P R E P R O C E S S D ATA T O O P T I M I Z E M AT C H E S

38. G Z I P ( T ( D ATA ) ) < G Z I P ( D ATA )

39. T R A N S P O S I N G J S O N
{
"name": "John",
"country": "USA"
},
{
"name": "Stephan",
"country": "Germany"
},
{
"name": "Rob",
"country": "USA"
}
{
"name": [
"John",
"Stephan",
"Rob"
],
"country": [
"USA",
"Germany",
"USA"
]
}

40. X M L / H T M L AT T R I B U T E S O R D E R
<input id='f1' class='field' name="f1" type="text" />
<input class="field" id="f2" type="text" name="f2" />
<input id="f1" class="field" name="f1" type="text" />
<input class="field" id="f2" type="text" name="f2" />
<input id="f1" class="field" name="f1" type="text" />
<input id="f2" class="field" name="f2" type="text" />
<input type="text" class="field" id="f1" name="f1" />
<input type="text" class="field" id="f2" name="f2" />
1 7 , 7 6
%
2 7 , 1 0
%
3 8 , 3 2
%
3 8 , 3 2
%
h t t p : / / g o o . g l / G g M w 2 6

41. R E F E R E N C E S

42. “ C o m p re s s o r H e a d ”
C o l t M c A n l i s

43. “ D a t a C o m p re s s i o n : T h e C o m p l e t e R e f e re n c e ”
D a v i d S a l o m o n

44. “ A U n i v e r s a l A l g o r i t h m f o r S e q u e n t i a l D a t a C o m p re s s i o n ”
J a c o b Z i v & A b r a h a m L e m p e l

45. “ A m e t h o d f o r t h e c o n s t r u c t i o n o f m i n i m u m re d u n d a n c y c o d e s ”
D a v i d A . H u ff m a n

46. T H A N K Y O U
R a ú l F r a i l e
@ r a u l f r a i l e