Adaptive Huffman Encoding (FGK)

Description

Test for SUPSI project

Compilation

make

or, manual compilation

gcc -lm *.c -o adaptive_huffman

Execution

Encode

./adaptive_huffman -c <input_file> <output_file>

Decode

./adaptive_huffman -d <input_file> <output_file>

utils

hexadecimal dump of a file: xxd

xxd -b ../test-res/singlechar
00000000: 01000001                                               A

xxd -b ./out.compressed 
00000000: 01101000 00100000                                      ..

xxd -b ../test-res/ff_ff_ff 
00000000: 11111111 11111111 11111111                             ...

ASCII table

https://en.wikipedia.org/wiki/ASCII

'A' = 0100 0001
idx = 0123 4567

'AB'= 0100 0001 0100 0010
idx = 0123 4567 8901 2345
                  11 1111

Our Adaptive Huffman implementation

encoding "A":

• first 3 bit = header, it contains number of bits (for last byte )to ignore. 5 in this example
• next 8 bit = plain char A, since it's a new char not in tree
• last 5 bit = bit to ignore. (see header)

101 01000001 00000
 H     A     -----                    

encoding "AB":

• first 3 bit = header, it contains number of bits (for last byte )to ignore. 4 in this example
• next 8 bit = plain char A, since it's a new char not in tree
• next 1 bit = NYT code, since next char is new
• next 8 bit = plain char B, since it's a new char not in tree
• last 4 bit = bit to ignore. (see header)

10001000 00100100 00100000

100 01000001  0   01000010    0000
 H     A     NYT     B        ----                      

encoding "ABA":

01101000 00100100 00101000

011 01000001  0  01000010   1   000
 H     A     NYT     B     (A)  ---

encoding "ABAB":

00101000 00100100 00101010

001 01000001  0  01000010   1    01   0
 H     A     NYT     B     (A)  (B)   -

Tests other implementations

encoding "abc(EOL)":

01100001  0  01100010    00     01100011    000   00001010  0000000110
   A     NYT    B      NYT(2)      C       NYT(3)    EOL    BOOOOOOOOH

encoding "abcd(EOL)":

01100001  0   01100010    00     01100011   000     01100100 100 00001010  0000000 00000001
    A    NYT      B     NYT(2)      C      NYT(3)       D    ???    EOL    BOOOOOOOOOOOOOOH

encoding "aba(EOL)":

01100001   0   01100010    1       00     00001010  000000000100
   A      NYT      B     PATH(A)  NYT(2)     EOL    BOOOOOOOOOOH

License

The MIT License (MIT)

Copyright (c) 2018 Massimo De Santi, Aleksandar Stojkovski

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.