https://github.com/osipxd/miee-otc-compression-labs

https://github.com/osipxd/miee-otc-compression-labs

Last synced: 9 days ago
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• Host: GitHub
• URL: https://github.com/osipxd/miee-otc-compression-labs
• Owner: osipxd
• License: gpl-3.0
• Created: 2017-11-13T14:42:53.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2017-11-27T15:50:26.000Z (about 7 years ago)
• Last Synced: 2024-11-08T19:52:58.306Z (2 months ago)
• Language: Python
• Size: 43.9 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# miee-otc-compression-labs

### file structure (compression's algorithm independent)

info | bytes

--- | ---

`signature` | `2E 43 45 59 4D`  (`.CEYM` in ASCII)

`name_len` | 1 byte integer

`name` | depends on `name_length` (utf-8 text)

`data` | depends on compression algorithm (see below)

### lab4 (shannon-fano)

`data` сonsists of `frequency table header`, `frequency table chunks` and `data chunks`

#### frequency table header structure

info | bytes

--- | ---

`freq_table_len` | 1 byte integer

`freq_table_chunks` | see `freq_table_lenght` (stucture below)

`data_chunks` | (stucture below)

#### frequency table chunk stucture 

info | bytes

--- | ---

`byte` | 1 byte integer

`n_significant_bits` | 1 byte integer

`significant_bits` | see `n_significant_bits`

#### data chunk stucture

info | bytes

--- | ---

`chunk_bit_len` | 1 byte integer

`data` | see `chunk_bit_len`