jpegdna.coders package¶

Module contents¶

Codecs collection for jpegdna

class jpegdna.coders.AbstractCoder[source]¶

Bases: abc.ABC

Abstract class for codec definition

abstract decode(code)[source]¶

Decoding method

Parameters: code (list|str) – Input to decode
Returns: Decoded message
Return type: list|str

abstract encode(inp)[source]¶

Encoding method

Parameters: inp (list|str) – Input to encode
Returns: Encoded message
Return type: list|str

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

full_encode(inp, *args)[source]¶

Encoding method

Parameters

inp (list|str) – Input to encode
args (any) – Encoding arguments

Returns

Encoded message, encoding state

Return type

list|str, any

get_state(case=None)[source]¶

Helper method to get the state of the codec if necessary

Return type: any

set_state(*args, case=None)[source]¶

Helper method to set the state of the codec if necessary

Return type: None

exception jpegdna.coders.AutomataException[source]¶: Bases: Exception

exception jpegdna.coders.AutomataGetterException[source]¶: Bases: jpegdna.coders.AutomataException

exception jpegdna.coders.AutomataGetterExceptionDecode[source]¶: Bases: jpegdna.coders.AutomataGetterException

exception jpegdna.coders.AutomataGetterExceptionEncode[source]¶: Bases: jpegdna.coders.AutomataGetterException

exception jpegdna.coders.AutomataSetterException[source]¶: Bases: jpegdna.coders.AutomataException

exception jpegdna.coders.AutomataSetterExceptionDecode[source]¶: Bases: jpegdna.coders.AutomataSetterException

exception jpegdna.coders.AutomataSetterExceptionEncode[source]¶: Bases: jpegdna.coders.AutomataSetterException

jpegdna.coders.categorycoder module¶

Coder for categories

class jpegdna.coders.categorycoder.ACCategoryCoder(d, lut, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

AC Category value coder

Parameters

d (dict) – Huffman n-ary dictionnary
lut (list) – Lut matrix
verbose – bool

Variables

verbose – Verbosity enabler
goldman_coder (jpegdna.coders.goldmancoder.GoldmanCoderDNA) – Goldman Coder
ad_bits (int) – length of the codeword for the category (initial value: 0)
code_length (int) – length of the codeword for the value (initial value: 0)

decode(code)[source]¶

Decode the category of an AC value

Stores the number of bits it took in the stream and stores the length of the codeword for this category

Parameters: code (str) – Sequence to be decoded
Returns: Decoded sequence
Return type: str

encode(inp)[source]¶

Encode the category of an AC value

Parameters: inp (str) – Value to be encoded
Returns: The encoded message for the category
Return type: str

static find_category(value)[source]¶

Find the category of an ac value

Parameters: value (int) – Value for which we want the category
Returns: Category corresponding to the value
Return type: int

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

get_state(case=None)[source]¶

Return new state after decoding

Returns: The number of bits it took in the stream and the length of the codeword for this category
Return type: int, int

class jpegdna.coders.categorycoder.DCCategoryCoder(d, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

DC Category value coder

Parameters

d (dict) – Huffman n-ary dictionnary
verbose – bool

Variables

verbose – Verbosity enabler
goldman_coder (jpegdna.coders.goldmancoder.GoldmanCoderDNA) – Goldman Coder
ad_bits (int) – length of the codeword for the category (initial value: 0)
code_length (int) – length of the codeword for the value (initial value: 0)

decode(code)[source]¶

Decode the category of a DC value

Parameters: code (str) – Sequence to be decoded
Returns: The decoded category
Return type: str

encode(inp)[source]¶

Encode the category of an DC value

Parameters: input (str) – Category to be encoded
Returns: The encoded message for the category
Return type: str

static find_category(value)[source]¶

Find the category of a dc value

Parameters: value (int) – Value for which we want the category
Returns: Category corresponding to the value
Return type: int

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

get_state(case=None)[source]¶

Return new state after decoding

Returns: The number of bits it took in the stream and the length of the codeword for this category
Return type: int, int

exception jpegdna.coders.categorycoder.NonDecodableCategory[source]¶: Bases: KeyError

jpegdna.coders.categorycoder.count_run_cat(seq_coeff, lut)[source]¶

Counts the number of categories

Parameters

seq_coeff (list(int)) – Sequence of coefficients
lut (list) – list of hexadecimal codes for categories

jpegdna.coders.categorycoder.find_category_ac(value)[source]¶

Find the category of an ac value

Parameters: value (int) – Value for which we want the category
Returns: Category corresponding to the value
Return type: int

jpegdna.coders.categorycoder.find_category_dc(value)[source]¶

Find the category of a dc value

Parameters: value (int) – Value for which we want the category
Returns: Category corresponding to the value
Return type: int

jpegdna.coders.coefficientcoder module¶

General AC and DC coefficients coder

class jpegdna.coders.coefficientcoder.ACCoefficientCoder(d, lut, codebook, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

AC Coefficient General Coder

Parameters

d (dict) – Huffman n-ary dictionnary
lut (list) – Lut matrix
verbose – bool

Variables

verbose – Verbosity enabler
category_coder (jpegdna.coders.categorycoder.ACCategoryCoder) – category coder associated with the value coder
value_coder (jpegdna.coders.valuecoder.ValueCoder) – value coder
gold_code (list) – goldman coded values for every hexa category value
count_runcat_len (int) – length of the encoded words for the categories

decode(code)[source]¶

Function for decoding AC coefficients

Parameters: code (str) – Sequence to be decoded

encode(inp)[source]¶

Function for coding AC coefficients

Parameters: inp (list(int)) – Input to be encoded

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

full_encode(inp, *args)[source]¶

Encoding method

Parameters

inp (list|str) – Input to encode
args (any) – Encoding arguments

Returns

Encoded message, encoding state

Return type

list|str, any

get_state(case=None)[source]¶

Return new state

Returns: The length of the codeword for this category (case 0: after encoding) or The number of zeros in the stream, number of bits it took in the stream, if it is the end of the block (case 1: after decoding)
Return type: int | int, int, bool

set_state(*args, case=None)[source]¶

Sets the state of the coder

Parameters: gold_code (str) – goldman code

class jpegdna.coders.coefficientcoder.DCCoefficientCoder(d, codebook, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

DC Coefficient General Coder

Parameters

d (dict) – Huffman n-ary dictionnary
verbose – bool

Variables

verbose – Verbosity enabler
category_coder (jpegdna.coders.categorycoder.DCCategoryCoder) – category coder associated with the value coder
value_coder (jpegdna.coders.valuecoder.ValueCoder) – value coder
gold_code (list) – goldman coded values for every hexa category value in the lut matrix
count_cat_len (int) – length of the encoded word for the category

decode(code)[source]¶

Function for decoding a DC coefficient

Parameters: code (str) – Sequence to be decoded

encode(inp)[source]¶

Function for coding a DC coefficient

Parameters: inp (int) – Value to encode

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

full_encode(inp, *args)[source]¶

Encoding method

Parameters

inp (list|str) – Input to encode
args (any) – Encoding arguments

Returns

Encoded message, encoding state

Return type

list|str, any

get_state(case=None)[source]¶

Return new state

Returns: The length of the codeword for this category (case 0: after encoding) or The number of bits it took in the stream (case 1: after decoding)
Return type: int

set_state(*args, case=None)[source]¶

Set new state

Parameters: gold_code (str) – Goldman code

jpegdna.coders.goldmancoder module¶

Goldman coder

class jpegdna.coders.goldmancoder.GoldmanCoder(alphabet, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

Goldman coder

Parameters: alphabet (list) – alphabet for encoding
Return type: None

decode(code)[source]¶

Function that decodes DNA data using Goldman coder

Parameters: code (str) – Signal to be decoded
Returns: Decoded signal
Return type: str

encode(inp)[source]¶

Function that encodes data into DNA using Goldman coder

Parameters: inp (str) – Signal to be encoded
Returns: Encoded signal
Return type: str

class jpegdna.coders.goldmancoder.GoldmanCoderDNA[source]¶

Bases: jpegdna.coders.goldmancoder.GoldmanCoder

DNA Goldman Coder

exception jpegdna.coders.goldmancoder.NonDecodableGoldman[source]¶: Bases: KeyError

jpegdna.coders.hexcoder module¶

Hexadecimal converter

class jpegdna.coders.hexcoder.HexCoder[source]¶

Bases: jpegdna.coders.AbstractCoder

Hexadecimal coder

decode(code)[source]¶

Decoding method

Parameters: code (list|str) – Input to decode
Returns: Decoded message
Return type: list|str

encode(inp)[source]¶

Encoding method

Parameters: inp (list|str) – Input to encode
Returns: Encoded message
Return type: list|str

jpegdna.coders.huffmancoder module¶

Huffman n-ary tree coder

class jpegdna.coders.huffmancoder.HuffmanCoder(*args, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

Huffman n-ary tree coder

case 1:

Parameters

alphabet (list) – List of elements that can be encoded
feqs – List of appearence frequencies for each element in the alphabet
n (int) – base of the n-ary tree
verbose – bool
debug – bool

Variables

verbose – Verbosity enabler
debug – Verbosity for debug enabler

case 2:

Parameters: dic (dict) – Huffman dictionnary

decode(code)[source]¶

Decode a signal using the Huffman n-ary dictionnary

Parameters: code (str) – Signal to be decoded
Returns: Decoded signal
Return type: list

encode(inp)[source]¶

Encode a signal using a Huffman n-ary dictionnary

Parameters: inp (list) – Signal to be encoded
Returns: Encoded signal
Return type: str

find_codeword_key(word)[source]¶

Find the symbol associated with a codeword in the huffman dictionnary

Parameters: word (str) – codeword for which we want the symbol
Returns: Symbol in the alphabet corresonding to the codeword
Return type: str

class jpegdna.coders.huffmancoder.TreeNode(key, data, children=None)[source]¶

Bases: object

Node with an arbitrary number of children.

As such, it’s missing a lot of features, but that’s okay. Don’t use it for a “real” tree.

print()[source]¶: Print the tree rooted at the node in tabular form. :returns: None

jpegdna.coders.huffmancoder.base_n(num, b, numerals='0123456789abcdefghijklmnopqrstuvwxyz')[source]¶

jpegdna.coders.huffmancoder.combine_and_replace(nodes, n)[source]¶

Combine n nodes from the front of the low-to-high list into one whose key is the sum of the merged nodes. The new node’s data is set to None, then inserted into its proper place in the list.

Note: The sum of keys made here is the smallest such combination.

In the contradictory style of Huffman, if any set of nodes were chosen except for the first n, then changing a node not in the first n to one that is from the first n would reduce the sum of their keys. Thus the smallest sum is made from the first n nodes.

Nodes: A list of TreeNodes.
N: Integer < len(nodes).
Returns: Low-to-high list that combines the last n nodes into one.

jpegdna.coders.huffmancoder.huffman_initial_count(message_count, digits)[source]¶

Return the number of messages that must be grouped in the first layer for Huffman Code generation.

Message_count: Positive integral message count.
Digits: Integer >= 2 representing how many digits are to be used in codes.
Returns: The number of messages that _must_ be grouped in the first level to form a digit-ary Huffman tree.

jpegdna.coders.huffmancoder.huffman_nary_tree(probabilities, digits, verbose=False)[source]¶

Return a Huffman tree using the given number of digits.

Probabilities: List of tuples (symbol, probability) where probability is any floating point and symbol is any object.
Digits: Integral number of digits to use in the Huffman encoding. Must be at least two.
Returns: TreeNode that is the root of the Huffman tree.

jpegdna.coders.huffmancoder.huffmandict(alphabet, freqs, n, verbose=False)[source]¶

Function that creates the dictionnary for the huffman coder

Parameters

alphabet (list) – List of elements that can be encoded
freqs (list) – List of appearence frequencies for each element in the alphabet
n (int) – base of the n-ary tree
verbose – bool
debug – bool

Variables

verbose – Verbosity enabler
debug – Verbosity for debug enabler

Returns

Codewords for each element of the alphabet

Return type

dict

jpegdna.coders.huffmancoder.indicies_to_code(path, digits)[source]¶

Convert the path into a string.

We join the indices directly, from most to least significant, keeping leading zeroes. Examples: [1, 2, 3] -> “123” [7, 2, 10] -> “72a” [0, 2, 1] -> “021”

jpegdna.coders.huffmancoder.x_in_y(query, base)[source]¶: Checks if query is a subsequence of base

jpegdna.coders.valuecoder module¶

Value coder

class jpegdna.coders.valuecoder.ValueCoder(codebook, verbose=False)[source]¶

Bases: jpegdna.coders.AbstractCoder

Value Coder

Variables

verbose – Verbosity enabler
category (int) – category in which belongs the value
ad_bits (int) – length of the word coding the value

Parameters

verbose – bool

decode(code)[source]¶

Decode a value

Parameters: code (str) – Sequence to be decoded

encode(inp)[source]¶

Encode a value according to a category

Parameters: inp (int) – value to be encoded

full_decode(code, *args)[source]¶

Encoding method

Parameters

code (list|str) – Input to decode
args (any) – Decoding arguments

Returns

Decoded message, decoding state

Return type

list|str, any

full_encode(inp, *args)[source]¶

Encoding method

Parameters

inp (list|str) – Input to encode
args (any) – Encoding arguments

Returns

Encoded message, encoding state

Return type

list|str, any

get_state(case=None)[source]¶

Return new state after encoding

Returns: The number of bits it took in the stream and the length of the codeword for this category
Return type: int, int

set_state(*args, case=None)[source]¶: Sets the state for the decoding

jpegdna.coders.valuecoder.compute_max_value(ad_bits)[source]¶

Compute the max value for the codebook with codewords of length ad_bits

Parameters: ad_bits (int) – codeword length
Returns: max value
Return type: int

jpegdna.coders.valuecoder.compute_min_value(ad_bits)[source]¶

Compute the min value for the codebook with codewords of length ad_bits

Parameters: ad_bits (int) – codeword length
Returns: min value
Return type: int

jpegdna.coders.valuecoder.get_codebook(ad_bits, codebook)[source]¶

Returns the exhaustive codebooks for a given codeword length

Parameters: ad_bits (int) – codewor length
Returns: Codebook
Return type: list(str)