mirror of https://github.com/gchq/CyberChef.git
49 lines
1.4 KiB
JavaScript
49 lines
1.4 KiB
JavaScript
/**
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* Binary Code Decimal resources.
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*
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* @author n1474335 [n1474335@gmail.com]
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* @copyright Crown Copyright 2017
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* @license Apache-2.0
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*/
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/**
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* BCD encoding schemes.
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*/
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export const ENCODING_SCHEME = [
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"8 4 2 1",
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"7 4 2 1",
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"4 2 2 1",
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"2 4 2 1",
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"8 4 -2 -1",
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"Excess-3",
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"IBM 8 4 2 1",
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];
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/**
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* Lookup table for the binary value of each digit representation.
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*
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* I wrote a very nice algorithm to generate 8 4 2 1 encoding programmatically,
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* but unfortunately it's much easier (if less elegant) to use lookup tables
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* when supporting multiple encoding schemes.
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*
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* "Practicality beats purity" - PEP 20
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*
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* In some schemes it is possible to represent the same value in multiple ways.
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* For instance, in 4 2 2 1 encoding, 0100 and 0010 both represent 2. Support
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* has not yet been added for this.
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*/
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export const ENCODING_LOOKUP = {
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"8 4 2 1": [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
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"7 4 2 1": [0, 1, 2, 3, 4, 5, 6, 8, 9, 10],
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"4 2 2 1": [0, 1, 4, 5, 8, 9, 12, 13, 14, 15],
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"2 4 2 1": [0, 1, 2, 3, 4, 11, 12, 13, 14, 15],
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"8 4 -2 -1": [0, 7, 6, 5, 4, 11, 10, 9, 8, 15],
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"Excess-3": [3, 4, 5, 6, 7, 8, 9, 10, 11, 12],
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"IBM 8 4 2 1": [10, 1, 2, 3, 4, 5, 6, 7, 8, 9],
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};
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/**
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* BCD formats.
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*/
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export const FORMAT = ["Nibbles", "Bytes", "Raw"];
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