METHOD FOR LOSSLESS DATA COMPRESSION AND RETRIEVAL Russian patent published in 2010 - IPC H03M7/30 

FIELD: information technology.

SUBSTANCE: number of zeros n₀ and number of ones n₁ is determined in a compressed data stream, an algorithm is selected for assigning non-repeating digital codes to all possible permutations with repetitions from n₀ zeroes and n₁ ones and finding the corresponding permutation with repetitions in accordance with the assigned digital code and the number of each character. A specific data stream from n₀ zeroes and n₁ ones is assigned a digital code N_c in accordance with the selected algorithm. The total number of characters in the digital code N_c n_c is determined. The value d₁ which is equal to the sum of n₁ and n₀ minus the value n_c is determined, as well as the value d₂ which is equal to half the difference between values n₀ and n₁, after which the assigned digital code N_c and values d₁ and d₂ are stored. To retrieve the data stream, reverse operations are carried out and in accordance with the selected algorithm on values n₀, n₁ and N_c, the specific permutation with repetitions from n₀ zeroes and n₁ ones is found, which corresponds to the initial data stream.

EFFECT: higher compression ratio of data and possibility of compressing previously compressed data.

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