LZ78avkodning

LZ78avkodning refers to the decoding process for data compressed using the LZ78 algorithm. The LZ78 algorithm is a dictionary-based lossless data compression method. It works by building a dictionary of strings encountered in the input data. When a string is found that is already in the dictionary, the algorithm outputs the code for that string. If a new string is encountered, it is added to the dictionary along with a reference to its preceding character.

Decoding LZ78-compressed data involves reconstructing the original data by using the dictionary created during compression. The decoder reads a sequence of codes. Each code represents either a single character or a previously seen string from the dictionary, followed by a new character. The decoder maintains its own dictionary, which mirrors the one built by the encoder. When a code is received, the decoder looks up the corresponding entry in its dictionary. If it's a new entry, it consists of a reference to a previous dictionary entry and a character. The decoder then reconstructs the string and adds it to its dictionary. If the code refers to an existing dictionary entry, the decoder outputs the associated string and appends the new character, then adds this new string to the dictionary. This process continues until the entire compressed data stream has been decoded, effectively rebuilding the original uncompressed data. The efficiency of LZ78 compression and its corresponding decoding relies on the redundancy present in the input data, allowing for repeated patterns to be represented by shorter codes.