Device and method for realizing prefix code construction

A method for realizing prefix code construction, comprising steps of:

• a sort indexer receiving a group of code lengths, sorting the code lengths to obtain a group of sorted code lengths, and recording a position correspondence relationship between the sorted code lengths and the code lengths;
• a generator receiving the sorted code lengths, orderly generating corresponding prefix codes, wherein except that a first prefix code is preconfigured, a current prefix code is obtained by adding 1 to an adjacently previous prefix code and shifting left by a certain number of bits, the certain number of the bits is the difference between the sorted code length corresponding to the current prefix and the sorted code length corresponding to the adjacently previous prefix code;
• the generator judges whether the adjacently previous prefix code is identical to the current prefix code from high bit, if yes, the construction fails, and error information is outputted to report an error, otherwise, the construction is successful, the prefix codes corresponding to the sorted code lengths are generated;
• and
• a sequence regulator receiving the prefix codes corresponding to the sorted code lengths, and regulating, according to the position correspondence relationship recorded by the sort indexer, a sequence of the prefix codes corresponding to the sorted code lengths to obtain the prefix codes corresponding to the code lengths.

A device for realizing prefix code construction, comprising sort indexing means, generating means, and sequence regulating means, wherein:

• the sort indexing means is configured to receive a group of code lengths, sort the code lengths to obtain a group of sorted code lengths, and record a position correspondence relationship between the sorted code lengths and the code lengths;
• the generating means receives the sorted code lengths, orderly generates prefix codes corresponding to the sorted code lengths, wherein except that a first prefix code is preconfigured, the generating means generates a current prefix code by adding 1 to an adjacently previous prefix code and then shifting left by a certain number of bits, the certain number of the bits is the difference between the sorted code length corresponding to the current prefix code and the sorted code length corresponding to the adjacently previous prefix code;
• and, when the current prefix code is generated, the generating means simultaneously judges whether the adjacently previous prefix code is identical to the current prefix code from high bit, if yes, outputs error information, otherwise, generates the prefix codes corresponding to the sorted code lengths;
• and
• the sequence regulating means is configured to receive the prefix codes corresponding to the sorted code lengths, and regulate, according to the position correspondence relationship recorded by the sort indexing means, a sequence of the prefix codes corresponding to the sorted code lengths to obtain the prefix codes corresponding to the code lengths.