Method and apparatus for compressively coding/decoding digital data to reduce the use of band-width or storage space

A coding method for compressing digital data, said coding method comprising:

• detecting either a number of continuous zeros or a number of continuous ones from a first endmost bit of the digital data as a number of continuous values;
• subtracting an addition value obtained by adding the number of continuous values and one from a number of bits of the digital data, to obtain a number of bits to-be-allocated to the digital data;
• allocating bits starting from a second endmost bit of the digital data which is opposite to the first endmost bit, and extracting the number of bits to-be-allocated from the digital data, to create a code comprising the allocated bits;
• and
• outputting the code and the number of bits to-be-allocated.

A decoding method for decoding digital data based one of (a) a code which is obtained by omitting a number of bits equal to an addition value obtained by adding either a number of continuous zeros or a number of continuous ones as a number of continuous values from a first endmost bit of the digital data and one, and a number of bits to-be-allocated indicating a number of bits in the code, and (b) the number of bits to-be-allocated, said decoding method comprising:

• subtracting the number of bits to-be-allocated from a number of bits of the digital data, to obtain a difference;
• generating a number of bits equal in number to the difference, wherein the number of bits generated are arranged such that a second endmost bit has a value different from the number of continuous values and bits other than the second endmost bit have values equal to the number of continuous values;
• and
• coupling the number of bits generated by said generating to the code, if the code exists, such that the second endmost bit of the number of bits generated by said generating is coupled to a side of the code on which the omitted bits have been omitted, to restore the digital data or data which can be defined as the digital data, or if the code does not exist, passing the number of bits generated by said generating as the digital data.