算术编码算法，用于图像压缩或者文本压缩（原理： 算术编码是把一个信源表示为实轴上0和1之间的一个区间，信源集合中的每一个元素都用来缩短这个区间）-Arithmetic coding algorithm for image compression, or text compression (Principle: arithmetic coding is to a source is expressed as the real axis between 0 and 1, a range of sou