arithmetic_coding.h

来自「算术码编码代码源程序」· C头文件 代码 · 共 17 行

/* DECLARATIONS USED FOR ARITHMETIC ENCODING AND DECODING */


/* SIZE OF ARITHMETIC CODE VALUES. */

#define Code_value_bits 16		/* Number of bits in a code value   */
typedef long code_value;		/* Type of an arithmetic code value */

#define Top_value (((long)1<<Code_value_bits)-1)      /* Largest code value */


/* HALF AND QUARTER POINTS IN THE CODE VALUE RANGE. */

#define First_qtr (Top_value/4+1)	/* Point after first quarter        */
#define Half	  (2*First_qtr)		/* Point after first half           */
#define Third_qtr (3*First_qtr)		/* Point after third quarter        */