float ent(float [], int );int image_size(char [], int *, int *);int encuqi(int, int *, int);int decuqi(int, int *);void stuffit(int , int , FILE *, int );int readnbits(int , FILE *);int uquan_enc(float ,  float , int , float );float uquan_dec(int,  float, float );int nuquan_enc(float ,  float [], int);float nuquan_dec(int,  float [] );extern float rangen(int);int vqencode( int *, int **,  int, int,float *);/* vqencode(input,codebook,codebook_size,dimension,&distortion)returns the index in the codebook of the closest codeword */void unstuff(int , FILE *, int *, int *);int readau(char filename[], short aufile[]);int get_file_size(char [], int *);float predictor(int ,int ,float [],float [], float *);void getim(char *fname, unsigned char *array, int size);void storeim(char *fname, unsigned char *array, int size);void sort(float *prob, int *loc,int num);void huff(float prob[], int loc[], int num, unsigned int *code, char *length);void diff(int *diffs, unsigned char *image, int rows, int cols,int num, unsigned char *dimage);void getcode(FILE *fp, int num, unsigned int *code, char *length);void value(int *values, unsigned char *image, int size,int num);void images(int rows, int cols, int *code,char *length, unsigned char *file, unsigned char *dimage);int files(int size,int *code,char *length,unsigned char *file);/* define the structure node */        struct node {                float pro; /* probabilities */                int l; /* location of probability before sorted */                unsigned int code; /* code */                struct node *left; /* pointer for binary tree */                struct node *right; /* pointer for binary tree */                struct node *forward;                struct node *back;                struct node *parent; /* pointer to parent */                int check;        };/* define subroutines and pointers to nodes */typedef struct node NODE;typedef struct NODE *BTREE;BTREE create_list(float prob[], int loc[], int num);void create_code(NODE *root, int lgth, unsigned int *code, char *length);BTREE make_list (int num);void write_code(NODE *root, int lgth, unsigned int *code, char *length, int *loc);   #define     myabs(x) ((x)<0? -(x): (x))