float ent(float [], int );
int image_size(char [], int *, int *);
void readimage(char [], unsigned 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))