/*
 * include needed system headers
 */
#include <stdio.h>       /* include standard i/o library */
#include <stdlib.h>      /* include standard library */
#include <string.h>      /* include string library */
#include <unistd.h>      /* include unix standard library */
#include <sys/types.h>   /* */
#include <sys/stat.h>    /* */
#include <fcntl.h>       /* */
#include <errno.h>       /* error simbol definitions */
#include <time.h>        /* system time definitions */
#include <math.h>        /* math library */

void unpacking(int ndata, unsigned short *output);

void dunpacker_(int *l_buffer, unsigned short *buffer, int *error, int *fd)

{
    int i;
    int nhead,nread;
    unsigned short word;

    *error = 0;

    nhead = 13;  /* packed */

//    printf("%i \n",*l_buffer);


/* /\*** read the data ***\/ */
//    if( nhead == 13) *l_buffer = (*l_buffer*13)/16+1; /* packed */
    nread=read(*fd, buffer, 2**l_buffer);

    if( nread==0 ) {
//	printf("dunpacker: Unexpected end of file %d at %d \n",*fd,nread);
	*error=1;
	return ;
    }
    if ( nread != 2**l_buffer) {
//	printf("dunpacker: Error on reading: nread = %d \n",nread);
	*error=-1;
 	return ; 
    }


/*** correct byte ***/
    for(i=0; i<*l_buffer; i++) {
	word = buffer[i];
	buffer[i] = ( (word&0x00ff) << 8 ) | ( (word&0xff00) >> 8 );
    }

/*** unpacking buffer data ***/
    if( nhead == 13) unpacking(*l_buffer, buffer);

//    int num = (*l_buffer-13-1)/13*16+3;//???
//  for( i=0; i<num; i++) printf("%i %x \n",i,buffer[i]);//???

/* /\***   Checksum ***\/ */
/* 	oi = buffer; */
/* 	word = 0; */
/* 	for( i=0; i<l_buffer; ++i) */
/* 	    word = (word + *oi++) & 0x03ff; */
/* 	if( word == ( header[6] & 0x03ff ) ) */
/* /\*  	    printf("Check Sum OK \n")*\/ ; */
/* 	else */
/* 	    printf("Wrong Check Sum: %x, %x \n",word,header[6]&0x03ff); */

}

/*========================================================= */
/*========================================================= */
/*
 * Routine to unpacking buffer file
 *
 */
/*========================================================= */
/*========================================================= */
void unpacking(int nwords, unsigned short *output) {
    unsigned short out[10000];
    int k;
    unsigned short *oi, *oo, *o1;
    
    for( k=0; k<10000; ++k)
	out[k]=0;
    oo=output;
    oi=out;
    for( k=0; k<nwords; ++k) {
	*oi++ = *oo;
	*oo++ = 0;
    }
    
    oo=output;
    oi=out;

    for(k=0; k<nwords; k+=13) {
	o1 = oi++;
	*oo++ = (*o1 & 0xfff8) >> 3;
	*oo++ = ( (*o1 & 0x0007) << 10 ) | ( (*oi & 0xffc0) >> 6);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x003f) << 7 ) | ( (*oi & 0xfe00) >> 9);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x01ff) << 4 ) | ( (*oi & 0xf000) >> 12);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x0fff) << 1 ) | ( (*oi & 0x8000) >> 15);
	*oo++ = (*oi & 0x7ffc) >> 2;
	o1 = oi++;
	*oo++ = ( (*o1 & 0x0003) << 11 ) | ( (*oi & 0xffe0) >> 5);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x001f) << 8 ) | ( (*oi & 0xff00) >> 8);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x00ff) << 5 ) | ( (*oi & 0xf800) >> 11);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x07ff) << 2 ) | ( (*oi & 0xc000) >> 14);
	*oo++ = (*oi & 0x3ffe) >> 1;
	o1 = oi++;
	*oo++ = ( (*o1 & 0x0001) << 12 ) | ( (*oi & 0xfff0) >> 4);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x000f) << 9 ) | ( (*oi & 0xff80) >> 7);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x007f) << 6 ) | ( (*oi & 0xfc00) >> 10);
	o1 = oi++;
	*oo++ = ( (*o1 & 0x03ff) << 3 ) | ( (*oi & 0xe000) >> 13);
	*oo++ = *oi++ & 0x1fff;
    }


    return; 
}