tracker/readraw/findstart.c

/*
 * 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 findstart_(unsigned short *buffer, int *error, int *fd)*/

/*{*/
/*     int nread; */
/*     unsigned short word;//, *p_buffer; */


/* /\*** reads a word ***\/ */
/* //    p_buffer=&buffer; */
/*     nread=read(*fd, buffer, 2); */
/*     if(nread == 0) { */
/*      printf("findstart: Unexpected end of file %d at %d \n",*fd,nread); */
/*      *error=1; */
/*      return ; */
/*     } */
/*     if(nread != 2) { */
/*      printf("findstart: Error on reading: nread = %d \n",nread); */
/*      *error=-1; */
/*      return ;  */
/*     } */

/* /\*** correct byte ***\/ //??????????????????????SCAMBIA */
/*     word = buffer; */
/*     buffer = ( (word&0x00ff) << 8 ) | ( (word&0xff00) >> 8 ); */
/* //    printf("buffer %x , word: %x: \n", buffer, word);//??? */


/*   looks for a DSP header beginning (a word beginning with 1110)   */
    
void findstart_(int *error, int *fd)

{
    int nread;
    unsigned short word;
    unsigned short temp;
   
    do {
        nread=read(*fd, &word, 2); //reads 16 bits
        if(nread == 0) {
            //printf("findstart: Unexpected end of file %d at %d \n",*fd,nread);
            *error=1;
            return ;
        }
        if(nread != 2) {
            //printf("findstart: Error on reading: bytes read -> nread = %d \n",nread);
            *error=-1;
            return ;
        }


        /*** corrects byte ***/ //endianess...
        temp = word;
        word = ( (temp&0x00ff) << 8 ) | ( (temp&0xff00) >> 8 );
//      printf("word %x , temp: %x: \n", word, temp);//??? */

        
        /*** goes back 8 bits ***/
        lseek(*fd, -1, SEEK_CUR); //SEEK_CUR ---> from current position

//      unsigned short num=lseek(*fd, -1, SEEK_CUR); //SEEK_CUR ---> from current position
//      printf("%i \n",num);
        
    }
    while ((word&0xf000) != 0xe000);
    
    /*** goes back 8 bits ***/
    lseek(*fd, -1, SEEK_CUR);


    return;
}
1	/*
2	* include needed system headers
3	*/
4	#include <stdio.h> /* include standard i/o library */
5	#include <stdlib.h> /* include standard library */
6	#include <string.h> /* include string library */
7	#include <unistd.h> /* include unix standard library */
8	#include <sys/types.h> /* */
9	#include <sys/stat.h> /* */
10	#include <fcntl.h> /* */
11	#include <errno.h> /* error simbol definitions */
12	#include <time.h> /* system time definitions */
13	#include <math.h> /* math library */
14
15	/void findstart_(unsigned short buffer, int error, int fd)*/
16
17	/{/
18	/* int nread; */
19	/* unsigned short word;//, p_buffer; /
20
21
22	/* /\* reads a word \/ /
23	/* // p_buffer=&buffer; */
24	/* nread=read(fd, buffer, 2); /
25	/* if(nread == 0) { */
26	/* printf("findstart: Unexpected end of file %d at %d \n",fd,nread); /
27	/* error=1; /
28	/* return ; */
29	/* } */
30	/* if(nread != 2) { */
31	/* printf("findstart: Error on reading: nread = %d \n",nread); */
32	/* error=-1; /
33	/* return ; */
34	/* } */
35
36	/* /\* correct byte \/ //??????????????????????SCAMBIA /
37	/* word = buffer; */
38	/* buffer = ( (word&0x00ff) << 8 ) \| ( (word&0xff00) >> 8 ); */
39	/* // printf("buffer %x , word: %x: \n", buffer, word);//??? */
40
41
42	/* looks for a DSP header beginning (a word beginning with 1110) */
43
44	void findstart_(int error, int fd)
45
46	{
47	int nread;
48	unsigned short word;
49	unsigned short temp;
50
51	do {
52	nread=read(*fd, &word, 2); //reads 16 bits
53	if(nread == 0) {
54	//printf("findstart: Unexpected end of file %d at %d \n",*fd,nread);
55	*error=1;
56	return ;
57	}
58	if(nread != 2) {
59	//printf("findstart: Error on reading: bytes read -> nread = %d \n",nread);
60	*error=-1;
61	return ;
62	}
63
64
65	/* corrects byte */ //endianess...
66	temp = word;
67	word = ( (temp&0x00ff) << 8 ) \| ( (temp&0xff00) >> 8 );
68	// printf("word %x , temp: %x: \n", word, temp);//??? */
69
70
71	/* goes back 8 bits */
72	lseek(*fd, -1, SEEK_CUR); //SEEK_CUR ---> from current position
73
74	// unsigned short num=lseek(*fd, -1, SEEK_CUR); //SEEK_CUR ---> from current position
75	// printf("%i \n",num);
76
77	}
78	while ((word&0xf000) != 0xe000);
79
80	/* goes back 8 bits */
81	lseek(*fd, -1, SEEK_CUR);
82
83
84	return;
85	}