/*
 * Salamander Server's Utility routines.
 *
 * G. Robert Malan (rmalan@eecs.umich.edu).
 * 2/25/97
 *
 * $Id: salamanderUtil.c,v 1.8 1997/05/08 20:39:46 rmalan Exp $
 */

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/time.h>

/***********************************************************************
 *
 * Routines used by both the server and various applications.
 *
 ***********************************************************************/
int
readn(int fd, char *ptr, int nbytes)
{
        int nleft, nread;

        nleft = nbytes;
        while(nleft > 0) {
                nread = read(fd, ptr, nleft);
                if (nread < 0) {
			if (errno == EAGAIN) {
#if	VERBOSE
				fprintf(stderr, "readn pausing for resouce.\n");
#endif
				sleep(1);
				continue;
			}
#if	VERBOSE
			fprintf(stderr, "readn failed (errno %d).\n", errno);
#endif	
                        return(nread);
                } else if (nread == 0)
                        break;

                nleft -= nread;
                ptr += nread;
        }
        return(nbytes - nleft);
}


int
writen(int fd, char *ptr, int nbytes)
{
        int nleft, nwritten;

        nleft = nbytes;
        while (nleft > 0) {
                nwritten = write (fd, ptr, nleft);
                if (nwritten <= 0) {
			if (errno == EAGAIN) {
#if	VERBOSE
				fprintf(stderr, "writen pausing for resouce.\n");
#endif
				sleep(1);
				continue;
			}
#if	VERBOSE
			fprintf(stderr, "writen failed (errno %d).\n", errno);
#endif
                        return (nwritten);
		}
                nleft -= nwritten;
                ptr += nwritten;
        }
        return (nbytes - nleft);
}


void
timediff(struct timeval new, struct timeval old, struct timeval * diff)
{
	diff->tv_usec = new.tv_usec - old.tv_usec;
	diff->tv_sec = new.tv_sec - old.tv_sec;

	if (diff->tv_usec < 0) {
		diff->tv_sec--;
		diff->tv_usec = 1000000 + diff->tv_usec;
	}
}


void
generateTimestamp(char * timebuf)
{
	struct timeval tv;

        gettimeofday(&tv, NULL);
        sprintf(timebuf, "%ld.%06ld", tv.tv_sec, tv.tv_usec);
}


/***********************************************************************
 *
 * Routines only used by the various applications.
 *
 ***********************************************************************/

int
readline(int fd, char *ptr, int maxlen)
{
        int n, rc;
        char c;

        for (n = 1; n < maxlen; n++) {
                if ((rc = read(fd, &c, 1)) == 1) {
                        *ptr++ = c;
                        if (c == '\n')
                                break;
                } else if (rc == 0) {
                        if (n == 1)
                                return (0);
                        else
                                break;
                } else {
			fprintf(stderr, "%d readline failed (errno %d).\n", errno);
                        return (-1);
		}
        }

        *ptr = 0;
        return(n);
}

/*
 * Returns strlen + 1.
 */
int
readstring(int fd, char *ptr, int maxlen)
{
        int n, rc;
        char c;

        for (n = 1; n < maxlen; n++) {
                if ((rc = read(fd, &c, 1)) == 1) {
                        *ptr++ = c;
                        if (c == '\0')
                                break;
                } else if (rc == 0) {
                        if (n == 1)
                                return (0);
                        else
                                break;
                } else {
			fprintf(stderr, "%d readstring failed (errno %d).\n", errno);
                        return (-1);
		}
        }

        *--ptr = '\0';  /* In case we go over the maxlen. */

        return(n);
}