veejay/veejay-current/libOSC/OSC-timetag.c

/*
Copyright © 1998. The Regents of the University of California (Regents). 
All Rights Reserved.

Written by Matt Wright, The Center for New Music and Audio Technologies,
University of California, Berkeley.

Permission to use, copy, modify, distribute, and distribute modified versions
of this software and its documentation without fee and without a signed
licensing agreement, is hereby granted, provided that the above copyright
notice, this paragraph and the following two paragraphs appear in all copies,
modifications, and distributions.

IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

The OpenSound Control WWW page is 
    http://www.cnmat.berkeley.edu/OpenSoundControl
*/


/*

 OSC_timeTag.c: library for manipulating OSC time tags
 Matt Wright, 5/29/97

 Version 0.2 (9/11/98): cleaned up so no explicit type names in the .c file.

*/

#include <libOSC/OSC-timetag.h>
#include <stdint.h>
#include <sys/time.h>

#ifdef HAS8BYTEINT
#define TWO_TO_THE_32_FLOAT 4294967296.0f

OSCTimeTag OSCTT_Immediately(void) {
    return (OSCTimeTag) 1;
}

OSCTimeTag OSCTT_BiggestPossibleTimeTag(void) {
    return (OSCTimeTag) 0xffffffffffffffff;
}

OSCTimeTag OSCTT_PlusSeconds(OSCTimeTag original, float secondsOffset) {
    int8 offset = (int8) (secondsOffset * TWO_TO_THE_32_FLOAT);

/*    printf("* OSCTT_PlusSeconds %llx plus %f seconds (i.e., %lld offset) is %llx\n", original,
	      secondsOffset, offset, original + offset);  */

    return original + offset;
}

int OSCTT_Compare(OSCTimeTag left, OSCTimeTag right) {
#if 0
    printf("***** OSCTT_Compare(%llx, %llx): %d\n", left, right,
	   (left<right) ? -1 : ((left == right) ? 0 : 1));
#endif
    if (left < right) {
        return -1;
    } else if (left == right) {
        return 0;
    } else {
        return 1;
    }
}

#ifdef __sgi
#include <sys/time.h>

#define SECONDS_FROM_1900_to_1970 2208988800 /* 17 leap years */
#define TWO_TO_THE_32_OVER_ONE_MILLION 4295


OSCTimeTag OSCTT_CurrentTime(void) {
    uint8 result;
    uint4 usecOffset;
    struct timeval tv;
    struct timezone tz;

    BSDgettimeofday(&tv, &tz);

    /* First get the seconds right */
    result = (unsigned) SECONDS_FROM_1900_to_1970 + 
	     (unsigned) tv.tv_sec - 
	     (unsigned) 60 * tz.tz_minuteswest +
             (unsigned) (tz.tz_dsttime ? 3600 : 0);

#if 0
    /* No timezone, no DST version ... */
    result = (unsigned) SECONDS_FROM_1900_to_1970 + 
	     (unsigned) tv.tv_sec;
#endif


    /* make seconds the high-order 32 bits */
    result = result << 32;
	
    /* Now get the fractional part. */
    usecOffset = (unsigned) tv.tv_usec * (unsigned) TWO_TO_THE_32_OVER_ONE_MILLION;
    /* printf("** %ld microsec is offset %x\n", tv.tv_usec, usecOffset); */

    result += usecOffset;

/*    printf("* OSCTT_CurrentTime is %llx\n", result); */
    return result;
}

#else /* __sgi */

/* Instead of asking your operating system what time it is, it might be
   clever to find out the current time at the instant your application 
   starts audio processing, and then keep track of the number of samples
   output to know how much time has passed. */

/* Loser version for systems that have no ability to tell the current time: */
OSCTimeTag OSCTT_CurrentTime(void) {
    return (OSCTimeTag) 1;
}

#endif /* __sgi */


#else /* Not HAS8BYTEINT */

OSCTimeTag OSCTT_CurrentTime(void) {
    OSCTimeTag result;
    result.seconds = 0;
    result.fraction = 1;
    return result;
}

OSCTimeTag OSCTT_BiggestPossibleTimeTag(void) {
    OSCTimeTag result;
    result.seconds = 0xffffffff;
    result.fraction = 0xffffffff;
    return result;
}

OSCTimeTag OSCTT_Immediately(void) {
    OSCTimeTag result;
    result.seconds = 0;
    result.fraction = 1;
    return result;
}

OSCTimeTag OSCTT_PlusSeconds(OSCTimeTag original, float secondsOffset) {
    OSCTimeTag result;
    result.seconds = 0;
    result.fraction = 1;
    return result;
}

int OSCTT_Compare(OSCTimeTag left, OSCTimeTag right) {
    /* Untested! */
    int highResult = left.seconds - right.seconds;

    if (highResult != 0) return highResult;

    return left.fraction - right.fraction;
}


#endif /* HAS8BYTEINT */