/* $Procedure SCDECD ( Decode spacecraft clock ) */
/* Subroutine */ int scdecd_(integer *sc, doublereal *sclkdp, char *sclkch,
ftnlen sclkch_len)
{
/* System generated locals */
integer i__1, i__2, i__3, i__4, i__5;
doublereal d__1;
/* Builtin functions */
double d_nint(doublereal *);
/* Subroutine */ int s_copy(char *, char *, ftnlen, ftnlen);
integer s_rnge(char *, integer, char *, integer), i_len(char *, ftnlen);
/* Local variables */
integer part, i__;
extern /* Subroutine */ int chkin_(char *, ftnlen), errdp_(char *,
doublereal *, ftnlen);
doublereal ticks;
extern /* Subroutine */ int scfmt_(integer *, doublereal *, char *,
ftnlen);
doublereal pstop[9999];
extern logical failed_(void);
extern integer lastnb_(char *, ftnlen);
integer prelen;
extern integer lstled_(doublereal *, integer *, doublereal *);
extern /* Subroutine */ int sigerr_(char *, ftnlen);
integer suflen;
extern /* Subroutine */ int scpart_(integer *, integer *, doublereal *,
doublereal *), chkout_(char *, ftnlen), prefix_(char *, integer *,
char *, ftnlen, ftnlen), setmsg_(char *, ftnlen), errint_(char *,
integer *, ftnlen), suffix_(char *, integer *, char *, ftnlen,
ftnlen);
integer nparts;
doublereal pstart[9999];
extern logical return_(void);
extern /* Subroutine */ int intstr_(integer *, char *, ftnlen);
doublereal ptotls[9999];
char prtstr[5];
/* $ Abstract */
/* Convert double precision encoding of spacecraft clock time into */
/* a character representation. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Required_Reading */
/* SCLK */
/* $ Keywords */
/* CONVERSION */
/* TIME */
/* $ Declarations */
/* $ Abstract */
/* Include file sclk.inc */
/* SPICE private file intended solely for the support of SPICE */
/* routines. Users should not include this file directly due */
/* to the volatile nature of this file */
/* The parameters below define sizes and limits used by */
/* the SCLK system. */
/* $ Disclaimer */
/* THIS SOFTWARE AND ANY RELATED MATERIALS WERE CREATED BY THE */
/* CALIFORNIA INSTITUTE OF TECHNOLOGY (CALTECH) UNDER A U.S. */
/* GOVERNMENT CONTRACT WITH THE NATIONAL AERONAUTICS AND SPACE */
/* ADMINISTRATION (NASA). THE SOFTWARE IS TECHNOLOGY AND SOFTWARE */
/* PUBLICLY AVAILABLE UNDER U.S. EXPORT LAWS AND IS PROVIDED "AS-IS" */
/* TO THE RECIPIENT WITHOUT WARRANTY OF ANY KIND, INCLUDING ANY */
/* WARRANTIES OF PERFORMANCE OR MERCHANTABILITY OR FITNESS FOR A */
/* PARTICULAR USE OR PURPOSE (AS SET FORTH IN UNITED STATES UCC */
/* SECTIONS 2312-2313) OR FOR ANY PURPOSE WHATSOEVER, FOR THE */
/* SOFTWARE AND RELATED MATERIALS, HOWEVER USED. */
/* IN NO EVENT SHALL CALTECH, ITS JET PROPULSION LABORATORY, OR NASA */
/* BE LIABLE FOR ANY DAMAGES AND/OR COSTS, INCLUDING, BUT NOT */
/* LIMITED TO, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND, */
/* INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS, */
/* REGARDLESS OF WHETHER CALTECH, JPL, OR NASA BE ADVISED, HAVE */
/* REASON TO KNOW, OR, IN FACT, SHALL KNOW OF THE POSSIBILITY. */
/* RECIPIENT BEARS ALL RISK RELATING TO QUALITY AND PERFORMANCE OF */
/* THE SOFTWARE AND ANY RELATED MATERIALS, AND AGREES TO INDEMNIFY */
/* CALTECH AND NASA FOR ALL THIRD-PARTY CLAIMS RESULTING FROM THE */
/* ACTIONS OF RECIPIENT IN THE USE OF THE SOFTWARE. */
/* $ Parameters */
/* See the declaration section below. */
/* $ Author_and_Institution */
/* N.J. Bachman (JPL) */
/* $ Literature_References */
/* None. */
/* $ Version */
/* - SPICELIB Version 2.0.0, 24-MAY-2010 (NJB) */
/* Increased value of maximum coefficient record count */
/* parameter MXCOEF from 10K to 50K. */
/* - SPICELIB Version 1.0.0, 11-FEB-2008 (NJB) */
/* -& */
/* Number of supported SCLK field delimiters: */
/* Supported SCLK string field delimiters: */
/* Maximum number of partitions: */
/* Partition string length. */
/* Since the maximum number of partitions is given by MXPART is */
/* 9999, PRTSTR needs at most 4 characters for the partition number */
/* and one character for the slash. */
/* Maximum number of coefficient records: */
/* Maximum number of fields in an SCLK string: */
/* Length of strings used to represent D.P. */
/* numbers: */
/* Maximum number of supported parallel time systems: */
/* End of include file sclk.inc */
/* $ Brief_I/O */
/* Variable I/O Description */
/* -------- --- -------------------------------------------------- */
/* SC I NAIF spacecraft identification code. */
/* SCLKDP I Encoded representation of a spacecraft clock count. */
/* SCLKCH O Character representation of a clock count. */
/* MXPART P Maximum number of spacecraft clock partitions. */
/* $ Detailed_Input */
/* SC is the NAIF integer code of the spacecraft whose */
/* clock's time is being decoded. */
/* SCLKDP is the double precision encoding of a clock time in */
/* units of ticks since the spacecraft clock start time. */
/* This value does reflect partition information. */
/* An analogy may be drawn between a spacecraft clock */
/* and a standard wall clock. The number of ticks */
/* corresponding to the wall clock string */
/* hh:mm:ss */
/* would be the number of seconds represented by that */
/* time. */
/* For example: */
/* Clock string Number of ticks */
/* ------------ --------------- */
/* 00:00:10 10 */
/* 00:01:00 60 */
/* 00:10:00 600 */
/* 01:00:00 3600 */
/* If SCLKDP contains a fractional part the result */
/* is the same as if SCLKDP had been rounded to the */
/* nearest whole number. */
/* $ Detailed_Output */
/* SCLKCH is the character representation of the clock count. */
/* The exact form that SCLKCH takes depends on the */
/* spacecraft. */
/* Nevertheless, SCLKCH will have the following general */
/* format: */
/* 'pp/sclk_string' */
/* 'pp' is an integer greater than or equal to one and */
/* represents a "partition number". */
/* Each mission is divided into some number of partitions. */
/* A new partition starts when the spacecraft clock */
/* resets, either to zero, or to some other */
/* value. Thus, the first partition for any mission */
/* starts with launch, and ends with the first clock */
/* reset. The second partition starts immediately when */
/* the first stopped, and so on. */
/* In order to be completely unambiguous about a */
/* particular time, you need to specify a partition number */
/* along with the standard clock string. */
/* Information about when partitions occur for different */
/* missions is contained in a spacecraft clock kernel */
/* file which needs to be loaded into the kernel pool */
/* before calling SCDECD. */
/* The routine SCPART may be used to read the partition */
/* start and stop times, in encoded units of ticks, from */
/* the kernel file. */
/* Since the end time of one partition is coincident with */
/* the begin time of the next, two different time strings */
/* with different partition numbers can encode into the */
/* same value. */
/* For example, if partition 1 ends at time t1, and */
/* partition 2 starts at time t2, then */
/* '1/t1' and '2/t2' */
/* will be encoded into the same value, say X. SCDECD */
/* always decodes such values into the latter of the */
/* two partitions. In this example, */
/* CALL SCDECD ( X, SC, CLKSTR ) */
/* will result in */
/* CLKSTR = '2/t2'. */
/* 'sclk_string' is a spacecraft specific clock string, */
/* typically consisting of a number of components */
/* separated by delimiters. */
/* Using Galileo as an example, the full format is */
/* wwwwwwww:xx:y:z */
/* where z is a mod-8 counter (values 0-7) which */
/* increments approximately once every 8 1/3 ms., y is a */
/* mod-10 counter (values 0-9) which increments once */
/* every time z turns over, i.e., approximately once every */
/* 66 2/3 ms., xx is a mod-91 (values 0-90) counter */
/* which increments once every time y turns over, i.e., */
/* once every 2/3 seconds. wwwwwwww is the Real-Time Image */
/* Count (RIM), which increments once every time xx turns */
/* over, i.e., once every 60 2/3 seconds. The roll-over */
/* expression for the RIM is 16777215, which corresponds */
/* to approximately 32 years. */
/* wwwwwwww, xx, y, and z are referred to interchangeably */
/* as the fields or components of the spacecraft clock. */
/* SCLK components may be separated by any of these five */
/* characters: ' ' ':' ',' '-' '.' */
/* The delimiter used is determined by a kernel pool */
/* variable and can be adjusted by the user. */
/* Some spacecraft clock components have offset, or */
/* starting, values different from zero. For example, */
/* with an offset value of 1, a mod 20 counter would */
/* cycle from 1 to 20 instead of from 0 to 19. */
/* See the SCLK required reading for a detailed */
/* description of the Voyager and Mars Observer clock */
/* formats. */
/* $ Parameters */
/* MXPART is the maximum number of spacecraft clock partitions */
/* expected in the kernel file for any one spacecraft. */
/* See the INCLUDE file sclk.inc for this parameter's */
/* value. */
/* $ Exceptions */
/* 1) If kernel variables required by this routine are unavailable, */
/* the error will be diagnosed by routines called by this routine. */
/* SCLKCH will be returned as a blank string in this case. */
/* 2) If the number of partitions in the kernel file for spacecraft */
/* SC exceeds the parameter MXPART, the error */
/* 'SPICE(TOOMANYPARTS)' is signaled. SCLKCH will be returned */
/* as a blank string in this case. */
/* 3) If the encoded value does not fall in the boundaries of the */
/* mission, the error 'SPICE(VALUEOUTOFRANGE)' is signaled. */
/* SCLKCH will be returned as a blank string in this case. */
/* 4) If the declared length of SCLKCH is not large enough to */
/* contain the output clock string the error */
/* 'SPICE(SCLKTRUNCATED)' is signaled either by this routine */
/* or by a routine called by this routine. On output SCLKCH */
/* will contain a portion of the truncated clock string. */
/* $ Files */
/* A kernel file containing spacecraft clock partition information */
/* for the desired spacecraft must be loaded, using the routine */
/* FURNSH, before calling this routine. */
/* $ Particulars */
/* In general, it is difficult to compare spacecraft clock counts */
/* numerically since there are too many clock components for a */
/* single comparison. The routine SCENCD provides a method of */
/* assigning a single double precision number to a spacecraft's */
/* clock count, given one of its character representations. */
/* This routine performs the inverse operation to SCENCD, converting */
/* an encoded double precision number to character format. */
/* To convert the number of ticks since the start of the mission to */
/* a clock format character string, SCDECD: */
/* 1) Determines the spacecraft clock partition that TICKS falls */
/* in. */
/* 2) Subtracts off the number of ticks occurring in previous */
/* partitions, to get the number of ticks since the beginning */
/* of the current partition. */
/* 3) Converts the resulting ticks to clock format and forms the */
/* string */
/* 'partition_number/clock_string' */
/* $ Examples */
/* Double precision encodings of spacecraft clock counts are used to */
/* tag pointing data in the C-kernel. */
/* In the following example, pointing for a sequence of images from */
/* the Voyager 2 narrow angle camera is requested from the C-kernel */
/* using an array of character spacecraft clock counts as input. */
/* The clock counts attached to the output are then decoded to */
/* character and compared with the input strings. */
/* CHARACTER*(25) CLKIN ( 4 ) */
/* CHARACTER*(25) CLKOUT */
/* CHARACTER*(25) CLKTOL */
/* DOUBLE PRECISION TIMEIN */
/* DOUBLE PRECISION TIMOUT */
/* DOUBLE PRECISION CMAT ( 3, 3 ) */
/* INTEGER NPICS */
/* INTEGER SC */
/* DATA NPICS / 4 / */
/* DATA CLKIN / '2/20538:39:768', */
/* . '2/20543:21:768', */
/* . '2/20550:37', */
/* . '2/20561:59' / */
/* DATA CLKTOL / ' 0:01:000' / */
/* C */
/* C The instrument we want pointing for is the Voyager 2 */
/* C narrow angle camera. The reference frame we want is */
/* C J2000. The spacecraft is Voyager 2. */
/* C */
/* INST = -32001 */
/* REF = 'J2000' */
/* SC = -32 */
/* C */
/* C Load the appropriate files. We need */
/* C */
/* C 1) CK file containing pointing data. */
/* C 2) Spacecraft clock kernel file, for SCENCD and SCDECD. */
/* C */
/* CALL CKLPF ( 'VGR2NA.CK' ) */
/* CALL FURNSH ( 'SCLK.KER' ) */
/* C */
/* C Convert the tolerance string to ticks. */
/* C */
/* CALL SCTIKS ( SC, CLKTOL, TOL ) */
/* DO I = 1, NPICS */
/* CALL SCENCD ( SC, CLKIN( I ), TIMEIN ) */
/* CALL CKGP ( INST, TIMEIN, TOL, REF, CMAT, TIMOUT, */
/* . FOUND ) */
/* CALL SCDECD ( SC, TIMOUT, CLKOUT ) */
/* WRITE (*,*) */
/* WRITE (*,*) 'Input s/c clock count: ', CLKIN( I ) */
/* WRITE (*,*) 'Output s/c clock count: ', CLKOUT */
/* WRITE (*,*) 'Output C-Matrix: ', CMAT */
/* END DO */
/* The output from such a program might look like: */
/* Input s/c clock count: 2/20538:39:768 */
/* Output s/c clock count: 2/20538:39:768 */
/* Output C-Matrix: 'first C-matrix' */
/* Input s/c clock count: 2/20543:21:768 */
/* Output s/c clock count: 2/20543:22:768 */
/* Output C-Matrix: 'second C-matrix' */
/* Input s/c clock count: 2/20550:37 */
/* Output s/c clock count: 2/20550:36:768 */
/* Output C-Matrix: 'third C-matrix' */
/* Input s/c clock count: 2/20561:59 */
/* Output s/c clock count: 2/20561:58:768 */
/* Output C-Matrix: 'fourth C-matrix' */
/* $ Restrictions */
/* 1) Assumes that an SCLK kernel file appropriate for the clock */
/* designated by SC is loaded in the kernel pool at the time */
/* this routine is called. */
/* $ Literature_References */
/* None. */
/* $ Author_and_Institution */
/* N.J. Bachman (JPL) */
/* J.M. Lynch (JPL) */
/* R.E. Thurman (JPL) */
/* $ Version */
/* - SPICELIB Version 2.1.0, 05-FEB-2008 (NJB) */
/* Values of parameter MXPART and PARTLN are now */
/* provided by the INCLUDE file sclk.inc. */
/* - SPICELIB Version 2.0.1, 22-AUG-2006 (EDW) */
/* Replaced references to LDPOOL with references */
/* to FURNSH. */
/* - SPICELIB Version 2.0.0, 17-APR-1992 (JML) (WLT) */
/* The routine was changed to signal an error when SCLKCH is */
/* not long enough to contain the output spacecraft clock */
/* string. */
/* FAILED is now checked after calling SCPART. */
/* References to CLPOOL were deleted. */
/* Miscellaneous minor updates to the header were performed. */
/* Comment section for permuted index source lines was added */
/* following the header. */
/* - SPICELIB Version 1.0.0, 06-SEP-1990 (JML) (RET) */
/* -& */
/* $ Index_Entries */
/* decode spacecraft_clock */
/* -& */
/* $ Revisions */
/* - SPICELIB Version 2.0.0, 10-APR-1992 (JML) (WLT) */
/* The routine was changed to signal an error when SCLKCH is */
/* not long enough to contain the output spacecraft clock */
/* string. Previously, the SCLK routines simply truncated */
/* the clock string on the right. It was determined that */
/* since this truncation could easily go undetected by the */
/* user ( only the leftmost field of a clock string is */
/* required when clock string is used as an input to a */
/* SCLK routine ), it would be better to signal an error */
/* when this happens. */
/* FAILED is checked after calling SCPART in case an */
/* error has occurred reading the kernel file and the */
/* error action is not set to 'abort'. */
/* References to CLPOOL were deleted. */
/* Miscellaneous minor updates to the header were performed. */
/* Comment section for permuted index source lines was added */
/* following the header. */
/* -& */
/* SPICELIB functions */
/* Local variables */
/* Standard SPICE error handling. */
if (return_()) {
return 0;
} else {
chkin_("SCDECD", (ftnlen)6);
}
/* Use a working copy of the input. */
ticks = d_nint(sclkdp);
s_copy(sclkch, " ", sclkch_len, (ftnlen)1);
/* Read the partition start and stop times (in ticks) for this */
/* mission. Error if there are too many of them. Also need to */
/* check FAILED in case error handling is not in ABORT or */
/* DEFAULT mode. */
scpart_(sc, &nparts, pstart, pstop);
if (failed_()) {
chkout_("SCDECD", (ftnlen)6);
return 0;
}
if (nparts > 9999) {
setmsg_("The number of partitions, #, for spacecraft # exceeds the v"
"alue for parameter MXPART, #.", (ftnlen)88);
errint_("#", &nparts, (ftnlen)1);
errint_("#", sc, (ftnlen)1);
errint_("#", &c__9999, (ftnlen)1);
sigerr_("SPICE(TOOMANYPARTS)", (ftnlen)19);
chkout_("SCDECD", (ftnlen)6);
return 0;
}
/* For each partition, compute the total number of ticks in that */
/* partition plus all preceding partitions. */
d__1 = pstop[0] - pstart[0];
ptotls[0] = d_nint(&d__1);
i__1 = nparts;
for (i__ = 2; i__ <= i__1; ++i__) {
d__1 = ptotls[(i__3 = i__ - 2) < 9999 && 0 <= i__3 ? i__3 : s_rnge(
"ptotls", i__3, "scdecd_", (ftnlen)495)] + pstop[(i__4 = i__
- 1) < 9999 && 0 <= i__4 ? i__4 : s_rnge("pstop", i__4, "scd"
"ecd_", (ftnlen)495)] - pstart[(i__5 = i__ - 1) < 9999 && 0 <=
i__5 ? i__5 : s_rnge("pstart", i__5, "scdecd_", (ftnlen)495)];
ptotls[(i__2 = i__ - 1) < 9999 && 0 <= i__2 ? i__2 : s_rnge("ptotls",
i__2, "scdecd_", (ftnlen)495)] = d_nint(&d__1);
}
/* The partition corresponding to the input ticks is the first one */
/* whose tick total is greater than the input value. The one */
/* exception is when the input ticks is equal to the total number */
/* of ticks represented by all the partitions. In this case the */
/* partition number is the last one, i.e. NPARTS. */
/* Error if TICKS comes before the first partition (that is, if it's */
/* negative), or after the last one. */
if (ticks == ptotls[(i__1 = nparts - 1) < 9999 && 0 <= i__1 ? i__1 :
s_rnge("ptotls", i__1, "scdecd_", (ftnlen)510)]) {
part = nparts;
} else {
part = lstled_(&ticks, &nparts, ptotls) + 1;
}
if (ticks < 0. || part > nparts) {
setmsg_("Value for ticks, #, does not fall in any partition for spac"
"ecraft #.", (ftnlen)68);
errdp_("#", &ticks, (ftnlen)1);
errint_("#", sc, (ftnlen)1);
sigerr_("SPICE(VALUEOUTOFRANGE)", (ftnlen)22);
chkout_("SCDECD", (ftnlen)6);
return 0;
}
/* To get the count in this partition, subtract off the total of */
/* the preceding partition counts and add the beginning count for */
/* this partition. */
if (part == 1) {
ticks += pstart[(i__1 = part - 1) < 9999 && 0 <= i__1 ? i__1 : s_rnge(
"pstart", i__1, "scdecd_", (ftnlen)535)];
} else {
ticks = ticks + pstart[(i__1 = part - 1) < 9999 && 0 <= i__1 ? i__1 :
s_rnge("pstart", i__1, "scdecd_", (ftnlen)537)] - ptotls[(
i__2 = part - 2) < 9999 && 0 <= i__2 ? i__2 : s_rnge("ptotls",
i__2, "scdecd_", (ftnlen)537)];
}
/* Now create the output SCLK clock string. */
/* First convert from ticks to clock string format. */
scfmt_(sc, &ticks, sclkch, sclkch_len);
/* Now convert the partition number to a character string and prefix */
/* it to the output string. */
intstr_(&part, prtstr, (ftnlen)5);
suffix_("/", &c__0, prtstr, (ftnlen)1, (ftnlen)5);
prelen = lastnb_(prtstr, (ftnlen)5);
suflen = lastnb_(sclkch, sclkch_len);
if (i_len(sclkch, sclkch_len) - suflen < prelen) {
setmsg_("Output string too short to contain clock string. Input tick"
" value: #, requires string of length #, but declared length "
"is #.", (ftnlen)124);
errdp_("#", sclkdp, (ftnlen)1);
i__1 = prelen + suflen;
errint_("#", &i__1, (ftnlen)1);
i__1 = i_len(sclkch, sclkch_len);
errint_("#", &i__1, (ftnlen)1);
sigerr_("SPICE(SCLKTRUNCATED)", (ftnlen)20);
chkout_("SCDECD", (ftnlen)6);
return 0;
}
prefix_(prtstr, &c__0, sclkch, (ftnlen)5, sclkch_len);
chkout_("SCDECD", (ftnlen)6);
return 0;
} /* scdecd_ */
void scfmt_c ( SpiceInt sc,
SpiceDouble ticks,
SpiceInt lenout,
SpiceChar * clkstr )
/*
-Brief_I/O
Variable I/O Description
-------- --- --------------------------------------------------
sc I NAIF spacecraft identification code.
ticks I Encoded representation of a spacecraft clock count.
lenout I Maximum allowed length of output string.
clkstr O Character representation of a clock count.
-Detailed_Input
sc is the NAIF ID number for the spacecraft whose clock's
time is being decoded.
ticks is the double precision encoding of a clock time in
units of ticks. Partition information is not reflected
in this value.
An analogy may be drawn between a spacecraft clock and
a standard wall clock. The number of ticks
corresponding to the wall clock string
hh:mm:ss
would be the number of seconds represented by that
time.
For example,
Clock string Number of ticks
------------ ---------------
00:00:10 10
00:01:00 60
00:10:00 600
01:00:00 3600
01:01:00 3660
If ticks contains a fractional part the result is the
same as if ticks had been rounded to the nearest whole
number.
See the Examples section below for examples of
actual spacecraft clock conversions.
lenout The allowed length of the output string. This length
must large enough to hold the 'clkstr' string plus the
null terminator. If the output string is expected to
have x characters, 'lenout' must be x + 1.
-Detailed_Output
clkstr is the spacecraft clock character string
corresponding to ticks. Partition information is
not included in clkstr.
Using Galileo as an example, the full format clock
string is
wwwwwwww:xx:y:z
where z is a mod-8 counter (values 0-7) which
increments approximately once every 8 1/3 ms., y is a
mod-10 counter (values 0-9) which increments once
every time z turns over, i.e., approximately once every
66 2/3 ms., xx is a mod-91 (values 0-90) counter
which increments once every time y turns over, i.e.,
once every 2/3 seconds. wwwwwwww is the Real-Time Image
Count (RIM), which increments once every time xx turns
over, i.e., once every 60 2/3 seconds. The roll-over
expression for the RIM is 16777215, which corresponds
to approximately 32 years.
wwwwwwww, xx, y, and z are referred to interchangeably
as the fields or components of the spacecraft clock.
SCLK components may be separated by any of these five
characters: " " ":" "," "-" "."
The delimiter used is determined by a kernel pool
variable and can be adjusted by the user.
Some spacecraft clock components have offset, or
starting, values different from zero. For example,
with an offset value of 1, a mod 20 counter would
cycle from 1 to 20 instead of from 0 to 19.
See the SCLK required reading for a detailed
description of the Voyager and Mars Observer clock
formats.
-Parameters
None.
-Exceptions
1) If the data type for the spacecraft is not supported
then the error SPICE(NOTSUPPORTED) is signaled.
2) If the value for ticks is negative, the error is diagnosed
by routines called by this routine.
3) If the SCLK kernel file does not contain data for the
spacecraft specified by sc, then the error is diagnosed
by routines called by this routine.
4) If the output string pointer is null, the error SPICE(NULLPOINTER)
is signaled.
5) If the output string has length less than two characters, it
is too short to contain one character of output data plus a null
terminator, so it cannot be passed to the underlying Fortran
routine. In this event, the error SPICE(STRINGTOOSHORT) is
signaled.
6) If the length of clkstr (indicated by lenout) is at least two
characters but not large enough to contain the output clock
string, the error is diagnosed by a routine called by this
routine.
-Files
None.
-Particulars
The routine sctiks_c performs the inverse operation to scfmt_c,
converting from clock format to number of ticks.
Note the important difference between scfmt_c and scdecd_c. scdecd_c
converts some number of ticks since the spacecraft clock start
time to a character string which includes a partition number.
scfmt_c, which is called by scdecd_c, does not make use of partition
information.
-Examples
The following program fragment finds partition start and stop
times for the Galileo spacecraft from a spacecraft clock partition
kernel file, called sclk.ker. Since those times are always
returned in units of ticks, the program uses scfmt_c to print the
times in Galileo clock format.
#include <stdio.h>
#include "SpiceUsr.h"
#define MXPART 9999
#define MAXLEN 30
SpiceChar start [ 30 ];
SpiceChar stop [ 30 ];
SpiceDouble pstart [ MXPART ];
SpiceDouble pstop [ MXPART ];
SpiceInt sc = -77;
SpiceInt i;
SpiceInt nparts;
furnsh_c ( "sclk.ker" );
scpart_c ( sc, &nparts, pstart, pstop );
for ( i = 0; i < nparts; i++ )
{
scfmt_c ( sc, pstart[ i ], MAXLEN, start );
scfmt_c ( sc, pstop [ i ], MAXLEN, stop );
printf ( "\n"
"partition %d: \n"
"start = %s\n"
"stop = %s\n",
i,
start,
stop );
}
Below are some examples illustrating various input numbers of
ticks and the resulting clock string outputs for the Galileo
spacecraft.
TICKS CLKSTR
---------------- --------------------
-1 Error: Ticks must be a positive number
0 "0:00:0:0"
1 "0:00:0:1"
1.3 "0:00:0:1"
1.5 "0:00:0:2"
2 "0:00:0:2"
7 "0:00:0:7"
8 "0:00:1:0"
80 "0:01:0:0"
88 "0:01:1:0"
7279 "0:90:9:7"
7280 "1:00:0:0"
1234567890 "169583:45:6:2"
The following examples are for the Voyager 2 spacecraft.
Note that the third component of the Voyager clock has an
offset value of one.
TICKS CLKSTR
---------------- --------------------
-1 Error: Ticks must be a positive number
0 "00000 00 001"
1 "00000 00 002"
1.3 "00000:00:002"
1.5 "00000.00.003"
2 "00000-00-003"
799 "00000,00,800"
800 "00000 01 001"
47999 "00000 59 800"
48000 "00001 00 001"
3145727999 "65535 59 800"
-Restrictions
None.
-Literature_References
None.
-Author_and_Institution
N.J. Bachman (JPL)
J.M. Lynch (JPL)
R.E. Thurman (JPL)
-Version
-CSPICE Version 1.1.4, 11-FEB-2008 (NJB)
Header example was updated to reflect current
MXPART value of 9999.
-CSPICE Version 1.1.3, 14-AUG-2006 (EDW)
Replace mention of ldpool_c with furnsh_c.
-CSPICE Version 1.1.2, 01-OCT-2003 (EDW)
Added description of the 'lenout' input in the
Detailed_Input section.
-CSPICE Version 1.1.1, 26-MAR-2003 (NJB)
Fixed description of exception (6): replaced "lenout-1"
with "lenout."
-CSPICE Version 1.1.0, 09-FEB-1998 (NJB)
Re-implemented routine without dynamically allocated, temporary
strings. Updated the Exceptions header section.
-CSPICE Version 1.0.0, 25-OCT-1997 (NJB)
Based on SPICELIB Version 1.0.1, 17-APR-1992 (JML) (WLT)
-Index_Entries
convert spacecraft_clock ticks to character clock format
-&
*/
{ /* Begin scfmt_c */
/*
Participate in error tracing.
*/
chkin_c ( "scfmt_c");
/*
Make sure the output clkstr has at least enough room for one output
character and a null terminator. Also check for a null pointer.
*/
CHKOSTR ( CHK_STANDARD, "scfmt_c", clkstr, lenout );
/*
Do the conversion.
*/
scfmt_ ( ( integer * ) &sc,
( doublereal * ) &ticks,
( char * ) clkstr,
( ftnlen ) lenout-1 );
/*
Convert the Fortran string to a C string by placing a null
after the last non-blank character. This operation is valid
whether or not the CSPICE routine signaled an error.
*/
F2C_ConvertStr ( lenout, clkstr );
chkout_c ( "scfmt_c");
} /* End scfmt_c */
