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SwRI can revise these Terms at any time * without notice by updating this posting. * * Trademarks * * The SwRI logo is a trademark of SwRI in the United States and other countries. * */ #ident "@(#) spin_time_frac.c 1.1 05/08/19 SwRI" #include "libbase_idfs.h" /**************************************************************************** * * * IR_SPIN_CALC_TIME_FRAC SUBROUTINE * * * * DESCRIPTION * * This routine determines the percentage of the current spin period * * covered by the current sweep. This is needed to determine the amount * * of data that should be included in the current spin. This is achieved * * by determining the amount of time, in seconds, covered by the sweep * * with respect to the beginning or the end of the spin and then dividing * * by the time duration of the spin, also in seconds. * * * * INPUT VARIABLES * * SDDAS_SHORT spin_btime_yr start of spin year component * * SDDAS_SHORT spin_btime_day start of spin day of year component * * SDDAS_LONG spin_btime_msec start of spin milliseconds time component * * SDDAS_LONG spin_btime_nsec start of spin nanoseconds time component * * SDDAS_SHORT spin_etime_yr end of spin year component * * SDDAS_SHORT spin_etime_day end of spin day of year component * * SDDAS_LONG spin_etime_msec end of spin milliseconds time component * * SDDAS_LONG spin_etime_nsec end of spin nanoseconds time component * * SDDAS_SHORT btime_yr start year for time period being examined * * SDDAS_SHORT btime_day start day for time period being examined * * SDDAS_LONG btime_msec start milliseconds for time period being * * examined * * SDDAS_LONG btime_nsec start nanoseconds for time period being * * examined * * SDDAS_SHORT etime_yr end day for time period being examined * * SDDAS_SHORT etime_day end day for time period being examined * * SDDAS_LONG etime_msec end milliseconds for time period being * * examined * * SDDAS_LONG etime_nsec end nanoseconds for time period being * * examined * * SDDAS_CHAR use_start flag which indicates if computation is * * with respect to the start of the spin or * * the end of the spin * * * * USAGE * * x = ir_spin_calc_time_frac (spin_btime_yr, spin_btime_day, * * spin_btime_msec, spin_btime_nsec, * * spin_etime_yr, spin_etime_day, * * spin_etime_msec, spin_etime_nsec, * * btime_yr, btime_day, btime_msec, * * btime_nsec, etime_yr, etime_day, * * etime_msec, etime_nsec, use_start) * * * * NECESSARY SUBPROGRAMS * * None * * * * EXTERNAL VARIABLES * * None * * * * INTERNAL VARIABLES * * reg SDDAS_DOUBLE ret_frac the percentage of the spin period covered * * by the current sample * * reg SDDAS_DOUBLE step_samp the time covered by the sample with respect* * to the start or end of the current spin * * reg SDDAS_DOUBLE step_width the time covered by the sample * * SDDAS_LONG diff_milli the milliseconds difference between the * * start and end time values being utilized * * SDDAS_LONG diff_nano the nanoseconds difference between the * * start and end time values being utilized * * SDDAS_SHORT diff_year the year difference between the start and * * end time values being utilized * * SDDAS_SHORT diff_day the day difference between the start and * * end time values being utilized * * SDDAS_SHORT days_in_yr the number of day in the year - takes leap * * year into account * * * * SUBSYSTEM * * Display Level * * * ***************************************************************************/ SDDAS_FLOAT ir_spin_calc_time_frac (SDDAS_SHORT spin_btime_yr, SDDAS_SHORT spin_btime_day, SDDAS_LONG spin_btime_msec, SDDAS_LONG spin_btime_nsec, SDDAS_SHORT spin_etime_yr, SDDAS_SHORT spin_etime_day, SDDAS_LONG spin_etime_msec, SDDAS_LONG spin_etime_nsec, SDDAS_SHORT btime_yr, SDDAS_SHORT btime_day, SDDAS_LONG btime_msec, SDDAS_LONG btime_nsec, SDDAS_SHORT etime_yr, SDDAS_SHORT etime_day, SDDAS_LONG etime_msec, SDDAS_LONG etime_nsec, SDDAS_CHAR use_start) { register SDDAS_DOUBLE ret_frac, step_samp, step_width; SDDAS_LONG diff_milli, diff_nano; SDDAS_SHORT diff_year, diff_day, days_in_yr; /******************************************************************/ /* Assumption is no more than a year difference, so check btime */ /* for leap year. */ /******************************************************************/ if ((btime_yr % 4 == 0 && btime_yr % 100 != 0) || btime_yr % 400 == 0) days_in_yr = 366; else days_in_yr = 365; /**********************************************************************/ /* Determine time covered by the whole sample in terms of seconds. */ /* 86400 - no. of seconds in a day. */ /**********************************************************************/ diff_year = etime_yr - btime_yr; diff_day = etime_day - btime_day; diff_milli = etime_msec - btime_msec; diff_nano = etime_nsec - btime_nsec; if (diff_nano < 0) { --diff_milli; diff_nano += 1000000; /* 1 milli = 1000000 nanoseconds */ } step_width = (diff_year * days_in_yr * 86400) + diff_day * 86400 + (diff_milli / 1000.0) + (diff_nano / 1000000000.0); /*************************************************************************/ /* Determine how much of the sample bypasses the start time of the spin.*/ /* |--------| sample */ /* |--------------| spin */ /*************************************************************************/ if (use_start) { diff_year = etime_yr - spin_btime_yr; diff_day = etime_day - spin_btime_day; diff_milli = etime_msec - spin_btime_msec; diff_nano = etime_nsec - spin_btime_nsec; if (diff_nano < 0) { --diff_milli; diff_nano += 1000000; /* 1 milli = 1000000 nanoseconds */ } step_samp = (diff_year * days_in_yr * 86400) + diff_day * 86400 + (diff_milli / 1000.0) + (diff_nano / 1000000000.0); } /******************************************************************/ /* Determine how much of the sample is contained within the spin.*/ /* |--------| sample */ /* |--------------| spin */ /******************************************************************/ else { diff_year = spin_etime_yr - btime_yr; diff_day = spin_etime_day - btime_day; diff_milli = spin_etime_msec - btime_msec; diff_nano = spin_etime_nsec - btime_nsec; if (diff_nano < 0) { --diff_milli; diff_nano += 1000000; /* 1 milli = 1000000 nanoseconds */ } step_samp = (diff_year * days_in_yr * 86400) + diff_day * 86400 + (diff_milli / 1000.0) + (diff_nano / 1000000000.0); } /*********************************************************************/ /* Calculate the amount of time covered by this sample within this */ /* spin with respect to the time covered by the sample. */ /*********************************************************************/ ret_frac = step_samp / step_width; return (ret_frac); }