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clk_rawdcf.c revision 1.1.1.10
      1 /*	$NetBSD: clk_rawdcf.c,v 1.1.1.10 2024/08/18 20:37:37 christos Exp $	*/
      2 
      3 /*
      4  * /src/NTP/REPOSITORY/ntp4-dev/libparse/clk_rawdcf.c,v 4.18 2006/06/22 18:40:01 kardel RELEASE_20060622_A
      5  *
      6  * clk_rawdcf.c,v 4.18 2006/06/22 18:40:01 kardel RELEASE_20060622_A
      7  *
      8  * Raw DCF77 pulse clock support
      9  *
     10  * Copyright (c) 1995-2015 by Frank Kardel <kardel <AT> ntp.org>
     11  * Copyright (c) 1989-1994 by Frank Kardel, Friedrich-Alexander Universitaet Erlangen-Nuernberg, Germany
     12  *
     13  * Redistribution and use in source and binary forms, with or without
     14  * modification, are permitted provided that the following conditions
     15  * are met:
     16  * 1. Redistributions of source code must retain the above copyright
     17  *    notice, this list of conditions and the following disclaimer.
     18  * 2. Redistributions in binary form must reproduce the above copyright
     19  *    notice, this list of conditions and the following disclaimer in the
     20  *    documentation and/or other materials provided with the distribution.
     21  * 3. Neither the name of the author nor the names of its contributors
     22  *    may be used to endorse or promote products derived from this software
     23  *    without specific prior written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     35  * SUCH DAMAGE.
     36  *
     37  */
     38 
     39 #ifdef HAVE_CONFIG_H
     40 # include <config.h>
     41 #endif
     42 
     43 #if defined(REFCLOCK) && defined(CLOCK_PARSE) && defined(CLOCK_RAWDCF)
     44 
     45 #include "ntp_fp.h"
     46 #include "timevalops.h"
     47 #include "ntp_unixtime.h"
     48 #include "ntp_calendar.h"
     49 
     50 #include "parse.h"
     51 #ifdef PARSESTREAM
     52 # include <sys/parsestreams.h>
     53 #endif
     54 
     55 #ifndef PARSEKERNEL
     56 # include "ntp_stdlib.h"
     57 #endif
     58 
     59 /*
     60  * DCF77 raw time code
     61  *
     62  * From "Zur Zeit", Physikalisch-Technische Bundesanstalt (PTB), Braunschweig
     63  * und Berlin, Maerz 1989
     64  *
     65  * Timecode transmission:
     66  * AM:
     67  *	time marks are send every second except for the second before the
     68  *	next minute mark
     69  *	time marks consist of a reduction of transmitter power to 25%
     70  *	of the nominal level
     71  *	the falling edge is the time indication (on time)
     72  *	time marks of a 100ms duration constitute a logical 0
     73  *	time marks of a 200ms duration constitute a logical 1
     74  * FM:
     75  *	see the spec. (basically a (non-)inverted psuedo random phase shift)
     76  *
     77  * Encoding:
     78  * Second	Contents
     79  * 0  - 10	AM: free, FM: 0
     80  * 11 - 14	free
     81  * 15		R     - "call bit" used to signalize irregularities in the control facilities
     82  *		        (until 2003 indicated transmission via alternate antenna)
     83  * 16		A1    - expect zone change (1 hour before)
     84  * 17 - 18	Z1,Z2 - time zone
     85  *		 0  0 illegal
     86  *		 0  1 MEZ  (MET)
     87  *		 1  0 MESZ (MED, MET DST)
     88  *		 1  1 illegal
     89  * 19		A2    - expect leap insertion/deletion (1 hour before)
     90  * 20		S     - start of time code (1)
     91  * 21 - 24	M1    - BCD (lsb first) Minutes
     92  * 25 - 27	M10   - BCD (lsb first) 10 Minutes
     93  * 28		P1    - Minute Parity (even)
     94  * 29 - 32	H1    - BCD (lsb first) Hours
     95  * 33 - 34      H10   - BCD (lsb first) 10 Hours
     96  * 35		P2    - Hour Parity (even)
     97  * 36 - 39	D1    - BCD (lsb first) Days
     98  * 40 - 41	D10   - BCD (lsb first) 10 Days
     99  * 42 - 44	DW    - BCD (lsb first) day of week (1: Monday -> 7: Sunday)
    100  * 45 - 49	MO    - BCD (lsb first) Month
    101  * 50           MO0   - 10 Months
    102  * 51 - 53	Y1    - BCD (lsb first) Years
    103  * 54 - 57	Y10   - BCD (lsb first) 10 Years
    104  * 58 		P3    - Date Parity (even)
    105  * 59		      - usually missing (minute indication), except for leap insertion
    106  */
    107 
    108 static parse_pps_fnc_t pps_rawdcf;
    109 static parse_cvt_fnc_t cvt_rawdcf;
    110 static parse_inp_fnc_t inp_rawdcf;
    111 
    112 typedef struct last_tcode {
    113 	time_t      tcode;	/* last converted time code */
    114         timestamp_t tminute;	/* sample time for minute start */
    115         timestamp_t timeout;	/* last timeout timestamp */
    116 } last_tcode_t;
    117 
    118 #define BUFFER_MAX	61
    119 
    120 clockformat_t clock_rawdcf =
    121 {
    122   inp_rawdcf,			/* DCF77 input handling */
    123   cvt_rawdcf,			/* raw dcf input conversion */
    124   pps_rawdcf,			/* examining PPS information */
    125   0,				/* no private configuration data */
    126   "RAW DCF77 Timecode",		/* direct decoding / time synthesis */
    127 
    128   BUFFER_MAX,			/* bit buffer */
    129   sizeof(last_tcode_t)
    130 };
    131 
    132 static struct dcfparam
    133 {
    134 	const unsigned char *onebits;
    135 	const unsigned char *zerobits;
    136 } dcfparameter =
    137 {
    138 	(const unsigned char *)"###############RADMLS1248124P124812P1248121241248112481248P??", /* 'ONE' representation */
    139 	(const unsigned char *)"--------------------s-------p------p----------------------p__"  /* 'ZERO' representation */
    140 };
    141 
    142 static struct rawdcfcode
    143 {
    144 	char offset;			/* start bit */
    145 } rawdcfcode[] =
    146 {
    147 	{  0 }, { 15 }, { 16 }, { 17 }, { 19 }, { 20 }, { 21 }, { 25 }, { 28 }, { 29 },
    148 	{ 33 }, { 35 }, { 36 }, { 40 }, { 42 }, { 45 }, { 49 }, { 50 }, { 54 }, { 58 }, { 59 }
    149 };
    150 
    151 #define DCF_M	0
    152 #define DCF_R	1
    153 #define DCF_A1	2
    154 #define DCF_Z	3
    155 #define DCF_A2	4
    156 #define DCF_S	5
    157 #define DCF_M1	6
    158 #define DCF_M10	7
    159 #define DCF_P1	8
    160 #define DCF_H1	9
    161 #define DCF_H10	10
    162 #define DCF_P2	11
    163 #define DCF_D1	12
    164 #define DCF_D10	13
    165 #define DCF_DW	14
    166 #define DCF_MO	15
    167 #define DCF_MO0	16
    168 #define DCF_Y1	17
    169 #define DCF_Y10	18
    170 #define DCF_P3	19
    171 
    172 static struct partab
    173 {
    174 	char offset;			/* start bit of parity field */
    175 } partab[] =
    176 {
    177 	{ 21 }, { 29 }, { 36 }, { 59 }
    178 };
    179 
    180 #define DCF_P_P1	0
    181 #define DCF_P_P2	1
    182 #define DCF_P_P3	2
    183 
    184 #define DCF_Z_MET 0x2
    185 #define DCF_Z_MED 0x1
    186 
    187 static u_long
    188 ext_bf(
    189 	unsigned char *buf,
    190 	int   idx,
    191 	const unsigned char *zero
    192 	)
    193 {
    194 	u_long sum = 0;
    195 	int i, first;
    196 
    197 	first = rawdcfcode[idx].offset;
    198 
    199 	for (i = rawdcfcode[idx+1].offset - 1; i >= first; i--)
    200 	{
    201 		sum <<= 1;
    202 		sum |= (buf[i] != zero[i]);
    203 	}
    204 	return sum;
    205 }
    206 
    207 static unsigned
    208 pcheck(
    209        unsigned char *buf,
    210        int   idx,
    211        const unsigned char *zero
    212        )
    213 {
    214 	int i,last;
    215 	unsigned psum = 1;
    216 
    217 	last = partab[idx+1].offset;
    218 
    219 	for (i = partab[idx].offset; i < last; i++)
    220 	    psum ^= (buf[i] != zero[i]);
    221 
    222 	return psum;
    223 }
    224 
    225 static int/*BOOL*/
    226 zeller_expand(
    227 	clocktime_t     *clock_time,
    228 	unsigned int	wd
    229 	)
    230 {
    231         unsigned int  y = (unsigned int)clock_time->year;
    232         unsigned int  m = (unsigned int)clock_time->month - 1u;
    233         unsigned int  d = (unsigned int)clock_time->day - 1u;
    234 	unsigned int  c;
    235 
    236 	/* Check basic constraints first. */
    237         if ((y >= 100u) || (m >= 12u) || (d >= 31u) || (--wd >= 7u))
    238 		return FALSE;
    239 
    240 	/* Get weekday of date in 1st century by a variation on Zeller's
    241 	 * congruence. All operands are non-negative, and the month
    242 	 * formula is adjusted to use a divider of 32, so we can do a
    243 	 * shift instead of a 'true' division:
    244 	 */
    245 	if ((m += 10u) >= 12u)		/* shift base to 0000-03-01 */
    246 		m -= 12u;
    247 	else if (--y >= 100u)
    248 		y += 100;
    249 	d += y + (y >> 2) + 2u;		/* year-related share */
    250 	d += (m * 83u + 16u) >> 5;	/* month-related share */
    251 
    252 	/* The next step combines the exact division by modular inverse
    253 	 * with the (mod 7) step in such way that no true division and
    254 	 * only one multiplication is needed. The multiplier is
    255 	 *      M <- ceil((3*8)/7 * 2**29)
    256 	 * and combines multiplication by invmod(5, 7) -> 3 and modulus
    257 	 * by 7 transformation to (mod 8) in one step.
    258 	 *   Note that 252 == 0 (mod 7) and that 'd' is less than 185,
    259 	 * so the number to invert and reduce is strictly positive. In
    260 	 * the end, 'c' is number of centuries since start of a great
    261 	 * cycle and must be in [0..3] or we had bad input.
    262 	 */
    263 	c = (((252u + wd - d) * 0x6db6db6eU) >> 29) & 7u;
    264 	if (c >= 4)
    265 		return FALSE;
    266 	/* undo calendar base shift now */
    267 	if ((m > 9u) && (++y >= 100u)) {
    268 		y -= 100u;
    269 		c = (c + 1u) & 3u;
    270 	}
    271 	/* combine year with centuries & map to [1970..2369] */
    272 	y += (c * 100u);
    273 	clock_time->year = (int)y + ((y < 370u) ? 2000 : 1600);
    274 	return TRUE;
    275 }
    276 
    277 static u_long
    278 convert_rawdcf(
    279 	       unsigned char   *buffer,
    280 	       int              size,
    281 	       struct dcfparam *dcfprm,
    282 	       clocktime_t     *clock_time
    283 	       )
    284 {
    285 	unsigned char *s = buffer;
    286 	const unsigned char *b = dcfprm->onebits;
    287 	const unsigned char *c = dcfprm->zerobits;
    288 	int i;
    289 
    290 	parseprintf(DD_RAWDCF,("parse: convert_rawdcf: \"%.*s\"\n", size, buffer));
    291 
    292 	if (size < 57)
    293 	{
    294 #ifndef PARSEKERNEL
    295 		msyslog(LOG_ERR, "parse: convert_rawdcf: INCOMPLETE DATA - time code only has %d bits", size);
    296 #endif
    297 		return CVT_FAIL|CVT_BADFMT;
    298 	}
    299 
    300 	for (i = 0; i < size; i++)
    301 	{
    302 		if ((*s != *b) && (*s != *c))
    303 		{
    304 			/*
    305 			 * we only have two types of bytes (ones and zeros)
    306 			 */
    307 #ifndef PARSEKERNEL
    308 			msyslog(LOG_ERR, "parse: convert_rawdcf: BAD DATA - no conversion");
    309 #endif
    310 			return CVT_FAIL|CVT_BADFMT;
    311 		}
    312 		if (*b) b++;
    313 		if (*c) c++;
    314 		s++;
    315 	}
    316 
    317 	/*
    318 	 * check Start and Parity bits
    319 	 */
    320 	if ((ext_bf(buffer, DCF_S, dcfprm->zerobits) == 1) &&
    321 	    pcheck(buffer, DCF_P_P1, dcfprm->zerobits) &&
    322 	    pcheck(buffer, DCF_P_P2, dcfprm->zerobits) &&
    323 	    pcheck(buffer, DCF_P_P3, dcfprm->zerobits))
    324 	{
    325 		/*
    326 		 * buffer OK
    327 		 */
    328 		parseprintf(DD_RAWDCF,("parse: convert_rawdcf: parity check passed\n"));
    329 
    330 		clock_time->flags  = PARSEB_S_CALLBIT|PARSEB_S_LEAP;
    331 		clock_time->utctime= 0;
    332 		clock_time->usecond= 0;
    333 		clock_time->second = 0;
    334 		clock_time->minute = ext_bf(buffer, DCF_M10, dcfprm->zerobits);
    335 		clock_time->minute = TIMES10(clock_time->minute) + ext_bf(buffer, DCF_M1, dcfprm->zerobits);
    336 		clock_time->hour   = ext_bf(buffer, DCF_H10, dcfprm->zerobits);
    337 		clock_time->hour   = TIMES10(clock_time->hour) + ext_bf(buffer, DCF_H1, dcfprm->zerobits);
    338 		clock_time->day    = ext_bf(buffer, DCF_D10, dcfprm->zerobits);
    339 		clock_time->day    = TIMES10(clock_time->day) + ext_bf(buffer, DCF_D1, dcfprm->zerobits);
    340 		clock_time->month  = ext_bf(buffer, DCF_MO0, dcfprm->zerobits);
    341 		clock_time->month  = TIMES10(clock_time->month) + ext_bf(buffer, DCF_MO, dcfprm->zerobits);
    342 		clock_time->year   = ext_bf(buffer, DCF_Y10, dcfprm->zerobits);
    343 		clock_time->year   = TIMES10(clock_time->year) + ext_bf(buffer, DCF_Y1, dcfprm->zerobits);
    344 
    345 		if (!zeller_expand(clock_time, ext_bf(buffer, DCF_DW, dcfprm->zerobits)))
    346 		    return CVT_FAIL|CVT_BADFMT;
    347 
    348 		switch (ext_bf(buffer, DCF_Z, dcfprm->zerobits))
    349 		{
    350 		    case DCF_Z_MET:
    351 			clock_time->utcoffset = -1*60*60;
    352 			break;
    353 
    354 		    case DCF_Z_MED:
    355 			clock_time->flags     |= PARSEB_DST;
    356 			clock_time->utcoffset  = -2*60*60;
    357 			break;
    358 
    359 		    default:
    360 			parseprintf(DD_RAWDCF,("parse: convert_rawdcf: BAD TIME ZONE\n"));
    361 			return CVT_FAIL|CVT_BADFMT;
    362 		}
    363 
    364 		if (ext_bf(buffer, DCF_A1, dcfprm->zerobits))
    365 		    clock_time->flags |= PARSEB_ANNOUNCE;
    366 
    367 		if (ext_bf(buffer, DCF_A2, dcfprm->zerobits))
    368 		    clock_time->flags |= PARSEB_LEAPADD; /* default: DCF77 data format deficiency */
    369 
    370 		if (ext_bf(buffer, DCF_R, dcfprm->zerobits))
    371 		    clock_time->flags |= PARSEB_CALLBIT;
    372 
    373 		parseprintf(DD_RAWDCF,("parse: convert_rawdcf: TIME CODE OK: %02d:%02d, %02d.%02d.%02d, flags 0x%lx\n",
    374 				       (int)clock_time->hour, (int)clock_time->minute, (int)clock_time->day, (int)clock_time->month,(int) clock_time->year,
    375 				       (u_long)clock_time->flags));
    376 		return CVT_OK;
    377 	}
    378 	else
    379 	{
    380 		/*
    381 		 * bad format - not for us
    382 		 */
    383 #ifndef PARSEKERNEL
    384 		msyslog(LOG_ERR, "parse: convert_rawdcf: start bit / parity check FAILED for \"%.*s\"", size, buffer);
    385 #endif
    386 		return CVT_FAIL|CVT_BADFMT;
    387 	}
    388 }
    389 
    390 /*
    391  * parse_cvt_fnc_t cvt_rawdcf
    392  * raw dcf input routine - needs to fix up 50 baud
    393  * characters for 1/0 decision
    394  */
    395 static u_long
    396 cvt_rawdcf(
    397 	   unsigned char   *buffer,
    398 	   int              size,
    399 	   struct format   *param,
    400 	   clocktime_t     *clock_time,
    401 	   void            *local
    402 	   )
    403 {
    404 	last_tcode_t  *t = (last_tcode_t *)local;
    405 	unsigned char *s = (unsigned char *)buffer;
    406 	unsigned char *e = s + size;
    407 	const unsigned char *b = dcfparameter.onebits;
    408 	const unsigned char *c = dcfparameter.zerobits;
    409 	u_long       rtc = CVT_NONE;
    410 	unsigned int i, lowmax, highmax, cutoff, span;
    411 #define BITS 9
    412 	unsigned char     histbuf[BITS];
    413 	/*
    414 	 * the input buffer contains characters with runs of consecutive
    415 	 * bits set. These set bits are an indication of the DCF77 pulse
    416 	 * length. We assume that we receive the pulse at 50 Baud. Thus
    417 	 * a 100ms pulse would generate a 4 bit train (20ms per bit and
    418 	 * start bit)
    419 	 * a 200ms pulse would create all zeroes (and probably a frame error)
    420 	 */
    421 
    422 	for (i = 0; i < BITS; i++)
    423 	{
    424 		histbuf[i] = 0;
    425 	}
    426 
    427 	cutoff = 0;
    428 	lowmax = 0;
    429 
    430 	while (s < e)
    431 	{
    432 		unsigned int ch = *s ^ 0xFF;
    433 		/*
    434 		 * these lines are left as an excercise to the reader 8-)
    435 		 */
    436 		if (!((ch+1) & ch) || !*s)
    437 		{
    438 
    439 			for (i = 0; ch; i++)
    440 			{
    441 				ch >>= 1;
    442 			}
    443 
    444 			*s = (unsigned char) i;
    445 			histbuf[i]++;
    446 			cutoff += i;
    447 			lowmax++;
    448 		}
    449 		else
    450 		{
    451 			parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: character check for 0x%x@%d FAILED\n", *s, (int)(s - (unsigned char *)buffer)));
    452 			*s = (unsigned char)~0;
    453 			rtc = CVT_FAIL|CVT_BADFMT;
    454 		}
    455 		s++;
    456 	}
    457 
    458 	if (lowmax)
    459 	{
    460 		cutoff /= lowmax;
    461 	}
    462 	else
    463 	{
    464 		cutoff = 4;	/* doesn't really matter - it'll fail anyway, but gives error output */
    465 	}
    466 
    467 	parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: average bit count: %d\n", cutoff));
    468 
    469 	lowmax = 0;
    470 	highmax = 0;
    471 
    472 	parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: histogram:"));
    473 	for (i = 0; i <= cutoff; i++)
    474 	{
    475 		lowmax+=histbuf[i] * i;
    476 		highmax += histbuf[i];
    477 		parseprintf(DD_RAWDCF,(" %d", histbuf[i]));
    478 	}
    479 	parseprintf(DD_RAWDCF, (" <M>"));
    480 
    481 	lowmax += highmax / 2;
    482 
    483 	if (highmax)
    484 	{
    485 		lowmax /= highmax;
    486 	}
    487 	else
    488 	{
    489 		lowmax = 0;
    490 	}
    491 
    492 	highmax = 0;
    493 	cutoff = 0;
    494 
    495 	for (; i < BITS; i++)
    496 	{
    497 		highmax+=histbuf[i] * i;
    498 		cutoff +=histbuf[i];
    499 		parseprintf(DD_RAWDCF,(" %d", histbuf[i]));
    500 	}
    501 	parseprintf(DD_RAWDCF,("\n"));
    502 
    503 	if (cutoff)
    504 	{
    505 		highmax /= cutoff;
    506 	}
    507 	else
    508 	{
    509 		highmax = BITS-1;
    510 	}
    511 
    512 	span = cutoff = lowmax;
    513 	for (i = lowmax; i <= highmax; i++)
    514 	{
    515 		if (histbuf[cutoff] > histbuf[i])
    516 		{
    517 			cutoff = i;
    518 			span = i;
    519 		}
    520 		else
    521 		    if (histbuf[cutoff] == histbuf[i])
    522 		    {
    523 			    span = i;
    524 		    }
    525 	}
    526 
    527 	cutoff = (cutoff + span) / 2;
    528 
    529 	parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: lower maximum %d, higher maximum %d, cutoff %d\n", lowmax, highmax, cutoff));
    530 
    531 	s = (unsigned char *)buffer;
    532 	while (s < e)
    533 	{
    534 		if (*s == (unsigned char)~0)
    535 		{
    536 			*s = '?';
    537 		}
    538 		else
    539 		{
    540 			*s = (*s >= cutoff) ? *b : *c;
    541 		}
    542 		s++;
    543 		if (*b) b++;
    544 		if (*c) c++;
    545 	}
    546 
    547 	*s = '\0';
    548 
    549         if (rtc == CVT_NONE)
    550         {
    551 	       rtc = convert_rawdcf(buffer, size, &dcfparameter, clock_time);
    552 	       if (rtc == CVT_OK)
    553 	       {
    554 			time_t newtime;
    555 
    556 			newtime = parse_to_unixtime(clock_time, &rtc);
    557 			if ((rtc == CVT_OK) && t)
    558 			{
    559 				if ((newtime - t->tcode) <= 600) /* require a successful telegram within last 10 minutes */
    560 				{
    561 				        parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: recent timestamp check OK\n"));
    562 					clock_time->utctime = newtime;
    563 				}
    564 				else
    565 				{
    566 					parseprintf(DD_RAWDCF,("parse: cvt_rawdcf: recent timestamp check FAIL - ignore timestamp\n"));
    567 					rtc = CVT_SKIP;
    568 				}
    569 				t->tcode            = newtime;
    570 			}
    571 	       }
    572         }
    573 
    574     	return rtc;
    575 }
    576 
    577 /*
    578  * parse_pps_fnc_t pps_rawdcf
    579  *
    580  * currently a very stupid version - should be extended to decode
    581  * also ones and zeros (which is easy)
    582  */
    583 /*ARGSUSED*/
    584 static u_long
    585 pps_rawdcf(
    586 	parse_t *parseio,
    587 	int status,
    588 	timestamp_t *ptime
    589 	)
    590 {
    591 	if (!status)		/* negative edge for simpler wiring (Rx->DCD) */
    592 	{
    593 		parseio->parse_dtime.parse_ptime  = *ptime;
    594 		parseio->parse_dtime.parse_state |= PARSEB_PPS|PARSEB_S_PPS;
    595 	}
    596 
    597 	return CVT_NONE;
    598 }
    599 
    600 static long
    601 calc_usecdiff(
    602 	timestamp_t *ref,
    603 	timestamp_t *base,
    604 	long         offset
    605 	)
    606 {
    607 	struct timeval delta;
    608 	long delta_usec = 0;
    609 
    610 #ifdef PARSEKERNEL
    611 	delta.tv_sec = ref->tv.tv_sec - offset - base->tv.tv_sec;
    612 	delta.tv_usec = ref->tv.tv_usec - base->tv.tv_usec;
    613 	if (delta.tv_usec < 0)
    614 	{
    615 		delta.tv_sec  -= 1;
    616 		delta.tv_usec += 1000000;
    617 	}
    618 #else
    619 	l_fp delt;
    620 
    621 	delt = ref->fp;
    622 	delt.l_i -= offset;
    623 	L_SUB(&delt, &base->fp);
    624 	TSTOTV(&delt, &delta);
    625 #endif
    626 
    627 	delta_usec = 1000000 * (int32_t)delta.tv_sec + delta.tv_usec;
    628 	return delta_usec;
    629 }
    630 
    631 static u_long
    632 snt_rawdcf(
    633 	parse_t *parseio,
    634 	timestamp_t *ptime
    635 	)
    636 {
    637 	/*
    638 	 * only synthesize if all of following conditions are met:
    639 	 * - CVT_OK parse_status (we have a time stamp base)
    640 	 * - ABS(ptime - tminute - (parse_index - 1) sec) < 500ms (spaced by 1 sec +- 500ms)
    641 	 * - minute marker is available (confirms minute raster as base)
    642 	 */
    643 	last_tcode_t  *t = (last_tcode_t *)parseio->parse_pdata;
    644 	long delta_usec = -1;
    645 
    646 	if (t != NULL && t->tminute.tv.tv_sec != 0) {
    647 		delta_usec = calc_usecdiff(ptime, &t->tminute, parseio->parse_index - 1);
    648 		if (delta_usec < 0)
    649 			delta_usec = -delta_usec;
    650 	}
    651 
    652 	parseprintf(DD_RAWDCF,("parse: snt_rawdcf: synth for offset %d seconds - absolute usec error %ld\n",
    653 			       parseio->parse_index - 1, delta_usec));
    654 
    655 	if (((parseio->parse_dtime.parse_status & CVT_MASK) == CVT_OK) &&
    656 	    (delta_usec < 500000 && delta_usec >= 0)) /* only if minute marker is available */
    657 	{
    658 		parseio->parse_dtime.parse_stime = *ptime;
    659 
    660 #ifdef PARSEKERNEL
    661 		parseio->parse_dtime.parse_time.tv.tv_sec++;
    662 #else
    663 		parseio->parse_dtime.parse_time.fp.l_ui++;
    664 #endif
    665 
    666 		parseprintf(DD_RAWDCF,("parse: snt_rawdcf: time stamp synthesized offset %d seconds\n", parseio->parse_index - 1));
    667 
    668 		return updatetimeinfo(parseio, parseio->parse_lstate);
    669 	}
    670 	return CVT_NONE;
    671 }
    672 
    673 /*
    674  * parse_inp_fnc_t inp_rawdcf
    675  *
    676  * grab DCF77 data from input stream
    677  */
    678 static u_long
    679 inp_rawdcf(
    680 	  parse_t      *parseio,
    681 	  char         ch,
    682 	  timestamp_t  *tstamp
    683 	  )
    684 {
    685 	static struct timeval timeout = { 1, 500000 }; /* 1.5 secongs denote second #60 */
    686 
    687 	parseprintf(DD_PARSE, ("inp_rawdcf(0x%p, 0x%x, ...)\n", (void*)parseio, ch));
    688 
    689 	parseio->parse_dtime.parse_stime = *tstamp; /* collect timestamp */
    690 
    691 	if (parse_timedout(parseio, tstamp, &timeout))
    692 	{
    693 		last_tcode_t *t = (last_tcode_t *)parseio->parse_pdata;
    694 		long delta_usec;
    695 
    696 		parseprintf(DD_RAWDCF, ("inp_rawdcf: time out seen\n"));
    697 		/* finish collection */
    698 		(void) parse_end(parseio);
    699 
    700 		if (t != NULL)
    701 		{
    702 			/* remember minute start sample time if timeouts occur in minute raster */
    703 			if (t->timeout.tv.tv_sec != 0)
    704 			{
    705 				delta_usec = calc_usecdiff(tstamp, &t->timeout, 60);
    706 				if (delta_usec < 0)
    707 					delta_usec = -delta_usec;
    708 			}
    709 			else
    710 			{
    711 				delta_usec = -1;
    712 			}
    713 
    714 			if (delta_usec < 500000 && delta_usec >= 0)
    715 			{
    716 				parseprintf(DD_RAWDCF, ("inp_rawdcf: timeout time difference %ld usec - minute marker set\n", delta_usec));
    717 				/* collect minute markers only if spaced by 60 seconds */
    718 				t->tminute = *tstamp;
    719 			}
    720 			else
    721 			{
    722 				parseprintf(DD_RAWDCF, ("inp_rawdcf: timeout time difference %ld usec - minute marker cleared\n", delta_usec));
    723 				memset((char *)&t->tminute, 0, sizeof(t->tminute));
    724 			}
    725 			t->timeout = *tstamp;
    726 		}
    727 		(void) parse_addchar(parseio, ch);
    728 
    729 		/* pass up to higher layers */
    730 		return PARSE_INP_TIME;
    731 	}
    732 	else
    733 	{
    734 		unsigned int rtc;
    735 
    736 		rtc = parse_addchar(parseio, ch);
    737 		if (rtc == PARSE_INP_SKIP)
    738 		{
    739 			if (snt_rawdcf(parseio, tstamp) == CVT_OK)
    740 				return PARSE_INP_SYNTH;
    741 		}
    742 		return rtc;
    743 	}
    744 }
    745 
    746 #else /* not (REFCLOCK && CLOCK_PARSE && CLOCK_RAWDCF) */
    747 NONEMPTY_TRANSLATION_UNIT
    748 #endif /* not (REFCLOCK && CLOCK_PARSE && CLOCK_RAWDCF) */
    749 
    750 /*
    751  * History:
    752  *
    753  * clk_rawdcf.c,v
    754  * Revision 4.18  2006/06/22 18:40:01  kardel
    755  * clean up signedness (gcc 4)
    756  *
    757  * Revision 4.17  2006/01/22 16:01:55  kardel
    758  * update version information
    759  *
    760  * Revision 4.16  2006/01/22 15:51:22  kardel
    761  * generate reasonable timecode output on invalid input
    762  *
    763  * Revision 4.15  2005/08/06 19:17:06  kardel
    764  * clean log output
    765  *
    766  * Revision 4.14  2005/08/06 17:39:40  kardel
    767  * cleanup size handling wrt/ to buffer boundaries
    768  *
    769  * Revision 4.13  2005/04/16 17:32:10  kardel
    770  * update copyright
    771  *
    772  * Revision 4.12  2004/11/14 15:29:41  kardel
    773  * support PPSAPI, upgrade Copyright to Berkeley style
    774  *
    775  * Revision 4.9  1999/12/06 13:42:23  kardel
    776  * transfer correctly converted time codes always into tcode
    777  *
    778  * Revision 4.8  1999/11/28 09:13:50  kardel
    779  * RECON_4_0_98F
    780  *
    781  * Revision 4.7  1999/04/01 20:07:20  kardel
    782  * added checking for minutie increment of timestamps in clk_rawdcf.c
    783  *
    784  * Revision 4.6  1998/06/14 21:09:37  kardel
    785  * Sun acc cleanup
    786  *
    787  * Revision 4.5  1998/06/13 12:04:16  kardel
    788  * fix SYSV clock name clash
    789  *
    790  * Revision 4.4  1998/06/12 15:22:28  kardel
    791  * fix prototypes
    792  *
    793  * Revision 4.3  1998/06/06 18:33:36  kardel
    794  * simplified condidional compile expression
    795  *
    796  * Revision 4.2  1998/05/24 11:04:18  kardel
    797  * triggering PPS on negative edge for simpler wiring (Rx->DCD)
    798  *
    799  * Revision 4.1  1998/05/24 09:39:53  kardel
    800  * implementation of the new IO handling model
    801  *
    802  * Revision 4.0  1998/04/10 19:45:30  kardel
    803  * Start 4.0 release version numbering
    804  *
    805  * from V3 3.24 log info deleted 1998/04/11 kardel
    806  *
    807  */
    808