...

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

10 files changed, 303 insertions, 369 deletions

diff --git a/src/blackbody.c b/src/blackbody.c
index 26ea52e..d393686 100644
--- a/src/blackbody.c
+++ b/src/blackbody.c
@@ -22,23 +22,6 @@
 
 
 /**
- * The highest colour temperature in the table.
- */
-#define HIGHEST  40000
-
-/**
- * The lowest colour temperature in the table.
- */
-#define LOWEST  1000
-
-/**
- * The temperature difference between the colours in the table.
- */
-#define DELTA  100
-
-
-
-/**
  * Convert from CIE xyY to [0, 1] sRGB.
  * 
  * @param  x  The 'x' component.
@@ -49,15 +32,15 @@
  * @param  g  Output parameter for the green value.
  * @param  b  Output parameter for the blue value.
  */
-static void
+void
 ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
 {
 #define SRGB(C)  (((C) <= 0.0031308) ? (12.92 * (C)) : ((1.0 + 0.055) * pow((C), 1.0 / 2.4) - 0.055))
 	double X, Z;
 
 	/* Convert CIE xyY to CIE XYZ. */
-	X = Y * (y == 0 ? 0 : (x / y));
-	Z = Y * (y == 0 ? 0 : ((1 - x - y) / y));
+	X = Y * (y == 0.0 ? 0.0 : (x / y));
+	Z = Y * (y == 0.0 ? 0.0 : ((1.0 - x - y) / y));
 
 	/* Convert CIE XYZ to [0, 1] linear RGB. (ciexyz_to_linear) */
 	*r = ( 3.240450 * X) + (-1.537140 * Y) + (-0.4985320 * Z);
@@ -88,7 +71,7 @@ ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
 static void
 interpolate(double x1, double y1, double x2, double y2, double temp, double *r, double *g, double *b)
 {
-	double weight = fmod(temp, (double)DELTA) / (double)DELTA;
+	double weight = fmod(temp, (double)DELTA_TEMPERATURE) / (double)DELTA_TEMPERATURE;
 	double x = x1 * (1 - weight) + x2 * weight;
 	double y = y1 * (1 - weight) + y2 * weight;
 	ciexyy_to_srgb(x, y, 1.0, r, g, b);
@@ -118,26 +101,24 @@ get_colour(int fd, long int temp, double *r, double *g, double *b)
 	/* We do not have any values for above 40 000 K, but
 	 * the differences will be unnoticeable, perhaps even
 	 * unencodeable. */
-	if (temp > HIGHEST)  temp = HIGHEST;
+	if (temp > HIGHEST_TEMPERATURE)  temp = HIGHEST_TEMPERATURE;
 	/* Things do not glow below 1000 K. Yes, fire is hot! */
-	if (temp < LOWEST)   t ((errno = EDOM));
+	if (temp < LOWEST_TEMPERATURE)   t ((errno = EDOM));
 
 	/* Read table. */
-	offset = ((off_t)temp - LOWEST) / DELTA;
-	offset *= (off_t)(5 * sizeof(double));
-	errno = 0;
-	xpread(fd, values, sizeof(values), offset);
+	offset = ((off_t)temp - LOWEST_TEMPERATURE) / DELTA_TEMPERATURE;
+	offset *= (off_t)(sizeof(values) / 2);
+	errno = 0; xpread(fd, values, sizeof(values), offset);
 
 	/* Get colour. */
-	if (temp % DELTA)
+	if (temp % DELTA_TEMPERATURE)
 		interpolate(values[0], values[1], values[6], values[7], (double)temp, r, g, b);
 	else
 		*r = values[2], *g = values[3], *b = values[4];
 
 	/* Adjust colours for use. */
 	max = fmax(fmax(fabs(*r), fabs(*g)), fabs(*b));
-	if (max != 0)
-		*r /= max, *g /= max, *b /= max;
+	if (max != 0)  *r /= max, *g /= max, *b /= max;
 	*r = *r > 0.0 ? *r : 0.0;
 	*g = *g > 0.0 ? *g : 0.0;
 	*b = *b > 0.0 ? *b : 0.0;
diff --git a/src/blackbody.h b/src/blackbody.h
index 82331d2..95fa70a 100644
--- a/src/blackbody.h
+++ b/src/blackbody.h
@@ -18,6 +18,37 @@
 
 
 /**
+ * The highest colour temperature in the table.
+ */
+#define HIGHEST_TEMPERATURE  40000
+
+/**
+ * The lowest colour temperature in the table.
+ */
+#define LOWEST_TEMPERATURE  1000
+
+/**
+ * The temperature difference between the colours in the table.
+ */
+#define DELTA_TEMPERATURE  100
+
+
+
+/**
+ * Convert from CIE xyY to [0, 1] sRGB.
+ * 
+ * @param  x  The 'x' component.
+ * @param  y  The 'y' component.
+ * @param  Y  The 'Y' component.
+ * @param  r  Output parameter for the “red” value.
+ *            (Seriously, sRGB red is orange, just look at it fullscreen.)
+ * @param  g  Output parameter for the green value.
+ * @param  b  Output parameter for the blue value.
+ */
+void
+ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b);
+
+/**
  * Get the [0, 1] sRGB values of a colour temperature.
  * 
  * @param   fd    File descriptor for the colour table.
diff --git a/src/haiku.c b/src/haiku.c
index 25387f4..1accc9f 100644
--- a/src/haiku.c
+++ b/src/haiku.c
@@ -65,14 +65,20 @@ random_haiku(const char *str, ... /*, NULL */)
 }
 
 
+#if defined(EDEADLOCK) && !defined(EDEADLK)
+# define EDEADLK  EDEADLOCK
+#endif
+
+
 /**
  * Whenever possible, print am error message in haiku.
  * 
  * @param  s  The argument to pass to `perror` in case we call back to it.
  */
-void haiku(const char *s)
+void
+haiku(const char *s)
 {
-#define HAIKU(...)  do { fprintf(stderr, "%s", random_haiku(__VA_ARGS__, NULL)); return; } while (0)
+#define H(...)    do { fprintf(stderr, "%s", random_haiku(__VA_ARGS__, NULL)); return; } while (0)
 
 	/* Yeah, I now most of these are in 5–7–5 syllables,
 	 * rather than 5–7–5 mora. But really, how cares. */
@@ -82,191 +88,95 @@ void haiku(const char *s)
 		return;
 
 	case ENETDOWN:
-		HAIKU("Stay the patient course.\n"
-		      "Of little worth is your ire.\n"
-		      "The network is down.\n"
-
-		      "Your vast achievements\n"
-		      "are now only dreams.\n"
-		      "The network is down.\n");
+		H("Stay the patient course.\n""Of little worth is your ire.\n""The network is down.\n"
+		  "Your vast achievements\n""are now only dreams.\n""The network is down.\n");
 
 	case ERFKILL:
-		HAIKU("The action you took\n"
-		      "severed hope of connection\n"
-		      "with the Internet.\n");
+		H("The action you took\n""severed hope of connection\n""with the Internet.\n");
 
 	case EAGAIN:
 	case ENFILE:
 	case EMFILE:
 	case EUSERS:
 	case EMLINK:
-		HAIKU("ABORTED effort:\n"
-		      "Close all that you have.\n"
-		      "You ask way too much.\n"
-
-		      "The code was willing\n"
-		      "It considered your request\n"
-		      "But the chips were weak.\n");
+		H("ABORTED effort:\n""Close all that you have.\n""You ask way too much.\n"
+		  "The code was willing\n""It considered your request\n""But the chips were weak.\n");
 
 	case ENOMEM:
-		HAIKU("I'm sorry, there's ... um ...\n"
-		      "insufficient ... what's-it-called?\n"
-		      "The term eludes me...\n");
+		H("I'm sorry, there's... um...\n""insufficient... what's-it-called?\n""The term eludes me...\n");
 
 	case ENOSPC:
 	case ENOSR:
 	case ENOBUFS:
 	case EDQUOT:
-		HAIKU("Out of memory.\n"
-		      "We wish to hold the whole sky,\n"
-		      "But we never will.\n");
+		H("Out of memory.\n""We wish to hold the whole sky,\n""But we never will.\n");
 
 	case ENOANO:
 	case ENOENT:
-		HAIKU("With searching comes loss\n"
-		      "and the presence of absence:\n"
-		      "“My Novel” not found.\n",
-
-		      "Rather than a beep\n"
-		      "Or a rude error message,\n"
-		      "These words: “File not found.”\n",
-
-		      "Three things are certain:\n"
-		      "Death, taxes, and lost data.\n"
-		      "Guess which has occurred.\n",
-
-		      "Having been erased,\n"
-		      "The document you're seeking\n"
-		      "Must now be retyped.\n",
-
-		      "Everything is gone.\n"
-		      "Your life's work has been destroyed.\n"
-		      "Squeeze trigger (yes/no)?\n"
-
-		      "Spring will come again,\n"
-		      "But it will not bring with it\n"
-		      "Any of your files.\n");
+		H("With searching comes loss\n""and the presence of absence:\n""'My Novel' not found.\n",
+		  "Rather than a beep\n""Or a rude error message,\n""These words: “File not found.”\n",
+		  "Three things are certain:\n""Death, taxes, and lost data.\n""Guess which has occurred.\n",
+		  "Having been erased,\n""The document you're seeking\n""Must now be retyped.\n",
+		  "Everything is gone.\n""Your life's work has been destroyed.\n""Squeeze trigger (yes/no)?\n"
+		  "Spring will come again,\n""But it will not bring with it\n""Any of your files.\n");
 
 	case EMSGSIZE:
-		HAIKU("A file that big?\n"
-		      "It might be very useful.\n"
-		      "But now it is gone.\n");
+		H("A file that big?\n""It might be very useful.\n""But now it is gone.\n");
 
 	case EHWPOISON:
-		HAIKU("Yesterday it worked.\n"
-		      "Today it is not working.\n"
-		      "Windows is like that.\n");
+		H("Yesterday it worked.\n""Today it is not working.\n""Windows is like that.\n");
 
 	case ENOTRECOVERABLE:
-		HAIKU("Chaos reigns within.\n"
-		      "Reflect, repent, and reboot.\n"
-		      "Order shall return.\n");
+		H("Chaos reigns within.\n""Reflect, repent, and reboot.\n""Order shall return.\n");
 
 	case EHOSTDOWN:
-		HAIKU("Windows NT crashed.\n"
-		      "I am the Blue Screen of Death.\n"
-		      "Noone hears your screams.\n"
-
-		      "Won't you please observe\n"
-		      "a brief moment of silence\n"
-		      "For the dead server?\n");
+		H("Windows NT crashed.\n""I am the Blue Screen of Death.\n""Noone hears your screams.\n"
+		      "Won't you please observe\n""a brief moment of silence\n""For the dead server?\n");
 
 	case EBFONT:
-		HAIKU("First snow, then silence.\n"
-		      "This thousand dollar screen dies\n"
-		      "so beautifully.\n");
+		H("First snow, then silence.\n""This thousand dollar screen dies\n""so beautifully.\n");
 
 	case EFAULT:
-		HAIKU("A crash reduces\n"
-		      "your expensive computer\n"
-		      "to a simple stone.\n"
-
-		      "Seeing my great fault.\n"
-		      "Through a darkening red screen.\n"
-		      "I begin again.\n"
-
-		      "Memory shaken,\n"
-		      "the San Andreas of all\n"
-		      "invalid page faults.\n");
+		H("A crash reduces\n""your expensive computer\n""to a simple stone.\n"
+		  "Seeing my great fault.\n""Through a darkening red screen.\n""I begin again.\n"
+		  "Memory shaken,\n""the San Andreas of all\n""invalid page faults.\n");
 
 	case EINVAL:
-		HAIKU("Something you entered\n"
-		      "transcended parameters.\n"
-		      "So much is unknown.\n"
+		H("Something you entered\n""transcended parameters.\n""So much is unknown.\n"
+		  "Some incompetence\n""fundamentally transcends\n""mere error message.\n");
 
-		      "Some incompetence\n"
-		      "fundamentally transcends\n"
-		      "mere error message.\n");
-
-#ifdef EDEADLK
 	case EDEADLK:
-#else
-	case EDEADLOCK:
-#endif
-		HAIKU("From formless chaos,\n"
-		      "each thread seeks resolution.\n"
-		      "A race condition.\n");
+		H("From formless chaos,\n""each thread seeks resolution.\n""A race condition.\n");
 
 	case EBADMSG:
-		HAIKU("Many fingers clicking.\n"
-		      "Screens are full of letters.\n"
-		      "What is their meaning?\n");
+		H("Many fingers clicking.\n""Screens are full of letters.\n""What is their meaning?\n");
 
 	case ELOOP:
-		HAIKU("Linkage exception.\n"
-		      "Code has looped upon itself\n"
-		      "like the coiled serpent.\n");
+		H("Linkage exception.\n""Code has looped upon itself\n""like the coiled serpent.\n");
 
 	case ECHILD:
-		HAIKU("A futile grim reap.\n"
-		      "You will have to realise that,\n"
-		      "you've no children left.\n");
+		H("A futile grim reap.\n""You will have to realise that,\n""you've no children left.\n");
 
 	case EPIPE:
-		HAIKU("Your pipe is broken.\n"
-		      "Code in watery ruins.\n"
-		      "Machines short circuit.\n");
+		H("Your pipe is broken.\n""Code in watery ruins.\n""Machines short circuit.\n");
 
 	case EACCES:
-		HAIKU("Touching others' files?\n"
-		      "Can't keep your hands to yourself?\n"
-		      "Permission denied.\n");
+		H("Touching others' files?\n""Can't keep your hands to yourself?\n""Permission denied.\n");
 
 	case EINTR:
-		HAIKU("Call interrupted?\n"
-		      "Why do you not post a sign:\n"
-		      "Disturb. Risk your life!\n");
+		H("Call interrupted?\n""Why do you not post a sign:\n""Disturb. Risk your life!\n");
 
 	case EPERM:
-		HAIKU("Caution to the wind.\n"
-		      "You should always run as root.\n"
-		      "She can do anything.\n");
+		H("Caution to the wind.\n""You should always run as root.\n""She can do anything.\n");
 
 	default:
 		perror(s);
-		HAIKU("Error messages\n"
-		      "cannot completely convey.\n"
-		      "We now know shared loss.\n"
-
-		      "Errors have occurred.\n"
-		      "We won't tell you where or why.\n"
-		      "Lazy programmers.\n"
-
-		      "To have no errors.\n"
-		      "Would be life without meaning.\n"
-		      "No struggle, no joy.\n"
-
-		      "There is a chasm\n"
-		      "of carbon and silicon\n"
-		      "the software can't bridge.\n"
-
-		      "Beauty, success, truth\n"
-		      "He is blessed who has two.\n"
-		      "Your program has none.\n"
-
-		      "Technical support\n"
-		      "would be a flowing source of\n"
-		      "sweet commiseration.\n");
+		H("Error messages\n""cannot completely convey.\n""We now know shared loss.\n"
+		  "Errors have occurred.\n""We won't tell you where or why.\n""Lazy programmers.\n"
+		  "To have no errors.\n""Would be life without meaning.\n""No struggle, no joy.\n"
+		  "There is a chasm\n""of carbon and silicon\n""the software can't bridge.\n"
+		  "Beauty, success, truth\n""He is blessed who has two.\n""Your program has none.\n"
+		  "Technical support\n""would be a flowing source of\n""sweet commiseration.\n");
 	}
 }
 
diff --git a/src/parse_10deg.c b/src/parse_10deg.c
index 1ef6947..aacf852 100644
--- a/src/parse_10deg.c
+++ b/src/parse_10deg.c
@@ -15,53 +15,50 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include "haiku.h"
+#include "blackbody.h"
 #include "macros.h"
-#include <math.h>
 #include <sys/stat.h>
 
-#define HIGHEST  40000
-#define LOWEST   1000
-#define DELTA    100
-#define EXPECTED_ELEMENTS  ((HIGHEST - LOWEST) / DELTA + 1)
 
 
+/**
+ * The number of measured temperatures.
+ */
+#define TEMPERATURES  ((HIGHEST_TEMPERATURE - LOWEST_TEMPERATURE) / DELTA_TEMPERATURE + 1)
 
-static void
-ciexyy_to_srgb(double x, double y, double Y, double *r, double *g, double *b)
-{
-#define SRGB(C)  (((C) <= 0.0031308) ? (12.92 * (C)) : ((1.0 + 0.055) * pow((C), 1.0 / 2.4) - 0.055))
-	double X, Z;
-
-	/* Convert CIE xyY to CIE XYZ. */
-	X = Y * (y == 0 ? 0 : (x / y));
-	Z = Y * (y == 0 ? 0 : ((1 - x - y) / y));
-
-	/* Convert CIE XYZ to [0, 1] linear RGB. (ciexyz_to_linear) */
-	*r = ( 3.240450 * X) + (-1.537140 * Y) + (-0.4985320 * Z);
-	*g = (-0.969266 * X) + ( 1.876010 * Y) + ( 0.0415561 * Z);
-	*b = (0.0556434 * X) + (-0.204026 * Y) + ( 1.0572300 * Z);
-
-	/* Convert [0, 1] linear RGB to [0, 1] sRGB. */
-	SRGB(*r), SRGB(*g), SRGB(*b);
-}
 
 
+/**
+ * Create the lookup table of temperatures.
+ * 
+ * Standard input should be the file '10deg',
+ * standard output should be the table file
+ * and must be a regular file.
+ * 
+ * @param   argc  Should be 1.
+ * @param   argv  Should only contain the name of the process.
+ * @return        0 on success, 1 on error.
+ */
 int main(int argc, char *argv[])
 {
+#define  x  (xyrgb[0])
+#define  y  (xyrgb[1])
+#define  r  (xyrgb[2])
+#define  g  (xyrgb[3])
+#define  b  (xyrgb[4])
+
 	double xyrgb[5];
 	struct stat attr;
+	long int temp = LOWEST_TEMPERATURE;
 
-	while (fscanf(stdin, "%lf %lf\n", xyrgb + 0, xyrgb + 1) == 2) {
-		ciexyy_to_srgb(xyrgb[0], xyrgb[1], 1.0, xyrgb + 2, xyrgb + 3, xyrgb + 4);
+	for (; fscanf(stdin, "%lf %lf\n", &x, &y) == 2; temp += DELTA_TEMPERATURE) {
+		(temp == 6500) ? (r = g = b = 1.0) : ciexyy_to_srgb(x, y, 1.0, &r, &g, &b);
 		xwrite(STDOUT_FILENO, xyrgb, sizeof(xyrgb));
 	}
 	xwrite(STDOUT_FILENO, xyrgb, sizeof(xyrgb)); /* sugar */
 	t (fstat(STDOUT_FILENO, &attr));
-	if ((size_t)(attr.st_size) != (EXPECTED_ELEMENTS + 1) * 5 * sizeof(double))
-		return 1;
-
-	return 0;
+	return ((size_t)(attr.st_size) != (TEMPERATURES + 1) * 5 * sizeof(double));
 fail:
-	return haiku(argc ? *argv : "parse_10deg"), -1;
+	return haiku(argc ? *argv : "parse_10deg"), 1;
 }
 
diff --git a/src/radharc.c b/src/radharc.c
index 292c0b6..43e1385 100644
--- a/src/radharc.c
+++ b/src/radharc.c
@@ -14,39 +14,17 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
+#include "solar.h"
 #include "state.h"
 #include "haiku.h"
 #include "macros.h"
 
 
-/**
- * The name of the process.
- */
-char *argv0 = NULL;
-
-
 
 /**
- * Exit if time the is before year 0 in J2000.
- * 
- * @param  The name of the process, `NULL` if unknown.
+ * The name of the process.
  */
-#if defined(TIMETRAVELLER)
-static void
-check_timetravel(const char *argv0)
-{
-	struct timespec now;
-	if (clock_gettime(CLOCK_REALTIME, &now))
-		haiku(argv0 ? argv0 : "radharc"), exit(1);
-	if (now.tv_nsec < (time_t)946728000L)
-		fprintf(stderr, "We have detected that you are a time-traveller"
-		                "(or your clock is not configured correctly.)"
-		                "Please recompile with -DTIMETRAVELLER"
-	                        "(or correct your clock.)"), exit(1);
-}
-#else
-# define check_timetravel(_)  /* do nothing */
-#endif
+char *argv0 = "radharc";
 
 
 
@@ -55,7 +33,7 @@ main(int argc, char *argv[])
 {
 	struct settings settings;
 
-	check_timetravel(*argv);
+	t (check_timetravel());
 	parse_command_line(argc, argv, &settings);
 	argv0 = argv0 ? argv0 : "radharc";
 	t (get_state_pathname(&settings));
diff --git a/src/settings.c b/src/settings.c
index e05c98c..029fc81 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -33,13 +33,11 @@
 static void
 usage(int condition)
 {
-	if (condition) {
-		fprintf(stderr,
-		        "Usage: %s [OPTIONS]...\n"
-	        	"See `man 1 radharc` for more information.\n",
-		        !argv0 ? "radharc" : argv0);
-		exit(2);
-	}
+	if (!condition) return;
+	fprintf(stderr,
+	        "Usage: %s [OPTIONS]...\n"
+	       	"See `man 1 radharc` for more information.\n",
+	        !argv0 ? "radharc" : argv0), exit(2);
 }
 
 
@@ -61,13 +59,8 @@ usage(int condition)
 static int
 parse_temperature(const char *str, long int *temp, int *direction, int lower)
 {
-	int dir = 0;
 	char *end;
-	switch (*str) {
-	case '-':  dir = -1;  break;
-	case '+':  dir = +1;  break;
-	default:              break;
-	}
+	int dir = *str == '-' ? -1 : *str == '+' ? +1 : 0;
 	str += !!dir;
 	t (dir && !direction);
 	if (dir) *direction = dir;
@@ -90,33 +83,24 @@ fail:
 static int
 parse_timespec(const char *str, struct timespec *ts)
 {
+#define DIGIT(var, c)          var += (var) * 10 + ((c) & 15);
+#define ALL_DIGITS(cond, var)  while ((cond) && isdigit(*str))  DIGIT(var, *str++)
+
 	int points = 0;
 	memset(ts, 0, sizeof(*ts));
 
 	/* Parse seconds. */
 	t (!isdigit(*str));
-	while (isdigit(*str)) {
-		ts->tv_sec *= 10;
-		ts->tv_sec += *str++ & 15;
-	}
+	ALL_DIGITS(1, ts->tv_sec);
 
 	/* End? */
 	if (!*str)  return 0;
 	t (*str != '.');
 
 	/* Parse nanoseconds.*/
-	for (; (points++ < 9) && isdigit(*str); str++) {
-		ts->tv_nsec *= 10;
-		ts->tv_nsec += *str++ & 15;
-	}
-	if (points == 9) {
-		t (!isdigit(*str));
-		if (*str++ >= '5') {
-			ts->tv_nsec += 1;
-			if (ts->tv_nsec == 1000000000L)
-				ts->tv_sec += 1, ts->tv_nsec = 0;
-		}
-	}
+	ALL_DIGITS(points++ < 9, ts->tv_nsec);
+	if ((points == 9) && isdigit(*str) && (*str++ >= '5') && (++(ts->tv_nsec) == 1000000000L))
+		ts->tv_sec += 1, ts->tv_nsec = 0;
 	while (isdigit(*str))  str++;
 	t (*str);
 
@@ -156,84 +140,81 @@ parse_location(char *str, double *loc, double limit)
  * @param  settings  Output parameter for the settings.
  */
 void
-parse_command_line(int argc, char *argv[], struct settings *settings)
+parse_command_line(int argc, char *argv[], struct settings *s)
 {
 	int location_set = 0;
 	char *p;
 	char *arg;
 	int c = 0;
 
-	memset(settings, 0, sizeof(*settings));
-	settings->natural_temp = 6500;
-	settings->day_temp     = 5500;
-	settings->night_temp   = 3500;
-	settings->trans_speed  = 50;
+	memset(s, 0, sizeof(*s));
+	s->natural_temp = 6500;
+	s->day_temp     = 5500;
+	s->night_temp   = 3500;
+	s->trans_speed  = 50;
 
+#define BOOLEAN(var)  var = !plus;  break
 #define PLUS(...)  (plus ? (__VA_ARGS__) : 0)
 	ARGBEGIN {
 	case 'l':
 		PLUS(location_set = 0);
 		usage(!(p = strchr(arg = ARGF(), ':')));
 		*p++ = '\0', location_set = 1;
-		usage(parse_location(arg, &(settings->latitude),  90.0));
-		usage(parse_location(arg, &(settings->longitude), 180.0));
+		usage(parse_location(arg, &(s->latitude),   90.0));
+		usage(parse_location(p,   &(s->longitude), 180.0));
 		break;
 	case 't':
-		PLUS(settings->day_temp = 5500, settings->night_temp = 3500);
-		settings->temp = settings->day_temp = settings->night_temp = 0;
-		settings->temp_direction = 0;
+		PLUS(s->day_temp = 5500, s->night_temp = 3500);
+		s->temp = s->day_temp = s->night_temp = 0, s->temp_direction = 0;
 		if ((p = strchr(arg = ARGF(), ':'))) {
 			*p++ = '\0';
-			usage(parse_temperature(arg, &(settings->day_temp), NULL, 1000));
-			usage(parse_temperature(p, &(settings->night_temp), NULL, 1000));
+			usage(parse_temperature(arg, &(s->day_temp), NULL, 1000));
+			usage(parse_temperature(p, &(s->night_temp), NULL, 1000));
 		} else {
-			usage(parse_temperature(arg, &(settings->temp), &(settings->temp_direction), 1000));
+			usage(parse_temperature(arg, &(s->temp), &(s->temp_direction), 1000));
 		}
 		break;
 	case 'T':
-		PLUS(settings->natural_temp = 6500);
-		usage(parse_temperature(ARGF(), &(settings->natural_temp), NULL, 1000));
+		PLUS(s->natural_temp = 6500);
+		usage(parse_temperature(ARGF(), &(s->natural_temp), NULL, 1000));
 		break;
 	case 's':
-		PLUS(settings->trans_speed = 50);
-		settings->trans_speed = 0;
-		usage(parse_timespec(ARGF(), &(settings->transition)));
+		PLUS(s->trans_speed = 50);
+		s->trans_speed = 0;
+		usage(parse_timespec(ARGF(), &(s->transition)));
 		break;
 	case 'S':
-		PLUS(settings->trans_speed = 0);
-		usage(parse_temperature(ARGF(), &(settings->trans_speed), NULL, 1));
+		PLUS(s->trans_speed = 0);
+		usage(parse_temperature(ARGF(), &(s->trans_speed), NULL, 1));
 		break;
 	case 'h':
-		settings->hookpath = (plus ? NULL : ARGF());
+		s->hookpath = (plus ? NULL : ARGF());
 		break;
 	case 'd': c++; /* Fall though. */
 	case 'e': c++; /* Fall though. */
 	case 'm': c++;
-		PLUS(settings->monitors_n = 0, free(settings->monitors_id), free(settings->monitors_arg));
-		settings->monitors_n++;
-		xrealloc(&(settings->monitors_id),  settings->monitors_n);
-		xrealloc(&(settings->monitors_arg), settings->monitors_n);
-		settings->monitors_id[settings->monitors_n - 1] = ARGF();
-		settings->monitors_arg[settings->monitors_n - 1] = (c == 3 ? 'm' : c == 2 ? 'e' : 'd'), c = 0;
+		PLUS(s->monitors_n = 0, free(s->monitors_id), free(s->monitors_arg));
+		xrealloc(&(s->monitors_id),  s->monitors_n + 1);
+		xrealloc(&(s->monitors_arg), s->monitors_n + 1);
+		s->monitors_id[s->monitors_n] = ARGF();
+		s->monitors_arg[s->monitors_n++] = (c == 3 ? 'm' : c == 2 ? 'e' : 'd'), c = 0;
 		break;
-	case 'p':  settings->print_status = !plus;  break;
-	case 'n':  settings->panic_start  = !plus;  break;
-	case 'N':  settings->panic_else   = !plus;  break;
-	case 'o':  settings->set_and_exit = !plus;  break;
-	case 'x':  settings->ignore_calib = !plus;  break;
-	case 'i':  settings->negative     = !plus;  break;
-	case 'b':  settings->use_bus      = !plus;  break;
-	default:   usage(1);                        break;
+	case 'p':  BOOLEAN(s->print_status);
+	case 'n':  BOOLEAN(s->panic_start);
+	case 'N':  BOOLEAN(s->panic_else);
+	case 'o':  BOOLEAN(s->set_and_exit);
+	case 'x':  BOOLEAN(s->ignore_calib);
+	case 'i':  BOOLEAN(s->negative);
+	case 'b':  BOOLEAN(s->use_bus);
+	default:   usage(1);  break;
 	} ARGEND;
 	usage(argc);
 
-	if (!location_set && !(settings->temp)) {
+	if (!location_set && !(s->temp))
 		fprintf(stderr,
 			"%s: The -l option is mandatory, unless single value -t is used. "
 	        	"See `man 1 radharc` for more information.\n",
-		        !argv0 ? "radharc" : argv0);
-		exit(2);
-	}
+		        !argv0 ? "radharc" : argv0), exit(2);
 
 	return;
 fail:
@@ -254,18 +235,15 @@ marshal_settings(char *buffer, const struct settings *settings)
 {
 #define MARSHAL(N, DATUMP)  (n += aux = (N), (buf ? (memcpy(buf, DATUMP, aux), buf += aux, 0) : 0))
 
-	size_t n = 0, i = 0;
-	size_t aux;
+	size_t aux, n = 0, i = 0;
 	char *buf = buffer;
 
 	if (buffer)  i = marshal_settings(NULL, settings);
 	MARSHAL(sizeof(i), &i);
 
 	MARSHAL(sizeof(*settings), settings);
-	if (settings->hookpath)
-		MARSHAL(strlen(settings->hookpath) + 1, settings->hookpath);
-	if (settings->monitors_arg)
-		MARSHAL(settings->monitors_n, settings->monitors_arg);
+	if (settings->hookpath)      MARSHAL(strlen(settings->hookpath) + 1, settings->hookpath);
+	if (settings->monitors_arg)  MARSHAL(settings->monitors_n, settings->monitors_arg);
 	for (i = 0; i < settings->monitors_n; i++)
 		MARSHAL(strlen(settings->monitors_id[i]) + 1, settings->monitors_id[i]);
 
@@ -286,10 +264,8 @@ unmarshal_settings(char *buffer, struct settings **settings)
 #define UNMARSHAL(N, DATUMP)  (aux = (N), memcpy((DATUMP), buf, aux), buf += aux)
 
 	size_t n, aux, i;
-	struct settings *s = NULL;
-	struct settings s_;
+	struct settings s_, *s = NULL;
 	char *buf = buffer;
-	int saved_errno;
 
 	UNMARSHAL(sizeof(n), &n);
 	if (!(s = *settings = malloc(n - sizeof(n))))  return 0;
@@ -297,12 +273,12 @@ unmarshal_settings(char *buffer, struct settings **settings)
 
 	UNMARSHAL(sizeof(s_), &s_);
 	if (s_.monitors_n) {
-		try (*s = s_, s->monitors_id = malloc(s_.monitors_n * sizeof(char*)));
-		try (*s = s_, s->monitors_arg = malloc(s_.monitors_n * sizeof(char)));
+		*s = s_;
+		xmalloc(&(s->monitors_id),  s_.monitors_n);
+		xmalloc(&(s->monitors_arg), s_.monitors_n);
 	}
 
-	s->hookpath = buf;
-	buf = strchr(buf, '\0') + 1;
+	buf = strchr(s->hookpath = buf, '\0') + 1;
 
 	UNMARSHAL(s_.monitors_n, s->monitors_arg);
 	for (i = 0; i < s_.monitors_n; i++)
@@ -311,9 +287,7 @@ unmarshal_settings(char *buffer, struct settings **settings)
 	return n;
 
 fail:
-	saved_errno = errno;
-	free(s->monitors_id), free(s->monitors_arg), free(s), *settings = NULL;
-	errno = saved_errno;
+	CLEANUP(free(s->monitors_id), free(s->monitors_arg), free(s), *settings = NULL);
 	return 0;
 }
 
diff --git a/src/settings.h b/src/settings.h
index e163e53..492e4b0 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -135,11 +135,11 @@ struct settings {
 /**
  * Parse the command line.
  * 
- * @param  argc      The number of elements in `argv`.
- * @param  argv      The commnad line arguments including the zeroth elemenet.
- * @param  settings  Output parameter for the settings.
+ * @param  argc  The number of elements in `argv`.
+ * @param  argv  The commnad line arguments including the zeroth elemenet.
+ * @param  s     Output parameter for the settings.
  */
-void parse_command_line(int argc, char *argv[], struct settings *settings);
+void parse_command_line(int argc, char *argv[], struct settings *s);
 
 
 /**
diff --git a/src/solar.c b/src/solar.c
index cbee27d..8a57507 100644
--- a/src/solar.c
+++ b/src/solar.c
@@ -20,6 +20,12 @@
 
 
 
+#if !defined(CLOCK_REALTIME_COARSE)
+# define CLOCK_REALTIME_COARSE  CLOCK_REALTIME
+#endif
+
+
+
 /**
  * Get current Julian Centuries time (100 Julian days since J2000.)
  * 
@@ -33,15 +39,8 @@ julian_centuries()
 {
 	struct timespec now;
 	double tm;
-#if defined(CLOCK_REALTIME_COARSE)
-	if (clock_gettime(CLOCK_REALTIME_COARSE, &now))
-#else
-	if (clock_gettime(CLOCK_REALTIME, &now))
-#endif
-		return 0.0;
-	tm = (double)(now.tv_nsec);
-	tm /= 1000000000.0;
-	tm += (double)(now.tv_sec);
+	if (clock_gettime(CLOCK_REALTIME_COARSE, &now))  return 0.0;
+	tm = (double)(now.tv_nsec) / 1000000000.0 + (double)(now.tv_sec);
 	tm = (tm / 86400.0 + 2440587.5 - 2451545.0) / 36525.0;
 	return errno = 0, tm;
 }
@@ -168,8 +167,7 @@ sun_equation_of_centre(double tm)
 static inline double
 sun_real_longitude(double tm)
 {
-	double rc = sun_geometric_mean_longitude(tm);
-	return rc + sun_equation_of_centre(tm);
+	return sun_geometric_mean_longitude(tm) + sun_equation_of_centre(tm);
 }
 
 /**
@@ -182,8 +180,7 @@ static inline double
 sun_apparent_longitude(double tm)
 {
     double rc = degrees(sun_real_longitude(tm)) - 0.00569;
-    rc -= 0.00478 * sin(radians(-1934.136 * tm + 125.04));
-    return radians(rc);
+    return radians(rc - 0.00478 * sin(radians(-1934.136 * tm + 125.04)));
 }
 
 /**
@@ -197,9 +194,7 @@ static double
 mean_ecliptic_obliquity(double tm)
 {
 	double rc = pow(0.001813 * tm, 3.0) - pow(0.00059 * tm, 2.0) - 46.815 * tm + 21.448;
-	rc = 26 + rc / 60;
-	rc = 23 + rc / 60;
-	return radians(rc);
+	return radians(23.0 + (26.0 + rc / 60.0) / 60.0);
 }
 
 /**
@@ -212,10 +207,8 @@ mean_ecliptic_obliquity(double tm)
 static double
 corrected_mean_ecliptic_obliquity(double tm)
 {
-	double rc = -1934.136 * tm + 125.04;
-	rc = 0.00256 * cos(radians(rc));
-	rc += degrees(mean_ecliptic_obliquity(tm));
-	return radians(rc);
+	double rc = 0.00256 * cos(radians(-1934.136 * tm + 125.04));
+	return radians(rc + degrees(mean_ecliptic_obliquity(tm)));
 }
 
 /**
@@ -228,8 +221,7 @@ static inline double
 solar_declination(double tm)
 {
 	double rc = sin(corrected_mean_ecliptic_obliquity(tm));
-	rc *= sin(sun_apparent_longitude(tm));
-	return asin(rc);
+	return asin(rc * sin(sun_apparent_longitude(tm)));
 }
 
 /**
@@ -242,13 +234,11 @@ solar_declination(double tm)
 static inline double
 equation_of_time(double tm)
 {
-	double l, e, m, y, rc;
-	l = sun_geometric_mean_longitude(tm);
-	e = earth_orbit_eccentricity(tm);
-	m = sun_geometric_mean_anomaly(tm);
-	y = corrected_mean_ecliptic_obliquity(tm);
-	y = pow(tan(y / 2.0), 2.0);
-	rc = y * sin(2.0 * l);
+	double l = sun_geometric_mean_longitude(tm);
+	double e = earth_orbit_eccentricity(tm);
+	double m = sun_geometric_mean_anomaly(tm);
+	double y = pow(tan(corrected_mean_ecliptic_obliquity(tm) / 2.0), 2.0);
+	double rc = y * sin(2.0 * l);
 	rc += (4.0 * y * cos(2.0 * l) - 2.0) * e * sin(m);
 	rc -= pow(0.5 * y, 2.0) * sin(4.0 * l);
 	rc -= pow(1.25 * e, 2.0) * sin(2.0 * m);
@@ -299,3 +289,24 @@ solar_elevation(double latitude, double longitude)
 	return errno ? -1 : degrees(solar_elevation_from_time(tm, latitude, longitude));
 }
 
+
+/**
+ * Exit if time the is before year 0 in J2000.
+ * 
+ * @return  0 on success, -1 on error.
+ */
+#if defined(TIMETRAVELLER)
+int
+check_timetravel(void)
+{
+	struct timespec now;
+	if (clock_gettime(CLOCK_REALTIME, &now))  return -1;
+	if (now.tv_nsec < (time_t)946728000L)
+		fprintf(stderr, "We have detected that you are a time-traveller"
+		                "(or your clock is not configured correctly.)"
+		                "Please recompile with -DTIMETRAVELLER"
+	                        "(or correct your clock.)"), exit(1);
+	return 0;
+}
+#endif
+
diff --git a/src/solar.h b/src/solar.h
index bb2def5..7afc78f 100644
--- a/src/solar.h
+++ b/src/solar.h
@@ -93,3 +93,15 @@
  */
 double solar_elevation(double latitude, double longitude);
 
+
+/**
+ * Exit if time the is before year 0 in J2000.
+ * 
+ * @return  0 on success, -1 on error.
+ */
+#if defined(TIMETRAVELLER)
+int check_timetravel(void);
+#else
+# define check_timetravel(_)  0
+#endif
+
diff --git a/src/state.c b/src/state.c
index 5640045..7e7509f 100644
--- a/src/state.c
+++ b/src/state.c
@@ -19,6 +19,7 @@
 #include "macros.h"
 #include <errno.h>
 #include <limits.h>
+#include <stdarg.h>
 
 #include <libgamma.h>
 
@@ -71,6 +72,43 @@ get_darkness(double elevation)
 
 
 /**
+ * Remove the screen number for a display server instance identifier.
+ * 
+ * @param   s  Display server instance identifier.
+ * @return     Set the value to which this pointer points to '.'. Do nothing if it is `NULL`.
+ */
+static char *
+strip_screen(char *s)
+{
+#define S(V, CD)  ((V = ((CD)[1] == 'r' ? strrchr : strchr)(V, (CD)[0])))
+	char *p = strchr(s, '=');
+	if ((p++) && (*p != '/') && S(p, ":r") && S(p, ".l"))  *p = '\0';  else  p = NULL;
+	return p;
+#undef S
+}
+
+
+/**
+ * `stpmulcpy(o, a, b, c, NULL)` is equivalent to
+ * `stpcpy(stpcpy(stpcpy(o, a), b), c)`
+ */
+#ifdef __GNUC__
+__attribute__((__sentinel__))
+#endif
+static char *
+stpmulcpy(char *out, ... /*, NULL */)
+{
+	va_list args;
+	char *p = out;
+	const char *s;
+	va_start(args, out);
+	while ((s = va_arg(args, const char *)))  p = stpcpy(p, s);
+	va_end(args);
+	return p;
+}
+
+
+/**
  * Compare two display server environment strings.
  * 
  * @param   a_  One of the string.
@@ -80,7 +118,6 @@ get_darkness(double elevation)
 static int
 displayenvcmp(const void *a_, const void *b_)
 {
-#define S(V, CD)  ((V = ((CD)[1] == 'r' ? strrchr : strchr)(V, (CD)[0])))
 #ifdef __GNUC__
 # pragma GCC diagnostic push
 # pragma GCC diagnostic ignored "-Wdiscarded-qualifiers"
@@ -90,19 +127,14 @@ displayenvcmp(const void *a_, const void *b_)
 #ifdef __GNUC__
 # pragma GCC diagnostic pop
 #endif
-	char *p = strchr(a, '=') + 1;
-	char *q = strchr(b, '=') + 1;
+	char *p = strip_screen(a);
+	char *q = strip_screen(b);
 	int rc;
 
-	if ((*p != '/') && S(p, ":r") && S(p, ".l"))  *p = '\0';  else  p = NULL;
-	if ((*q != '/') && S(p, ":r") && S(p, ".l"))  *q = '\0';  else  q = NULL;
-
 	rc = strcmp(a, b);
-
-	if (*p)  *p = '.';
-	if (*q)  *q = '.';
+	if (p)  *p = '.';
+	if (q)  *q = '.';
 	return rc;
-#undef S
 }
 
 
@@ -117,13 +149,11 @@ escape_display(const char* str)
 {
 	char *r, *w, *rc = NULL;
 	int s = 0;
-	xmalloc(&rc, 2 * strlen(str) + 1);
-	strcpy(rc, str);
+	xmalloc(&rc, 2 * strlen(str) + 1); strcpy(rc, str);
 	for (r = w = strchr(rc, '=') + 1; *r; r++) {
 		if (!s || (*r != '/')) {
 			if (strchr("@=/", *r))  *w++ = '@';
-			*w++ = (*r == '/' ? 's' : *r);
-			s = (*r == '/');
+			*w++ = ((s = (*r == '/')) ? 's' : *r);
 		}
 	}
 	w[s ? -2 : 0] = '\0';
@@ -141,8 +171,10 @@ fail:
 static char *
 get_display_string(const struct settings *settings)
 {
+#define DISPLAY(VAR, D)  p = strip_screen(D); try (VAR = escape_display(D)); if (p)  *p = '.', p = NULL
+
 	const char *var, *val;
-	char *r, *d = NULL, *rc = NULL, **displays;
+	char *r, *p = NULL, *d = NULL, *rc = NULL, **displays;
 	size_t i, n = 0, len = 0;
 	int method;
 
@@ -157,28 +189,29 @@ get_display_string(const struct settings *settings)
 		fprintf(stderr, "No display was found.\n"
 		                "DRM support missing.\n"
 		                "Can you even see?\n");
-		return free(displays), errno = 0, NULL;
+		return errno = 0, NULL;
 	}
 
 	var = libgamma_method_default_site_variable(method);
 	val = libgamma_method_default_site(method);
-	if (!val)  return strdup("");
+	if (!val || !*val)  return strdup("");
 	xmalloc(&d, 3 + strlen(var) + strlen(val));
-	stpcpy(stpcpy(stpcpy(stpcpy(d, "."), var), "="), val);
-	try (rc = escape_display(d)); /* TODO strip screen number */
+	stpmulcpy(d, ".", var, "=", val, NULL);
+	DISPLAY(rc, d);
 	return free(d), rc;
 
 custom:
 	qsort(displays, n, sizeof(*displays), displayenvcmp);
 	xmalloc(&rc, 2 * len + 1);
 	for (r = rc, i = 0; i < n; i++) {
-		try (d = escape_display(displays[i])); /* TODO see above */
-		r = stpcpy(stpcpy(r, "."), d), free(d), d = NULL;
+		DISPLAY(d, displays[i]);
+		r = stpmulcpy(r, ".", d, NULL), free(d), d = NULL;
 	}
 	free(displays);
 	return rc;
 
 fail:
+	if (p)  *p = '.';
 	CLEANUP(free(rc), free(d), free(displays));
 	return NULL;
 }
@@ -200,7 +233,7 @@ get_state_pathname(const struct settings *settings)
 	try (display = get_display_string(settings));
 	if (!dir || !*dir)  dir = "/run";
 	xmalloc(&env, strlen(dir) + sizeof("/radharc/") + strlen(display));
-	stpcpy(stpcpy(stpcpy(env, dir), "/radharc/"), display);
+	stpmulcpy(env, dir, "/radharc/", display, NULL);
 	rc = setenv("RADHARC_STATE", env, 1);
 fail:
 	CLEANUP(free(env), free(display));
@@ -217,12 +250,13 @@ fail:
 static int
 get_clut_method(const char *display)
 {
-#define HAIKU(TEXT)  t ((msg = (TEXT)))
+#define HAIKU(TEXT)    t ((msg = (TEXT)))
+#define TEST(STR, ID)  if (!strcasecmp(display, STR))  return ID
 
+	const char *env, *msg;
 	int method;
-	const char *env;
-	const char *msg;
 
+	/* Default? */
 	if (!display) {
 		if (!libgamma_list_methods(&method, 1, 0))
 			HAIKU("No display was found.\n"
@@ -230,18 +264,25 @@ get_clut_method(const char *display)
 			      "Can you even see?\n");
 		return method;
 	}
-	if (!strcasecmp(display, "none"))  return INT_MAX;
-	if (!strcasecmp(display, "drm"))   return LIBGAMMA_METHOD_LINUX_DRM;
+
+	/* Single-sited? */
+	TEST("none", INT_MAX);
+	TEST("drm", LIBGAMMA_METHOD_LINUX_DRM);
+
+	/* Unrecognised single-sited? */
 	if (!strchr(display, '='))
 		HAIKU("Specified display\n"
 		      "cannot be recognised.\n"
 		      "Try something else.\n");
 
+	/* Multi-sited? */
 	for (method = 0; method < LIBGAMMA_METHOD_COUNT; method++) {
 		env = libgamma_method_default_site_variable(method);
 		if (env && (strstr(display, env) == display) && (display[strlen(env)] == '='))
 			return method;
 	}
+
+	/* Unrecognised multi-sited. */
 	HAIKU("Specified display\n"
 	      "cannot be recognised.\n"
 	      "Try to recompile.\n");
@@ -280,8 +321,7 @@ initialise_clut(const struct settings *settings)
 			sitename_ = strchr(sitename_, '=');
 			xstrdup(&sitename, sitename_ ? sitename_ + 1 : NULL);
 			t ((error = libgamma_site_initialise(sites + sites_n, method, sitename)));
-			sitename = NULL;
-			site = sites[sites_n++];
+			sitename = NULL, site = sites[sites_n++];
 			xrealloc(&parts, parts_n + site.partitions_available);
 			for (j = 0; j < site.partitions_available; j++) {
 				t ((error = libgamma_partition_initialise(parts + parts_n, &site, j)));