Changeset 324d46b in mainline for uspace/lib/posix/time.c

Timestamp:

2011-07-07T01:32:53Z (13 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

3f466c33

Parents:

08053f7

Message:

Partial time.h implementation (WIP, untested)

File:

• uspace/lib/posix/time.c (modified) (4 diffs)

uspace/lib/posix/time.c

@@ -36 +36 @@
 #define LIBPOSIX_INTERNAL
 
+/* Must be first. */
+#include "stdbool.h"
+
 #include "internal/common.h"
 #include "time.h"
+
+#include "ctype.h"
+#include "errno.h"
 
 #include "libc/malloc.h"
 #include "libc/task.h"
 #include "libc/stats.h"
+
+// TODO: documentation
+// TODO: test everything in this file
+
+/* Helper functions ***********************************************************/
+
+#define HOURS_PER_DAY (24)
+#define MINS_PER_HOUR (60)
+#define SECS_PER_MIN (60)
+#define MINS_PER_DAY (MINS_PER_HOUR * HOURS_PER_DAY)
+#define SECS_PER_HOUR (SECS_PER_MIN * MINS_PER_HOUR)
+#define SECS_PER_DAY (SECS_PER_HOUR * HOURS_PER_DAY)
+
+static bool _is_leap_year(time_t year)
+{
+        year += 1900;
+
+        if (year % 400 == 0)
+                return true;
+        if (year % 100 == 0)
+                return false;
+        if (year % 4 == 0)
+                return true;
+        return false;
+}
+
+static int _days_in_month(time_t year, time_t mon)
+{
+        assert(mon >= 0 && mon <= 11);
+        year += 1900;
+
+        static int month_days[] =
+                { 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+        if (mon == 1) {
+                /* february */
+                return _is_leap_year(year) ? 29 : 28;
+        } else {
+                return month_days[mon];
+        }
+}
+
+static int _day_of_year(time_t year, time_t mon, time_t mday)
+{
+        static int mdays[] =
+            { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
+        static int leap_mdays[] =
+            { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 };
+
+        return (_is_leap_year(year) ? leap_mdays[mon] : mdays[mon]) + mday - 1;
+}
+
+/* Integer division that rounds to negative infinity.
+ */
+static time_t _floor_div(time_t op1, time_t op2)
+{
+        if (op1 >= 0 || op1 % op2 == 0) {
+                return op1 / op2;
+        } else {
+                return op1 / op2 - 1;
+        }
+}
+
+/* Modulo that rounds to negative infinity.
+ */
+static time_t _floor_mod(time_t op1, time_t op2)
+{
+        int div = _floor_div(op1, op2);
+
+        /* (a / b) * b + a % b == a */
+        /* thus, a % b == a - (a / b) * b */
+
+        int result = op1 - div * op2;
+        
+        /* Some paranoid checking to ensure I didn't make a mistake here. */
+        assert(result >= 0);
+        assert(result < op2);
+        assert(div * op2 + result == op1);
+        
+        return result;
+}
+
+static time_t _days_since_epoch(time_t year, time_t mon, time_t mday)
+{
+        return (year - 70) * 365 + _floor_div(year - 69, 4) -
+            _floor_div(year - 1, 100) + _floor_div(year + 299, 400) +
+            _day_of_year(year, mon, mday);
+}
+
+/* Assumes normalized broken-down time. */
+static time_t _secs_since_epoch(const struct posix_tm *tm)
+{
+        return _days_since_epoch(tm->tm_year, tm->tm_mon, tm->tm_mday) *
+            SECS_PER_DAY + tm->tm_hour * SECS_PER_HOUR +
+            tm->tm_min * SECS_PER_MIN + tm->tm_sec;
+}
+
+static int _day_of_week(time_t year, time_t mon, time_t mday)
+{
+        /* 1970-01-01 is Thursday */
+        return (_days_since_epoch(year, mon, mday) + 4) % 7;
+}
+
+struct _long_tm {
+        time_t tm_sec;
+        time_t tm_min;
+        time_t tm_hour;
+        time_t tm_mday;
+        time_t tm_mon;
+        time_t tm_year;
+        int tm_wday;
+        int tm_yday;
+        int tm_isdst;
+};
+
+static void _posix_to_long_tm(struct _long_tm *ltm, struct posix_tm *ptm)
+{
+        assert(ltm != NULL && ptm != NULL);
+        ltm->tm_sec = ptm->tm_sec;
+        ltm->tm_min = ptm->tm_min;
+        ltm->tm_hour = ptm->tm_hour;
+        ltm->tm_mday = ptm->tm_mday;
+        ltm->tm_mon = ptm->tm_mon;
+        ltm->tm_year = ptm->tm_year;
+        ltm->tm_wday = ptm->tm_wday;
+        ltm->tm_yday = ptm->tm_yday;
+        ltm->tm_isdst = ptm->tm_isdst;
+}
+
+static void _long_to_posix_tm(struct posix_tm *ptm, struct _long_tm *ltm)
+{
+        assert(ltm != NULL && ptm != NULL);
+        // FIXME: the cast should be unnecessary, libarch/common.h brain-damage
+        assert((ltm->tm_year >= (int) INT_MIN) && (ltm->tm_year <= (int) INT_MAX));
+
+        ptm->tm_sec = ltm->tm_sec;
+        ptm->tm_min = ltm->tm_min;
+        ptm->tm_hour = ltm->tm_hour;
+        ptm->tm_mday = ltm->tm_mday;
+        ptm->tm_mon = ltm->tm_mon;
+        ptm->tm_year = ltm->tm_year;
+        ptm->tm_wday = ltm->tm_wday;
+        ptm->tm_yday = ltm->tm_yday;
+        ptm->tm_isdst = ltm->tm_isdst;
+}
+
+static void _normalize_time(struct _long_tm *tm)
+{
+        // TODO: DST correction
+
+        /* Adjust time. */
+        tm->tm_min += _floor_div(tm->tm_sec, SECS_PER_MIN);
+        tm->tm_sec = _floor_mod(tm->tm_sec, SECS_PER_MIN);
+        tm->tm_hour += _floor_div(tm->tm_min, MINS_PER_HOUR);
+        tm->tm_min = _floor_mod(tm->tm_min, MINS_PER_HOUR);
+        tm->tm_mday += _floor_div(tm->tm_hour, HOURS_PER_DAY);
+        tm->tm_hour = _floor_mod(tm->tm_hour, HOURS_PER_DAY);
+
+        /* Adjust month. */
+        tm->tm_year += _floor_div(tm->tm_mon, 12);
+        tm->tm_mon = _floor_mod(tm->tm_mon, 12);
+
+        /* Now the difficult part - days of month. */
+        /* Slow, but simple. */
+        // TODO: do this faster
+
+        while (tm->tm_mday < 1) {
+                tm->tm_mon--;
+                if (tm->tm_mon == -1) {
+                        tm->tm_mon = 11;
+                        tm->tm_year--;
+                }
+                
+                tm->tm_mday += _days_in_month(tm->tm_year, tm->tm_mon);
+        }
+
+        while (tm->tm_mday > _days_in_month(tm->tm_year, tm->tm_mon)) {
+                tm->tm_mday -= _days_in_month(tm->tm_year, tm->tm_mon);
+                
+                tm->tm_mon++;
+                if (tm->tm_mon == 12) {
+                        tm->tm_mon = 0;
+                        tm->tm_year++;
+                }
+        }
+
+        /* Calculate the remaining two fields. */
+        tm->tm_yday = _day_of_year(tm->tm_year, tm->tm_mon, tm->tm_mday);
+        tm->tm_wday = _day_of_week(tm->tm_year, tm->tm_mon, tm->tm_mday);
+}
+
+/* Which day the week-based year starts on relative to the first calendar day.
+ * E.g. if the year starts on December 31st, the return value is -1.
+ */
+static int _wbyear_offset(int year)
+{
+        int start_wday = _day_of_week(year, 0, 1);
+        return _floor_mod(4 - start_wday, 7) - 3;
+}
+
+/* Returns week-based year of the specified time.
+ * Assumes normalized broken-down time.
+ */
+static int _wbyear(const struct posix_tm *tm)
+{
+        if (tm->tm_yday < _wbyear_offset(tm->tm_year)) {
+                return tm->tm_year - 1;
+        }
+        if (tm->tm_yday > (364 + _is_leap_year(tm->tm_year) +
+            _wbyear_offset(tm->tm_year + 1))) {
+                return tm->tm_year + 1;
+        }
+        return tm->tm_year;
+}
+
+/* Number of week in year, when week starts on sunday.
+ */
+static int _sun_week_number(const struct posix_tm *tm)
+{
+        // TODO
+        not_implemented();
+}
+
+/* Number of week in week-based year.
+ */
+static int _iso_week_number(const struct posix_tm *tm)
+{
+        // TODO
+        not_implemented();
+}
+
+/* Number of week in year, when week starts on monday.
+ */
+static int _mon_week_number(const struct posix_tm *tm)
+{
+        // TODO
+        not_implemented();
+}
+
+/******************************************************************************/
+
+int posix_daylight;
+long posix_timezone;
+char *posix_tzname[2];
+
+void posix_tzset(void)
+{
+        // TODO: read environment
+        posix_tzname[0] = (char *) "GMT";
+        posix_tzname[1] = (char *) "GMT";
+        posix_daylight = 0;
+        posix_timezone = 0;
+}
+
+double posix_difftime(time_t time1, time_t time0)
+{
+        return (double) (time1 - time0);
+}
+
+/** This function first normalizes the provided broken-down time
+ *  (moves all values to their proper bounds) and then tries to
+ *  calculate the appropriate time_t representation.
+ *
+ * @param timeptr Broken-down time.
+ * @return time_t representation of the time, undefined value on overflow
+ */
+time_t posix_mktime(struct posix_tm *tm)
+{
+        // TODO: take DST flag into account
+        // TODO: detect overflow
+
+        struct _long_tm ltm;
+        _posix_to_long_tm(&ltm, tm);
+        _normalize_time(&ltm);
+        _long_to_posix_tm(tm, &ltm);
+
+        return _secs_since_epoch(tm);
+}
 
 /**
@@ -50 +334 @@
 struct posix_tm *posix_localtime(const time_t *timep)
 {
-        // TODO
-        static struct posix_tm result = { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
-        return &result;
+        static struct posix_tm result;
+        return posix_localtime_r(timep, &result);
+}
+
+struct posix_tm *posix_localtime_r(const time_t *restrict timer,
+    struct posix_tm *restrict result)
+{
+        assert(timer != NULL);
+        assert(result != NULL);
+
+        // TODO: deal with timezone
+        // currently assumes system and all times are in GMT
+
+        /* Set epoch and seconds to _long_tm struct and normalize to get
+         * correct values.
+         */
+        struct _long_tm ltm = {
+                .tm_sec = *timer,
+                .tm_min = 0,
+                .tm_hour = 0, /* 00:00:xx */
+                .tm_mday = 1,
+                .tm_mon = 0, /* January 1st */
+                .tm_year = 70, /* 1970 */
+        };
+        _normalize_time(&ltm);
+
+        if (ltm.tm_year < (int) INT_MIN || ltm.tm_year > (int) INT_MAX) {
+                errno = EOVERFLOW;
+                return NULL;
+        }
+
+        _long_to_posix_tm(result, &ltm);
+        return result;
 }
 
@@ -60 +374 @@
  * @return
  */
-char *posix_asctime(const struct posix_tm *tm)
-{
-        // TODO
-        static char result[] = "Sun Jan 01 00:00:00 1900\n";
-        return result;
+char *posix_asctime(const struct posix_tm *timeptr)
+{
+        static char buf[ASCTIME_BUF_LEN];
+        return posix_asctime_r(timeptr, buf);
+}
+
+char *posix_asctime_r(const struct posix_tm *restrict timeptr,
+    char *restrict buf)
+{
+        assert(timeptr != NULL);
+        assert(buf != NULL);
+
+        static const char *wday[] = {
+                "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+        };
+        static const char *mon[] = {
+                "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+                "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+        };
+
+        snprintf(buf, ASCTIME_BUF_LEN, "%s %s %2d %02d:%02d:%02d %d\n",
+            wday[timeptr->tm_wday],
+            mon[timeptr->tm_mon],
+            timeptr->tm_mday, timeptr->tm_hour,
+            timeptr->tm_min, timeptr->tm_sec,
+            1900 + timeptr->tm_year);
+
+        return buf;
 }
 
@@ -85 +422 @@
  * @return
  */
-size_t posix_strftime(char *s, size_t maxsize, const char *format, const struct posix_tm *tm)
-{
-        // TODO
-        if (maxsize >= 1) {
-                *s = '\0';
-        }
-        return 0;
+size_t posix_strftime(char *s, size_t maxsize,
+    const char *format, const struct posix_tm *tm)
+{
+        // TODO: use locale
+        static const char *wday_abbr[] = {
+                "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+        };
+        static const char *wday[] = {
+                "Sunday", "Monday", "Tuesday", "Wednesday",
+                "Thursday", "Friday", "Saturday"
+        };
+        static const char *mon_abbr[] = {
+                "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+                "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+        };
+        static const char *mon[] = {
+                "January", "February", "March", "April", "May", "June", "July",
+                "August", "September", "October", "November", "December"
+        };
+        
+        if (maxsize < 1) {
+                return 0;
+        }
+        
+        char *ptr = s;
+        size_t consumed;
+        size_t remaining = maxsize;
+        
+        #define append(...) { \
+                /* FIXME: this requires POSIX-correct snprintf */ \
+                /*        otherwise it won't work with non-ascii chars */ \
+                consumed = snprintf(ptr, remaining, __VA_ARGS__); \
+                if (consumed >= remaining) { \
+                        return 0; \
+                } \
+                ptr += consumed; \
+                remaining -= consumed; \
+        }
+        
+        #define recurse(fmt) { \
+                consumed = posix_strftime(ptr, remaining, fmt, tm); \
+                if (consumed == 0) { \
+                        return 0; \
+                } \
+                ptr += consumed; \
+                remaining -= consumed; \
+        }
+        
+        #define TO_12H(hour) (((hour) > 12) ? ((hour) - 12) : \
+            (((hour) == 0) ? 12 : (hour)))
+        
+        while (*format != '\0') {
+                if (*format != '%') {
+                        append("%c", *format);
+                        format++;
+                        continue;
+                }
+                
+                format++;
+                if (*format == '0' || *format == '+') {
+                        // TODO: padding
+                        format++;
+                }
+                while (isdigit(*format)) {
+                        // TODO: padding
+                        format++;
+                }
+                if (*format == 'O' || *format == 'E') {
+                        // TODO: locale's alternative format
+                        format++;
+                }
+                
+                switch (*format) {
+                case 'a':
+                        append("%s", wday_abbr[tm->tm_wday]); break;
+                case 'A':
+                        append("%s", wday[tm->tm_wday]); break;
+                case 'b':
+                        append("%s", mon_abbr[tm->tm_mon]); break;
+                case 'B':
+                        append("%s", mon[tm->tm_mon]); break;
+                case 'c':
+                        // TODO: locale-specific datetime format
+                        recurse("%Y-%m-%d %H:%M:%S"); break;
+                case 'C':
+                        append("%02d", (1900 + tm->tm_year) / 100); break;
+                case 'd':
+                        append("%02d", tm->tm_mday); break;
+                case 'D':
+                        recurse("%m/%d/%y"); break;
+                case 'e':
+                        append("%2d", tm->tm_mday); break;
+                case 'F':
+                        recurse("%+4Y-%m-%d"); break;
+                case 'g':
+                        append("%02d", _wbyear(tm) % 100); break;
+                case 'G':
+                        append("%d", _wbyear(tm)); break;
+                case 'h':
+                        recurse("%b"); break;
+                case 'H':
+                        append("%02d", tm->tm_hour); break;
+                case 'I':
+                        append("%02d", TO_12H(tm->tm_hour)); break;
+                case 'j':
+                        append("%03d", tm->tm_yday); break;
+                case 'k':
+                        append("%2d", tm->tm_hour); break;
+                case 'l':
+                        append("%2d", TO_12H(tm->tm_hour)); break;
+                case 'm':
+                        append("%02d", tm->tm_mon); break;
+                case 'M':
+                        append("%02d", tm->tm_min); break;
+                case 'n':
+                        append("\n"); break;
+                case 'p':
+                        append("%s", tm->tm_hour < 12 ? "AM" : "PM"); break;
+                case 'P':
+                        append("%s", tm->tm_hour < 12 ? "am" : "PM"); break;
+                case 'r':
+                        recurse("%I:%M:%S %p"); break;
+                case 'R':
+                        recurse("%H:%M"); break;
+                case 's':
+                        append("%ld", _secs_since_epoch(tm)); break;
+                case 'S':
+                        append("%02d", tm->tm_sec); break;
+                case 't':
+                        append("\t"); break;
+                case 'T':
+                        recurse("%H:%M:%S"); break;
+                case 'u':
+                        append("%d", (tm->tm_wday == 0) ? 7 : tm->tm_wday); break;
+                case 'U':
+                        append("%02d", _sun_week_number(tm)); break;
+                case 'V':
+                        append("%02d", _iso_week_number(tm)); break;
+                case 'w':
+                        append("%d", tm->tm_wday); break;
+                case 'W':
+                        append("%02d", _mon_week_number(tm)); break;
+                case 'x':
+                        // TODO: locale-specific date format
+                        recurse("%Y-%m-%d"); break;
+                case 'X':
+                        // TODO: locale-specific time format
+                        recurse("%H:%M:%S"); break;
+                case 'y':
+                        append("%02d", tm->tm_year % 100); break;
+                case 'Y':
+                        append("%d", 1900 + tm->tm_year); break;
+                case 'z':
+                        // TODO: timezone
+                        break;
+                case 'Z':
+                        // TODO: timezone
+                        break;
+                case '%':
+                        append("%%");
+                        break;
+                default:
+                        /* Invalid specifier, print verbatim. */
+                        while (*format != '%') {
+                                format--;
+                        }
+                        append("%%");
+                        break;
+                }
+                format++;
+        }
+        
+        #undef append
+        #undef recurse
+        
+        return maxsize - remaining;
 }