From 0b8bd28b705e3b85b9e22d2372a6377a99adb13e Mon Sep 17 00:00:00 2001
From: =?utf8?q?Janosch=20Gr=C3=A4f?= <janosch@majestix.majestix>
Date: Wed, 24 Dec 2008 17:22:45 +0100
Subject: [PATCH] stdlibc/time: +calculation of weekday and yearday

---
 apps/include/time.h     | 13 ++++++------
 apps/lib/stdlibc/time.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/apps/include/time.h b/apps/include/time.h
index 9e116c6..db49dbf 100644
--- a/apps/include/time.h
+++ b/apps/include/time.h
@@ -19,7 +19,12 @@
 #ifndef _TIME_H_
 #define _TIME_H_
 
-#include <syscall.h>
+#include <sys/types.h>
+
+#define CLOCKS_PER_SEC  100 /// @see kernel2/cpu.h
+#define CLOCK_REALTIME  0   // ID of Realtime clock (?) ///< @see ?
+#define TIMER_ABSTIME   0   // Flag indicating time is absolute ///< @see ?
+#define CLOCK_MONOTONIC 1   // ID of monotonic clock (?) ///< @see ?
 
 struct tm {
   int tm_sec;   // Seconds [0..59]
@@ -41,13 +46,9 @@ struct itimerspec {
   struct timespec it_value;    // Timer expiration.
 };
 
-#define CLOCKS_PER_SEC  100 /// @see kernel2/cpu.h
-#define CLOCK_REALTIME  0   // ID of Realtime clock (?) ///< @see ?
-#define TIMER_ABSTIME   0   // Flag indicating time is absolute ///< @see ?
-#define CLOCK_MONOTONIC 1   // ID of monotonic clock (?) ///< @see ?
-
 time_t time(time_t *tloc);
 time_t mktime(struct tm *tm);
+char *asctime(const struct tm *timeptr);
 clock_t clock();
 
 #endif
diff --git a/apps/lib/stdlibc/time.c b/apps/lib/stdlibc/time.c
index 303c14c..2dfeb8d 100644
--- a/apps/lib/stdlibc/time.c
+++ b/apps/lib/stdlibc/time.c
@@ -19,10 +19,59 @@
 #include <sys/types.h>
 #include <time.h>
 #include <cmos.h>
+#include <syscall.h>
+#include <stdio.h>
 
 static time_t start_time = 0;
 static clock_t start_ticks;
 
+static int is_leapyear(unsigned int year) {
+  if (year%400==0) return 1;
+  else if (year%100==0) return 0;
+  else if (year%4==0) return 1;
+  else return 0;
+}
+
+static void getyday(struct tm *tm) {
+  unsigned int mdays[12] = {
+    31,
+    31+28,
+    31+28+31,
+    31+28+31+30,
+    31+28+31+30+31,
+    31+28+31+30+31+30,
+    31+28+31+30+31+30+31,
+    31+28+31+30+31+30+31+31,
+    31+28+31+30+31+30+31+31+30,
+    31+28+31+30+31+30+31+31+30+31,
+    31+28+31+30+31+30+31+31+30+31+30,
+    31+28+31+30+31+30+31+31+30+31+30+31
+  };
+
+  tm->tm_yday = (tm->tm_mon>0?mdays[tm->tm_mon-1]:0)+tm->tm_mday;
+  if (is_leapyear(tm->tm_year+1900)) tm->tm_yday++;
+}
+
+static void getwday(struct tm *tm) {
+  unsigned int doomsdays[] = {1,6,4,2};
+  unsigned int year = tm->tm_year+1900;
+  unsigned int dday_idx = (year/100)%4;
+  unsigned int step1 = (year%100)/12;
+  unsigned int step2 = (year%100)%12;
+  unsigned int step3 = step2/4;
+  unsigned int dday_year = (doomsdays[dday_idx]+((step1+step2+step3)%7))%7;
+  unsigned int january0 = dday_year+(7-((59+is_leapyear(year)?1:0)%7));
+  tm->tm_wday = ((january0+(tm->tm_yday%7))%7)-1;
+}
+
+char *asctime(const struct tm *timeptr) {
+  char *wday_name[] = {"Sun","Mon","Tue","Wed","Thu", "Fri","Sat"};
+  char *mon_name[] = {"Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};
+  static char result[26];
+  sprintf(result,"%s %s %u %02u:%02u:%02u %u\n",wday_name[timeptr->tm_wday],mon_name[timeptr->tm_mon],timeptr->tm_mday,timeptr->tm_hour,timeptr->tm_min, timeptr->tm_sec,1900+timeptr->tm_year);
+  return result;
+}
+
 time_t time(time_t *tloc) {
   if (start_time==0) {
     struct tm tm = {
@@ -33,6 +82,8 @@ time_t time(time_t *tloc) {
       .tm_mon = cmos_getmonth()-1,
       .tm_year = cmos_getyear()-1900
     };
+    getyday(&tm);
+    getwday(&tm);
 
     start_time = mktime(&tm);
     start_ticks = clock();
@@ -45,7 +96,9 @@ time_t time(time_t *tloc) {
 }
 
 time_t mktime(struct tm *tm) {
-  return 0;
+  return tm->tm_sec + tm->tm_min*60 + tm->tm_hour*3600 + tm->tm_yday*86400 +
+         (tm->tm_year-70)*31536000 + ((tm->tm_year-69)/4)*86400 -
+         ((tm->tm_year-1)/100)*86400 + ((tm->tm_year+299)/400)*86400;
 }
 
 static clock_t start_clock = -1;
-- 
2.11.4.GIT