Lua: add support for os library

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21106 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 58 insertions, 0 deletions

diff --git a/apps/plugins/lua/gmtime.c b/apps/plugins/lua/gmtime.c
new file mode 100644
index 0000000000..f13c855de8
--- /dev/null
+++ b/apps/plugins/lua/gmtime.c
@@ -0,0 +1,58 @@
+#include <time.h>
+
+/* seconds per day */
+#define SPD 24*60*60
+
+/* days per month -- nonleap! */
+const short __spm[13] =
+  { 0,
+    (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),
+  };
+
+int __isleap(int year) {
+  /* every fourth year is a leap year except for century years that are
+   * not divisible by 400. */
+/*  return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); */
+  return (!(year%4) && ((year%100) || !(year%400)));
+}
+
+struct tm *gmtime(const time_t *timep) {
+  static struct tm r;
+  time_t i;
+  register time_t work=*timep%(SPD);
+  r.tm_sec=work%60; work/=60;
+  r.tm_min=work%60; r.tm_hour=work/60;
+  work=*timep/(SPD);
+  r.tm_wday=(4+work)%7;
+  for (i=1970; ; ++i) {
+    register time_t k=__isleap(i)?366:365;
+    if (work>=k)
+      work-=k;
+    else
+      break;
+  }
+  r.tm_year=i-1900;
+  r.tm_yday=work;
+
+  r.tm_mday=1;
+  if (__isleap(i) && (work>58)) {
+    if (work==59) r.tm_mday=2; /* 29.2. */
+    work-=1;
+  }
+
+  for (i=11; i && (__spm[i]>work); --i) ;
+  r.tm_mon=i;
+  r.tm_mday+=work-__spm[i];
+  return &r;
+}