opc source code

third_party/open62541/deps/libc_time.c

@@ -0,0 +1,147 @@
+/* Originally released by the musl project (http://www.musl-libc.org/) under the
+ * MIT license. Taken from the file /src/time/__secs_to_tm.c */
+
+#include <limits.h>
+#include "libc_time.h"
+
+/* 2000-03-01 (mod 400 year, immediately after feb29 */
+#define LEAPOCH (946684800LL + 86400*(31+29))
+
+#define DAYS_PER_400Y (365*400 + 97)
+#define DAYS_PER_100Y (365*100 + 24)
+#define DAYS_PER_4Y   (365*4   + 1)
+
+int __secs_to_tm(long long t, struct mytm *tm) {
+    long long days, secs, years;
+    int remdays, remsecs, remyears;
+    int qc_cycles, c_cycles, q_cycles;
+    int months;
+    static const char days_in_month[] = {31,30,31,30,31,31,30,31,30,31,31,29};
+
+    /* Reject time_t values whose year would overflow int */
+    if (t < INT_MIN * 31622400LL || t > INT_MAX * 31622400LL)
+        return -1;
+
+    secs = t - LEAPOCH;
+    days = secs / 86400LL;
+    remsecs = (int)(secs % 86400);
+    if (remsecs < 0) {
+        remsecs += 86400;
+        --days;
+    }
+
+    qc_cycles = (int)(days / DAYS_PER_400Y);
+    remdays = (int)(days % DAYS_PER_400Y);
+    if (remdays < 0) {
+        remdays += DAYS_PER_400Y;
+        --qc_cycles;
+    }
+
+    c_cycles = remdays / DAYS_PER_100Y;
+    if (c_cycles == 4) --c_cycles;
+    remdays -= c_cycles * DAYS_PER_100Y;
+
+    q_cycles = remdays / DAYS_PER_4Y;
+    if (q_cycles == 25) --q_cycles;
+    remdays -= q_cycles * DAYS_PER_4Y;
+
+    remyears = remdays / 365;
+    if (remyears == 4) --remyears;
+    remdays -= remyears * 365;
+
+    years = remyears + 4*q_cycles + 100*c_cycles + 400LL*qc_cycles;
+
+    for (months=0; days_in_month[months] <= remdays; ++months)
+        remdays -= days_in_month[months];
+
+    if (years+100 > INT_MAX || years+100 < INT_MIN)
+        return -1;
+
+    tm->tm_year = (int)(years + 100);
+    tm->tm_mon = months + 2;
+    if (tm->tm_mon >= 12) {
+        tm->tm_mon -=12;
+        ++tm->tm_year;
+    }
+    tm->tm_mday = remdays + 1;
+    tm->tm_hour = remsecs / 3600;
+    tm->tm_min = remsecs / 60 % 60;
+    tm->tm_sec = remsecs % 60;
+
+    return 0;
+}
+
+static const int secs_through_month[] =
+    {0, 31*86400, 59*86400, 90*86400,
+     120*86400, 151*86400, 181*86400, 212*86400,
+     243*86400, 273*86400, 304*86400, 334*86400 };
+
+static int
+__month_to_secs(int month, int is_leap) {
+    int t = secs_through_month[month];
+    if (is_leap && month >= 2)
+        t+=86400;
+    return t;
+}
+
+static long long
+__year_to_secs(const long long year, int *is_leap) {
+    int cycles, centuries, leaps, rem;
+    int is_leap_val = 0;
+    if (!is_leap) {
+        is_leap = &is_leap_val;
+    }
+    cycles = (int)((year-100) / 400);
+    rem = (int)((year-100) % 400);
+    if (rem < 0) {
+        cycles--;
+        rem += 400;
+    }
+    if (!rem) {
+        *is_leap = 1;
+        centuries = 0;
+        leaps = 0;
+    } else {
+        if (rem >= 200) {
+            if (rem >= 300) centuries = 3, rem -= 300;
+            else centuries = 2, rem -= 200;
+        } else {
+            if (rem >= 100) centuries = 1, rem -= 100;
+            else centuries = 0;
+        }
+        if (!rem) {
+            *is_leap = 0;
+            leaps = 0;
+        } else {
+            leaps = (rem / (int)4U);
+            rem %= (int)4U;
+            *is_leap = !rem;
+        }
+    }
+
+    leaps += 97*cycles + 24*centuries - *is_leap;
+
+    return (year-100) * 31536000LL + leaps * 86400LL + 946684800 + 86400;
+}
+
+long long __tm_to_secs(const struct mytm *tm) {
+    int is_leap;
+    long long year = tm->tm_year;
+    int month = tm->tm_mon;
+    if (month >= 12 || month < 0) {
+        int adj = month / 12;
+        month %= 12;
+        if (month < 0) {
+            adj--;
+            month += 12;
+        }
+        year += adj;
+    }
+    long long t = __year_to_secs(year, &is_leap);
+    t += __month_to_secs(month, is_leap);
+    t += 86400LL * (tm->tm_mday-1);
+    t += 3600LL * tm->tm_hour;
+    t += 60LL * tm->tm_min;
+    t += tm->tm_sec;
+    return t;
+}