rework langinfo code for ABI compat and for use by time code

[musl] / src / time / strftime.c

diff --git a/src/time/strftime.c b/src/time/strftime.c
index b69a83a..592b214 100644 (file)
--- a/src/time/strftime.c
+++ b/src/time/strftime.c
@@ -1,14 +1,50 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <langinfo.h>
+#include <locale.h>
 #include <time.h>
-#include "__time.h"
+#include <limits.h>
+#include "libc.h"
 
 // FIXME: integer overflows
 
-const char *__langinfo(nl_item);
+const char *__nl_langinfo_l(nl_item, locale_t);
 
-size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm)
+static int is_leap(int y)
+{
+       /* Avoid overflow */
+       if (y>INT_MAX-1900) y -= 2000;
+       y += 1900;
+       return !(y%4) && ((y%100) || !(y%400));
+}
+
+static int week_num(const struct tm *tm)
+{
+       int val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7;
+       /* If 1 Jan is just 1-3 days past Monday,
+        * the previous week is also in this year. */
+       if ((tm->tm_wday - tm->tm_yday - 2 + 371) % 7 <= 2)
+               val++;
+       if (!val) {
+               val = 52;
+               /* If 31 December of prev year a Thursday,
+                * or Friday of a leap year, then the
+                * prev year has 53 weeks. */
+               int dec31 = (tm->tm_wday - tm->tm_yday - 1 + 7) % 7;
+               if (dec31 == 4 || (dec31 == 5 && is_leap(tm->tm_year%400-1)))
+                       val++;
+       } else if (val == 53) {
+               /* If 1 January is not a Thursday, and not
+                * a Wednesday of a leap year, then this
+                * year has only 52 weeks. */
+               int jan1 = (tm->tm_wday - tm->tm_yday + 371) % 7;
+               if (jan1 != 4 && (jan1 != 3 || !is_leap(tm->tm_year)))
+                       val = 1;
+       }
+       return val;
+}
+
+size_t __strftime_l(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm, locale_t loc)
 {
        nl_item item;
        int val;
@@ -58,14 +94,15 @@ do_fmt:
                        fmt = "%Y-%m-%d";
                        goto recu_strftime;
                case 'g':
-                       // FIXME
-                       val = 0; //week_based_year(tm)%100;
-                       fmt = "%02d";
-                       goto number;
                case 'G':
-                       // FIXME
-                       val = 0; //week_based_year(tm);
                        fmt = "%04d";
+                       val = tm->tm_year + 1900;
+                       if (tm->tm_yday < 3 && week_num(tm) != 1) val--;
+                       else if (tm->tm_yday > 360 && week_num(tm) == 1) val++;
+                       if (*f=='g') {
+                               fmt = "%02d";
+                               val %= 100;
+                       }
                        goto number;
                case 'H':
                        val = tm->tm_hour;
@@ -116,10 +153,17 @@ do_fmt:
                        fmt = "%d";
                        goto number;
                case 'U':
-               case 'V':
+                       val = (tm->tm_yday + 7 - tm->tm_wday) / 7;
+                       fmt = "%02d";
+                       goto number;
                case 'W':
-                       // FIXME: week number mess..
-                       continue;
+                       val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7;
+                       fmt = "%02d";
+                       goto number;
+               case 'V':
+                       val = week_num(tm);
+                       fmt = "%02d";
+                       goto number;
                case 'w':
                        val = tm->tm_wday;
                        fmt = "%d";
@@ -139,14 +183,11 @@ do_fmt:
                        fmt = "%04d";
                        goto number;
                case 'z':
-                       if (tm->tm_isdst < 0) continue;
-                       val = -__timezone - (tm->tm_isdst ? __dst_offset : 0);
+                       val = -tm->__tm_gmtoff;
                        l += snprintf(s+l, n-l, "%+.2d%.2d", val/3600, abs(val%3600)/60);
                        continue;
                case 'Z':
-                       if (tm->tm_isdst < 0 || !__tzname[0] || !__tzname[0][0])
-                               continue;
-                       l += snprintf(s+l, n-l, "%s", __tzname[!!tm->tm_isdst]);
+                       l += snprintf(s+l, n-l, "%s", tm->__tm_zone);
                        continue;
                default:
                        return 0;
@@ -159,14 +200,21 @@ number:
                l += snprintf(s+l, n-l, fmt, val);
                continue;
 nl_strcat:
-               l += snprintf(s+l, n-l, "%s", __langinfo(item));
+               l += snprintf(s+l, n-l, "%s", __nl_langinfo_l(item, loc));
                continue;
 nl_strftime:
-               fmt = __langinfo(item);
+               fmt = __nl_langinfo_l(item, loc);
 recu_strftime:
-               l += strftime(s+l, n-l, fmt, tm);
+               l += __strftime_l(s+l, n-l, fmt, tm, loc);
        }
        if (l >= n) return 0;
        s[l] = 0;
        return l;
 }
+
+size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm)
+{
+       return __strftime_l(s, n, f, tm, LC_GLOBAL_LOCALE);
+}
+
+weak_alias(__strftime_l, strftime_l);