From 813c4dda8b6d75dc1f8e7ab1237d0efc468d3fbb Mon Sep 17 00:00:00 2001
From: David Seifert <soap@gentoo.org>
Date: Sun, 8 Nov 2026 10:59:01 +0100
Subject: [PATCH] Fix parsing of ordinal ISO 8601 dates on musl.

POSIX does not require strptime() to derive tm_mon/tm_mday from %j, and
musl does not, so ordinal ISO 8601 dates (e.g. "2001-34") were mis-parsed
on musl. Compute tm_mon and tm_mday from tm_yday after parsing.

Bug: https://bugs.gentoo.org/922481
---
 src/unix.c  |  7 ++++++-
 src/utils.c | 21 +++++++++++++++++++++
 src/utils.h |  4 ++++
 src/win32.c | 20 +-------------------
 4 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/src/unix.c b/src/unix.c
index 746b42f..9158d3e 100644
--- a/src/unix.c
+++ b/src/unix.c
@@ -4,6 +4,7 @@
 #include <time.h>
 #include "compiler.h" /* _hidden */
 #include "libdatovka/isds.h"
+#include "utils.h"
 
 #if HAVE_LIBCURL
 /* Convert UTF-8 @string representation of ISO 8601 date to @time.
@@ -22,8 +23,12 @@ _hidden isds_error _isds_datestring2tm(const xmlChar *string, struct tm *time) {
         return IE_SUCCESS;
 
     offset = strptime((char*)string, "%Y-%j", time);
-    if (offset && *offset == '\0')
+    if (offset && *offset == '\0') {
+        /* POSIX does not require strptime() to set tm_mon and tm_mday
+         * from %j, and musl only sets tm_yday. */
+        _isds_yday2mday(time);
         return IE_SUCCESS;
+    }
 
     return IE_NOTSUP;
 }
diff --git a/src/utils.c b/src/utils.c
index 514403d..8f31fdc 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -378,3 +378,24 @@ _hidden int _isds_hex2i(char digit) {
 _hidden int _isds_sizet2int(size_t val) {
     return (val <= INT_MAX) ? (int) val : -1;
 }
+
+/* Set tm_mon and tm_mday from tm_year and tm_yday. */
+_hidden void _isds_yday2mday(struct tm *time) {
+    static const int mtab[12] =
+        {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+    int i, mdays, year = 1900 + time->tm_year;
+    const int leap = (!(year % 4) && ((year % 100) || !(year %400))) ? 1 : 0;
+
+    time->tm_mday = time->tm_yday + 1;
+
+    for (i = 0; i < 12; i++) {
+        mdays = mtab[i] + ((i == 1) ? leap : 0);
+        if (time->tm_mday > mdays) {
+            time->tm_mday -= mdays;
+        } else {
+            break;
+        }
+    }
+
+    time->tm_mon = i;
+}
diff --git a/src/utils.h b/src/utils.h
index b9718d0..721dbae 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -4,6 +4,7 @@
 #include <stdlib.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <time.h>
 
 /* PANIC macro aborts current process without any clean up.
  * Use it as last resort fatal error solution */
@@ -103,4 +104,7 @@ int _isds_sizet2int(size_t val);
     (memory) = NULL; \
 }
 
+/* Set tm_mon and tm_mday from tm_year and tm_yday. */
+void _isds_yday2mday(struct tm *time);
+
 #endif
diff --git a/src/win32.c b/src/win32.c
index 431a4e8..d4593cc 100644
--- a/src/win32.c
+++ b/src/win32.c
@@ -7,24 +7,6 @@
 #include "win32.h"
 
 #if HAVE_LIBCURL
-static void yday2mday(struct tm *time) {
-    static int mtab[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
-    int i, year = 1900 + time->tm_year;
-
-    mtab[1] = (!(year % 4) && ((year % 100) || !(year %400))) ? 29 : 28;
-    time->tm_mday = time->tm_yday + 1;
-
-    for (i = 0; i < 12; i++) {
-        if (time->tm_mday > mtab[i]) {
-            time->tm_mday -= mtab[i];
-        } else {
-            break;
-        }
-    }
-
-    time->tm_mon = i;
-}
-
 /* Convert UTF-8 @string representation of ISO 8601 date to @time.
  * XXX: Not all ISO formats are supported */
 isds_error _isds_datestring2tm(const xmlChar *string, struct tm *time) {
@@ -49,7 +31,7 @@ isds_error _isds_datestring2tm(const xmlChar *string, struct tm *time) {
             && tmp == strlen((const char*)string)) {
         time->tm_yday--;
         time->tm_year -= 1900;
-        yday2mday(time);
+        _isds_yday2mday(time);
             return IE_SUCCESS;
     }
 
-- 
2.56.0