[newlib-cygwin/main] strptime: fix am/pm converting to 24-hour system

[newlib-cygwin/main] strptime: fix am/pm converting to 24-hour system

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=acf176104fc5410bfec0635ed2c5a21971b9c938

commit acf176104fc5410bfec0635ed2c5a21971b9c938
Author:     Alexey Lapshin <alexey.lapshin@espressif.com>
AuthorDate: Tue Feb 20 18:51:04 2024 +0000
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Wed Feb 21 15:52:14 2024 +0100

    strptime: fix am/pm converting to 24-hour system
    
    Fix the issue of parsing 08:00AM, which currently gives a 20:00 representation.

Diff:
---
 newlib/libc/time/strptime.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/newlib/libc/time/strptime.c b/newlib/libc/time/strptime.c
index 6220ff73ad27..188218059a36 100644
--- a/newlib/libc/time/strptime.c
+++ b/newlib/libc/time/strptime.c
@@ -292,11 +292,12 @@ strptime_l (const char *buf, const char *format, struct tm *timeptr,
 		ret = match_string (&buf, _ctloc (am_pm), locale);
 		if (ret < 0)
 		    return NULL;
-		if (timeptr->tm_hour == 0) {
-		    if (ret == 1)
-			timeptr->tm_hour = 12;
-		} else
-		    timeptr->tm_hour += 12;
+		if (timeptr->tm_hour > 12)
+		    return NULL;
+		else if (timeptr->tm_hour == 12)
+		    timeptr->tm_hour = ret * 12;
+		else
+		    timeptr->tm_hour += ret * 12;
 		break;
 	    case 'q' :		/* quarter year - GNU extension */
 		ret = strtol_l (buf, &s, 10, locale);