From dcbca9b6367537f550fe775254c91310de6e4b43 Mon Sep 17 00:00:00 2001
From: sayed nabhan <nabhan@bugqore.com>
Date: Thu, 2 Jul 2026 12:39:47 +0530
Subject: [PATCH] cast char to unsigned char before ctype calls in cctz parser

---
 .../internal/cctz/src/time_zone_format.cc     | 23 +++++++++++--------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/absl/time/internal/cctz/src/time_zone_format.cc b/absl/time/internal/cctz/src/time_zone_format.cc
index 91b46219d2d..1122294454d 100644
--- a/absl/time/internal/cctz/src/time_zone_format.cc
+++ b/absl/time/internal/cctz/src/time_zone_format.cc
@@ -553,7 +553,7 @@ std::string format(const std::string& format, const time_point<seconds>& tp,
       bp = Format64(ep, 4, al.cs.year());
       result.append(bp, ep);
       pending = cur += 2;
-    } else if (std::isdigit(*cur)) {
+    } else if (std::isdigit(static_cast<unsigned char>(*cur))) {
       // Possibly found %E#S or %E#f.
       int n = 0;
       if (const char* np = ParseInt(cur, 0, 0, 1024, &n)) {
@@ -620,7 +620,8 @@ const char* ParseOffset(const char* dp, const char* mode, int* offset) {
 const char* ParseZone(const char* dp, std::string* zone) {
   zone->clear();
   if (dp != nullptr) {
-    while (*dp != '\0' && !std::isspace(*dp)) zone->push_back(*dp++);
+    while (*dp != '\0' && !std::isspace(static_cast<unsigned char>(*dp)))
+      zone->push_back(*dp++);
     if (zone->empty()) dp = nullptr;
   }
   return dp;
@@ -706,7 +707,7 @@ bool parse(const std::string& format, const std::string& input,
   const char* const edata = data + input.size();
 
   // Skips leading whitespace.
-  while (std::isspace(*data)) ++data;
+  while (std::isspace(static_cast<unsigned char>(*data))) ++data;
 
   const year_t kyearmax = std::numeric_limits<year_t>::max();
   const year_t kyearmin = std::numeric_limits<year_t>::min();
@@ -744,9 +745,9 @@ bool parse(const std::string& format, const std::string& input,
 
   // Steps through format, one specifier at a time.
   while (data != nullptr && fmt != efmt) {
-    if (std::isspace(*fmt)) {
-      while (std::isspace(*data)) ++data;
-      while (std::isspace(*++fmt)) continue;
+    if (std::isspace(static_cast<unsigned char>(*fmt))) {
+      while (std::isspace(static_cast<unsigned char>(*data))) ++data;
+      while (std::isspace(static_cast<unsigned char>(*++fmt))) continue;
       continue;
     }
 
@@ -898,7 +899,8 @@ bool parse(const std::string& format, const std::string& input,
           continue;
         }
         if (fmt[0] == '*' && fmt[1] == 'f') {
-          if (data != nullptr && std::isdigit(*data)) {
+          if (data != nullptr &&
+              std::isdigit(static_cast<unsigned char>(*data))) {
             data = ParseSubSeconds(data, &subseconds);
           }
           fmt += 2;
@@ -917,7 +919,7 @@ bool parse(const std::string& format, const std::string& input,
           fmt += 2;
           continue;
         }
-        if (std::isdigit(*fmt)) {
+        if (std::isdigit(static_cast<unsigned char>(*fmt))) {
           int n = 0;  // value ignored
           if (const char* np = ParseInt(fmt, 0, 0, 1024, &n)) {
             if (*np == 'S') {
@@ -929,7 +931,8 @@ bool parse(const std::string& format, const std::string& input,
               continue;
             }
             if (*np == 'f') {
-              if (data != nullptr && std::isdigit(*data)) {
+              if (data != nullptr &&
+                  std::isdigit(static_cast<unsigned char>(*data))) {
                 data = ParseSubSeconds(data, &subseconds);
               }
               fmt = ++np;
@@ -977,7 +980,7 @@ bool parse(const std::string& format, const std::string& input,
   }
 
   // Skip any remaining whitespace.
-  while (std::isspace(*data)) ++data;
+  while (std::isspace(static_cast<unsigned char>(*data))) ++data;
 
   // parse() must consume the entire input string.
   if (data != edata) {