From d304e529408c816ef6c22ddcd9cc2305dc89d449 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Poczkodi?= <gabest11@gmail.com>
Date: Mon, 25 Mar 2024 23:34:47 +0100
Subject: [PATCH] Don't compile strptime unless its required (#6424)

---
 esphome/core/time.cpp | 6 ++++++
 esphome/core/time.h   | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/esphome/core/time.cpp b/esphome/core/time.cpp
index 2e46a611e6..ae4fabac52 100644
--- a/esphome/core/time.cpp
+++ b/esphome/core/time.cpp
@@ -1,4 +1,6 @@
+#ifdef USE_DATETIME
 #include <regex>
+#endif
 
 #include "helpers.h"
 #include "time.h"  // NOLINT
@@ -64,6 +66,8 @@ std::string ESPTime::strftime(const std::string &format) {
   return timestr;
 }
 
+#ifdef USE_DATETIME
+
 bool ESPTime::strptime(const std::string &time_to_parse, ESPTime &esp_time) {
   // clang-format off
   std::regex dt_regex(R"(^
@@ -102,6 +106,8 @@ bool ESPTime::strptime(const std::string &time_to_parse, ESPTime &esp_time) {
   return true;
 }
 
+#endif
+
 void ESPTime::increment_second() {
   this->timestamp++;
   if (!increment_time_value(this->second, 0, 60))
diff --git a/esphome/core/time.h b/esphome/core/time.h
index 4300cf26b7..738a0261c7 100644
--- a/esphome/core/time.h
+++ b/esphome/core/time.h
@@ -67,6 +67,8 @@ struct ESPTime {
            this->day_of_year < 367 && this->month > 0 && this->month < 13;
   }
 
+#ifdef USE_DATETIME
+
   /** Convert a string to ESPTime struct as specified by the format argument.
    * @param time_to_parse null-terminated c string formatet like this: 2020-08-25 05:30:00.
    * @param esp_time an instance of a ESPTime struct
@@ -74,6 +76,8 @@ struct ESPTime {
    */
   static bool strptime(const std::string &time_to_parse, ESPTime &esp_time);
 
+#endif
+
   /// Convert a C tm struct instance with a C unix epoch timestamp to an ESPTime instance.
   static ESPTime from_c_tm(struct tm *c_tm, time_t c_time);