Simplify PROGMEM variant to strncasecmp_P and compile it only on ESP8266

esphome/components/audio/audio.cpp

@@ -1,6 +1,7 @@
 #include "audio.h"
 
 #include "esphome/core/helpers.h"
+#include "esphome/core/progmem.h"
 
 #include <cstring>
 
@@ -86,7 +87,8 @@ AudioFileType detect_audio_file_type(const char *content_type, const char *url)
     // Match "audio/ogg" with a codecs parameter containing "opus"
     // Valid forms: audio/ogg;codecs=opus, audio/ogg; codecs="opus", etc.
     // Plain "audio/ogg" without opus is not matched (almost always Ogg Vorbis)
-    if (strncasecmp(content_type, "audio/ogg", 9) == 0 && str_contains_ignore_case(content_type + 9, "opus")) {
+    if (strncasecmp(content_type, "audio/ogg", 9) == 0 &&
+        str_contains_ignore_case_p(content_type + 9, ESPHOME_PSTR("opus"))) {
       return AudioFileType::OPUS;
     }
 #endif

esphome/core/helpers.cpp

@@ -233,27 +233,23 @@ bool str_contains_ignore_case_fallback(const char *haystack, const char *needle)
   return false;
 }
 
-bool str_contains_ignore_case_p(const char *haystack, const char *needle) {
+#ifdef USE_ESP8266
+bool str_contains_ignore_case_p(const char *haystack, PGM_P needle) {
   if (haystack == nullptr || needle == nullptr) {
     return false;
   }
-  const auto *needle_p = reinterpret_cast<const uint8_t *>(needle);
-  if (progmem_read_byte(needle_p) == '\0') {
+  const size_t needle_len = strlen_P(needle);
+  if (needle_len == 0) {
     return true;
   }
   for (const char *p = haystack; *p != '\0'; p++) {
-    size_t i = 0;
-    uint8_t n;
-    // Never reads past the haystack terminator: comparing '\0' against a non-'\0' needle byte fails
-    while ((n = progmem_read_byte(needle_p + i)) != '\0' && ::tolower(static_cast<uint8_t>(p[i])) == ::tolower(n)) {
-      i++;
-    }
-    if (n == '\0') {
+    if (strncasecmp_P(p, needle, needle_len) == 0) {
       return true;
     }
   }
   return false;
 }
+#endif  // USE_ESP8266
 
 // str_truncate, str_until, str_lower_case, str_upper_case, str_snake_case moved to alloc_helpers.cpp
 char *str_sanitize_to(char *buffer, size_t buffer_size, const char *str) {

esphome/core/helpers.h

@@ -984,13 +984,10 @@ inline bool str_endswith_ignore_case(const std::string &str, const char *suffix)
 /// Fallback implementation for case insensitive substring comparison.
 bool str_contains_ignore_case_fallback(const char *haystack, const char *needle);
 
-/// Case-insensitive check if needle string is contained in haystack (no heap allocation).
-/// ESP8266 internal implementation — prefer the `str_contains_ignore_case` macro which wraps
-/// needle literals with `PSTR()` automatically so they stay in flash instead of eating RAM.
-/// The needle must be a PROGMEM pointer on ESP8266; reads are plain dereferences elsewhere.
-bool str_contains_ignore_case_p(const char *haystack, const char *needle);
-
 #ifdef USE_ESP8266
+/// ESP8266 internal implementation reading the needle from flash — prefer the
+/// `str_contains_ignore_case` macro which wraps needle literals with PSTR() automatically.
+bool str_contains_ignore_case_p(const char *haystack, PGM_P needle);
 /// Case-insensitive check if needle string is contained in haystack (no heap allocation).
 /// On ESP8266 the needle literal is wrapped with PSTR() so it stays in flash.
 #define str_contains_ignore_case(haystack, needle) str_contains_ignore_case_p(haystack, PSTR(needle))
@@ -1010,6 +1007,10 @@ inline bool str_contains_ignore_case(const char *haystack, const char *needle) {
   return strcasestr(haystack, needle) != nullptr;
 #endif  // defined(USE_LIBRETINY) || defined(USE_RP2) || defined(USE_ZEPHYR)
 }
+/// PROGMEM is a no-op on this platform, so the flash-needle variant is the plain check.
+inline bool str_contains_ignore_case_p(const char *haystack, const char *needle) {
+  return str_contains_ignore_case(haystack, needle);
+}
 #endif  // USE_ESP8266
 
 // str_truncate moved to alloc_helpers.h - remove this include before 2026.11.0

tests/components/core/helpers_test.cpp

@@ -90,6 +90,10 @@ TEST(StringContainsIgnoreCaseTest, NullPointerAlwaysFalse) {
   EXPECT_FALSE(str_contains_ignore_case(haystack, needle));
   EXPECT_FALSE(str_contains_ignore_case("Hello World", needle));
   EXPECT_FALSE(str_contains_ignore_case(haystack, "anything"));
+
+  EXPECT_FALSE(str_contains_ignore_case_p(haystack, needle));
+  EXPECT_FALSE(str_contains_ignore_case_p("Hello World", needle));
+  EXPECT_FALSE(str_contains_ignore_case_p(haystack, "anything"));
 }
 
 TEST(StringContainsIgnoreCaseTest, EmptySearchMatches) {
@@ -121,29 +125,14 @@ TEST(StringContainsIgnoreCaseTest, MiscNotMatching) {
 
 TEST(StringContainsIgnoreCaseTest, FallbackMatchesLibc) {
   const char *haystack = "Hello World";
-  for (const char *needle : {"", "Hello", "hELLO", "Hell", "world", "Heaven", "Hello!", "d"}) {
+  for (const char *needle : {"", "Hello", "hELLO", "HELLO", "Hell", "world", "World", "Heaven", "Hello!", "d"}) {
     EXPECT_EQ(str_contains_ignore_case_fallback(haystack, needle), str_contains_ignore_case(haystack, needle))
         << "needle: " << needle;
+    EXPECT_EQ(str_contains_ignore_case_p(haystack, needle), str_contains_ignore_case(haystack, needle))
+        << "needle: " << needle;
   }
   EXPECT_EQ(str_contains_ignore_case_fallback("", ""), str_contains_ignore_case("", ""));
   EXPECT_EQ(str_contains_ignore_case_fallback("ab", "abc"), str_contains_ignore_case("ab", "abc"));
-}
-
-TEST(StringContainsIgnoreCaseTest, ProgmemVariantNullPointerAlwaysFalse) {
-  const char *haystack = nullptr;
-  const char *needle = nullptr;
-
-  EXPECT_FALSE(str_contains_ignore_case_p(haystack, needle));
-  EXPECT_FALSE(str_contains_ignore_case_p("Hello World", needle));
-  EXPECT_FALSE(str_contains_ignore_case_p(haystack, "anything"));
-}
-
-TEST(StringContainsIgnoreCaseTest, ProgmemVariantMatchesFallback) {
-  const char *haystack = "Hello World";
-  for (const char *needle : {"", "Hello", "hELLO", "HELLO", "Hell", "world", "World", "Heaven", "Hello!", "d"}) {
-    EXPECT_EQ(str_contains_ignore_case_p(haystack, needle), str_contains_ignore_case_fallback(haystack, needle))
-        << "needle: " << needle;
-  }
   EXPECT_TRUE(str_contains_ignore_case_p("", ""));
   EXPECT_FALSE(str_contains_ignore_case_p("", "a"));
   EXPECT_FALSE(str_contains_ignore_case_p("ab", "abc"));