Allow numbers and capital letters in Audio Unit identifiers.

hi_backend/backend/CompileExporter.cpp

@@ -651,19 +651,17 @@ bool CompileExporter::checkSanity(BuildOption option)
 
     const String pluginCode = SettingWindows::getSettingValue((int)SettingWindows::ProjectSettingWindow::Attributes::PluginCode, handler);
 
-    const String codeWildcard = "[A-Z][a-z][a-z][a-z]";
-
-    if(!RegexFunctions::matchesWildcard(codeWildcard, pluginCode))
+    if(!AudioUnitCodeValidator::isValidSubtype(pluginCode))
     {
-        printErrorMessage("Illegal Project code", "The Plugin Code must have this structure: 'Abcd'");
+        printErrorMessage("Illegal Project code", "The Plugin Code must match [a-zA-Z0-9-_]{4}");
         return false;
     }
 
     const String companyCode = SettingWindows::getSettingValue((int)SettingWindows::UserSettingWindow::Attributes::CompanyCode, handler);
-    
-    if(!RegexFunctions::matchesWildcard(codeWildcard, companyCode))
+
+    if(!AudioUnitCodeValidator::isValidManufacturer(companyCode))
     {
-        printErrorMessage("Illegal Company code", "The Company Code must have this structure: 'Abcd'");
+        printErrorMessage("Illegal Company code", "The Company Code must match [a-zA-Z0-9-_]{4} with at least one upper case letter");
         return false;
     }
 

hi_core/hi_core/SettingsWindows.cpp

@@ -296,12 +296,11 @@ String SettingWindows::ProjectSettingWindow::sanityCheck(const XmlElement& xmlSe
 			   "This is required for the user presets to detect whether it should ask for updating the presets after a version bump.";
 	};
 
-	const String pluginCode = GET_VALUE_FROM_XML(ProjectSettingWindow::Attributes::PluginCode);
-	const String codeWildcard = "[A-Z][a-z][a-z][a-z]";
+	const String pluginCode = GET_VALUE_FROM_XML(ProjectSettingWindow::Attributes::PluginCode);
 
-	if (!RegexFunctions::matchesWildcard(codeWildcard, pluginCode))
+	if (!AudioUnitCodeValidator::isValidSubtype(pluginCode))
 	{
-		return "The plugin code doesn't match the required formula. Use something like 'Abcd'\n" \
+		return "The plugin code must contain only upper- or lower-case letters from a-z, numbers from 0-9, and - or _.\n" \
 			   "This is required for exported AU plugins to pass the AU validation.";
 	};
 

hi_core/hi_core/UtilityClasses.cpp

@@ -566,7 +566,34 @@ bool RegexFunctions::matchesWildcard(const String &wildcard, const String &strin
 		return false;
 	}
 #endif
-}
+}
+
+/**
+    Apple's documentation
+    (https://developer.apple.com/library/content/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/AudioUnitDevelopmentFundamentals/AudioUnitDevelopmentFundamentals.html#//apple_ref/doc/uid/TP40003278-CH7-SW1)
+    states that we "are free to use any subtype code, including subtypes named with only lowercase letters" and
+    "Manufacturer codes must contain at least one uppercase character."
+
+    This is evidenced by many large vendors' plugins:
+    - Native Instruments uses "-NI-" as their manufacturer code,
+    using numbers in subtype codes (i.e.: Maschine 2 is "NiM2")
+    - TAL Software's TAL Filter 2 uses "025e" as its subtype code
+    - Waves uses "ksWV" as their manufacturer code
+    - iZotope uses "iZtp" as their manufacturer code
+
+    To satisfy these requirements as simply as possible, these methods check that:
+    - all characters are within [a-zA-Z0-9_-]
+    - for manufacturer codes, at least one character is an upper case letter.
+*/
+bool AudioUnitCodeValidator::isValidSubtype(const String &fourCC)
+{
+    return fourCC.length() == 4 && fourCC.containsOnly("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_-");
+}
+
+bool AudioUnitCodeValidator::isValidManufacturer(const String &fourCC)
+{
+    return AudioUnitCodeValidator::isValidSubtype(fourCC) && fourCC.containsAnyOf("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
+}
 
 ScopedNoDenormals::ScopedNoDenormals()
 {

hi_core/hi_core/UtilityClasses.h

@@ -56,7 +56,17 @@ class RegexFunctions
     static bool matchesWildcard(const String &wildcard, const String &stringToTest, const Processor* /*processorForErrorOutput*/=nullptr);
 
 };
-
+
+/** A Helper class for validating Audio Unit codes */
+class AudioUnitCodeValidator
+{
+public:
+    /** Checks if the given string is a valid Apple AU subtype code. */
+    static bool isValidSubtype(const String &fourCC);
+
+    /** Checks if the given string is a valid Apple AU manufacturer code. */
+    static bool isValidManufacturer(const String &fourCC);
+};
 
 /** A small helper class that uses RAII for enabling flush to zero mode. */
 class ScopedNoDenormals