Add HTML5/UTF-8 spec-compliant text decoder.

ext/standard/basic_functions.c

@@ -305,6 +305,7 @@ PHP_MINIT_FUNCTION(basic) /* {{{ */
 
  assertion_error_ce = register_class_AssertionError(zend_ce_error);
 
+ html_context_ce = register_class_HtmlContext();
  rounding_mode_ce = register_class_RoundingMode();
 
  BASIC_MINIT_SUBMODULE(var)

ext/standard/basic_functions.stub.php

@@ -541,6 +541,14 @@
 */
 const ENT_HTML5 = UNKNOWN;
 
+enum HtmlContext {
+ case Attribute;
+ case BodyText;
+ case ForeignText;
+ case Script;
+ case Style;
+}
+
 /* image.c */
 
 /**
@@ -2264,6 +2272,11 @@ function htmlspecialchars(string $string, int $flags = ENT_QUOTES | ENT_SUBSTITU
 
 function htmlspecialchars_decode(string $string, int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401): string {}
 
+function decode_html(HtmlContext $context, string $html, int $offset = 0, ?int $length = null): ?string {}
+
+/** @param int $matched_byte_length */
+function decode_html_ref(HtmlContext $context, string $html, int $offset = 0, &$matched_byte_length = null): ?string {}
+
 function html_entity_decode(string $string, int $flags = ENT_QUOTES | ENT_SUBSTITUTE | ENT_HTML401, ?string $encoding = null): string {}
 
 /** @refcount 1 */