From 3cba9be8b71ffc76b6c3f6bdcdfc18ee06cc9e28 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adam=20Zieli=C5=84ski?= <adam@adamziel.com>
Date: Sat, 1 Nov 2025 23:08:45 +0100
Subject: [PATCH] Remove utf8_codepoint_at

---
 components/Encoding/composer.json    |   3 +-
 components/Encoding/utf8-decoder.php | 154 ---------------------------
 components/Encoding/utf8.php         |  28 +++++
 composer-ci-matrix-tests.json        |   1 -
 composer.json                        |   1 -
 5 files changed, 29 insertions(+), 158 deletions(-)
 delete mode 100644 components/Encoding/utf8-decoder.php

diff --git a/components/Encoding/composer.json b/components/Encoding/composer.json
index 187b7559..72058a5c 100644
--- a/components/Encoding/composer.json
+++ b/components/Encoding/composer.json
@@ -20,8 +20,7 @@
 		"files": [
 			"utf8.php",
 			"compat-utf8.php",
-			"utf8-encoder.php",
-			"utf8-decoder.php"
+			"utf8-encoder.php"
 		],
 		"exclude-from-classmap": [
 			"/Tests/"
diff --git a/components/Encoding/utf8-decoder.php b/components/Encoding/utf8-decoder.php
deleted file mode 100644
index ddcc4acc..00000000
--- a/components/Encoding/utf8-decoder.php
+++ /dev/null
@@ -1,154 +0,0 @@
-<?php
-
-namespace WordPress\Encoding;
-
-use function WordPress\Encoding\compat\_wp_scan_utf8;
-
-/*
- * UTF-8 decoding pipeline by Dennis Snell (@dmsnell), originally
- * proposed in https://github.com/WordPress/wordpress-develop/pull/6883.
- *
- * It enables parsing XML documents with incomplete UTF-8 byte sequences
- * without crashing or depending on the mbstring extension.
- */
-
-if ( ! defined( 'UTF8_DECODER_ACCEPT' ) ) {
-	define( 'UTF8_DECODER_ACCEPT', 0 );
-}
-
-if ( ! defined( 'UTF8_DECODER_REJECT' ) ) {
-	define( 'UTF8_DECODER_REJECT', 1 );
-}
-
-/**
- * Extract a unicode codepoint from a specific offset in text.
- * Invalid byte sequences count as a single code point, U+FFFD
- * (the Unicode replacement character ``).
- *
- * This function does not permit passing negative indices and will return
- * null if such are provided.
- *
- * @param  string $text  Input text from which to extract.
- * @param  int    $byte_offset  Start at this byte offset in the input text.
- * @param  int    $matched_bytes  How many bytes were matched to produce the codepoint.
- *
- * @return int Unicode codepoint.
- */
-function utf8_codepoint_at( string $text, int $byte_offset = 0, &$matched_bytes = 0 ) {
-	$position_in_input = $byte_offset;
-	$codepoint_at      = $byte_offset;
-	$end_byte          = strlen( $text );
-	$codepoint         = null;
-	$decoder_state     = UTF8_DECODER_ACCEPT;
-
-	// Get to the start of the string.
-	while ( $position_in_input < $end_byte ) {
-		$decoder_state = utf8_decoder_apply_byte( $text[ $position_in_input ], $decoder_state );
-
-		if ( UTF8_DECODER_ACCEPT === $decoder_state ) {
-			++$position_in_input;
-			$codepoint = utf8_ord( substr( $text, $codepoint_at, $position_in_input - $codepoint_at ) );
-			break;
-		} elseif ( UTF8_DECODER_REJECT === $decoder_state ) {
-			// "\u{FFFD}" is not supported in PHP 5.6.
-			$codepoint = utf8_ord( "\xEF\xBF\xBD" );
-			break;
-		} else {
-			++$position_in_input;
-		}
-	}
-
-	$matched_bytes = $position_in_input - $byte_offset;
-
-	return $codepoint;
-}
-
-/**
- * Convert a UTF-8 byte sequence to its Unicode codepoint.
- *
- * @param  string $character  UTF-8 encoded byte sequence representing a single Unicode character.
- *
- * @return int Unicode codepoint.
- */
-function utf8_ord( string $character ): int {
-	// Convert the byte sequence to its binary representation.
-	$bytes = unpack( 'C*', $character );
-
-	// Initialize the codepoint.
-	$codepoint = 0;
-
-	// Calculate the codepoint based on the number of bytes.
-	if ( 1 === count( $bytes ) ) {
-		$codepoint = $bytes[1];
-	} elseif ( 2 === count( $bytes ) ) {
-		$codepoint = ( ( $bytes[1] & 0x1F ) << 6 ) | ( $bytes[2] & 0x3F );
-	} elseif ( 3 === count( $bytes ) ) {
-		$codepoint = ( ( $bytes[1] & 0x0F ) << 12 ) | ( ( $bytes[2] & 0x3F ) << 6 ) | ( $bytes[3] & 0x3F );
-	} elseif ( 4 === count( $bytes ) ) {
-		$codepoint = ( ( $bytes[1] & 0x07 ) << 18 ) | ( ( $bytes[2] & 0x3F ) << 12 ) | ( ( $bytes[3] & 0x3F ) << 6 ) | ( $bytes[4] & 0x3F );
-	}
-
-	return $codepoint;
-}
-
-
-/**
- * Inner loop for a number of UTF-8 decoding-related functions.
- *
- * You probably don't need this! This is highly-specific and optimized
- * code for UTF-8 operations used in other functions.
- *
- * @see http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
- *
- * @since {WP_VERSION}
- *
- * @access private
- *
- * @param  string   $byte  Next byte to be applied in UTF-8 decoding or validation.
- * @param  int      $state  UTF-8 decoding state, one of the following values:<br><ul>
- *                                 <li>`UTF8_DECODER_ACCEPT`: Decoder is ready for a new code point.<br>
- *                                 <li>`UTF8_DECODER_REJECT`: An error has occurred.<br>
- *                                 Any other positive value: Decoder is waiting for additional bytes.
- * @param  int|null $codepoint  Optional. If provided, will accumulate the decoded code point as
- *                            each byte is processed. If not provided or unable to decode, will
- *                            not be set, or will be set to invalid and unusable data.
- *
- * @return int Next decoder state after processing the current byte.
- */
-function utf8_decoder_apply_byte( string $byte, int $state, int &$codepoint = 0 ): int {
-	/**
-	 * State classification and transition table for UTF-8 validation.
-	 *
-	 * > The first part of the table maps bytes to character classes that
-	 * > to reduce the size of the transition table and create bitmasks.
-	 * >
-	 * > The second part is a transition table that maps a combination
-	 * > of a state of the automaton and a character class to a state.
-	 *
-	 * @see http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
-	 */
-	static $state_table = (
-		"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" .
-		"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" .
-		"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" .
-		"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" .
-		"\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09\x09" .
-		"\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07\x07" .
-		"\x08\x08\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02\x02" .
-		"\x10\x03\x03\x03\x03\x03\x03\x03\x03\x03\x03\x03\x03\x04\x03\x03" .
-		"\x11\x06\x06\x06\x05\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08\x08" .
-		"\x00\x01\x02\x03\x05\x08\x07\x01\x01\x01\x04\x06\x01\x01\x01\x01" .
-		"\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x00\x01\x01\x01\x01\x01\x00\x01\x00\x01\x01\x01\x01\x01\x01" .
-		"\x01\x02\x01\x01\x01\x01\x01\x02\x01\x02\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x02\x01\x01\x01\x01\x01\x01\x01\x01" .
-		"\x01\x02\x01\x01\x01\x01\x01\x01\x01\x02\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x03\x01\x03\x01\x01\x01\x01\x01\x01" .
-		"\x01\x03\x01\x01\x01\x01\x01\x03\x01\x03\x01\x01\x01\x01\x01\x01\x01\x03\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01"
-	);
-
-	$byte      = ord( $byte );
-	$type      = ord( $state_table[ $byte ] );
-	$codepoint = ( UTF8_DECODER_ACCEPT === $state )
-		? ( ( 0xFF >> $type ) & $byte )
-		: ( ( $byte & 0x3F ) | ( $codepoint << 6 ) );
-
-	return ord( $state_table[ 256 + ( $state * 16 ) + $type ] );
-}
diff --git a/components/Encoding/utf8.php b/components/Encoding/utf8.php
index 0c74f7c1..2c266703 100644
--- a/components/Encoding/utf8.php
+++ b/components/Encoding/utf8.php
@@ -197,3 +197,31 @@ function wp_has_noncharacters( string $text ): bool {
 		return _wp_has_noncharacters_fallback( $text );
 	}
 endif;
+
+/**
+ * Convert a UTF-8 byte sequence to its Unicode codepoint.
+ *
+ * @param  string $character  UTF-8 encoded byte sequence representing a single Unicode character.
+ *
+ * @return int Unicode codepoint.
+ */
+function utf8_ord( string $character ): int {
+	// Convert the byte sequence to its binary representation.
+	$bytes = unpack( 'C*', $character );
+
+	// Initialize the codepoint.
+	$codepoint = 0;
+
+	// Calculate the codepoint based on the number of bytes.
+	if ( 1 === count( $bytes ) ) {
+		$codepoint = $bytes[1];
+	} elseif ( 2 === count( $bytes ) ) {
+		$codepoint = ( ( $bytes[1] & 0x1F ) << 6 ) | ( $bytes[2] & 0x3F );
+	} elseif ( 3 === count( $bytes ) ) {
+		$codepoint = ( ( $bytes[1] & 0x0F ) << 12 ) | ( ( $bytes[2] & 0x3F ) << 6 ) | ( $bytes[3] & 0x3F );
+	} elseif ( 4 === count( $bytes ) ) {
+		$codepoint = ( ( $bytes[1] & 0x07 ) << 18 ) | ( ( $bytes[2] & 0x3F ) << 12 ) | ( ( $bytes[3] & 0x3F ) << 6 ) | ( $bytes[4] & 0x3F );
+	}
+
+	return $codepoint;
+}
diff --git a/composer-ci-matrix-tests.json b/composer-ci-matrix-tests.json
index 948e04a0..de4747f7 100644
--- a/composer-ci-matrix-tests.json
+++ b/composer-ci-matrix-tests.json
@@ -51,7 +51,6 @@
 			"components/Encoding/utf8.php",
 			"components/Encoding/compat-utf8.php",
 			"components/Encoding/utf8-encoder.php",
-			"components/Encoding/utf8-decoder.php",
 			"components/Filesystem/functions.php",
 			"components/Zip/functions.php",
 			"components/Polyfill/wordpress.php",
diff --git a/composer.json b/composer.json
index 1423cfa3..6d52bb4b 100644
--- a/composer.json
+++ b/composer.json
@@ -63,7 +63,6 @@
 			"components/Encoding/utf8.php",
 			"components/Encoding/compat-utf8.php",
 			"components/Encoding/utf8-encoder.php",
-			"components/Encoding/utf8-decoder.php",
 			"components/Filesystem/functions.php",
 			"components/Zip/functions.php",
 			"components/Polyfill/wordpress.php",