Priority File Manager

Base Directory:

/home/ecedu/public_html/wp-includes

Name	Type	Size	Actions
📁 ..	Folder	-
📁 ID3	Folder	-
📁 IXR	Folder	-
📁 PHPMailer	Folder	-
📁 Requests	Folder	-
📁 SimplePie	Folder	-
📁 Text	Folder	-
📄 admin-bar.php	File	37106	Edit Download
📁 assets	Folder	-
📄 atomlib.php	File	12078	Edit Download
📄 author-template.php	File	18951	Edit Download
📁 block-bindings	Folder	-
📄 block-bindings.php	File	5594	Edit Download
📄 block-editor.php	File	28797	Edit Download
📄 block-i18n.json	File	316	Edit Download
📁 block-patterns	Folder	-
📄 block-patterns.php	File	13213	Edit Download
📁 block-supports	Folder	-
📄 block-template-utils.php	File	61907	Edit Download
📄 block-template.php	File	15356	Edit Download
📁 blocks	Folder	-
📄 blocks.php	File	113051	Edit Download
📄 bookmark-template.php	File	12768	Edit Download
📄 bookmark.php	File	15427	Edit Download
📄 cache-compat.php	File	5969	Edit Download
📄 cache.php	File	13474	Edit Download
📄 canonical.php	File	34523	Edit Download
📄 capabilities.php	File	42718	Edit Download
📄 category-template.php	File	57003	Edit Download
📄 category.php	File	12829	Edit Download
📁 certificates	Folder	-
📄 class-IXR.php	File	2616	Edit Download
📄 class-avif-info.php	File	29615	Edit Download
📄 class-feed.php	File	539	Edit Download
📄 class-http.php	File	367	Edit Download
📄 class-json.php	File	43684	Edit Download
📄 class-oembed.php	File	401	Edit Download
📄 class-phpass.php	File	6771	Edit Download
📄 class-phpmailer.php	File	664	Edit Download
📄 class-pop3.php	File	21121	Edit Download
📄 class-requests.php	File	2237	Edit Download
📄 class-simplepie.php	File	453	Edit Download
📄 class-smtp.php	File	457	Edit Download
📄 class-snoopy.php	File	37715	Edit Download
📄 class-walker-category-dropdown.php	File	2469	Edit Download
📄 class-walker-category.php	File	8477	Edit Download
📄 class-walker-comment.php	File	14221	Edit Download
📄 class-walker-nav-menu.php	File	12044	Edit Download
📄 class-walker-page-dropdown.php	File	2710	Edit Download
📄 class-walker-page.php	File	7612	Edit Download
📄 class-wp-admin-bar.php	File	17874	Edit Download
📄 class-wp-ajax-response.php	File	5266	Edit Download
📄 class-wp-application-passwords.php	File	17099	Edit Download
📄 class-wp-block-bindings-registry.php	File	8463	Edit Download
📄 class-wp-block-bindings-source.php	File	2992	Edit Download
📄 class-wp-block-editor-context.php	File	1350	Edit Download
📄 class-wp-block-list.php	File	4757	Edit Download
📄 class-wp-block-metadata-registry.php	File	11895	Edit Download
📄 class-wp-block-parser-block.php	File	2555	Edit Download
📄 class-wp-block-parser-frame.php	File	2017	Edit Download
📄 class-wp-block-parser.php	File	11532	Edit Download
📄 class-wp-block-pattern-categories-registry.php	File	5371	Edit Download
📄 class-wp-block-patterns-registry.php	File	10783	Edit Download
📄 class-wp-block-styles-registry.php	File	6403	Edit Download
📄 class-wp-block-supports.php	File	5626	Edit Download
📄 class-wp-block-template.php	File	2033	Edit Download
📄 class-wp-block-templates-registry.php	File	7231	Edit Download
📄 class-wp-block-type-registry.php	File	5013	Edit Download
📄 class-wp-block-type.php	File	17265	Edit Download
📄 class-wp-block.php	File	23041	Edit Download
📄 class-wp-classic-to-block-menu-converter.php	File	4088	Edit Download
📄 class-wp-comment-query.php	File	48395	Edit Download
📄 class-wp-comment.php	File	9437	Edit Download
📄 class-wp-customize-control.php	File	25851	Edit Download
📄 class-wp-customize-manager.php	File	202593	Edit Download
📄 class-wp-customize-nav-menus.php	File	57660	Edit Download
📄 class-wp-customize-panel.php	File	10710	Edit Download
📄 class-wp-customize-section.php	File	11209	Edit Download
📄 class-wp-customize-setting.php	File	29962	Edit Download
📄 class-wp-customize-widgets.php	File	72210	Edit Download
📄 class-wp-date-query.php	File	35732	Edit Download
📄 class-wp-dependencies.php	File	15139	Edit Download
📄 class-wp-dependency.php	File	2627	Edit Download
📄 class-wp-duotone.php	File	40783	Edit Download
📄 class-wp-editor.php	File	72335	Edit Download
📄 class-wp-embed.php	File	15931	Edit Download
📄 class-wp-error.php	File	7502	Edit Download
📄 class-wp-exception.php	File	253	Edit Download
📄 class-wp-fatal-error-handler.php	File	8150	Edit Download
📄 class-wp-feed-cache-transient.php	File	3176	Edit Download
📄 class-wp-feed-cache.php	File	969	Edit Download
📄 class-wp-hook.php	File	16000	Edit Download
📄 class-wp-http-cookie.php	File	7389	Edit Download
📄 class-wp-http-curl.php	File	12541	Edit Download
📄 class-wp-http-encoding.php	File	6689	Edit Download
📄 class-wp-http-ixr-client.php	File	3501	Edit Download
📄 class-wp-http-proxy.php	File	5980	Edit Download
📄 class-wp-http-requests-hooks.php	File	2022	Edit Download
📄 class-wp-http-requests-response.php	File	4400	Edit Download
📄 class-wp-http-response.php	File	2977	Edit Download
📄 class-wp-http-streams.php	File	16859	Edit Download
📄 class-wp-http.php	File	41579	Edit Download
📄 class-wp-image-editor-gd.php	File	20162	Edit Download
📄 class-wp-image-editor-imagick.php	File	34735	Edit Download
📄 class-wp-image-editor.php	File	17527	Edit Download
📄 class-wp-list-util.php	File	7443	Edit Download
📄 class-wp-locale-switcher.php	File	6776	Edit Download
📄 class-wp-locale.php	File	16883	Edit Download
📄 class-wp-matchesmapregex.php	File	1828	Edit Download
📄 class-wp-meta-query.php	File	30531	Edit Download
📄 class-wp-metadata-lazyloader.php	File	6833	Edit Download
📄 class-wp-navigation-fallback.php	File	9211	Edit Download
📄 class-wp-network-query.php	File	19857	Edit Download
📄 class-wp-network.php	File	12296	Edit Download
📄 class-wp-object-cache.php	File	17524	Edit Download
📄 class-wp-oembed-controller.php	File	6905	Edit Download
📄 class-wp-oembed.php	File	31606	Edit Download
📄 class-wp-paused-extensions-storage.php	File	5111	Edit Download
📄 class-wp-phpmailer.php	File	3802	Edit Download
📄 class-wp-plugin-dependencies.php	File	25315	Edit Download
📄 class-wp-post-type.php	File	30680	Edit Download
📄 class-wp-post.php	File	6488	Edit Download
📄 class-wp-query.php	File	158023	Edit Download
📄 class-wp-recovery-mode-cookie-service.php	File	6877	Edit Download
📄 class-wp-recovery-mode-email-service.php	File	11183	Edit Download
📄 class-wp-recovery-mode-key-service.php	File	4884	Edit Download
📄 class-wp-recovery-mode-link-service.php	File	3463	Edit Download
📄 class-wp-recovery-mode.php	File	11453	Edit Download
📄 class-wp-rewrite.php	File	63688	Edit Download
📄 class-wp-role.php	File	2523	Edit Download
📄 class-wp-roles.php	File	8586	Edit Download
📄 class-wp-script-modules.php	File	19463	Edit Download
📄 class-wp-scripts.php	File	28344	Edit Download
📄 class-wp-session-tokens.php	File	7319	Edit Download
📄 class-wp-simplepie-file.php	File	3408	Edit Download
📄 class-wp-simplepie-sanitize-kses.php	File	1910	Edit Download
📄 class-wp-site-query.php	File	31625	Edit Download
📄 class-wp-site.php	File	7454	Edit Download
📄 class-wp-speculation-rules.php	File	7527	Edit Download
📄 class-wp-styles.php	File	11010	Edit Download
📄 class-wp-tax-query.php	File	19555	Edit Download
📄 class-wp-taxonomy.php	File	18559	Edit Download
📄 class-wp-term-query.php	File	40869	Edit Download
📄 class-wp-term.php	File	5298	Edit Download
📄 class-wp-text-diff-renderer-inline.php	File	979	Edit Download
📄 class-wp-text-diff-renderer-table.php	File	18880	Edit Download
📄 class-wp-textdomain-registry.php	File	10481	Edit Download
📄 class-wp-theme-json-data.php	File	1809	Edit Download
📄 class-wp-theme-json-resolver.php	File	35738	Edit Download
📄 class-wp-theme-json-schema.php	File	7367	Edit Download
📄 class-wp-theme-json.php	File	163545	Edit Download
📄 class-wp-theme.php	File	65810	Edit Download
📄 class-wp-token-map.php	File	28618	Edit Download
📄 class-wp-url-pattern-prefixer.php	File	4802	Edit Download
📄 class-wp-user-meta-session-tokens.php	File	2990	Edit Download
📄 class-wp-user-query.php	File	43655	Edit Download
📄 class-wp-user-request.php	File	2305	Edit Download
📄 class-wp-user.php	File	22994	Edit Download
📄 class-wp-walker.php	File	13322	Edit Download
📄 class-wp-widget-factory.php	File	3347	Edit Download
📄 class-wp-widget.php	File	18429	Edit Download
📄 class-wp-xmlrpc-server.php	File	215444	Edit Download
📄 class-wp.php	File	26318	Edit Download
📄 class-wpdb.php	File	118284	Edit Download
📄 class.wp-dependencies.php	File	373	Edit Download
📄 class.wp-scripts.php	File	343	Edit Download
📄 class.wp-styles.php	File	338	Edit Download
📄 comment-template.php	File	103104	Edit Download
📄 comment.php	File	131547	Edit Download
📄 compat.php	File	16376	Edit Download
📄 cron.php	File	42658	Edit Download
📁 css	Folder	-
📁 customize	Folder	-
📄 date.php	File	400	Edit Download
📄 default-constants.php	File	11365	Edit Download
📄 default-filters.php	File	36697	Edit Download
📄 default-widgets.php	File	2295	Edit Download
📄 deprecated.php	File	191563	Edit Download
📄 embed-template.php	File	338	Edit Download
📄 embed.php	File	38172	Edit Download
📄 error-protection.php	File	4121	Edit Download
📄 feed-atom-comments.php	File	5504	Edit Download
📄 feed-atom.php	File	3121	Edit Download
📄 feed-rdf.php	File	2668	Edit Download
📄 feed-rss.php	File	1189	Edit Download
📄 feed-rss2-comments.php	File	4136	Edit Download
📄 feed-rss2.php	File	3799	Edit Download
📄 feed.php	File	23411	Edit Download
📁 fonts	Folder	-
📄 fonts.php	File	9751	Edit Download
📄 formatting.php	File	342921	Edit Download
📄 functions.php	File	287546	Edit Download
📄 functions.wp-scripts.php	File	14558	Edit Download
📄 functions.wp-styles.php	File	8583	Edit Download
📄 general-template.php	File	172498	Edit Download
📄 global-styles-and-settings.php	File	21261	Edit Download
📁 html-api	Folder	-
📄 http.php	File	25312	Edit Download
📄 https-detection.php	File	5857	Edit Download
📄 https-migration.php	File	4741	Edit Download
📁 images	Folder	-
📁 interactivity-api	Folder	-
📁 js	Folder	-
📄 kses.php	File	74472	Edit Download
📁 l10n	Folder	-
📄 l10n.php	File	68530	Edit Download
📄 link-template.php	File	157801	Edit Download
📄 load.php	File	56440	Edit Download
📄 locale.php	File	162	Edit Download
📄 media-template.php	File	63060	Edit Download
📄 media.php	File	220496	Edit Download
📄 meta.php	File	65243	Edit Download
📄 ms-blogs.php	File	25845	Edit Download
📄 ms-default-constants.php	File	4921	Edit Download
📄 ms-default-filters.php	File	6636	Edit Download
📄 ms-deprecated.php	File	21759	Edit Download
📄 ms-files.php	File	2744	Edit Download
📄 ms-functions.php	File	91582	Edit Download
📄 ms-load.php	File	19883	Edit Download
📄 ms-network.php	File	3782	Edit Download
📄 ms-settings.php	File	4197	Edit Download
📄 ms-site.php	File	41320	Edit Download
📄 nav-menu-template.php	File	25990	Edit Download
📄 nav-menu.php	File	44373	Edit Download
📄 option.php	File	103065	Edit Download
📁 php-compat	Folder	-
📄 pluggable-deprecated.php	File	6324	Edit Download
📄 pluggable.php	File	122700	Edit Download
📄 plugin.php	File	35465	Edit Download
📁 pomo	Folder	-
📄 post-formats.php	File	7102	Edit Download
📄 post-template.php	File	68648	Edit Download
📄 post-thumbnail-template.php	File	10879	Edit Download
📄 post.php	File	291712	Edit Download
📄 query.php	File	37035	Edit Download
📄 registration-functions.php	File	200	Edit Download
📄 registration.php	File	200	Edit Download
📁 rest-api	Folder	-
📄 rest-api.php	File	100257	Edit Download
📄 revision.php	File	30741	Edit Download
📄 rewrite.php	File	19541	Edit Download
📄 robots-template.php	File	5185	Edit Download
📄 rss-functions.php	File	255	Edit Download
📄 rss.php	File	23113	Edit Download
📄 script-loader.php	File	133262	Edit Download
📄 script-modules.php	File	7712	Edit Download
📄 session.php	File	258	Edit Download
📄 shortcodes.php	File	24051	Edit Download
📁 sitemaps	Folder	-
📄 sitemaps.php	File	3238	Edit Download
📁 sodium_compat	Folder	-
📄 speculative-loading.php	File	8558	Edit Download
📄 spl-autoload-compat.php	File	441	Edit Download
📁 style-engine	Folder	-
📄 style-engine.php	File	7563	Edit Download
📄 taxonomy.php	File	176227	Edit Download
📄 template-canvas.php	File	544	Edit Download
📄 template-loader.php	File	3012	Edit Download
📄 template.php	File	24154	Edit Download
📁 theme-compat	Folder	-
📄 theme-i18n.json	File	1526	Edit Download
📄 theme-previews.php	File	2832	Edit Download
📄 theme-templates.php	File	6238	Edit Download
📄 theme.json	File	8704	Edit Download
📄 theme.php	File	134303	Edit Download
📄 update.php	File	37503	Edit Download
📄 user.php	File	175823	Edit Download
📄 vars.php	File	6562	Edit Download
📄 version.php	File	1090	Edit Download
📁 widgets	Folder	-
📄 widgets.php	File	70719	Edit Download
📄 wp-db.php	File	445	Edit Download
📄 wp-diff.php	File	799	Edit Download

📝 Editing: class-avif-info.php Size: 29,615 bytes Lines: 782 Type: .php

<?php
/**
 * Copyright (c) 2021, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 *
 * Note: this class is from libavifinfo - https://aomedia.googlesource.com/libavifinfo/+/refs/heads/main/avifinfo.php at f509487.
 * It is used as a fallback to parse AVIF files when the server doesn't support AVIF,
 * primarily to identify the width and height of the image.
 *
 * Note PHP 8.2 added native support for AVIF, so this class can be removed when WordPress requires PHP 8.2.
 */

namespace Avifinfo;

const FOUND     = 0; // Input correctly parsed and information retrieved.
const NOT_FOUND = 1; // Input correctly parsed but information is missing or elsewhere.
const TRUNCATED = 2; // Input correctly parsed until missing bytes to continue.
const ABORTED   = 3; // Input correctly parsed until stopped to avoid timeout or crash.
const INVALID   = 4; // Input incorrectly parsed.

const MAX_SIZE      = 4294967295; // Unlikely to be insufficient to parse AVIF headers.
const MAX_NUM_BOXES = 4096;       // Be reasonable. Avoid timeouts and out-of-memory.
const MAX_VALUE     = 255;
const MAX_TILES     = 16;
const MAX_PROPS     = 32;
const MAX_FEATURES  = 8;
const UNDEFINED     = 0;          // Value was not yet parsed.

/**
 * Reads an unsigned integer with most significant bits first.
 *
 * @param binary string $input     Must be at least $num_bytes-long.
 * @param int           $num_bytes Number of parsed bytes.
 * @return int                     Value.
 */
function read_big_endian( $input, $num_bytes ) {
  if ( $num_bytes == 1 ) {
    return unpack( 'C', $input ) [1];
  } else if ( $num_bytes == 2 ) {
    return unpack( 'n', $input ) [1];
  } else if ( $num_bytes == 3 ) {
    $bytes = unpack( 'C3', $input );
    return ( $bytes[1] << 16 ) | ( $bytes[2] << 8 ) | $bytes[3];
  } else { // $num_bytes is 4
    // This might fail to read unsigned values >= 2^31 on 32-bit systems.
    // See https://www.php.net/manual/en/function.unpack.php#106041
    return unpack( 'N', $input ) [1];
  }
}

/**
 * Reads bytes and advances the stream position by the same count.
 *
 * @param stream               $handle    Bytes will be read from this resource.
 * @param int                  $num_bytes Number of bytes read. Must be greater than 0.
 * @return binary string|false            The raw bytes or false on failure.
 */
function read( $handle, $num_bytes ) {
  $data = fread( $handle, $num_bytes );
  return ( $data !== false && strlen( $data ) >= $num_bytes ) ? $data : false;
}

/**
 * Advances the stream position by the given offset.
 *
 * @param stream $handle    Bytes will be skipped from this resource.
 * @param int    $num_bytes Number of skipped bytes. Can be 0.
 * @return bool             True on success or false on failure.
 */
// Skips 'num_bytes' from the 'stream'. 'num_bytes' can be zero.
function skip( $handle, $num_bytes ) {
  return ( fseek( $handle, $num_bytes, SEEK_CUR ) == 0 );
}

//------------------------------------------------------------------------------
// Features are parsed into temporary property associations.

class Tile { // Tile item id <-> parent item id associations.
  public $tile_item_id;
  public $parent_item_id;
}

class Prop { // Property index <-> item id associations.
  public $property_index;
  public $item_id;
}

class Dim_Prop { // Property <-> features associations.
  public $property_index;
  public $width;
  public $height;
}

class Chan_Prop { // Property <-> features associations.
  public $property_index;
  public $bit_depth;
  public $num_channels;
}

class Features {
  public $has_primary_item = false; // True if "pitm" was parsed.
  public $has_alpha = false; // True if an alpha "auxC" was parsed.
  public $primary_item_id;
  public $primary_item_features = array( // Deduced from the data below.
    'width'        => UNDEFINED, // In number of pixels.
    'height'       => UNDEFINED, // Ignores mirror and rotation.
    'bit_depth'    => UNDEFINED, // Likely 8, 10 or 12 bits per channel per pixel.
    'num_channels' => UNDEFINED  // Likely 1, 2, 3 or 4 channels:
                                          //   (1 monochrome or 3 colors) + (0 or 1 alpha)
  );

public $tiles = array(); // Tile[]
  public $props = array(); // Prop[]
  public $dim_props = array(); // Dim_Prop[]
  public $chan_props = array(); // Chan_Prop[]

/**
   * Binds the width, height, bit depth and number of channels from stored internal features.
   *
   * @param int     $target_item_id Id of the item whose features will be bound.
   * @param int     $tile_depth     Maximum recursion to search within tile-parent relations.
   * @return Status                 FOUND on success or NOT_FOUND on failure.
   */
  private function get_item_features( $target_item_id, $tile_depth ) {
    foreach ( $this->props as $prop ) {
      if ( $prop->item_id != $target_item_id ) {
        continue;
      }

// Retrieve the width and height of the primary item if not already done.
      if ( $target_item_id == $this->primary_item_id &&
           ( $this->primary_item_features['width'] == UNDEFINED ||
             $this->primary_item_features['height'] == UNDEFINED ) ) {
        foreach ( $this->dim_props as $dim_prop ) {
          if ( $dim_prop->property_index != $prop->property_index ) {
            continue;
          }
          $this->primary_item_features['width']  = $dim_prop->width;
          $this->primary_item_features['height'] = $dim_prop->height;
          if ( $this->primary_item_features['bit_depth'] != UNDEFINED &&
               $this->primary_item_features['num_channels'] != UNDEFINED ) {
            return FOUND;
          }
          break;
        }
      }
      // Retrieve the bit depth and number of channels of the target item if not
      // already done.
      if ( $this->primary_item_features['bit_depth'] == UNDEFINED ||
           $this->primary_item_features['num_channels'] == UNDEFINED ) {
        foreach ( $this->chan_props as $chan_prop ) {
          if ( $chan_prop->property_index != $prop->property_index ) {
            continue;
          }
          $this->primary_item_features['bit_depth']    = $chan_prop->bit_depth;
          $this->primary_item_features['num_channels'] = $chan_prop->num_channels;
          if ( $this->primary_item_features['width'] != UNDEFINED &&
              $this->primary_item_features['height'] != UNDEFINED ) {
            return FOUND;
          }
          break;
        }
      }
    }

// Check for the bit_depth and num_channels in a tile if not yet found.
    if ( $tile_depth < 3 ) {
      foreach ( $this->tiles as $tile ) {
        if ( $tile->parent_item_id != $target_item_id ) {
          continue;
        }
        $status = $this->get_item_features( $tile->tile_item_id, $tile_depth + 1 );
        if ( $status != NOT_FOUND ) {
          return $status;
        }
      }
    }
    return NOT_FOUND;
  }

/**
   * Finds the width, height, bit depth and number of channels of the primary item.
   *
   * @return Status FOUND on success or NOT_FOUND on failure.
   */
  public function get_primary_item_features() {
    // Nothing to do without the primary item ID.
    if ( !$this->has_primary_item ) {
      return NOT_FOUND;
    }
    // Early exit.
    if ( empty( $this->dim_props ) || empty( $this->chan_props ) ) {
      return NOT_FOUND;
    }
    $status = $this->get_item_features( $this->primary_item_id, /*tile_depth=*/ 0 );
    if ( $status != FOUND ) {
      return $status;
    }

// "auxC" is parsed before the "ipma" properties so it is known now, if any.
    if ( $this->has_alpha ) {
      ++$this->primary_item_features['num_channels'];
    }
    return FOUND;
  }
}

//------------------------------------------------------------------------------

class Box {
  public $size; // In bytes.
  public $type; // Four characters.
  public $version; // 0 or actual version if this is a full box.
  public $flags; // 0 or actual value if this is a full box.
  public $content_size; // 'size' minus the header size.

/**
   * Reads the box header.
   *
   * @param stream  $handle              The resource the header will be parsed from.
   * @param int     $num_parsed_boxes    The total number of parsed boxes. Prevents timeouts.
   * @param int     $num_remaining_bytes The number of bytes that should be available from the resource.
   * @return Status                      FOUND on success or an error on failure.
   */
  public function parse( $handle, &$num_parsed_boxes, $num_remaining_bytes = MAX_SIZE ) {
    // See ISO/IEC 14496-12:2012(E) 4.2
    $header_size = 8; // box 32b size + 32b type (at least)
    if ( $header_size > $num_remaining_bytes ) {
      return INVALID;
    }
    if ( !( $data = read( $handle, 8 ) ) ) {
      return TRUNCATED;
    }
    $this->size = read_big_endian( $data, 4 );
    $this->type = substr( $data, 4, 4 );
    // 'box->size==1' means 64-bit size should be read after the box type.
    // 'box->size==0' means this box extends to all remaining bytes.
    if ( $this->size == 1 ) {
      $header_size += 8;
      if ( $header_size > $num_remaining_bytes ) {
        return INVALID;
      }
      if ( !( $data = read( $handle, 8 ) ) ) {
        return TRUNCATED;
      }
      // Stop the parsing if any box has a size greater than 4GB.
      if ( read_big_endian( $data, 4 ) != 0 ) {
        return ABORTED;
      }
      // Read the 32 least-significant bits.
      $this->size = read_big_endian( substr( $data, 4, 4 ), 4 );
    } else if ( $this->size == 0 ) {
      $this->size = $num_remaining_bytes;
    }
    if ( $this->size < $header_size ) {
      return INVALID;
    }
    if ( $this->size > $num_remaining_bytes ) {
      return INVALID;
    }

$has_fullbox_header = $this->type == 'meta' || $this->type == 'pitm' ||
                          $this->type == 'ipma' || $this->type == 'ispe' ||
                          $this->type == 'pixi' || $this->type == 'iref' ||
                          $this->type == 'auxC';
    if ( $has_fullbox_header ) {
      $header_size += 4;
    }
    if ( $this->size < $header_size ) {
      return INVALID;
    }
    $this->content_size = $this->size - $header_size;
    // Avoid timeouts. The maximum number of parsed boxes is arbitrary.
    ++$num_parsed_boxes;
    if ( $num_parsed_boxes >= MAX_NUM_BOXES ) {
      return ABORTED;
    }

$this->version = 0;
    $this->flags   = 0;
    if ( $has_fullbox_header ) {
      if ( !( $data = read( $handle, 4 ) ) ) {
        return TRUNCATED;
      }
      $this->version = read_big_endian( $data, 1 );
      $this->flags   = read_big_endian( substr( $data, 1, 3 ), 3 );
      // See AV1 Image File Format (AVIF) 8.1
      // at https://aomediacodec.github.io/av1-avif/#avif-boxes (available when
      // https://github.com/AOMediaCodec/av1-avif/pull/170 is merged).
      $is_parsable = ( $this->type == 'meta' && $this->version <= 0 ) ||
                     ( $this->type == 'pitm' && $this->version <= 1 ) ||
                     ( $this->type == 'ipma' && $this->version <= 1 ) ||
                     ( $this->type == 'ispe' && $this->version <= 0 ) ||
                     ( $this->type == 'pixi' && $this->version <= 0 ) ||
                     ( $this->type == 'iref' && $this->version <= 1 ) ||
                     ( $this->type == 'auxC' && $this->version <= 0 );
      // Instead of considering this file as invalid, skip unparsable boxes.
      if ( !$is_parsable ) {
        $this->type = 'unknownversion';
      }
    }
    // print_r( $this ); // Uncomment to print all boxes.
    return FOUND;
  }
}

//------------------------------------------------------------------------------

class Parser {
  private $handle; // Input stream.
  private $num_parsed_boxes = 0;
  private $data_was_skipped = false;
  public $features;

function __construct( $handle ) {
    $this->handle   = $handle;
    $this->features = new Features();
  }

/**
   * Parses an "ipco" box.
   *
   * "ispe" is used for width and height, "pixi" and "av1C" are used for bit depth
   * and number of channels, and "auxC" is used for alpha.
   *
   * @param stream  $handle              The resource the box will be parsed from.
   * @param int     $num_remaining_bytes The number of bytes that should be available from the resource.
   * @return Status                      FOUND on success or an error on failure.
   */
  private function parse_ipco( $num_remaining_bytes ) {
    $box_index = 1; // 1-based index. Used for iterating over properties.
    do {
      $box    = new Box();
      $status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
      if ( $status != FOUND ) {
        return $status;
      }

if ( $box->type == 'ispe' ) {
        // See ISO/IEC 23008-12:2017(E) 6.5.3.2
        if ( $box->content_size < 8 ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, 8 ) ) ) {
          return TRUNCATED;
        }
        $width  = read_big_endian( substr( $data, 0, 4 ), 4 );
        $height = read_big_endian( substr( $data, 4, 4 ), 4 );
        if ( $width == 0 || $height == 0 ) {
          return INVALID;
        }
        if ( count( $this->features->dim_props ) <= MAX_FEATURES &&
             $box_index <= MAX_VALUE ) {
          $dim_prop_count = count( $this->features->dim_props );
          $this->features->dim_props[$dim_prop_count]                 = new Dim_Prop();
          $this->features->dim_props[$dim_prop_count]->property_index = $box_index;
          $this->features->dim_props[$dim_prop_count]->width          = $width;
          $this->features->dim_props[$dim_prop_count]->height         = $height;
        } else {
          $this->data_was_skipped = true;
        }
        if ( !skip( $this->handle, $box->content_size - 8 ) ) {
          return TRUNCATED;
        }
      } else if ( $box->type == 'pixi' ) {
        // See ISO/IEC 23008-12:2017(E) 6.5.6.2
        if ( $box->content_size < 1 ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, 1 ) ) ) {
          return TRUNCATED;
        }
        $num_channels = read_big_endian( $data, 1 );
        if ( $num_channels < 1 ) {
          return INVALID;
        }
        if ( $box->content_size < 1 + $num_channels ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, 1 ) ) ) {
          return TRUNCATED;
        }
        $bit_depth = read_big_endian( $data, 1 );
        if ( $bit_depth < 1 ) {
          return INVALID;
        }
        for ( $i = 1; $i < $num_channels; ++$i ) {
          if ( !( $data = read( $this->handle, 1 ) ) ) {
            return TRUNCATED;
          }
          // Bit depth should be the same for all channels.
          if ( read_big_endian( $data, 1 ) != $bit_depth ) {
            return INVALID;
          }
          if ( $i > 32 ) {
            return ABORTED; // Be reasonable.
          }
        }
        if ( count( $this->features->chan_props ) <= MAX_FEATURES &&
             $box_index <= MAX_VALUE && $bit_depth <= MAX_VALUE &&
             $num_channels <= MAX_VALUE ) {
          $chan_prop_count = count( $this->features->chan_props );
          $this->features->chan_props[$chan_prop_count]                 = new Chan_Prop();
          $this->features->chan_props[$chan_prop_count]->property_index = $box_index;
          $this->features->chan_props[$chan_prop_count]->bit_depth      = $bit_depth;
          $this->features->chan_props[$chan_prop_count]->num_channels   = $num_channels;
        } else {
          $this->data_was_skipped = true;
        }
        if ( !skip( $this->handle, $box->content_size - ( 1 + $num_channels ) ) ) {
          return TRUNCATED;
        }
      } else if ( $box->type == 'av1C' ) {
        // See AV1 Codec ISO Media File Format Binding 2.3.1
        // at https://aomediacodec.github.io/av1-isobmff/#av1c
        // Only parse the necessary third byte. Assume that the others are valid.
        if ( $box->content_size < 3 ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, 3 ) ) ) {
          return TRUNCATED;
        }
        $byte          = read_big_endian( substr( $data, 2, 1 ), 1 );
        $high_bitdepth = ( $byte & 0x40 ) != 0;
        $twelve_bit    = ( $byte & 0x20 ) != 0;
        $monochrome    = ( $byte & 0x10 ) != 0;
        if ( $twelve_bit && !$high_bitdepth ) {
            return INVALID;
        }
        if ( count( $this->features->chan_props ) <= MAX_FEATURES &&
             $box_index <= MAX_VALUE ) {
          $chan_prop_count = count( $this->features->chan_props );
          $this->features->chan_props[$chan_prop_count]                 = new Chan_Prop();
          $this->features->chan_props[$chan_prop_count]->property_index = $box_index;
          $this->features->chan_props[$chan_prop_count]->bit_depth      =
              $high_bitdepth ? $twelve_bit ? 12 : 10 : 8;
          $this->features->chan_props[$chan_prop_count]->num_channels   = $monochrome ? 1 : 3;
        } else {
          $this->data_was_skipped = true;
        }
        if ( !skip( $this->handle, $box->content_size - 3 ) ) {
          return TRUNCATED;
        }
      } else if ( $box->type == 'auxC' ) {
        // See AV1 Image File Format (AVIF) 4
        // at https://aomediacodec.github.io/av1-avif/#auxiliary-images
        $kAlphaStr       = "urn:mpeg:mpegB:cicp:systems:auxiliary:alpha\0";
        $kAlphaStrLength = 44; // Includes terminating character.
        if ( $box->content_size >= $kAlphaStrLength ) {
          if ( !( $data = read( $this->handle, $kAlphaStrLength ) ) ) {
            return TRUNCATED;
          }
          if ( substr( $data, 0, $kAlphaStrLength ) == $kAlphaStr ) {
            // Note: It is unlikely but it is possible that this alpha plane does
            //       not belong to the primary item or a tile. Ignore this issue.
            $this->features->has_alpha = true;
          }
          if ( !skip( $this->handle, $box->content_size - $kAlphaStrLength ) ) {
            return TRUNCATED;
          }
        } else {
          if ( !skip( $this->handle, $box->content_size ) ) {
            return TRUNCATED;
          }
        }
      } else {
        if ( !skip( $this->handle, $box->content_size ) ) {
          return TRUNCATED;
        }
      }
      ++$box_index;
      $num_remaining_bytes -= $box->size;
    } while ( $num_remaining_bytes > 0 );
    return NOT_FOUND;
  }

/**
   * Parses an "iprp" box.
   *
   * The "ipco" box contain the properties which are linked to items by the "ipma" box.
   *
   * @param stream  $handle              The resource the box will be parsed from.
   * @param int     $num_remaining_bytes The number of bytes that should be available from the resource.
   * @return Status                      FOUND on success or an error on failure.
   */
  private function parse_iprp( $num_remaining_bytes ) {
    do {
      $box    = new Box();
      $status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
      if ( $status != FOUND ) {
        return $status;
      }

if ( $box->type == 'ipco' ) {
        $status = $this->parse_ipco( $box->content_size );
        if ( $status != NOT_FOUND ) {
          return $status;
        }
      } else if ( $box->type == 'ipma' ) {
        // See ISO/IEC 23008-12:2017(E) 9.3.2
        $num_read_bytes = 4;
        if ( $box->content_size < $num_read_bytes ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, $num_read_bytes ) ) ) {
          return TRUNCATED;
        }
        $entry_count        = read_big_endian( $data, 4 );
        $id_num_bytes       = ( $box->version < 1 ) ? 2 : 4;
        $index_num_bytes    = ( $box->flags & 1 ) ? 2 : 1;
        $essential_bit_mask = ( $box->flags & 1 ) ? 0x8000 : 0x80;

for ( $entry = 0; $entry < $entry_count; ++$entry ) {
          if ( $entry >= MAX_PROPS ||
               count( $this->features->props ) >= MAX_PROPS ) {
            $this->data_was_skipped = true;
            break;
          }
          $num_read_bytes += $id_num_bytes + 1;
          if ( $box->content_size < $num_read_bytes ) {
            return INVALID;
          }
          if ( !( $data = read( $this->handle, $id_num_bytes + 1 ) ) ) {
            return TRUNCATED;
          }
          $item_id           = read_big_endian(
              substr( $data, 0, $id_num_bytes ), $id_num_bytes );
          $association_count = read_big_endian(
              substr( $data, $id_num_bytes, 1 ), 1 );

for ( $property = 0; $property < $association_count; ++$property ) {
            if ( $property >= MAX_PROPS ||
                 count( $this->features->props ) >= MAX_PROPS ) {
              $this->data_was_skipped = true;
              break;
            }
            $num_read_bytes += $index_num_bytes;
            if ( $box->content_size < $num_read_bytes ) {
              return INVALID;
            }
            if ( !( $data = read( $this->handle, $index_num_bytes ) ) ) {
              return TRUNCATED;
            }
            $value          = read_big_endian( $data, $index_num_bytes );
            // $essential = ($value & $essential_bit_mask);  // Unused.
            $property_index = ( $value & ~$essential_bit_mask );
            if ( $property_index <= MAX_VALUE && $item_id <= MAX_VALUE ) {
              $prop_count = count( $this->features->props );
              $this->features->props[$prop_count]                 = new Prop();
              $this->features->props[$prop_count]->property_index = $property_index;
              $this->features->props[$prop_count]->item_id        = $item_id;
            } else {
              $this->data_was_skipped = true;
            }
          }
          if ( $property < $association_count ) {
            break; // Do not read garbage.
          }
        }

// If all features are available now, do not look further.
        $status = $this->features->get_primary_item_features();
        if ( $status != NOT_FOUND ) {
          return $status;
        }

// Mostly if 'data_was_skipped'.
        if ( !skip( $this->handle, $box->content_size - $num_read_bytes ) ) {
          return TRUNCATED;
        }
      } else {
        if ( !skip( $this->handle, $box->content_size ) ) {
          return TRUNCATED;
        }
      }
      $num_remaining_bytes -= $box->size;
    } while ( $num_remaining_bytes > 0 );
    return NOT_FOUND;
  }

/**
   * Parses an "iref" box.
   *
   * The "dimg" boxes contain links between tiles and their parent items, which
   * can be used to infer bit depth and number of channels for the primary item
   * when the latter does not have these properties.
   *
   * @param stream  $handle              The resource the box will be parsed from.
   * @param int     $num_remaining_bytes The number of bytes that should be available from the resource.
   * @return Status                      FOUND on success or an error on failure.
   */
  private function parse_iref( $num_remaining_bytes ) {
    do {
      $box    = new Box();
      $status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
      if ( $status != FOUND ) {
        return $status;
      }

if ( $box->type == 'dimg' ) {
        // See ISO/IEC 14496-12:2015(E) 8.11.12.2
        $num_bytes_per_id = ( $box->version == 0 ) ? 2 : 4;
        $num_read_bytes   = $num_bytes_per_id + 2;
        if ( $box->content_size < $num_read_bytes ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, $num_read_bytes ) ) ) {
          return TRUNCATED;
        }
        $from_item_id    = read_big_endian( $data, $num_bytes_per_id );
        $reference_count = read_big_endian( substr( $data, $num_bytes_per_id, 2 ), 2 );

for ( $i = 0; $i < $reference_count; ++$i ) {
          if ( $i >= MAX_TILES ) {
            $this->data_was_skipped = true;
            break;
          }
          $num_read_bytes += $num_bytes_per_id;
          if ( $box->content_size < $num_read_bytes ) {
            return INVALID;
          }
          if ( !( $data = read( $this->handle, $num_bytes_per_id ) ) ) {
            return TRUNCATED;
          }
          $to_item_id = read_big_endian( $data, $num_bytes_per_id );
          $tile_count = count( $this->features->tiles );
          if ( $from_item_id <= MAX_VALUE && $to_item_id <= MAX_VALUE &&
               $tile_count < MAX_TILES ) {
            $this->features->tiles[$tile_count]                 = new Tile();
            $this->features->tiles[$tile_count]->tile_item_id   = $to_item_id;
            $this->features->tiles[$tile_count]->parent_item_id = $from_item_id;
          } else {
            $this->data_was_skipped = true;
          }
        }

// If all features are available now, do not look further.
        $status = $this->features->get_primary_item_features();
        if ( $status != NOT_FOUND ) {
          return $status;
        }

/**
   * Parses a "meta" box.
   *
   * It looks for the primary item ID in the "pitm" box and recurses into other boxes
   * to find its features.
   *
   * @param stream  $handle              The resource the box will be parsed from.
   * @param int     $num_remaining_bytes The number of bytes that should be available from the resource.
   * @return Status                      FOUND on success or an error on failure.
   */
  private function parse_meta( $num_remaining_bytes ) {
    do {
      $box    = new Box();
      $status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );
      if ( $status != FOUND ) {
        return $status;
      }

if ( $box->type == 'pitm' ) {
        // See ISO/IEC 14496-12:2015(E) 8.11.4.2
        $num_bytes_per_id = ( $box->version == 0 ) ? 2 : 4;
        if ( $num_bytes_per_id > $num_remaining_bytes ) {
          return INVALID;
        }
        if ( !( $data = read( $this->handle, $num_bytes_per_id ) ) ) {
          return TRUNCATED;
        }
        $primary_item_id = read_big_endian( $data, $num_bytes_per_id );
        if ( $primary_item_id > MAX_VALUE ) {
          return ABORTED;
        }
        $this->features->has_primary_item = true;
        $this->features->primary_item_id  = $primary_item_id;
        if ( !skip( $this->handle, $box->content_size - $num_bytes_per_id ) ) {
          return TRUNCATED;
        }
      } else if ( $box->type == 'iprp' ) {
        $status = $this->parse_iprp( $box->content_size );
        if ( $status != NOT_FOUND ) {
          return $status;
        }
      } else if ( $box->type == 'iref' ) {
        $status = $this->parse_iref( $box->content_size );
        if ( $status != NOT_FOUND ) {
          return $status;
        }
      } else {
        if ( !skip( $this->handle, $box->content_size ) ) {
          return TRUNCATED;
        }
      }
      $num_remaining_bytes -= $box->size;
    } while ( $num_remaining_bytes != 0 );
    // According to ISO/IEC 14496-12:2012(E) 8.11.1.1 there is at most one "meta".
    return INVALID;
  }

/**
   * Parses a file stream.
   *
   * The file type is checked through the "ftyp" box.
   *
   * @return bool True if the input stream is an AVIF bitstream or false.
   */
  public function parse_ftyp() {
    $box    = new Box();
    $status = $box->parse( $this->handle, $this->num_parsed_boxes );
    if ( $status != FOUND ) {
      return false;
    }

if ( $box->type != 'ftyp' ) {
      return false;
    }
    // Iterate over brands. See ISO/IEC 14496-12:2012(E) 4.3.1
    if ( $box->content_size < 8 ) {
      return false;
    }
    for ( $i = 0; $i + 4 <= $box->content_size; $i += 4 ) {
      if ( !( $data = read( $this->handle, 4 ) ) ) {
        return false;
      }
      if ( $i == 4 ) {
        continue; // Skip minor_version.
      }
      if ( substr( $data, 0, 4 ) == 'avif' || substr( $data, 0, 4 ) == 'avis' ) {
        return skip( $this->handle, $box->content_size - ( $i + 4 ) );
      }
      if ( $i > 32 * 4 ) {
        return false; // Be reasonable.
      }

}
    return false; // No AVIF brand no good.
  }

/**
   * Parses a file stream.
   *
   * Features are extracted from the "meta" box.
   *
   * @return bool True if the main features of the primary item were parsed or false.
   */
  public function parse_file() {
    $box = new Box();
    while ( $box->parse( $this->handle, $this->num_parsed_boxes ) == FOUND ) {
      if ( $box->type === 'meta' ) {
        if ( $this->parse_meta( $box->content_size ) != FOUND ) {
          return false;
        }
        return true;
      }
      if ( !skip( $this->handle, $box->content_size ) ) {
        return false;
      }
    }
    return false; // No "meta" no good.
  }
}

✅ File saved successfully!