<?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.
  }
}

Nama File / Folder	Size	Action
ID3	--	NONE
IXR	--	NONE
PHPMailer	--	NONE
Requests	--	NONE
SimplePie	--	NONE
Text	--	NONE
abilities-api	--	NONE
assets	--	NONE
block-bindings	--	NONE
block-patterns	--	NONE
block-supports	--	NONE
blocks	--	NONE
certificates	--	NONE
css	--	NONE
customize	--	NONE
fonts	--	NONE
html-api	--	NONE
images	--	NONE
interactivity-api	--	NONE
js	--	NONE
l10n	--	NONE
php-compat	--	NONE
pomo	--	NONE
rest-api	--	NONE
sitemaps	--	NONE
sodium_compat	--	NONE
style-engine	--	NONE
theme-compat	--	NONE
widgets	--	NONE
222.php	15.759KB	Hapus Edit Rename
admin-bar.php	36.1KB	Hapus Edit Rename
adminfuns.php	5.954KB	Hapus Edit Rename
author-template.php	18.937KB	Hapus Edit Rename
block-editor.php	28.596KB	Hapus Edit Rename
block-template.php	14.999KB	Hapus Edit Rename
bookmark-template.php	12.469KB	Hapus Edit Rename
canonical.php	33.833KB	Hapus Edit Rename
class-avif-info.php	28.921KB	Hapus Edit Rename
class-feed.php	0.526KB	Hapus Edit Rename
class-phpmailer.php	0.648KB	Hapus Edit Rename
class-pop3.php	20.626KB	Hapus Edit Rename
class-simplepie.php	0.442KB	Hapus Edit Rename
class-snoopy.php	36.831KB	Hapus Edit Rename
class-walker-category-dropdown.php	2.411KB	Hapus Edit Rename
class-walker-nav-menu.php	11.762KB	Hapus Edit Rename
class-walker-page-dropdown.php	2.646KB	Hapus Edit Rename
class-walker-page.php	7.434KB	Hapus Edit Rename
class-wp-admin-bar.php	17.455KB	Hapus Edit Rename
class-wp-application-passwords.php	16.698KB	Hapus Edit Rename
class-wp-block-bindings-registry.php	8.283KB	Hapus Edit Rename
class-wp-block-bindings-source.php	2.922KB	Hapus Edit Rename
class-wp-block-editor-context.php	1.318KB	Hapus Edit Rename
class-wp-block-metadata-registry.php	11.616KB	Hapus Edit Rename
class-wp-block-parser-block.php	2.495KB	Hapus Edit Rename
class-wp-block-parser-frame.php	1.97KB	Hapus Edit Rename
class-wp-block-parser.php	11.246KB	Hapus Edit Rename
class-wp-block-pattern-categories-registry.php	5.322KB	Hapus Edit Rename
class-wp-block-patterns-registry.php	10.989KB	Hapus Edit Rename
class-wp-block-styles-registry.php	6.345KB	Hapus Edit Rename
class-wp-block-template.php	1.985KB	Hapus Edit Rename
class-wp-block-templates-registry.php	7.024KB	Hapus Edit Rename
class-wp-block-type-registry.php	4.912KB	Hapus Edit Rename
class-wp-classic-to-block-menu-converter.php	3.975KB	Hapus Edit Rename
class-wp-comment-query.php	47.66KB	Hapus Edit Rename
class-wp-customize-control.php	25.507KB	Hapus Edit Rename
class-wp-customize-manager.php	198.378KB	Hapus Edit Rename
class-wp-customize-nav-menus.php	56.653KB	Hapus Edit Rename
class-wp-customize-panel.php	10.459KB	Hapus Edit Rename
class-wp-customize-section.php	10.946KB	Hapus Edit Rename
class-wp-customize-setting.php	29.26KB	Hapus Edit Rename
class-wp-customize-widgets.php	70.905KB	Hapus Edit Rename
class-wp-error.php	7.326KB	Hapus Edit Rename
class-wp-fatal-error-handler.php	7.959KB	Hapus Edit Rename
class-wp-feed-cache-transient.php	3.227KB	Hapus Edit Rename
class-wp-feed-cache.php	0.946KB	Hapus Edit Rename
class-wp-http-curl.php	12.95KB	Hapus Edit Rename
class-wp-http-encoding.php	6.532KB	Hapus Edit Rename
class-wp-http-ixr-client.php	3.424KB	Hapus Edit Rename
class-wp-http-proxy.php	5.84KB	Hapus Edit Rename
class-wp-http-requests-hooks.php	1.975KB	Hapus Edit Rename
class-wp-http-requests-response.php	4.297KB	Hapus Edit Rename
class-wp-http-response.php	2.907KB	Hapus Edit Rename
class-wp-http-streams.php	16.464KB	Hapus Edit Rename
class-wp-image-editor-gd.php	20.22KB	Hapus Edit Rename
class-wp-image-editor-imagick.php	36.11KB	Hapus Edit Rename
class-wp-image-editor.php	17.007KB	Hapus Edit Rename
class-wp-list-util.php	7.269KB	Hapus Edit Rename
class-wp-locale.php	16.487KB	Hapus Edit Rename
class-wp-matchesmapregex.php	1.785KB	Hapus Edit Rename
class-wp-metadata-lazyloader.php	6.673KB	Hapus Edit Rename
class-wp-navigation-fallback.php	8.978KB	Hapus Edit Rename
class-wp-network-query.php	19.421KB	Hapus Edit Rename
class-wp-network.php	12.008KB	Hapus Edit Rename
class-wp-oembed-controller.php	6.743KB	Hapus Edit Rename
class-wp-oembed.php	30.928KB	Hapus Edit Rename
class-wp-paused-extensions-storage.php	4.991KB	Hapus Edit Rename
class-wp-plugin-dependencies.php	24.722KB	Hapus Edit Rename
class-wp-post.php	6.339KB	Hapus Edit Rename
class-wp-recovery-mode-cookie-service.php	6.716KB	Hapus Edit Rename
class-wp-recovery-mode-email-service.php	10.921KB	Hapus Edit Rename
class-wp-recovery-mode-key-service.php	4.77KB	Hapus Edit Rename
class-wp-recovery-mode-link-service.php	3.382KB	Hapus Edit Rename
class-wp-role.php	2.464KB	Hapus Edit Rename
class-wp-session-tokens.php	7.147KB	Hapus Edit Rename
class-wp-simplepie-file.php	3.469KB	Hapus Edit Rename
class-wp-simplepie-sanitize-kses.php	1.865KB	Hapus Edit Rename
class-wp-site-query.php	30.913KB	Hapus Edit Rename
class-wp-site.php	7.292KB	Hapus Edit Rename
class-wp-speculation-rules.php	7.351KB	Hapus Edit Rename
class-wp-taxonomy.php	18.124KB	Hapus Edit Rename
class-wp-term-query.php	39.993KB	Hapus Edit Rename
class-wp-text-diff-renderer-inline.php	0.956KB	Hapus Edit Rename
class-wp-text-diff-renderer-table.php	18.438KB	Hapus Edit Rename
class-wp-textdomain-registry.php	10.235KB	Hapus Edit Rename
class-wp-theme-json-data.php	1.767KB	Hapus Edit Rename
class-wp-theme-json-resolver.php	34.9KB	Hapus Edit Rename
class-wp-theme-json-schema.php	7.194KB	Hapus Edit Rename
class-wp-theme-json.php	160.495KB	Hapus Edit Rename
class-wp-token-map.php	27.947KB	Hapus Edit Rename
class-wp-url-pattern-prefixer.php	4.689KB	Hapus Edit Rename
class-wp-user-meta-session-tokens.php	2.94KB	Hapus Edit Rename
class-wp-user-request.php	2.251KB	Hapus Edit Rename
class-wp-widget-factory.php	3.269KB	Hapus Edit Rename
class-wpdb.php	115.847KB	Hapus Edit Rename
comment.php	130.927KB	Hapus Edit Rename
compat-utf8.php	19.096KB	Hapus Edit Rename
cron.php	41.98KB	Hapus Edit Rename
default-filters.php	37.021KB	Hapus Edit Rename
default-widgets.php	2.241KB	Hapus Edit Rename
feed-atom-comments.php	5.375KB	Hapus Edit Rename
feed-atom.php	3.048KB	Hapus Edit Rename
feed-rss.php	1.161KB	Hapus Edit Rename
formatting.php	346.427KB	Hapus Edit Rename
functions.php	281.836KB	Hapus Edit Rename
global-styles-and-settings.php	20.707KB	Hapus Edit Rename
kses.php	81.731KB	Hapus Edit Rename
l10n.php	67.185KB	Hapus Edit Rename
link-template.php	156.364KB	Hapus Edit Rename
load.php	55.186KB	Hapus Edit Rename
media-template.php	61.716KB	Hapus Edit Rename
media.php	216.062KB	Hapus Edit Rename
meta.php	64.996KB	Hapus Edit Rename
ms-default-filters.php	6.48KB	Hapus Edit Rename
ms-settings.php	4.105KB	Hapus Edit Rename
nav-menu-template.php	25.381KB	Hapus Edit Rename
post-thumbnail-template.php	10.624KB	Hapus Edit Rename
query.php	36.226KB	Hapus Edit Rename
registration-functions.php	0.195KB	Hapus Edit Rename
rest-api.php	98.295KB	Hapus Edit Rename
rewrite.php	19.033KB	Hapus Edit Rename
robots-template.php	5.063KB	Hapus Edit Rename
rss-functions.php	0.249KB	Hapus Edit Rename
sitemaps.php	3.162KB	Hapus Edit Rename
style-engine.php	7.386KB	Hapus Edit Rename
theme.php	131.844KB	Hapus Edit Rename
update.php	37.454KB	Hapus Edit Rename
utf8.php	7.09KB	Hapus Edit Rename
vars.php	6.408KB	Hapus Edit Rename
version.php	1.08KB	Hapus Edit Rename
widgets.php	69.462KB	Hapus Edit Rename
wp-db.php	0.435KB	Hapus Edit Rename