File "class-avif-info-20250117071512.php"
Full Path: /home/siazco/grocery.siazco.se/wp-includes/blocks/site-title/class-avif-info-20250117071512.php
File size: 8 KB
MIME-type: text/x-php
Charset: utf-8
<?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;
}
}
//------------------------------------------------------------------------