Parser::parse_iprp( int $num_remaining_bytes ): Avifinfo\Status

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$num_remaining_bytesint

The number of bytes that should be available from the resource.

Return value

Avifinfo\Status

FOUND on success or an error on failure.

Performance profile

How much work a call to Parser::parse_iprp() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

18–139

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 231.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 12 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost Parser::parse_iprp() can have, taken from its control-flow graph on PHP 8.5.

Uses · 6

• read()Reads bytes and advances the stream position by the same count.
• read_big_endian()Reads an unsigned integer with most significant bits first.
• skip()Advances the stream position by the given offset.
• \Avifinfo\Box::__construct()
• \Avifinfo\Parser::parse_ipco()
• \Avifinfo\Prop::__construct()

Source code

View on Trac ↗View on GitHub ↗

499  private function parse_iprp( $num_remaining_bytes ) {500    do {501      $box    = new Box();502      $status = $box->parse( $this->handle, $this->num_parsed_boxes, $num_remaining_bytes );503      if ( $status != FOUND ) {504        return $status;505      }506 507      if ( $box->type == 'ipco' ) {508        $status = $this->parse_ipco( $box->content_size );509        if ( $status != NOT_FOUND ) {510          return $status;511        }512      } else if ( $box->type == 'ipma' ) {513        // See ISO/IEC 23008-12:2017(E) 9.3.2514        $num_read_bytes = 4;515        if ( $box->content_size < $num_read_bytes ) {516          return INVALID;517        }518        if ( !( $data = read( $this->handle, $num_read_bytes ) ) ) {519          return TRUNCATED;520        }521        $entry_count        = read_big_endian( $data, 4 );522        $id_num_bytes       = ( $box->version < 1 ) ? 2 : 4;523        $index_num_bytes    = ( $box->flags & 1 ) ? 2 : 1;524        $essential_bit_mask = ( $box->flags & 1 ) ? 0x8000 : 0x80;525 526        for ( $entry = 0; $entry < $entry_count; ++$entry ) {527          if ( $entry >= MAX_PROPS ||528               count( $this->features->props ) >= MAX_PROPS ) {529            $this->data_was_skipped = true;530            break;531          }532          $num_read_bytes += $id_num_bytes + 1;533          if ( $box->content_size < $num_read_bytes ) {534            return INVALID;535          }536          if ( !( $data = read( $this->handle, $id_num_bytes + 1 ) ) ) {537            return TRUNCATED;538          }539          $item_id           = read_big_endian(540              substr( $data, 0, $id_num_bytes ), $id_num_bytes );541          $association_count = read_big_endian(542              substr( $data, $id_num_bytes, 1 ), 1 );543 544          for ( $property = 0; $property < $association_count; ++$property ) {545            if ( $property >= MAX_PROPS ||546                 count( $this->features->props ) >= MAX_PROPS ) {547              $this->data_was_skipped = true;548              break;549            }550            $num_read_bytes += $index_num_bytes;551            if ( $box->content_size < $num_read_bytes ) {552              return INVALID;553            }554            if ( !( $data = read( $this->handle, $index_num_bytes ) ) ) {555              return TRUNCATED;556            }557            $value          = read_big_endian( $data, $index_num_bytes );558            // $essential = ($value & $essential_bit_mask);  // Unused.559            $property_index = ( $value & ~$essential_bit_mask );560            if ( $property_index <= MAX_VALUE && $item_id <= MAX_VALUE ) {561              $prop_count = count( $this->features->props );562              $this->features->props[$prop_count]                 = new Prop();563              $this->features->props[$prop_count]->property_index = $property_index;564              $this->features->props[$prop_count]->item_id        = $item_id;565            } else {566              $this->data_was_skipped = true;567            }568          }569          if ( $property < $association_count ) {570            break; // Do not read garbage.571          }572        }573 574        // If all features are available now, do not look further.575        $status = $this->features->get_primary_item_features();576        if ( $status != NOT_FOUND ) {577          return $status;578        }

Changelog

Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/class-avif-info.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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