Document
in package
An existing PDF, read far enough to revise it with an incremental update.
It follows the chain of cross-reference sections from the end of the file, tables and streams alike, reads objects on demand, including those packed into object streams, and walks the page tree. Where an offset is wrong it falls back to finding objects by scanning the file, as PDF viewers do.
Table of Contents
Properties
- $bytes : string
- $objects : array<int, mixed>
-
$objectStreams
: array<int, array{0: string, 1: array
- $pages : array<int, Page>|null
- $scanned : array<int, int>|null
- $startxref : int
- $trailer : Dictionary
- $xref : array<int, array{0: int, 1: int, 2: int}>
- Where each object is: `[1, offset, generation]`, `[2, object stream, index]`, or `[0, 0, 0]` when it is free.
- $xrefIsStream : bool
Methods
- bytes() : string
- The document's bytes, exactly as read.
- fromString() : self
- Reads a PDF from its bytes.
- hasDigitalSignatures() : bool
- Whether the document carries a digital signature, which rewriting it would invalidate.
- isEncrypted() : bool
- Whether the document is encrypted.
- object() : mixed
- An indirect object's value, or null when it does not exist, as PDF defines a missing object.
- open() : self
- Reads a PDF file.
- pages() : array<int, Page>
- The pages, in order.
- resolve() : mixed
- A value with any indirect references followed.
- size() : int
- One more than the highest object number in use: where new objects start.
- startxref() : int
- The offset of the newest cross-reference section, which an update's `/Prev` points to.
- trailer() : Dictionary
- The newest trailer, with entries only older ones set filled in from them.
- xrefIsStream() : bool
- Whether the newest cross-reference section is a stream, which an update should then use too.
- __construct() : mixed
- box() : array{float, float, float, float}|null
- A rectangle, normalised to lower-left and upper-right, or null when it is not one.
- collectPages() : void
- Adds the pages under a page tree node, applying the attributes pages inherit.
- parser() : Parser
- A parser over the whole file that can resolve an indirect stream length.
- readAt() : mixed
- Reads the object at an offset, falling back to scanning when it is not the object expected there.
- readCompressed() : mixed
- Reads an object packed into an object stream.
- readCrossReferences() : void
- Follows the cross-reference sections from the last `startxref` back through `/Prev`.
- readScanned() : mixed
- Reads an object from where scanning the file found it, or null when it is nowhere.
- readSection() : Dictionary, 1: bool}
- Reads one cross-reference section, table or stream.
- readStreamEntries() : void
- Reads a cross-reference stream's entries.
- readTable() : Dictionary
- Reads a cross-reference table's entries, and the trailer after them.
- rebuildFromScan() : void
- Rebuilds the document's structure by scanning, for a file whose cross-references are missing or broken.
- resolveLength() : mixed
- Resolves a stream's indirect `/Length`.
- scan() : void
- Finds every `n g obj` in the file; the last one for a number wins, as in an update.
Properties
$bytes read-only
private
string
$bytes
$objects
private
array<int, mixed>
$objects
= []
$objectStreams
private
array<int, array{0: string, 1: array}>
$objectStreams
= []
Decoded object streams: their data, and each object's offset in it.
$pages
private
array<int, Page>|null
$pages
= null
$scanned
private
array<int, int>|null
$scanned
= null
Offsets found by scanning, when the cross-reference sections cannot be trusted.
$startxref
private
int
$startxref
= 0
$trailer
private
Dictionary
$trailer
$xref
Where each object is: `[1, offset, generation]`, `[2, object stream, index]`, or `[0, 0, 0]` when it is free.
private
array<int, array{0: int, 1: int, 2: int}>
$xref
= []
$xrefIsStream
private
bool
$xrefIsStream
= false
Methods
bytes()
The document's bytes, exactly as read.
public
bytes() : string
Return values
stringfromString()
Reads a PDF from its bytes.
public
static fromString(string $bytes) : self
Parameters
- $bytes : string
-
The PDF.
Tags
Return values
selfhasDigitalSignatures()
Whether the document carries a digital signature, which rewriting it would invalidate.
public
hasDigitalSignatures() : bool
Return values
boolisEncrypted()
Whether the document is encrypted.
public
isEncrypted() : bool
Return values
boolobject()
An indirect object's value, or null when it does not exist, as PDF defines a missing object.
public
object(int $number) : mixed
Parameters
- $number : int
-
The object number.
open()
Reads a PDF file.
public
static open(string $path) : self
Parameters
- $path : string
-
The file.
Tags
Return values
selfpages()
The pages, in order.
public
pages() : array<int, Page>
Tags
Return values
array<int, Page>resolve()
A value with any indirect references followed.
public
resolve(mixed $value) : mixed
Parameters
- $value : mixed
-
A value that may be a Reference.
size()
One more than the highest object number in use: where new objects start.
public
size() : int
Return values
intstartxref()
The offset of the newest cross-reference section, which an update's `/Prev` points to.
public
startxref() : int
Return values
inttrailer()
The newest trailer, with entries only older ones set filled in from them.
public
trailer() : Dictionary
Return values
DictionaryxrefIsStream()
Whether the newest cross-reference section is a stream, which an update should then use too.
public
xrefIsStream() : bool
Return values
bool__construct()
private
__construct(string $bytes) : mixed
Parameters
- $bytes : string
box()
A rectangle, normalised to lower-left and upper-right, or null when it is not one.
private
box(mixed $value) : array{float, float, float, float}|null
Parameters
- $value : mixed
-
The rectangle as stored.
Return values
array{float, float, float, float}|nullcollectPages()
Adds the pages under a page tree node, applying the attributes pages inherit.
private
collectPages(mixed $node, array<string, mixed> $inherited, array<int, true> &$visited) : void
Parameters
- $node : mixed
-
The node, usually a reference.
- $inherited : array<string, mixed>
-
Resources, MediaBox, CropBox and Rotate set by its ancestors.
- $visited : array<int, true>
-
Nodes already walked, so a loop in the tree cannot recurse forever.
parser()
A parser over the whole file that can resolve an indirect stream length.
private
parser() : Parser
Return values
ParserreadAt()
Reads the object at an offset, falling back to scanning when it is not the object expected there.
private
readAt(int $offset, int $number) : mixed
Parameters
- $offset : int
-
Where the cross-reference section says it is.
- $number : int
-
The object number expected.
readCompressed()
Reads an object packed into an object stream.
private
readCompressed(int $streamNumber, int $index, int $number) : mixed
Parameters
- $streamNumber : int
-
The object stream.
- $index : int
-
The object's position in it.
- $number : int
-
The object number.
readCrossReferences()
Follows the cross-reference sections from the last `startxref` back through `/Prev`.
private
readCrossReferences() : void
readScanned()
Reads an object from where scanning the file found it, or null when it is nowhere.
private
readScanned(int $number) : mixed
Parameters
- $number : int
-
The object number.
readSection()
Reads one cross-reference section, table or stream.
private
readSection(int $offset) : Dictionary, 1: bool}
Parameters
- $offset : int
-
Where it starts.
Return values
Dictionary, 1: bool} —Its trailer dictionary, and whether it was a stream.
readStreamEntries()
Reads a cross-reference stream's entries.
private
readStreamEntries(Stream $stream) : void
Parameters
- $stream : Stream
-
The stream, whose dictionary is also a trailer.
readTable()
Reads a cross-reference table's entries, and the trailer after them.
private
readTable(int $offset) : Dictionary
Parameters
- $offset : int
-
Just after the
xrefkeyword.
Return values
DictionaryrebuildFromScan()
Rebuilds the document's structure by scanning, for a file whose cross-references are missing or broken.
private
rebuildFromScan() : void
Tags
resolveLength()
Resolves a stream's indirect `/Length`.
private
resolveLength(Reference $reference) : mixed
Parameters
- $reference : Reference
-
The length object.
scan()
Finds every `n g obj` in the file; the last one for a number wins, as in an update.
private
scan() : void