parser

package
v0.6.0 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Feb 24, 2026 License: MIT Imports: 15 Imported by: 0

Documentation

Overview

Package parser implements PDF lexical analysis (tokenization) according to PDF 1.7 specification, Section 7.2 (Lexical Conventions).

Package primitive implements PDF primitive object types as defined in PDF specification.

PDF specification defines 8 basic object types: - Boolean values - Integer and Real numbers - Strings (literal and hexadecimal) - Names - Arrays - Dictionaries - Streams - The null object

Reference: PDF 1.7 specification, Section 7.3 "Objects"

Package parser implements PDF document reading and parsing.

Package parser implements PDF cross-reference table parsing according to PDF 1.7 specification, Section 7.5.4-7.5.8 (File Structure).

Index

Constants

View Source 
const (
	KeywordObj       = "obj"
	KeywordEndobj    = "endobj"
	KeywordStream    = "stream"
	KeywordEndstream = "endstream"
	KeywordXref      = "xref"
	KeywordTrailer   = "trailer"
	KeywordStartxref = "startxref"
)

PDF keyword string constants.

Variables

This section is empty.

Functions

func IsContentStreamOperator 

func IsContentStreamOperator(s string) bool

IsContentStreamOperator checks if a string is a PDF content stream operator. These are operators used in content streams for graphics and text operations.

Reference: PDF 1.7 specification, Appendix A (Operator Summary).

func IsKeyword 

func IsKeyword(s string) bool

IsKeyword checks if a string is a PDF keyword.

func ReadPDFInfo 

func ReadPDFInfo(filename string) (version string, pageCount int, err error)

ReadPDFInfo is a convenience function that reads basic PDF information without loading the entire document structure.

Returns: version, page count, error.

This is useful for quickly checking PDF properties without loading all objects into memory.

Types

type Array 

type Array struct {
	// contains filtered or unexported fields
}

Array represents a PDF array object. Arrays are ordered collections of objects: [obj1 obj2 obj3] Arrays can contain any PDF objects, including other arrays and dictionaries.

func NewArray 

func NewArray() *Array

NewArray creates a new empty Array.

func NewArrayFromSlice 

func NewArrayFromSlice(objects []PdfObject) *Array

NewArrayFromSlice creates an Array from a slice of objects.

func NewArrayWithCapacity 

func NewArrayWithCapacity(capacity int) *Array

NewArrayWithCapacity creates a new Array with specified capacity.

func (*Array) Append 

func (a *Array) Append(obj PdfObject)

Append adds an element to the end of the array.

func (*Array) AppendAll 

func (a *Array) AppendAll(objects ...PdfObject)

AppendAll adds multiple elements to the end of the array.

func (*Array) Clear 

func (a *Array) Clear()

Clear removes all elements from the array.

func (*Array) Clone 

func (a *Array) Clone() *Array

Clone creates a deep copy of the array.

func (*Array) Elements 

func (a *Array) Elements() []PdfObject

Elements returns a copy of all elements. Returns a new slice to prevent external modification.

func (*Array) Get 

func (a *Array) Get(i int) PdfObject

Get returns the element at index i. Returns nil if index is out of bounds.

func (*Array) Insert 

func (a *Array) Insert(i int, obj PdfObject) error

Insert inserts an element at index i.

func (*Array) Len 

func (a *Array) Len() int

Len returns the number of elements in the array.

func (*Array) Remove 

func (a *Array) Remove(i int) error

Remove removes the element at index i.

func (*Array) Set 

func (a *Array) Set(i int, obj PdfObject) error

Set sets the element at index i. Returns error if index is out of bounds.

func (*Array) String 

func (a *Array) String() string

String returns a string representation of the array.

func (*Array) WriteTo 

func (a *Array) WriteTo(w io.Writer) (int64, error)

WriteTo writes the PDF representation of the array to w.

type Boolean 

type Boolean struct {
	// contains filtered or unexported fields
}

Boolean represents a PDF boolean value (true or false).

func NewBoolean 

func NewBoolean(value bool) *Boolean

NewBoolean creates a new Boolean object.

func (*Boolean) String 

func (b *Boolean) String() string

String returns "true" or "false".

func (*Boolean) Value 

func (b *Boolean) Value() bool

Value returns the boolean value.

func (*Boolean) WriteTo 

func (b *Boolean) WriteTo(w io.Writer) (int64, error)

WriteTo writes "true" or "false" to w.

type Dictionary 

type Dictionary struct {
	// contains filtered or unexported fields
}

Dictionary represents a PDF dictionary object. Dictionaries are associative tables: << /Key1 value1 /Key2 value2 >> Keys are always Name objects, values can be any PDF object.

func NewDictionary 

func NewDictionary() *Dictionary

NewDictionary creates a new empty Dictionary.

func NewDictionaryWithCapacity 

func NewDictionaryWithCapacity(capacity int) *Dictionary

NewDictionaryWithCapacity creates a new Dictionary with specified capacity.

func (*Dictionary) Clear 

func (d *Dictionary) Clear()

Clear removes all entries from the dictionary.

func (*Dictionary) Clone 

func (d *Dictionary) Clone() *Dictionary

Clone creates a deep copy of the dictionary.

func (*Dictionary) Get 

func (d *Dictionary) Get(key string) PdfObject

Get returns the value for a key. Returns nil if key doesn't exist.

func (*Dictionary) GetArray 

func (d *Dictionary) GetArray(key string) *Array

GetArray is a convenience method to get an Array value. Returns nil if key doesn't exist or value is not an Array.

func (*Dictionary) GetBoolean 

func (d *Dictionary) GetBoolean(key string) bool

GetBoolean is a convenience method to get a Boolean value. Returns false if key doesn't exist or value is not a Boolean.

func (*Dictionary) GetDictionary 

func (d *Dictionary) GetDictionary(key string) *Dictionary

GetDictionary is a convenience method to get a Dictionary value. Returns nil if key doesn't exist or value is not a Dictionary.

func (*Dictionary) GetInteger 

func (d *Dictionary) GetInteger(key string) int64

GetInteger is a convenience method to get an Integer value. Returns 0 if key doesn't exist or value is not an Integer.

func (*Dictionary) GetName 

func (d *Dictionary) GetName(key string) *Name

GetName is a convenience method to get a Name value. Returns nil if key doesn't exist or value is not a Name.

func (*Dictionary) GetReal 

func (d *Dictionary) GetReal(key string) float64

GetReal is a convenience method to get a Real value. Returns 0.0 if key doesn't exist or value is not a Real.

func (*Dictionary) GetString 

func (d *Dictionary) GetString(key string) string

GetString is a convenience method to get a String value. Returns empty string if key doesn't exist or value is not a String.

func (*Dictionary) Has 

func (d *Dictionary) Has(key string) bool

Has checks if a key exists in the dictionary.

func (*Dictionary) Keys 

func (d *Dictionary) Keys() []string

Keys returns all keys in insertion order.

func (*Dictionary) KeysSorted 

func (d *Dictionary) KeysSorted() []string

KeysSorted returns all keys in alphabetical order.

func (*Dictionary) Len 

func (d *Dictionary) Len() int

Len returns the number of entries in the dictionary.

func (*Dictionary) Merge 

func (d *Dictionary) Merge(other *Dictionary)

Merge merges another dictionary into this one. Existing keys are overwritten.

func (*Dictionary) Remove 

func (d *Dictionary) Remove(key string)

Remove removes a key from the dictionary.

func (*Dictionary) Set 

func (d *Dictionary) Set(key string, value PdfObject)

Set sets a key-value pair in the dictionary. If key already exists, its value is replaced.

func (*Dictionary) SetBoolean 

func (d *Dictionary) SetBoolean(key string, value bool)

SetBoolean is a convenience method to set a Boolean value.

func (*Dictionary) SetInteger 

func (d *Dictionary) SetInteger(key string, value int64)

SetInteger is a convenience method to set an Integer value.

func (*Dictionary) SetName 

func (d *Dictionary) SetName(key, value string)

SetName is a convenience method to set a Name value.

func (*Dictionary) SetReal 

func (d *Dictionary) SetReal(key string, value float64)

SetReal is a convenience method to set a Real value.

func (*Dictionary) SetString 

func (d *Dictionary) SetString(key, value string)

SetString is a convenience method to set a String value.

func (*Dictionary) String 

func (d *Dictionary) String() string

String returns a string representation of the dictionary.

func (*Dictionary) WriteTo 

func (d *Dictionary) WriteTo(w io.Writer) (int64, error)

WriteTo writes the PDF representation of the dictionary to w.

type DocInfo 

type DocInfo struct {
	Version   string
	Title     string
	Author    string
	Subject   string
	Keywords  string
	Creator   string
	Producer  string
	Encrypted bool
}

DocInfo contains document metadata from the Info dictionary.

type IndirectObject 

type IndirectObject struct {
	Number     int       // Object number
	Generation int       // Generation number
	Object     PdfObject // The actual object
}

IndirectObject represents an indirect PDF object. Format: objNum genNum obj ... endobj

Example: 1 0 obj (Hello) endobj

Reference: PDF 1.7 specification, Section 7.3.10 (Indirect Objects).

func NewIndirectObject 

func NewIndirectObject(number, generation int, obj PdfObject) *IndirectObject

NewIndirectObject creates a new indirect object.

func (*IndirectObject) String 

func (o *IndirectObject) String() string

String returns a string representation of the indirect object.

func (*IndirectObject) WriteTo 

func (o *IndirectObject) WriteTo(w io.Writer) (int64, error)

WriteTo writes the PDF representation to w.

type IndirectReference 

type IndirectReference struct {
	Number     int // Object number being referenced
	Generation int // Generation number being referenced
}

IndirectReference represents a reference to an indirect object. Format: objNum genNum R

Example: 1 0 R (refers to object 1, generation 0)

Reference: PDF 1.7 specification, Section 7.3.10 (Indirect Objects).

func NewIndirectReference 

func NewIndirectReference(number, generation int) *IndirectReference

NewIndirectReference creates a new indirect reference.

func (*IndirectReference) Clone 

func (r *IndirectReference) Clone() *IndirectReference

Clone creates a copy of the indirect reference.

func (*IndirectReference) Equals 

func (r *IndirectReference) Equals(other *IndirectReference) bool

Equals checks if two references point to the same object.

func (*IndirectReference) String 

func (r *IndirectReference) String() string

String returns the PDF representation of the reference.

func (*IndirectReference) WriteTo 

func (r *IndirectReference) WriteTo(w io.Writer) (int64, error)

WriteTo writes the PDF representation to w.

type Integer 

type Integer struct {
	// contains filtered or unexported fields
}

Integer represents a PDF integer object. PDF integers are signed 32-bit values.

func NewInteger 

func NewInteger(value int64) *Integer

NewInteger creates a new Integer object.

func (*Integer) Int 

func (i *Integer) Int() int

Int returns the value as int (may overflow on 32-bit systems).

func (*Integer) String 

func (i *Integer) String() string

String returns the string representation of the integer.

func (*Integer) Value 

func (i *Integer) Value() int64

Value returns the integer value.

func (*Integer) WriteTo 

func (i *Integer) WriteTo(w io.Writer) (int64, error)

WriteTo writes the integer to w.

type Lexer 

type Lexer struct {
	// contains filtered or unexported fields
}

Lexer tokenizes a PDF byte stream according to PDF 1.7 specification, Section 7.2 (Lexical Conventions).

func NewLexer 

func NewLexer(r io.Reader) *Lexer

NewLexer creates a new lexer that reads from the given reader.

func (*Lexer) NextToken 

func (l *Lexer) NextToken() (Token, error)

NextToken returns the next token from the input stream.

func (*Lexer) Peek 

func (l *Lexer) Peek() (Token, error)

Peek returns the next token without consuming it.

func (*Lexer) Position 

func (l *Lexer) Position() (line, column int)

Position returns the current line and column.

func (*Lexer) ReadAll 

func (l *Lexer) ReadAll() ([]Token, error)

ReadAll reads all tokens from the input until EOF. Useful for debugging and testing.

func (*Lexer) Reset 

func (l *Lexer) Reset(r io.Reader)

Reset resets the lexer to read from a new reader.

type Name 

type Name struct {
	// contains filtered or unexported fields
}

Name represents a PDF name object. Names are unique identifiers and always start with '/'.

func NewName 

func NewName(value string) *Name

NewName creates a new Name object. The leading '/' is added automatically if not present.

func (*Name) Equals 

func (n *Name) Equals(other *Name) bool

Equals checks if two names are equal.

func (*Name) String 

func (n *Name) String() string

String returns the name with leading '/'.

func (*Name) Value 

func (n *Name) Value() string

Value returns the name without the leading '/'.

func (*Name) WriteTo 

func (n *Name) WriteTo(w io.Writer) (int64, error)

WriteTo writes the name to w.

type Null 

type Null struct{}

Null represents the PDF null object.

func NewNull 

func NewNull() *Null

NewNull creates a new Null object.

func (*Null) String 

func (n *Null) String() string

String returns "null".

func (*Null) WriteTo 

func (n *Null) WriteTo(w io.Writer) (int64, error)

WriteTo writes "null" to w.

type Parser 

type Parser struct {
	// contains filtered or unexported fields
}

Parser parses PDF objects from a token stream. It builds higher-level objects (arrays, dictionaries, streams, indirect objects) from tokens produced by the Lexer.

Reference: PDF 1.7 specification, Section 7.3 (Objects).

func NewParser 

func NewParser(r io.Reader) *Parser

NewParser creates a new parser that reads from the given reader.

func NewParserFromLexer 

func NewParserFromLexer(lexer *Lexer) *Parser

NewParserFromLexer creates a new parser from an existing lexer.

func (*Parser) ParseIndirectObject 

func (p *Parser) ParseIndirectObject() (*IndirectObject, error)

ParseIndirectObject parses an indirect object: N G obj ... endobj.

func (*Parser) ParseObject 

func (p *Parser) ParseObject() (PdfObject, error)

ParseObject parses any PDF direct object. Returns the parsed object or an error.

func (*Parser) ParseObjectStream 

func (p *Parser) ParseObjectStream(decodedData []byte, numObjects, firstOffset int) (map[int]PdfObject, error)

ParseObjectStream parses an Object Stream (PDF 1.5+) and returns the contained objects.

Object Streams compress multiple objects together for efficiency. The format is: 

N 0 obj
<< /Type /ObjStm /N numObjects /First firstByteOffset /Length ... >>
stream
obj1_num offset1 obj2_num offset2 ... objN_num offsetN
[object1_data] [object2_data] ... [objectN_data]
endstream
endobj

The first part contains pairs of (object_number, offset_from_First). The second part (starting at /First) contains the actual object data.

Reference: PDF 1.7 specification, Section 7.5.7 (Object Streams).

Parameters:

  • decodedData: The decoded stream content (after decompression)
  • numObjects: The /N value (number of objects)
  • firstOffset: The /First value (offset to first object data)

Returns: Map of object number -> parsed object.

func (*Parser) ParseStartXRef 

func (p *Parser) ParseStartXRef() (int64, error)

ParseStartXRef parses the startxref section at the end of a PDF file.

Expected format: 

startxref
byte_offset
%%EOF

Returns the byte offset of the cross-reference table.

Reference: PDF 1.7 specification, Section 7.5.5 (File Trailer).

func (*Parser) ParseXRef 

func (p *Parser) ParseXRef() (*XRefTable, error)

ParseXRef parses a cross-reference table and trailer.

Handles both traditional xref tables (PDF < 1.5) and xref streams (PDF 1.5+):

Traditional format: 

xref
startNum count
offset1 generation1 type1
offset2 generation2 type2
...
trailer
<< trailer dictionary >>

XRef stream format (PDF 1.5+): 

90 0 obj
<< /Type /XRef /Size 100 /W [1 3 2] ... >>
stream
...compressed xref data...
endstream
endobj

Reference: PDF 1.7 specification, Section 7.5.4 and 7.5.8.

func (*Parser) ParseXRefStream 

func (p *Parser) ParseXRefStream() (*XRefTable, error)

ParseXRefStream parses a cross-reference stream object (PDF 1.5+).

When a PDF uses xref streams, the startxref pointer points to an indirect object (e.g., "90 0 obj") instead of the "xref" keyword.

The stream dictionary contains:

  • /Type /XRef
  • /Size: number of entries
  • /W [w1 w2 w3]: field widths for parsing binary data
  • /Index: optional array of [start count ...] pairs (default [0 Size])
  • Trailer entries: /Root, /Info, /ID, etc.

Reference: PDF 1.7 specification, Section 7.5.8 (Cross-Reference Streams).

func (*Parser) ParseXRefStreamWithFileAccess 

func (p *Parser) ParseXRefStreamWithFileAccess(file io.ReadSeeker, xrefOffset int64) (*XRefTable, error)

ParseXRefStreamWithFileAccess parses a cross-reference stream with direct file access.

This version is used when we have access to an io.ReadSeeker (file handle) and can seek to the exact stream data position, avoiding lexer buffer issues.

func (*Parser) Position 

func (p *Parser) Position() (line, column int)

Position returns the current parser position (line, column).

func (*Parser) Reset 

func (p *Parser) Reset(r io.Reader)

Reset resets the parser with a new reader.

type PdfObject 

type PdfObject interface {
	// String returns a string representation of the object.
	String() string

	// WriteTo writes the PDF representation to w.
	// Returns the number of bytes written and any error.
	WriteTo(w io.Writer) (int64, error)
}

PdfObject is the base interface for all PDF objects. All PDF primitive types implement this interface.

func Clone 

func Clone(obj PdfObject) PdfObject

Clone creates a deep copy of a PDF object. This is useful when you need to modify an object without affecting the original.

func Resolve 

func Resolve(obj PdfObject) PdfObject

Resolve resolves indirect references to direct objects. For direct objects, it returns the object itself.

Note: Full indirect object support (e.g., "1 0 R" references) will be implemented in Phase 2 (PDF Parser) as part of the document reader. See SUMMARY.md for the complete roadmap.

type Reader 

type Reader struct {
	// contains filtered or unexported fields
}

Reader reads and parses PDF documents, providing access to document structure.

The Reader ties together all parser components (Lexer, Parser, XRef) to read actual PDF files according to PDF 1.7 specification.

PDF File Structure (Section 7.5):

  • Header: %PDF-X.Y
  • Body: Indirect objects
  • Cross-reference table: Object locations
  • Trailer: Document metadata
  • startxref: XRef table offset
  • %%EOF: End of file marker

Thread Safety: Reader is thread-safe for concurrent reads using sync.RWMutex for cache and sync.Mutex for file access. Multiple goroutines can safely call GetObject() simultaneously.

Reference: PDF 1.7 specification, Section 7.5 (File Structure).

func NewReader 

func NewReader(filename string) *Reader

NewReader creates a new PDF document reader.

The filename is stored but the file is not opened until Open() is called. This allows for resource management and lazy loading.

func OpenPDF 

func OpenPDF(filename string) (*Reader, error)

OpenPDF is a convenience function that creates a Reader and opens the PDF.

This is equivalent to: 

reader := NewReader(filename)
err := reader.Open()

Remember to call Close() when done: 

defer reader.Close()

func OpenPDFWithPassword added in v0.6.0 

func OpenPDFWithPassword(filename, password string) (*Reader, error)

OpenPDFWithPassword is a convenience function that creates a Reader and opens an encrypted PDF with the given password.

For PDFs with an empty user password (permissions-only encryption), use OpenPDF instead — it handles empty passwords transparently.

Example: 

reader, err := parser.OpenPDFWithPassword("encrypted.pdf", "secret")
if err != nil {
    log.Fatal(err)
}
defer reader.Close()

func (*Reader) Close 

func (r *Reader) Close() error

Close closes the PDF file and releases resources.

func (*Reader) GetAcroForm added in v0.2.0 

func (r *Reader) GetAcroForm() (*Dictionary, error)

GetAcroForm returns the interactive form dictionary (AcroForm).

Returns nil if the document has no interactive form. The AcroForm dictionary contains form field definitions and settings.

Reference: PDF 1.7 specification, Section 12.7 (Interactive Forms).

func (*Reader) GetCatalog 

func (r *Reader) GetCatalog() (*Dictionary, error)

GetCatalog returns the document catalog (root object).

The catalog must be loaded via Open() before calling this method.

Reference: PDF 1.7 specification, Section 7.7.2 (Document Catalog).

func (*Reader) GetDocumentInfo 

func (r *Reader) GetDocumentInfo() DocInfo

GetDocumentInfo returns document metadata from the Info dictionary.

Reference: PDF 1.7 specification, Section 14.3.3 (Document Information Dictionary).

func (*Reader) GetObject 

func (r *Reader) GetObject(objectNum int) (PdfObject, error)

GetObject retrieves and resolves an indirect object by number.

The object is looked up in the cross-reference table, loaded from the file at the specified offset, and cached for future access.

For PDF 1.5+ compressed objects (stored in Object Streams), the method automatically loads and parses the containing ObjStm.

Nested indirect references are automatically resolved.

Thread-safe: Multiple goroutines can call this method concurrently.

Returns error if object is not found or cannot be parsed.

func (*Reader) GetPage 

func (r *Reader) GetPage(pageNum int) (*Dictionary, error)

GetPage returns the page dictionary for the specified page number.

Page numbers are 0-based (first page is 0).

The method traverses the page tree to find the requested page. The page tree can have intermediate nodes (/Type /Pages) and leaf nodes (/Type /Page).

Reference: PDF 1.7 specification, Section 7.7.3 (Page Tree).

func (*Reader) GetPageCount 

func (r *Reader) GetPageCount() (int, error)

GetPageCount returns the total number of pages in the document.

The count is read from the /Count entry in the page tree root.

Reference: PDF 1.7 specification, Section 7.7.3.2 (Page Tree Nodes).

func (*Reader) GetPages 

func (r *Reader) GetPages() (*Dictionary, error)

GetPages returns the page tree root.

The page tree is a hierarchical structure containing all pages.

Reference: PDF 1.7 specification, Section 7.7.3 (Page Tree).

func (*Reader) Open 

func (r *Reader) Open() error

Open opens the PDF file and parses its structure.

For encrypted PDFs with an empty user password (the most common case for "permissions-only" encryption), Open will transparently decrypt the document. For PDFs requiring a non-empty password, use OpenWithPassword.

Steps performed:

  1. Open file
  2. Read and validate PDF header
  3. Find startxref offset
  4. Parse cross-reference table and trailer
  5. Initialize decryption (if encrypted)
  6. Load document catalog
  7. Load page tree root

Returns error if file cannot be opened or is not a valid PDF.

Reference: PDF 1.7 specification, Section 7.5 (File Structure).

func (*Reader) ResolveArray added in v0.2.0 

func (r *Reader) ResolveArray(obj PdfObject) (*Array, error)

ResolveArray resolves an object and ensures it's an array. This is the exported version of resolveArray.

func (*Reader) ResolveReferences added in v0.2.0 

func (r *Reader) ResolveReferences(obj PdfObject) PdfObject

ResolveReferences recursively resolves indirect references in an object. This is the exported version of resolveReferences.

func (*Reader) String 

func (r *Reader) String() string

String returns a string representation of the reader's state.

func (*Reader) Trailer 

func (r *Reader) Trailer() *Dictionary

Trailer returns the trailer dictionary.

The trailer contains document-level metadata like:

  • /Size: Number of entries in xref table
  • /Root: Reference to catalog
  • /Info: Document information dictionary
  • /ID: File identifier array

Reference: PDF 1.7 specification, Section 7.5.5 (File Trailer).

func (*Reader) Version 

func (r *Reader) Version() string

Version returns the PDF version string from the file header.

Returns empty string if Open() has not been called.

Reference: PDF 1.7 specification, Section 7.5.1 (File Header).

func (*Reader) XRefTable 

func (r *Reader) XRefTable() *XRefTable

XRefTable returns the cross-reference table.

The xref table maps object numbers to byte offsets in the file.

Reference: PDF 1.7 specification, Section 7.5.4 (Cross-Reference Table).

type Real 

type Real struct {
	// contains filtered or unexported fields
}

Real represents a PDF real (floating-point) number.

func NewReal 

func NewReal(value float64) *Real

NewReal creates a new Real object.

func (*Real) String 

func (r *Real) String() string

String returns the string representation of the real number. Uses minimal precision to keep PDF files compact.

func (*Real) Value 

func (r *Real) Value() float64

Value returns the float64 value.

func (*Real) WriteTo 

func (r *Real) WriteTo(w io.Writer) (int64, error)

WriteTo writes the real number to w.

type Stream 

type Stream struct {
	// contains filtered or unexported fields
}

Stream represents a PDF stream object. A stream consists of a dictionary followed by zero or more bytes bracketed between the keywords stream (followed by newline) and endstream.

Reference: PDF 1.7 specification, Section 7.3.8 (Stream Objects).

func NewStream 

func NewStream(dict *Dictionary, content []byte) *Stream

NewStream creates a new Stream with the given dictionary and content.

func (*Stream) Bytes 

func (s *Stream) Bytes() []byte

Bytes returns the raw stream content as a byte slice. Alias for Content() for convenience.

func (*Stream) Clone 

func (s *Stream) Clone() *Stream

Clone creates a deep copy of the stream.

func (*Stream) Content 

func (s *Stream) Content() []byte

Content returns the raw stream content.

func (*Stream) Decode 

func (s *Stream) Decode() ([]byte, error)

Decode decodes the stream content based on the filters in the dictionary. This is a placeholder for Phase 3 (Stream Processing). Currently returns the raw content.

func (*Stream) Dictionary 

func (s *Stream) Dictionary() *Dictionary

Dictionary returns the stream's dictionary.

func (*Stream) Encode 

func (s *Stream) Encode(_ []string) error

Encode encodes the stream content with the specified filters. This is a placeholder for Phase 3 (Stream Processing).

func (*Stream) GetDecodeParams 

func (s *Stream) GetDecodeParams() PdfObject

GetDecodeParams returns the decode parameters for the filters. Returns nil if no decode parameters are specified.

func (*Stream) GetFilter 

func (s *Stream) GetFilter() PdfObject

GetFilter returns the filter(s) applied to this stream. Returns nil if no filters are applied.

func (*Stream) Length 

func (s *Stream) Length() int64

Length returns the length of the stream content.

func (*Stream) Reader 

func (s *Stream) Reader() io.Reader

Reader returns an io.Reader for the stream content.

func (*Stream) SetContent 

func (s *Stream) SetContent(content []byte)

SetContent sets the stream content and updates the Length entry in the dictionary.

func (*Stream) String 

func (s *Stream) String() string

String returns a string representation of the stream. Only shows the dictionary and length, not the full content.

func (*Stream) WriteTo 

func (s *Stream) WriteTo(w io.Writer) (int64, error)

WriteTo writes the PDF representation of the stream to w. Format: dictionary\nstream\ncontent\nendstream.

type String 

type String struct {
	// contains filtered or unexported fields
}

String represents a PDF string object. PDF strings can be literal strings (text) or hexadecimal strings (<hex>).

func NewHexString 

func NewHexString(value string) *String

NewHexString creates a new hexadecimal String object.

func NewString 

func NewString(value string) *String

NewString creates a new literal String object.

func NewStringBytes 

func NewStringBytes(value []byte) *String

NewStringBytes creates a new literal String from bytes.

func (*String) Bytes 

func (s *String) Bytes() []byte

Bytes returns the raw bytes.

func (*String) IsHex 

func (s *String) IsHex() bool

IsHex returns true if this is a hexadecimal string.

func (*String) String 

func (s *String) String() string

String returns the string representation. For debugging purposes, not PDF format.

func (*String) Value 

func (s *String) Value() string

Value returns the string value as a Go string.

func (*String) WriteTo 

func (s *String) WriteTo(w io.Writer) (int64, error)

WriteTo writes the PDF representation to w.

type Token 

type Token struct {
	Type   TokenType // Type of the token
	Value  string    // String value of the token
	Line   int       // Line number (1-based)
	Column int       // Column number (1-based)
}

Token represents a single token from the PDF byte stream.

func EOFToken 

func EOFToken(line, column int) Token

EOFToken creates an end-of-file token.

func ErrorToken 

func ErrorToken(msg string, line, column int) Token

ErrorToken creates an error token with the given message.

func NewToken 

func NewToken(typ TokenType, value string, line, column int) Token

NewToken creates a new token with the given type, value, line, and column.

func Tokenize 

func Tokenize(input string) ([]Token, error)

Tokenize is a convenience function that tokenizes the entire input string.

func (Token) String 

func (t Token) String() string

String returns a string representation of the token for debugging.

type TokenType 

type TokenType int

TokenType represents the type of a PDF token. 

const (
	// TokenError represents an error during tokenization.
	TokenError TokenType = iota

	// TokenEOF represents end of file.
	TokenEOF

	// Basic types.
	TokenInteger   // 123, -456, +789
	TokenReal      // 3.14, -2.5, .5
	TokenString    // (Hello) - literal string
	TokenHexString // <48656C6C6F> - hexadecimal string
	TokenName      // /Type, /Page, /Name#20With#20Spaces
	TokenBoolean   // true, false
	TokenNull      // null

	// Keywords.
	TokenKeyword // obj, endobj, stream, endstream, xref, trailer, startxref, R, n, f

	// Delimiters.
	TokenArrayStart // [
	TokenArrayEnd   // ]
	TokenDictStart  // <<
	TokenDictEnd    // >>
)

Token types recognized by the PDF lexer. Based on PDF 1.7 specification, Section 7.2 (Lexical Conventions).

func (TokenType) String 

func (t TokenType) String() string

String returns the string representation of a TokenType.

type Type 

type Type int

Type represents the type of a PDF object. This is useful for type assertions and debugging. 

const (
	// TypeNull represents the null type.
	TypeNull Type = iota
	TypeBoolean
	TypeInteger
	TypeReal
	TypeString
	TypeName
	TypeArray
	TypeDictionary
	TypeStream
	TypeIndirect
	TypeReference
)

PDF object type constants.

func TypeOf 

func TypeOf(obj PdfObject) Type

TypeOf returns the type of a PDF object.

func (Type) String 

func (t Type) String() string

String returns the name of the type.

type XRefEntry 

type XRefEntry struct {
	Type       XRefEntryType // Entry type (free, in-use, compressed)
	Offset     int64         // Byte offset (in-use) or next free object (free)
	Generation int           // Generation number
	ObjectNum  int           // Object number (for convenience)
}

XRefEntry represents a single entry in the cross-reference table.

For in-use entries (type 'n'):

  • Offset: byte offset in file where object starts
  • Generation: generation number of the object

For free entries (type 'f'):

  • Offset: object number of next free object (or 0 if last)
  • Generation: generation number to use when object is reused

Reference: PDF 1.7 specification, Section 7.5.4 (Cross-Reference Table).

func NewXRefEntry 

func NewXRefEntry(objectNum int, entryType XRefEntryType, offset int64, generation int) *XRefEntry

NewXRefEntry creates a new cross-reference entry.

func (*XRefEntry) IsFree 

func (e *XRefEntry) IsFree() bool

IsFree returns true if this entry represents a free (deleted) object.

func (*XRefEntry) IsInUse 

func (e *XRefEntry) IsInUse() bool

IsInUse returns true if this entry represents an in-use object.

func (*XRefEntry) String 

func (e *XRefEntry) String() string

String returns a string representation of the entry.

type XRefEntryType 

type XRefEntryType int

XRefEntryType represents the type of cross-reference entry. 

const (
	// XRefEntryFree represents a free (deleted) object entry.
	// Format: next_free_object_num generation f.
	XRefEntryFree XRefEntryType = iota

	// XRefEntryInUse represents an in-use object entry.
	// Format: byte_offset generation n.
	XRefEntryInUse

	// XRefEntryCompressed represents a compressed object entry (PDF 1.5+).
	// Found in XRef streams, format varies based on stream /W array.
	XRefEntryCompressed
)

func (XRefEntryType) String 

func (t XRefEntryType) String() string

String returns the string representation of the XRefEntryType.

type XRefStream 

type XRefStream struct {
	Stream  *Stream      // The stream object containing compressed xref data
	Entries []*XRefEntry // Parsed entries (if decoded)
	W       []int        // Field widths from /W array in stream dictionary
	Index   []int        // Object number ranges from /Index array
}

XRefStream represents a compressed cross-reference stream (PDF 1.5+).

Cross-reference streams provide a more compact alternative to traditional cross-reference tables by using stream compression.

Note: Full XRef stream support requires stream decoding (compression), which will be implemented in a later phase.

Reference: PDF 1.7 specification, Section 7.5.8 (Cross-Reference Streams).

func NewXRefStream 

func NewXRefStream(stream *Stream) *XRefStream

NewXRefStream creates a new XRef stream structure.

type XRefTable 

type XRefTable struct {
	Entries map[int]*XRefEntry // Map: object number -> XRef entry
	Trailer *Dictionary        // Trailer dictionary
}

XRefTable represents a PDF cross-reference table.

The cross-reference table contains information about the location of objects in the PDF file. Each object is identified by an object number and generation number.

Reference: PDF 1.7 specification, Section 7.5.4 (Cross-Reference Table).

func NewXRefTable 

func NewXRefTable() *XRefTable

NewXRefTable creates a new empty cross-reference table.

func (*XRefTable) AddEntry 

func (t *XRefTable) AddEntry(entry *XRefEntry)

AddEntry adds an entry to the cross-reference table.

func (*XRefTable) GetEntry 

func (t *XRefTable) GetEntry(objectNum int) (*XRefEntry, bool)

GetEntry retrieves an entry by object number. Returns nil if the entry doesn't exist.

func (*XRefTable) GetFreeEntries 

func (t *XRefTable) GetFreeEntries() []*XRefEntry

GetFreeEntries returns all free entries in the table.

func (*XRefTable) GetInUseEntries 

func (t *XRefTable) GetInUseEntries() []*XRefEntry

GetInUseEntries returns all in-use entries in the table.

func (*XRefTable) GetTrailer 

func (t *XRefTable) GetTrailer() *Dictionary

GetTrailer returns the trailer dictionary.

func (*XRefTable) HasObject 

func (t *XRefTable) HasObject(objectNum int) bool

HasObject returns true if the table contains an entry for the given object number.

func (*XRefTable) MergeOlder added in v0.2.1 

func (t *XRefTable) MergeOlder(older *XRefTable)

MergeOlder merges entries from an older cross-reference table.

Entries already present in this table (newer) are preserved. Only entries missing from this table are added from the older table. This implements the PDF incremental update semantics where newer xref sections take precedence over older ones.

Reference: PDF 1.7 specification, Section 7.5.6 (Incremental Updates).

func (*XRefTable) SetTrailer 

func (t *XRefTable) SetTrailer(trailer *Dictionary)

SetTrailer sets the trailer dictionary.

func (*XRefTable) Size 

func (t *XRefTable) Size() int

Size returns the number of entries in the table.

func (*XRefTable) String 

func (t *XRefTable) String() string

String returns a string representation of the XRef table.

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.