Module: Pdfrb::PdfConstants

Defined in:

lib/pdfrb/pdf_constants.rb

Overview

PDF lexical and structural constants. Sourced from ISO 32000-2:2020 subclause 7.2 ("Lexical Conventions"). These are the bytes and tokens the Tokenizer operates on.

Constant Summary

HEADER_PREFIX =

The header magic every PDF file begins with (after optional BOM or leading whitespace, which the spec discourages but tolerates).

"%PDF-"

BINARY_MARKER =

Binary-marketing comment recommended after the header so tools that sniff for binary content treat the file correctly.

"%\xE2\xE3\xCF\xD3".b

EOF_MARKER =

End-of-file marker (technically just a comment, but conventional).

"%%EOF"

WHITESPACE =

Whitespace bytes per s7.2.2. NUL, TAB, LF, FF, CR, SPACE.

"\x00\t\n\f\r ".b

DELIMITERS =

Delimiter bytes per s7.2.2.

"()<>[]{}/%".b

TERMINATORS =

Bytes that terminate a name token, a number, or a keyword.

(WHITESPACE + DELIMITERS).b

PDF_VERSIONS =

PDF versions Pdfrb recognises, sorted oldest to newest. The Arlington model defines the canonical version set; this is its Ruby mirror.

%w[1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 2.0].freeze

LATEST_VERSION =

Latest PDF version Pdfrb fully understands. Versions newer than this raise UnsupportedVersionError on read.

"2.0"

KEYWORDS =

PDF "object" grammar keywords the Tokenizer treats specially.

%w[
  obj endobj stream endstream xref startxref trailer true false null
].freeze