#pdfread

#Overview

• Read PDF files from disk, channels, or memory
• Parse cross-reference tables and object streams
• Handle encrypted documents with password support
• Support lazy loading for large files
• Query document revisions and encryption

#Types

#PdfRead

pub struct PdfRead { ... }
pub fn PdfRead::new() -> PdfRead

#Reading PDFs

#From Input Stream

// Read with all stream data loaded

///|
let pdf = @pdfread.PdfRead::new().pdf_of_input(
  user_password=None,
  owner_password=None,
  input,
)

#Lazy Loading

// Streams loaded on-demand

///|
let pdf = @pdfread.PdfRead::new().pdf_of_input_lazy(
  user_password=None,
  owner_password=None,
  input,
)

#From File (async)

///|
let pdf = @pdfreadfs.PdfReadFs::new().pdf_of_file(
  user_password=None,
  owner_password=None,
  filename="/path/to/document.pdf",
)

#From Channel (async)

///|
let pdf = @pdfreadfs.PdfReadFs::new().pdf_of_channel(
  user_password=None,
  owner_password=None,
  channel,
)

#Password-Protected Documents

// With user password

///|
let pdf = @pdfread.PdfRead::new().pdf_of_input(
  user_password=Some("secret"),
  owner_password=None,
  input,
)

// With owner password

///|
let pdf = @pdfread.PdfRead::new().pdf_of_input(
  user_password=None,
  owner_password=Some("admin123"),
  input,
)

#Document Revisions

// Count revisions

///|
let num_revisions = @pdfread.PdfRead::new().revisions(input)

// Read specific revision

///|
let pdf = @pdfread.PdfRead::new().pdf_of_input(
  revision=2,
  user_password=None,
  owner_password=None, // Read second revision
  input,
)

#Encryption Information

#Query Encryption Method

let method = @pdfread.PdfRead::new().what_encryption(pdf)
match method {
  None => println("Not encrypted")
  Some(AES128) => println("AES 128-bit")
  Some(AES256) => println("AES 256-bit")
  Some(ARC4(40)) => println("RC4 40-bit")
  Some(ARC4(128)) => println("RC4 128-bit")
  _ => ()
}

#Query Permissions

let perms = @pdfread.PdfRead::new().permissions(pdf)
for perm in perms {
  match perm {
    Print => println("Printing allowed")
    Copy => println("Copying allowed")
    Edit => println("Editing allowed")
    _ => ()
  }
}

#Debug Options

// Enable debug output

///|
let reader = @pdfread.PdfRead::new(read_debug=true)

// Treat all documents as malformed (for testing)

///|
let reader_force_malformed = @pdfread.PdfRead::new(
  debug_always_treat_malformed=true,
)

// Raise errors on malformed documents

///|
let reader_strict = @pdfread.PdfRead::new(error_on_malformed=true)

#Error Handling

try {
  let pdf = @pdfread.PdfRead::new().pdf_of_input!(
    user_password=None,
    owner_password=None,
    input,
  )
  // use pdf...
} catch {
  @pdf.PdfError::Msg(msg) => println("Parse error: \{msg}")
}

#Internal Structure

• Cross-reference tables: Traditional xref tables and compressed xref streams
• Object streams: Compressed object storage (PDF 1.5+)
• Linearization: Optimized web viewing (detected and handled)
• Encryption: RC4 and AES decryption with key derivation