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/*!
A low-level library for reading PDF files.
This crate implements the `Syntax` chapter of the PDF reference, and therefore
serves as a very good basis for building various abstractions on top of it, without having to reimplement
the PDF parsing logic.
This crate does not provide more high-level functionality, such as parsing fonts or color spaces.
Such functionality is out-of-scope for `hayro-syntax`, since this crate is supposed to be
as *light-weight* and *application-agnostic* as possible.
Functionality-wise, this crate is therefore close to feature-complete. The main missing feature
is support for password-protected documents, as well as improved support for JPEG2000
documents. In addition to that, more low-level APIs might be added in the future.
# Example
This short example shows you how to load a PDF file and iterate over the content streams of all
pages.
```rust
use hayro_syntax::Pdf;
use std::path::PathBuf;
use std::sync::Arc;
// First load the data that constitutes the PDF file.
let data = std::fs::read(
PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../hayro-tests/pdfs/custom/text_with_rise.pdf"),
)
.unwrap();
// Then create a new PDF file from it.
//
// Here we are just unwrapping in case reading the file failed, but you
// might instead want to apply proper error handling.
let pdf = Pdf::new(Arc::new(data)).unwrap();
// First access all pages, and then iterate over the operators of each page's
// content stream and print them.
let pages = pdf.pages();
for page in pages.iter() {
for op in page.typed_operations() {
println!("{op:?}");
}
}
```
# Safety
There is one usage of `unsafe`, needed to implement caching using a self-referential struct. Other
than that, there is no usage of `unsafe`, especially in _any_ of the parser code.
# Features
The supported features include:
- Parsing xref tables in all its possible formats, including xref streams.
- Best-effort attempt at repairing PDF files with broken xref tables.
- Parsing of all objects types (also in object streams).
- Parsing and evaluating PDF functions.
- Parsing and decoding PDF streams.
- Iterating over pages as well as their content streams in a typed or untyped fashion.
- The crate is very lightweight, especially in comparison to other PDF crates, assuming you don't
enable the `jpeg2000` feature (see further below for more information).
# Limitations
- There are still a few features missing, for example, support for
password-protected PDFs. In addition to that, many properties (like page annotations) are
currently not exposed.
- This crate is for read-only processing, you cannot directly use it to manipulate PDF files.
If you need to do that, there are other crates in the Rust ecosystem that are suitable for this.
# Cargo features
This crate has one feature, `jpeg2000`. PDF allows for the insertion of JPEG2000 images. However,
unfortunately, JPEG2000 is a very complicated format. There exists a Rust
[jpeg2k](https://github.com/Neopallium/jpeg2k) crate that allows decoding such images. However, it is a
relatively heavy dependency, has a lot of unsafe code (due to having been ported with
[c2rust](https://c2rust.com/)), and also has a dependency on libc, meaning that you might be
restricted in the targets you can build to. Because of this, I recommend not enabling this feature
unless you absolutely need to be able to support such images.
*/
use Arc;
pub
pub
pub
pub
pub
// This module should only be used by hayro crates and is considered an implementation detail.
pub use *;
/// A container for the bytes of a PDF file.
pub type PdfData = ;