bpx 3.1.0

// Copyright (c) 2021, BlockProject 3D
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
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//       this list of conditions and the following disclaimer.
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//! This library is the official implementation for the [BPX](https://gitlab.com/bp3d/bpx/bpx/-/blob/master/BPX_Format.pdf) container format.

use std::vec::Vec;

pub mod variant;
pub mod builder;
mod compression;
pub mod decoder;
pub mod encoder;
pub mod error;
mod garraylen;
pub mod header;
pub mod sd;
pub mod section;
pub mod strings;
pub mod utils;

/// Represents a pointer to a section.
///
/// *Allows indirect access to a given section instead of sharing mutable references in user code.*
#[derive(Copy, Clone, Debug)]
pub struct SectionHandle(usize);

/// The interface implemented by both the BPX encoder and decoder.
pub trait Interface
{
    /// Searches for the first section of a given type.
    /// Returns None if no section could be found.
    ///
    /// # Arguments
    ///
    /// * `btype`: section type byte.
    ///
    /// returns: Option<SectionHandle>
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    ///
    /// let file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// assert!(file.find_section_by_type(0).is_none());
    /// ```
    fn find_section_by_type(&self, btype: u8) -> Option<SectionHandle>;

    /// Searches for all sections of a given type.
    /// Returns None if no section could be found.
    ///
    /// # Arguments
    ///
    /// * `btype`: section type byte.
    ///
    /// returns: Vec<SectionHandle, Global>
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    ///
    /// let file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// assert_eq!(file.find_all_sections_of_type(0).len(), 0);
    /// ```
    fn find_all_sections_of_type(&self, btype: u8) -> Vec<SectionHandle>;

    /// Locates a section by its index in the file.
    /// Returns None if the section does not exist.
    ///
    /// # Arguments
    ///
    /// * `index`: the section index to search for.
    ///
    /// returns: Option<SectionHandle>
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    ///
    /// let file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// assert!(file.find_section_by_index(0).is_none());
    /// ```
    fn find_section_by_index(&self, index: u32) -> Option<SectionHandle>;

    /// Returns the BPX section header of a section.
    ///
    /// # Arguments
    ///
    /// * `handle`: a handle to the section.
    ///
    /// returns: &SectionHeader
    ///
    /// # Panics
    ///
    /// Panics if the given section handle is invalid.
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    /// use bpx::builder::SectionHeaderBuilder;
    ///
    /// let mut file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// let handle = file.create_section(SectionHeaderBuilder::new().with_type(1).build()).unwrap();
    /// let header = file.get_section_header(handle);
    /// assert_eq!(header.btype, 1);
    /// ```
    fn get_section_header(&self, handle: SectionHandle) -> &header::SectionHeader;

    /// Returns the section index from a section handle.
    ///
    /// # Arguments
    ///
    /// * `handle`: a handle to the section.
    ///
    /// returns: u32
    ///
    /// # Panics
    ///
    /// Panics if the given section handle is invalid.
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    /// use bpx::builder::SectionHeaderBuilder;
    ///
    /// let mut file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// let handle = file.create_section(SectionHeaderBuilder::new().build()).unwrap();
    /// assert_eq!(file.get_section_index(handle), 0);
    /// ```
    fn get_section_index(&self, handle: SectionHandle) -> u32;

    /// Opens a section for read and/or write.
    ///
    /// # Arguments
    ///
    /// * `handle`: a handle to the section.
    ///
    /// returns: Result<&mut dyn SectionData, Error>
    ///
    /// # Errors
    ///
    /// A BPX [Error](error::Error) if an IO or any other file error occurs
    /// while reading the section from the file.
    ///
    /// # Panics
    ///
    /// Panics if the given section handle is invalid.
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    /// use bpx::builder::SectionHeaderBuilder;
    ///
    /// let mut file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// let handle = file.create_section(SectionHeaderBuilder::new().build()).unwrap();
    /// let section = file.open_section(handle).unwrap();
    /// let data = section.load_in_memory().unwrap();
    /// assert_eq!(data.len(), 0);
    /// ```
    fn open_section(&mut self, handle: SectionHandle) -> Result<&mut dyn section::SectionData>;

    /// Returns a read-only reference to the BPX main header.
    ///
    /// # Examples
    ///
    /// ```
    /// use bpx::encoder::Encoder;
    /// use bpx::Interface;
    /// use bpx::builder::SectionHeaderBuilder;
    ///
    /// let mut file = Encoder::new(Vec::<u8>::new()).unwrap();
    /// let header = file.get_main_header();
    /// //Default BPX variant/type is 'P'
    /// assert_eq!(header.btype, 'P' as u8);
    /// ```
    fn get_main_header(&self) -> &header::MainHeader;
}

/// Represents a result from this library.
///
/// *This acts as a shortcut to [Result](std::result::Result)<T, [Error](error::Error)>.*
pub type Result<T> = std::result::Result<T, error::Error>;