<commit_before>//! Mutex and RwLock types that do not poison themselves.
#![warn(missing_docs)]

use std::error::Error;
use std::fmt;
use std::ops::{Deref, DerefMut};
use std::sync;

/// Like `std::sync::Mutex` except that it does not poison itself.
pub struct Mutex<T: ?Sized>(sync::Mutex<T>);

impl<T> Mutex<T> {
    /// Like `std::sync::Mutex::new`.
    pub fn new(t: T) -> Mutex<T> {
        Mutex(sync::Mutex::new(t))
    }

    /// Like `std::sync::Mutex::into_inner`.
    pub fn into_inner(self) -> T {
        self.0.into_inner().unwrap_or_else(|e| e.into_inner())
    }
}

impl<T: ?Sized> Mutex<T> {
    /// Like `std::sync::Mutex::lock`.
    pub fn lock<'a>(&'a self) -> MutexGuard<'a, T> {
        MutexGuard(self.0.lock().unwrap_or_else(|e| e.into_inner()))
    }

    /// Like `std::sync::Mutex::try_lock`.
    pub fn try_lock<'a>(&'a self) -> TryLockResult<MutexGuard<'a, T>> {
        match self.0.try_lock() {
            Ok(t) => Ok(MutexGuard(t)),
            Err(sync::TryLockError::Poisoned(e)) => Ok(MutexGuard(e.into_inner())),
            Err(sync::TryLockError::WouldBlock) => Err(TryLockError(())),
        }
    }

    /// Like `std::sync::Mutex::get_mut`.
    pub fn get_mut(&mut self) -> &mut T {
        self.0.get_mut().unwrap_or_else(|e| e.into_inner())
    }
}

/// Like `std::sync::MutexGuard`.
#[must_use]
pub struct MutexGuard<'a, T: ?Sized + 'a>(sync::MutexGuard<'a, T>);

impl<'a, T: ?Sized> Deref for MutexGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.0.deref()
    }
}

impl<'a, T: ?Sized> DerefMut for MutexGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut T {
        self.0.deref_mut()
    }
}

/// Like `std::sync::TryLockResult`.
pub type TryLockResult<T> = Result<T, TryLockError>;

/// Like `std::sync::TryLockError`.
#[derive(Debug)]
pub struct TryLockError(());

impl fmt::Display for TryLockError {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.write_str(self.description())
    }
}

impl Error for TryLockError {
    fn description(&self) -> &str {
        "try_lock failed because the operation would block"
    }
}

/// Like `std::sync::RwLock` except that it does not poison itself.
pub struct RwLock<T: ?Sized>(sync::RwLock<T>);

impl<T> RwLock<T> {
    /// Like `std::sync::RwLock::new`.
    pub fn new(t: T) -> RwLock<T> {
        RwLock(sync::RwLock::new(t))
    }

    /// Like `std::sync::RwLock::into_inner`.
    pub fn into_inner(self) -> T where T: Sized {
        self.0.into_inner().unwrap_or_else(|e| e.into_inner())
    }
}

impl<T: ?Sized> RwLock<T> {
    /// Like `std::sync::RwLock::read`.
    pub fn read<'a>(&'a self) -> RwLockReadGuard<'a, T> {
        RwLockReadGuard(self.0.read().unwrap_or_else(|e| e.into_inner()))
    }

    /// Like `std::sync::RwLock::try_read`.
    pub fn try_read<'a>(&'a self) -> TryLockResult<RwLockReadGuard<'a, T>> {
        match self.0.try_read() {
            Ok(t) => Ok(RwLockReadGuard(t)),
            Err(sync::TryLockError::Poisoned(e)) => Ok(RwLockReadGuard(e.into_inner())),
            Err(sync::TryLockError::WouldBlock) => Err(TryLockError(())),
        }
    }

    /// Like `std::sync::RwLock::write`.
    pub fn write<'a>(&'a self) -> RwLockWriteGuard<'a, T> {
        RwLockWriteGuard(self.0.write().unwrap_or_else(|e| e.into_inner()))
    }

    /// Like `std::sync::RwLock::try_write`.
    pub fn try_write<'a>(&'a self) -> TryLockResult<RwLockWriteGuard<'a, T>> {
        match self.0.try_write() {
            Ok(t) => Ok(RwLockWriteGuard(t)),
            Err(sync::TryLockError::Poisoned(e)) => Ok(RwLockWriteGuard(e.into_inner())),
            Err(sync::TryLockError::WouldBlock) => Err(TryLockError(())),
        }
    }

    /// Like `std::sync::RwLock::get_mut`.
    pub fn get_mut(&mut self) -> &mut T {
        self.0.get_mut().unwrap_or_else(|e| e.into_inner())
    }
}

/// Like `std::sync::RwLockReadGuard`.
#[must_use]
pub struct RwLockReadGuard<'a, T: ?Sized + 'a>(sync::RwLockReadGuard<'a, T>);

impl<'a, T: ?Sized> Deref for RwLockReadGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.0.deref()
    }
}

/// Like `std::sync::RwLockWriteGuard`.
#[must_use]
pub struct RwLockWriteGuard<'a, T: ?Sized + 'a>(sync::RwLockWriteGuard<'a, T>);

impl<'a, T: ?Sized> Deref for RwLockWriteGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.0.deref()
    }
}

impl<'a, T: ?Sized> DerefMut for RwLockWriteGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut T {
        self.0.deref_mut()
    }
}
<commit_msg>Add to docs a bit<commit_after>//! Mutex and RwLock types that do not poison themselves.
//!
//! These types expose identical APIs to the standard library `Mutex` and
//! `RwLock` except that they do not return `PoisonError`s.
#![warn(missing_docs)]

use std::error::Error;
use std::fmt;
use std::ops::{Deref, DerefMut};
use std::sync;

/// Like `std::sync::Mutex` except that it does not poison itself.
pub struct Mutex<T: ?Sized>(sync::Mutex<T>);

impl<T> Mutex<T> {
    /// Like `std::sync::Mutex::new`.
    pub fn new(t: T) -> Mutex<T> {
        Mutex(sync::Mutex::new(t))
    }

    /// Like `std::sync::Mutex::into_inner`.
    pub fn into_inner(self) -> T {
        self.0.into_inner().unwrap_or_else(|e| e.into_inner())
    }
}

impl<T: ?Sized> Mutex<T> {
    /// Like `std::sync::Mutex::lock`.
    pub fn lock<'a>(&'a self) -> MutexGuard<'a, T> {
        MutexGuard(self.0.lock().unwrap_or_else(|e| e.into_inner()))
    }

    /// Like `std::sync::Mutex::try_lock`.
    pub fn try_lock<'a>(&'a self) -> TryLockResult<MutexGuard<'a, T>> {
        match self.0.try_lock() {
            Ok(t) => Ok(MutexGuard(t)),
            Err(sync::TryLockError::Poisoned(e)) => Ok(MutexGuard(e.into_inner())),
            Err(sync::TryLockError::WouldBlock) => Err(TryLockError(())),
        }
    }

    /// Like `std::sync::Mutex::get_mut`.
    pub fn get_mut(&mut self) -> &mut T {
        self.0.get_mut().unwrap_or_else(|e| e.into_inner())
    }
}

/// Like `std::sync::MutexGuard`.
#[must_use]
pub struct MutexGuard<'a, T: ?Sized + 'a>(sync::MutexGuard<'a, T>);

impl<'a, T: ?Sized> Deref for MutexGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.0.deref()
    }
}

impl<'a, T: ?Sized> DerefMut for MutexGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut T {
        self.0.deref_mut()
    }
}

/// Like `std::sync::TryLockResult`.
pub type TryLockResult<T> = Result<T, TryLockError>;

/// Like `std::sync::TryLockError`.
#[derive(Debug)]
pub struct TryLockError(());

impl fmt::Display for TryLockError {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.write_str(self.description())
    }
}

impl Error for TryLockError {
    fn description(&self) -> &str {
        "try_lock failed because the operation would block"
    }
}

/// Like `std::sync::RwLock` except that it does not poison itself.
pub struct RwLock<T: ?Sized>(sync::RwLock<T>);

impl<T> RwLock<T> {
    /// Like `std::sync::RwLock::new`.
    pub fn new(t: T) -> RwLock<T> {
        RwLock(sync::RwLock::new(t))
    }

    /// Like `std::sync::RwLock::into_inner`.
    pub fn into_inner(self) -> T where T: Sized {
        self.0.into_inner().unwrap_or_else(|e| e.into_inner())
    }
}

impl<T: ?Sized> RwLock<T> {
    /// Like `std::sync::RwLock::read`.
    pub fn read<'a>(&'a self) -> RwLockReadGuard<'a, T> {
        RwLockReadGuard(self.0.read().unwrap_or_else(|e| e.into_inner()))
    }

    /// Like `std::sync::RwLock::try_read`.
    pub fn try_read<'a>(&'a self) -> TryLockResult<RwLockReadGuard<'a, T>> {
        match self.0.try_read() {
            Ok(t) => Ok(RwLockReadGuard(t)),
            Err(sync::TryLockError::Poisoned(e)) => Ok(RwLockReadGuard(e.into_inner())),
            Err(sync::TryLockError::WouldBlock) => Err(TryLockError(())),
        }
    }

    /// Like `std::sync::RwLock::write`.
    pub fn write<'a>(&'a self) -> RwLockWriteGuard<'a, T> {
        RwLockWriteGuard(self.0.write().unwrap_or_else(|e| e.into_inner()))
    }

    /// Like `std::sync::RwLock::try_write`.
    pub fn try_write<'a>(&'a self) -> TryLockResult<RwLockWriteGuard<'a, T>> {
        match self.0.try_write() {
            Ok(t) => Ok(RwLockWriteGuard(t)),
            Err(sync::TryLockError::Poisoned(e)) => Ok(RwLockWriteGuard(e.into_inner())),
            Err(sync::TryLockError::WouldBlock) => Err(TryLockError(())),
        }
    }

    /// Like `std::sync::RwLock::get_mut`.
    pub fn get_mut(&mut self) -> &mut T {
        self.0.get_mut().unwrap_or_else(|e| e.into_inner())
    }
}

/// Like `std::sync::RwLockReadGuard`.
#[must_use]
pub struct RwLockReadGuard<'a, T: ?Sized + 'a>(sync::RwLockReadGuard<'a, T>);

impl<'a, T: ?Sized> Deref for RwLockReadGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.0.deref()
    }
}

/// Like `std::sync::RwLockWriteGuard`.
#[must_use]
pub struct RwLockWriteGuard<'a, T: ?Sized + 'a>(sync::RwLockWriteGuard<'a, T>);

impl<'a, T: ?Sized> Deref for RwLockWriteGuard<'a, T> {
    type Target = T;

    fn deref(&self) -> &T {
        self.0.deref()
    }
}

impl<'a, T: ?Sized> DerefMut for RwLockWriteGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut T {
        self.0.deref_mut()
    }
}
<|endoftext|>


<commit_before>extern crate git2;
extern crate chrono;

#[macro_use]
extern crate nom;

use git2::{ObjectType, Oid, Repository};
use chrono::{UTC, TimeZone, Datelike};
use nom::{IResult, alpha, alphanumeric, digit, newline, rest, space};

use std::fmt;
use std::str;

#[derive(Debug)]
pub enum GitJournalError {
    GitError(git2::Error),
    ParserError,
    CommitMessageLengthError,
}

pub struct GitJournal {
    repo: Repository,
    tags: Vec<(Oid, String)>,
}

impl From<git2::Error> for GitJournalError {
    fn from(err: git2::Error) -> GitJournalError {
        GitJournalError::GitError(err)
    }
}

impl fmt::Display for GitJournalError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            GitJournalError::GitError(ref err) => write!(f, "Git error: {}", err),
            GitJournalError::ParserError => write!(f, "Parser error."),
            GitJournalError::CommitMessageLengthError => write!(f, "Commit message length too small."),
        }
    }
}

impl GitJournal {
    /// Constructs a new `GitJournal`.
    pub fn new(path: &str) -> Result<GitJournal, GitJournalError> {
        // Open the repository
        let new_repo = try!(Repository::open(path));

        // Get all available tags in some vector of tuples
        let mut new_tags = vec![];
        for name in try!(new_repo.tag_names(None)).iter() {
            let name = try!(name.ok_or(git2::Error::from_str("Could not receive tag name")));
            let obj = try!(new_repo.revparse_single(name));
            if let Ok(tag) = obj.into_tag() {
                let tag_name = try!(tag.name().ok_or(git2::Error::from_str("Could not parse tag name"))).to_owned();
                new_tags.push((tag.target_id(), tag_name));
            }
        }

        // Return the git journal object
        Ok(GitJournal {
            repo: new_repo,
            tags: new_tags,
        })
    }

    /// Parses a revision range for a `GitJournal`.
    pub fn parse_log(&self,
                     revision_range: &str,
                     tag_skip_pattern: &str,
                     max_tags_count: &u32,
                     all: &bool)
                     -> Result<(), GitJournalError> {

        let mut revwalk = try!(self.repo.revwalk());
        revwalk.set_sorting(git2::SORT_TIME);

        // Fill the revwalk with the selected revisions.
        let revspec = try!(self.repo.revparse(&revision_range));
        if revspec.mode().contains(git2::REVPARSE_SINGLE) {
            // A single commit was given
            let from = try!(revspec.from().ok_or(git2::Error::from_str("Could not set revision range start")));
            try!(revwalk.push(from.id()));
        } else {
            // A specific commit range was given
            let from = try!(revspec.from().ok_or(git2::Error::from_str("Could not set revision range start")));
            let to = try!(revspec.to().ok_or(git2::Error::from_str("Could not set revision range end")));
            try!(revwalk.push(to.id()));
            if revspec.mode().contains(git2::REVPARSE_MERGE_BASE) {
                let base = try!(self.repo.merge_base(from.id(), to.id()));
                let o = try!(self.repo.find_object(base, Some(ObjectType::Commit)));
                try!(revwalk.push(o.id()));
            }
            try!(revwalk.hide(from.id()));
        }

        // Iterate over the git objects and collect them in a vector of tuples
        let mut result: Vec<(String, Vec<String>)> = vec![];
        let mut current_entries: Vec<String> = vec![];
        let today = UTC::today();
        let mut parsed_tags: u32 = 1;
        let mut current_tag = format!("Unreleased ({}-{}-{})",
                                      today.year(),
                                      today.month(),
                                      today.day());
        'revloop: for (index, id) in revwalk.enumerate() {
            let oid = try!(id);
            let commit = try!(self.repo.find_commit(oid));
            for tag in self.tags
                .iter()
                .filter(|tag| tag.0.as_bytes() == oid.as_bytes() && !tag.1.contains(tag_skip_pattern)) {

                // Parsing entries of the last tag done
                if !current_entries.is_empty() {
                    result.push((current_tag.clone(), current_entries.clone()));
                    current_entries.clear();
                }

                // If a single revision is given stop at the first seen tag
                if !all && index > 0 && parsed_tags > *max_tags_count {
                    break 'revloop;
                }

                // Format the tag and set as current
                parsed_tags += 1;
                let date = UTC.timestamp(commit.time().seconds(), 0).date();
                current_tag = format!("{} ({}-{}-{})",
                                      tag.1,
                                      date.year(),
                                      date.month(),
                                      date.day());
            }
            // Add the commit message to the current entries of the tag
            let message = try!(commit.message().ok_or(git2::Error::from_str("Could not parse commit message")));
            match self.parse_commit_message(message) {
                Ok(parsed_message) => current_entries.push(parsed_message),
                Err(e) => println!("Skip commit: {}", e),
            }
        }
        // Add the last processed items as well
        if !current_entries.is_empty() {
            result.push((current_tag, current_entries));
        }

        // Print for testing purposes
        for (tag, mut commits) in result {
            println!("\n{}:", tag);
            commits.sort();
            for commit in commits {
                println!("{}", commit);
            }
        }
        Ok(())
    }

    /// Parses a single commit message and returns a changelog ready form
    fn parse_commit_message(&self, message: &str) -> Result<String, GitJournalError> {
        named!(commit_parser<(&str, &str, Vec<&str>)>,
            chain!(
                separated_pair!(alpha, char!('-'), digit)? ~
                space? ~
                cat: map_res!(
                    alt!(
                        tag!("Added") |
                        tag!("Changed") |
                        tag!("Fixed") |
                        tag!("Improved") |
                        tag!("Removed") |
                        tag!("Changed")),
                str::from_utf8) ~
                sum: map_res!(
                    take_until!("\n"),
                    str::from_utf8
                ) ~
                many1!(newline) ~
                items: many0!(
                    map_res!(
                        chain!(
                            tag!("-") ~
                            space? ~
                            r: take_until!("\n") ~
                            many1!(newline),
                            || r
                        ),
                        str::from_utf8
                    )
                ) ~
                rest,
            || (cat, sum, items))
        );
        match commit_parser(message.as_bytes()) {
             IResult::Done(_, parsed) => {
                 return Ok(format!("- [{}]{}{}", parsed.0, parsed.1, parsed.2.join("\n    - ")));
             },
             _ => {
                 println!("Could not parse:\n{}\n", message.lines().nth(0).unwrap());
                 return Err(GitJournalError::ParserError);
             },
        };
    }
}
<commit_msg>Dont use unused includes<commit_after>extern crate git2;
extern crate chrono;

#[macro_use]
extern crate nom;

use git2::{ObjectType, Oid, Repository};
use chrono::{UTC, TimeZone, Datelike};
use nom::{IResult, alpha, digit, newline, rest, space};

use std::fmt;
use std::str;

#[derive(Debug)]
pub enum GitJournalError {
    GitError(git2::Error),
    ParserError,
    CommitMessageLengthError,
}

pub struct GitJournal {
    repo: Repository,
    tags: Vec<(Oid, String)>,
}

impl From<git2::Error> for GitJournalError {
    fn from(err: git2::Error) -> GitJournalError {
        GitJournalError::GitError(err)
    }
}

impl fmt::Display for GitJournalError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            GitJournalError::GitError(ref err) => write!(f, "Git error: {}", err),
            GitJournalError::ParserError => write!(f, "Parser error."),
            GitJournalError::CommitMessageLengthError => write!(f, "Commit message length too small."),
        }
    }
}

impl GitJournal {
    /// Constructs a new `GitJournal`.
    pub fn new(path: &str) -> Result<GitJournal, GitJournalError> {
        // Open the repository
        let new_repo = try!(Repository::open(path));

        // Get all available tags in some vector of tuples
        let mut new_tags = vec![];
        for name in try!(new_repo.tag_names(None)).iter() {
            let name = try!(name.ok_or(git2::Error::from_str("Could not receive tag name")));
            let obj = try!(new_repo.revparse_single(name));
            if let Ok(tag) = obj.into_tag() {
                let tag_name = try!(tag.name().ok_or(git2::Error::from_str("Could not parse tag name"))).to_owned();
                new_tags.push((tag.target_id(), tag_name));
            }
        }

        // Return the git journal object
        Ok(GitJournal {
            repo: new_repo,
            tags: new_tags,
        })
    }

    /// Parses a revision range for a `GitJournal`.
    pub fn parse_log(&self,
                     revision_range: &str,
                     tag_skip_pattern: &str,
                     max_tags_count: &u32,
                     all: &bool)
                     -> Result<(), GitJournalError> {

        let mut revwalk = try!(self.repo.revwalk());
        revwalk.set_sorting(git2::SORT_TIME);

        // Fill the revwalk with the selected revisions.
        let revspec = try!(self.repo.revparse(&revision_range));
        if revspec.mode().contains(git2::REVPARSE_SINGLE) {
            // A single commit was given
            let from = try!(revspec.from().ok_or(git2::Error::from_str("Could not set revision range start")));
            try!(revwalk.push(from.id()));
        } else {
            // A specific commit range was given
            let from = try!(revspec.from().ok_or(git2::Error::from_str("Could not set revision range start")));
            let to = try!(revspec.to().ok_or(git2::Error::from_str("Could not set revision range end")));
            try!(revwalk.push(to.id()));
            if revspec.mode().contains(git2::REVPARSE_MERGE_BASE) {
                let base = try!(self.repo.merge_base(from.id(), to.id()));
                let o = try!(self.repo.find_object(base, Some(ObjectType::Commit)));
                try!(revwalk.push(o.id()));
            }
            try!(revwalk.hide(from.id()));
        }

        // Iterate over the git objects and collect them in a vector of tuples
        let mut result: Vec<(String, Vec<String>)> = vec![];
        let mut current_entries: Vec<String> = vec![];
        let today = UTC::today();
        let mut parsed_tags: u32 = 1;
        let mut current_tag = format!("Unreleased ({}-{}-{})",
                                      today.year(),
                                      today.month(),
                                      today.day());
        'revloop: for (index, id) in revwalk.enumerate() {
            let oid = try!(id);
            let commit = try!(self.repo.find_commit(oid));
            for tag in self.tags
                .iter()
                .filter(|tag| tag.0.as_bytes() == oid.as_bytes() && !tag.1.contains(tag_skip_pattern)) {

                // Parsing entries of the last tag done
                if !current_entries.is_empty() {
                    result.push((current_tag.clone(), current_entries.clone()));
                    current_entries.clear();
                }

                // If a single revision is given stop at the first seen tag
                if !all && index > 0 && parsed_tags > *max_tags_count {
                    break 'revloop;
                }

                // Format the tag and set as current
                parsed_tags += 1;
                let date = UTC.timestamp(commit.time().seconds(), 0).date();
                current_tag = format!("{} ({}-{}-{})",
                                      tag.1,
                                      date.year(),
                                      date.month(),
                                      date.day());
            }
            // Add the commit message to the current entries of the tag
            let message = try!(commit.message().ok_or(git2::Error::from_str("Could not parse commit message")));
            match self.parse_commit_message(message) {
                Ok(parsed_message) => current_entries.push(parsed_message),
                Err(e) => println!("Skip commit: {}", e),
            }
        }
        // Add the last processed items as well
        if !current_entries.is_empty() {
            result.push((current_tag, current_entries));
        }

        // Print for testing purposes
        for (tag, mut commits) in result {
            println!("\n{}:", tag);
            commits.sort();
            for commit in commits {
                println!("{}", commit);
            }
        }
        Ok(())
    }

    /// Parses a single commit message and returns a changelog ready form
    fn parse_commit_message(&self, message: &str) -> Result<String, GitJournalError> {
        named!(commit_parser<(&str, &str, Vec<&str>)>,
            chain!(
                separated_pair!(alpha, char!('-'), digit)? ~
                space? ~
                cat: map_res!(
                    alt!(
                        tag!("Added") |
                        tag!("Changed") |
                        tag!("Fixed") |
                        tag!("Improved") |
                        tag!("Removed") |
                        tag!("Changed")),
                str::from_utf8) ~
                sum: map_res!(
                    take_until!("\n"),
                    str::from_utf8
                ) ~
                many1!(newline) ~
                items: many0!(
                    map_res!(
                        chain!(
                            tag!("-") ~
                            space? ~
                            r: take_until!("\n") ~
                            many1!(newline),
                            || r
                        ),
                        str::from_utf8
                    )
                ) ~
                rest,
            || (cat, sum, items))
        );
        match commit_parser(message.as_bytes()) {
             IResult::Done(_, parsed) => {
                 return Ok(format!("- [{}]{}{}", parsed.0, parsed.1, parsed.2.join("\n    - ")));
             },
             _ => {
                 println!("Could not parse:\n{}\n", message.lines().nth(0).unwrap());
                 return Err(GitJournalError::ParserError);
             },
        };
    }
}
<|endoftext|>


<commit_before>// Filebuffer -- Fast and simple file reading
// Copyright 2016 Ruud van Asseldonk
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// A copy of the License has been included in the root of the repository.

//! Filebuffer, a library for fast and simple file reading.
//!
//! # Examples
//!
//! Map a file into memory and access it as a slice of bytes. This is simple and will generally
//! outperform `Read::read_to_end()`.
//!
//! ```
//! use filebuffer::FileBuffer;
//! let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
//! assert_eq!(&fbuffer[3..45], &b"Filebuffer -- Fast and simple file reading"[..]);
//! ```

#![warn(missing_docs)]

use std::cmp;
use std::io;
use std::fs;
use std::ops::Deref;
use std::path::Path;
use std::ptr;
use std::slice;

#[cfg(unix)]
mod unix;

#[cfg(windows)]
mod windows;

#[cfg(unix)]
use unix::{PlatformData, get_resident, get_page_size, map_file, unmap_file, prefetch};

#[cfg(windows)]
use windows::{PlatformData, get_resident, get_page_size, map_file, unmap_file, prefetch};

/// A memory-mapped file.
///
/// # Safety
///
/// **On Unix-ish platforms, external modifications to the file made after the `FileBuffer` was
/// opened can show up in this `FileBuffer`.** On Windows it is possible to prevent this by opening
/// the file in exclusive mode, but that functionality is not available in stable Rust currently.
/// (Filestream will be updated after stabilization.)
///
/// It is recommended to ensure that other applications do not write to the file when it is mapped,
/// possibly by marking the file read-only. (Though even this is no guarantee.)
pub struct FileBuffer {
    page_size: usize,
    buffer: *const u8,
    length: usize,

    #[allow(dead_code)] // This field is not dead, it might have an effectful destructor.
    platform_data: PlatformData,
}

/// Rounds `size` up to the nearest multiple of `power_of_two`.
fn round_up_to(size: usize, power_of_two: usize) -> usize {
    (size + (power_of_two - 1)) & !(power_of_two - 1)
}

#[test]
fn verify_round_up_to() {
    assert_eq!(1024, round_up_to(23, 1024));
    assert_eq!(1024, round_up_to(1024, 1024));
    assert_eq!(2048, round_up_to(1025, 1024));
}

/// Rounds `size` down to the nearest multiple of `power_of_two`.
fn round_down_to(size: usize, power_of_two: usize) -> usize {
    size & !(power_of_two - 1)
}

#[test]
fn verify_round_down_to() {
    assert_eq!(0, round_down_to(23, 1024));
    assert_eq!(1024, round_down_to(1024, 1024));
    assert_eq!(1024, round_down_to(1025, 1024));
}

impl FileBuffer {
    /// Maps the file at `path` into memory.
    pub fn open<P: AsRef<Path>>(path: P) -> io::Result<FileBuffer> {
        // Open the `fs::File` so we get all of std's error handling for free, then use it to
        // extract the file descriptor. The file is closed again when `map_file` returns on
        // Unix-ish platforms, but `mmap` only requires the descriptor to be open for the `mmap`
        // call, so this is fine. On Windows, the file must be kept open for the lifetime of the
        // mapping, so `map_file` moves the file into the platform data.
        let mut open_opts = fs::OpenOptions::new();
        open_opts.read(true);

        // TODO: On Windows, set `share_mode()` to read-only. This requires the `open_options_ext`
        // feature that is currently unstable, but it is required to ensure that a different
        // process does not suddenly modify the contents of the file.

        let file = try!(open_opts.open(path));
        let (buffer, length, platform_data) = try!(map_file(file));
        let fbuffer = FileBuffer {
            page_size: get_page_size(),
            buffer: buffer,
            length: length,
            platform_data: platform_data
        };
        Ok(fbuffer)
    }

    /// Returns the number of bytes resident in physical memory, starting from `offset`.
    ///
    /// The slice `[offset..offset + resident_len]` can be accessed without causing page faults or
    /// disk access. Note that this is only a snapshot, and the kernel might decide to evict pages
    /// or make them resident at any time.
    ///
    /// The returned resident length is at most `length`.
    ///
    /// # Panics
    ///
    /// Panics if the specified range lies outside of the buffer.
    ///
    /// # Remarks
    ///
    /// Windows does not expose a mechanism to query which pages are resident in physical
    /// memory. Therefore this function optimistically claims that the entire range is resident
    /// on Windows.
    pub fn resident_len(&self, offset: usize, length: usize) -> usize {
        // The specified offset and length must lie within the buffer.
        assert!(offset + length <= self.length);

        // This is a no-op for empty files.
        if self.buffer == ptr::null() { return 0; }

        let aligned_offset = round_down_to(offset, self.page_size);
        let aligned_length = round_up_to(length + (offset - aligned_offset), self.page_size);
        let num_pages = aligned_length / self.page_size;

        // There is a tradeoff here: to store residency information, we need an array of booleans.
        // The requested range can potentially be very large and it is only known at runtime. We
        // could allocate a vector here, but that requires a heap allocation just to get residency
        // information (which might in turn cause a page fault). Instead, check at most 32 pages at
        // once. This means more syscalls for large ranges, but it saves us the heap allocation,
        // and for ranges up to 32 pages (128 KiB typically) there is only one syscall.
        let mut residency = [false; 32];
        let mut pages_checked = 0;
        let mut pages_resident = 0;

        while pages_checked < num_pages {
            let pages_to_check = cmp::min(32, num_pages - pages_checked);
            let check_offset = (aligned_offset + pages_checked * self.page_size) as isize;
            let check_buffer = unsafe { self.buffer.offset(check_offset) };
            let check_length = pages_to_check * self.page_size;
            get_resident(check_buffer, check_length, &mut residency);

            // Count the number of resident pages.
            match residency[..pages_to_check].iter().position(|resident| !resident) {
                Some(non_resident) => {
                    // The index of the non-resident page is the number of resident pages.
                    pages_resident += non_resident;
                    break;
                }
                None => {
                    pages_resident += pages_to_check;
                    pages_checked += pages_to_check;
                }
            }
        }

        let resident_length = pages_resident * self.page_size + aligned_offset - offset;

        // Never return more than the requested length. The resident length might be larger than
        // the length of the buffer, because it is rounded up to the page size.
        cmp::min(length, resident_length)
    }

    /// Returns the system page size.
    ///
    /// When the kernel makes the file resident in physical memory, it does so with page
    /// granularity. (In practice this happens in larger chunks, but still in multiples of
    /// the page size.) Therefore, when processing the file in chunks, this is a good chunk
    /// length.
    pub fn chunk_len_hint(&self) -> usize {
        self.page_size
    }

    /// Advises the kernel to make a slice of the file resident in physical memory.
    ///
    /// This method does not block, meaning that when the function returns, the slice is not
    /// necessarily resident. After this function returns, the kernel may read the requested slice
    /// from disk and make it resident. Note that this is only an advice, the kernel need not honor
    /// it.
    ///
    /// To check whether the slice is resident at a later time, use `resident_len()`.
    ///
    /// # Panics
    ///
    /// Panics if the specified range lies outside of the buffer.
    pub fn prefetch(&self, offset: usize, length: usize) {
        // The specified offset and length must lie within the buffer.
        assert!(offset + length <= self.length);

        // This is a no-op for empty files.
        if self.buffer == ptr::null() { return; }

        let aligned_offset = round_down_to(offset, self.page_size);
        let aligned_length = round_up_to(length + (offset - aligned_offset), self.page_size);

        let buffer = unsafe { self.buffer.offset(aligned_offset as isize) };
        prefetch(buffer, aligned_length);
    }

    /// Leaks the file buffer as a byte slice.
    ///
    /// This prevents the buffer from being freed, keeping the file mapped until the program ends.
    /// This is not as bad as it sounds, because the kernel is free to evict pages from physical
    /// memory in case of memory pressure. Because the file is mapped read-only, it can always be
    /// read from disk again.
    ///
    /// If the file buffer is going to be open for the entire duration of the program anyway, this
    /// method can avoid some lifetime issues. Still, it is good practice to close the file buffer
    /// if possible.
    pub fn leak(mut self) -> &'static [u8] {
        let buffer = unsafe { slice::from_raw_parts(self.buffer, self.length) };

        // Prevent `drop()` from freeing the buffer.
        self.buffer = ptr::null();
        self.length = 0;

        buffer
    }
}

// There is no possibility of data races when passing `&FileBuffer` across threads,
// because the buffer is read-only. `&FileBuffer` has no interior mutability.
unsafe impl Sync for FileBuffer {}

// It is safe to move a `FileBuffer` into a different thread.
unsafe impl Send for FileBuffer {}

impl Drop for FileBuffer {
    fn drop(&mut self) {
        if self.buffer != ptr::null() { unmap_file(self.buffer, self.length); }
    }
}

impl Deref for FileBuffer {
    type Target = [u8];

    fn deref(&self) -> &[u8] {
        unsafe { slice::from_raw_parts(self.buffer, self.length) }
    }
}

#[test]
fn open_file() {
    let fbuffer = FileBuffer::open("src/lib.rs");
    assert!(fbuffer.is_ok());
}

#[test]
fn make_resident() {
    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();

    // Touch the first page to make it resident.
    assert_eq!(&fbuffer[3..13], &b"Filebuffer"[..]);

    // Now at least that part should be resident.
    assert_eq!(fbuffer.resident_len(3, 10), 10);
}

#[test]
fn prefetch_is_not_harmful() {
    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();

    // It is impossible to test that this actually works without root access to instruct the kernel
    // to drop its caches, but at least we can verify that calling `prefetch` is not harmful.
    fbuffer.prefetch(0, fbuffer.len());

    // Reading from the file should still work as normal.
    assert_eq!(&fbuffer[3..13], &b"Filebuffer"[..]);
}

#[test]
fn drop_after_leak() {
    let mut bytes = &[0u8][..];
    assert_eq!(bytes[0], 0);
    {
        let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
        bytes = fbuffer.leak();
    }
    assert_eq!(&bytes[3..13], &b"Filebuffer"[..]);
}

#[test]
fn fbuffer_can_be_moved_into_thread() {
    use std::thread;

    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
    thread::spawn(move || {
        assert_eq!(&fbuffer[3..13], &b"Filebuffer"[..]);
    });
}

#[test]
fn fbuffer_can_be_shared_among_threads() {
    use std::sync;
    use std::thread;

    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
    let buffer1 = sync::Arc::new(fbuffer);
    let buffer2 = buffer1.clone();
    thread::spawn(move || {
        assert_eq!(&buffer2[3..13], &b"Filebuffer"[..]);
    });
    assert_eq!(&buffer1[17..45], &b"Fast and simple file reading"[..]);
}

#[test]
fn open_empty_file_is_fine() {
    FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
}

#[test]
fn empty_file_prefetch_is_fine() {
    let fbuffer = FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
    fbuffer.prefetch(0, 0);
}

#[test]
fn empty_file_deref_is_fine() {
    let fbuffer = FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
    assert_eq!(fbuffer.iter().any(|_| true), false);
}

#[test]
fn empty_file_has_zero_resident_len() {
    let fbuffer = FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
    assert_eq!(fbuffer.resident_len(0, 0), 0);
}

#[test]
fn page_size_at_least_4096() {
    // There is no reason why the page size cannot be smaller, it is just that in practice there
    // is no platform with a smaller page size, so this tests that `get_page_size()` returns
    // a plausible value.
    assert!(get_page_size() >= 4096);
}
<commit_msg>Improve documentation<commit_after>// Filebuffer -- Fast and simple file reading
// Copyright 2016 Ruud van Asseldonk
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// A copy of the License has been included in the root of the repository.

//! Filebuffer, a library for fast and simple file reading.
//!
//! # Examples
//!
//! Map a file into memory and access it as a slice of bytes. This is simple and will generally
//! outperform `Read::read_to_end()`.
//!
//! ```
//! use filebuffer::FileBuffer;
//! let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
//! assert_eq!(&fbuffer[3..45], &b"Filebuffer -- Fast and simple file reading"[..]);
//! ```

#![warn(missing_docs)]

use std::cmp;
use std::io;
use std::fs;
use std::ops::Deref;
use std::path::Path;
use std::ptr;
use std::slice;

#[cfg(unix)]
mod unix;

#[cfg(windows)]
mod windows;

#[cfg(unix)]
use unix::{PlatformData, get_resident, get_page_size, map_file, unmap_file, prefetch};

#[cfg(windows)]
use windows::{PlatformData, get_resident, get_page_size, map_file, unmap_file, prefetch};

/// A memory-mapped file.
///
/// # Safety
///
/// **On Unix-ish platforms, external modifications to the file made after the file buffer was
/// opened can show up in this file buffer.** In particular, if a file is truncated after opening,
/// accessing the removed part causes undefined behavior. On Windows it is possible to prevent this
/// by opening the file in exclusive mode, but that functionality is not available in stable Rust
/// currently. (Filestream will be updated after stabilization.)
///
/// It is recommended to ensure that other applications do not write to the file when it is mapped,
/// possibly by marking the file read-only. (Though even this is no guarantee.)
pub struct FileBuffer {
    page_size: usize,
    buffer: *const u8,
    length: usize,

    #[allow(dead_code)] // This field is not dead, it might have an effectful destructor.
    platform_data: PlatformData,
}

/// Rounds `size` up to the nearest multiple of `power_of_two`.
fn round_up_to(size: usize, power_of_two: usize) -> usize {
    (size + (power_of_two - 1)) & !(power_of_two - 1)
}

#[test]
fn verify_round_up_to() {
    assert_eq!(1024, round_up_to(23, 1024));
    assert_eq!(1024, round_up_to(1024, 1024));
    assert_eq!(2048, round_up_to(1025, 1024));
}

/// Rounds `size` down to the nearest multiple of `power_of_two`.
fn round_down_to(size: usize, power_of_two: usize) -> usize {
    size & !(power_of_two - 1)
}

#[test]
fn verify_round_down_to() {
    assert_eq!(0, round_down_to(23, 1024));
    assert_eq!(1024, round_down_to(1024, 1024));
    assert_eq!(1024, round_down_to(1025, 1024));
}

impl FileBuffer {
    /// Maps the file at `path` into memory.
    pub fn open<P: AsRef<Path>>(path: P) -> io::Result<FileBuffer> {
        // Open the `fs::File` so we get all of std's error handling for free, then use it to
        // extract the file descriptor. The file is closed again when `map_file` returns on
        // Unix-ish platforms, but `mmap` only requires the descriptor to be open for the `mmap`
        // call, so this is fine. On Windows, the file must be kept open for the lifetime of the
        // mapping, so `map_file` moves the file into the platform data.
        let mut open_opts = fs::OpenOptions::new();
        open_opts.read(true);

        // TODO: On Windows, set `share_mode()` to read-only. This requires the `open_options_ext`
        // feature that is currently unstable, but it is required to ensure that a different
        // process does not suddenly modify the contents of the file.

        let file = try!(open_opts.open(path));
        let (buffer, length, platform_data) = try!(map_file(file));
        let fbuffer = FileBuffer {
            page_size: get_page_size(),
            buffer: buffer,
            length: length,
            platform_data: platform_data
        };
        Ok(fbuffer)
    }

    /// Returns the number of bytes resident in physical memory, starting from `offset`.
    ///
    /// The slice `[offset..offset + resident_len]` can be accessed without causing page faults or
    /// disk access. Note that this is only a snapshot, and the kernel might decide to evict pages
    /// or make them resident at any time.
    ///
    /// The returned resident length is at most `length`.
    ///
    /// # Panics
    ///
    /// Panics if the specified range lies outside of the buffer.
    ///
    /// # Remarks
    ///
    /// Windows does not expose a mechanism to query which pages are resident in physical
    /// memory. Therefore this function optimistically claims that the entire range is resident
    /// on Windows.
    pub fn resident_len(&self, offset: usize, length: usize) -> usize {
        // The specified offset and length must lie within the buffer.
        assert!(offset + length <= self.length);

        // This is a no-op for empty files.
        if self.buffer == ptr::null() { return 0; }

        let aligned_offset = round_down_to(offset, self.page_size);
        let aligned_length = round_up_to(length + (offset - aligned_offset), self.page_size);
        let num_pages = aligned_length / self.page_size;

        // There is a tradeoff here: to store residency information, we need an array of booleans.
        // The requested range can potentially be very large and it is only known at runtime. We
        // could allocate a vector here, but that requires a heap allocation just to get residency
        // information (which might in turn cause a page fault). Instead, check at most 32 pages at
        // once. This means more syscalls for large ranges, but it saves us the heap allocation,
        // and for ranges up to 32 pages (128 KiB typically) there is only one syscall.
        let mut residency = [false; 32];
        let mut pages_checked = 0;
        let mut pages_resident = 0;

        while pages_checked < num_pages {
            let pages_to_check = cmp::min(32, num_pages - pages_checked);
            let check_offset = (aligned_offset + pages_checked * self.page_size) as isize;
            let check_buffer = unsafe { self.buffer.offset(check_offset) };
            let check_length = pages_to_check * self.page_size;
            get_resident(check_buffer, check_length, &mut residency);

            // Count the number of resident pages.
            match residency[..pages_to_check].iter().position(|resident| !resident) {
                Some(non_resident) => {
                    // The index of the non-resident page is the number of resident pages.
                    pages_resident += non_resident;
                    break;
                }
                None => {
                    pages_resident += pages_to_check;
                    pages_checked += pages_to_check;
                }
            }
        }

        let resident_length = pages_resident * self.page_size + aligned_offset - offset;

        // Never return more than the requested length. The resident length might be larger than
        // the length of the buffer, because it is rounded up to the page size.
        cmp::min(length, resident_length)
    }

    /// Returns the system page size.
    ///
    /// When the kernel makes the file resident in physical memory, it does so with page
    /// granularity. (In practice this happens in larger chunks, but still in multiples of
    /// the page size.) Therefore, when processing the file in chunks, this is a good chunk
    /// length.
    pub fn chunk_len_hint(&self) -> usize {
        self.page_size
    }

    /// Advises the kernel to make a slice of the file resident in physical memory.
    ///
    /// This method does not block, meaning that when the function returns, the slice is not
    /// necessarily resident. After this function returns, the kernel may read the requested slice
    /// from disk and make it resident. Note that this is only an advice, the kernel need not honor
    /// it.
    ///
    /// To check whether the slice is resident at a later time, use `resident_len()`.
    ///
    /// # Panics
    ///
    /// Panics if the specified range lies outside of the buffer.
    pub fn prefetch(&self, offset: usize, length: usize) {
        // The specified offset and length must lie within the buffer.
        assert!(offset + length <= self.length);

        // This is a no-op for empty files.
        if self.buffer == ptr::null() { return; }

        let aligned_offset = round_down_to(offset, self.page_size);
        let aligned_length = round_up_to(length + (offset - aligned_offset), self.page_size);

        let buffer = unsafe { self.buffer.offset(aligned_offset as isize) };
        prefetch(buffer, aligned_length);
    }

    /// Leaks the file buffer as a byte slice.
    ///
    /// This prevents the buffer from being unmapped, keeping the file mapped until the program
    /// ends. This is not as bad as it sounds, because the kernel is free to evict pages from
    /// physical memory in case of memory pressure. Because the file is mapped read-only, it can
    /// always be read from disk again.
    ///
    /// If the file buffer is going to be open for the entire duration of the program anyway, this
    /// method can avoid some lifetime issues. Still, it is good practice to close the file buffer
    /// if possible. This method should be a last resort.
    pub fn leak(mut self) -> &'static [u8] {
        let buffer = unsafe { slice::from_raw_parts(self.buffer, self.length) };

        // Prevent `drop()` from freeing the buffer.
        self.buffer = ptr::null();
        self.length = 0;

        buffer
    }
}

// There is no possibility of data races when passing `&FileBuffer` across threads,
// because the buffer is read-only. `&FileBuffer` has no interior mutability.
unsafe impl Sync for FileBuffer {}

// It is safe to move a `FileBuffer` into a different thread.
unsafe impl Send for FileBuffer {}

impl Drop for FileBuffer {
    fn drop(&mut self) {
        if self.buffer != ptr::null() { unmap_file(self.buffer, self.length); }
    }
}

impl Deref for FileBuffer {
    type Target = [u8];

    fn deref(&self) -> &[u8] {
        unsafe { slice::from_raw_parts(self.buffer, self.length) }
    }
}

#[test]
fn open_file() {
    let fbuffer = FileBuffer::open("src/lib.rs");
    assert!(fbuffer.is_ok());
}

#[test]
fn make_resident() {
    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();

    // Touch the first page to make it resident.
    assert_eq!(&fbuffer[3..13], &b"Filebuffer"[..]);

    // Now at least that part should be resident.
    assert_eq!(fbuffer.resident_len(3, 10), 10);
}

#[test]
fn prefetch_is_not_harmful() {
    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();

    // It is impossible to test that this actually works without root access to instruct the kernel
    // to drop its caches, but at least we can verify that calling `prefetch` is not harmful.
    fbuffer.prefetch(0, fbuffer.len());

    // Reading from the file should still work as normal.
    assert_eq!(&fbuffer[3..13], &b"Filebuffer"[..]);
}

#[test]
fn drop_after_leak() {
    let mut bytes = &[0u8][..];
    assert_eq!(bytes[0], 0);
    {
        let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
        bytes = fbuffer.leak();
    }
    assert_eq!(&bytes[3..13], &b"Filebuffer"[..]);
}

#[test]
fn fbuffer_can_be_moved_into_thread() {
    use std::thread;

    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
    thread::spawn(move || {
        assert_eq!(&fbuffer[3..13], &b"Filebuffer"[..]);
    });
}

#[test]
fn fbuffer_can_be_shared_among_threads() {
    use std::sync;
    use std::thread;

    let fbuffer = FileBuffer::open("src/lib.rs").unwrap();
    let buffer1 = sync::Arc::new(fbuffer);
    let buffer2 = buffer1.clone();
    thread::spawn(move || {
        assert_eq!(&buffer2[3..13], &b"Filebuffer"[..]);
    });
    assert_eq!(&buffer1[17..45], &b"Fast and simple file reading"[..]);
}

#[test]
fn open_empty_file_is_fine() {
    FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
}

#[test]
fn empty_file_prefetch_is_fine() {
    let fbuffer = FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
    fbuffer.prefetch(0, 0);
}

#[test]
fn empty_file_deref_is_fine() {
    let fbuffer = FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
    assert_eq!(fbuffer.iter().any(|_| true), false);
}

#[test]
fn empty_file_has_zero_resident_len() {
    let fbuffer = FileBuffer::open("src/empty_file_for_testing.rs").unwrap();
    assert_eq!(fbuffer.resident_len(0, 0), 0);
}

#[test]
fn page_size_at_least_4096() {
    // There is no reason why the page size cannot be smaller, it is just that in practice there
    // is no platform with a smaller page size, so this tests that `get_page_size()` returns
    // a plausible value.
    assert!(get_page_size() >= 4096);
}
<|endoftext|>


<commit_before>//! Ropey is a utf8 text rope for Rust.  It is fast, robust, and can handle
//! huge texts and memory-incoherent edits with ease.
//!
//! Ropey's atomic unit of text is Unicode scalar values (or `char`s in Rust)
//! encoded as utf8.  All of Ropey's editing and slicing operations are done
//! in terms of char indices which prevents accidental creation of invalid
//! utf8 data.
//!
//! The library is made up of four main components:
//!
//! - [`Rope`](struct.Rope.html): the main rope type.
//! - [`RopeSlice`](struct.RopeSlice.html): an immutable view into part of a
//!   `Rope`.
//! - [`iter`](iter/index.html): iterators over `Rope`/`RopeSlice` data.
//! - [`RopeBuilder`](struct.RopeBuilder.html): an efficient incremental
//!   `Rope` builder.
//!
//!
//! # A Basic Example
//!
//! Let's say we want to open up a text file, replace the 516th line (the
//! writing was terrible!), and save it back to disk.  It's contrived, but will
//! give a good sampling of the APIs and how they work together.
//!
//! ```no_run
//! # use std::io::Result;
//! use std::fs::File;
//! use std::io::{BufReader, BufWriter};
//! use ropey::Rope;
//!
//! # fn do_stuff() -> Result<()> {
//! // Load a text file.
//! let mut text = Rope::from_reader(
//!     BufReader::new(File::open("my_great_book.txt")?)
//! )?;
//!
//! // Print the 516th line (zero-indexed) to see the terrible
//! // writing.
//! println!("{}", text.line(515));
//!
//! // Get the start/end char indices of the line.
//! let start_idx = text.line_to_char(515);
//! let end_idx = text.line_to_char(516);
//!
//! // Remove the line...
//! text.remove(start_idx..end_idx);
//!
//! // ...and replace it with something better.
//! text.insert(start_idx, "The flowers are... so... dunno.\n");
//!
//! // Print the changes, along with the previous few lines for context.
//! let start_idx = text.line_to_char(511);
//! let end_idx = text.line_to_char(516);
//! println!("{}", text.slice(start_idx..end_idx));
//!
//! // Write the file back out to disk.
//! text.write_to(
//!     BufWriter::new(File::create("my_great_book.txt")?)
//! )?;
//! # Ok(())
//! # }
//! # do_stuff().unwrap();
//! ```
//!
//! More examples can be found in the `examples` directory of the git
//! repository.  Many of those examples demonstrate doing non-trivial things
//! with Ropey such grapheme handling, search-and-replace, and streaming
//! loading of non-utf8 text files.
//!
//!
//! # Low-level APIs
//!
//! Ropey also provides access to some of its low-level APIs, enabling client
//! code to efficiently work with a `Rope`'s data and implement new
//! functionality.  The most important of those API's are:
//!
//! - The [`chunk_at_*()`](struct.Rope.html#method.chunk_at_byte)
//!   chunk-fetching methods of `Rope` and `RopeSlice`.
//! - The [`Chunks`](iter/struct.Chunks.html) iterator.
//! - The functions in [`str_utils`](str_utils/index.html) for operating on
//!   `&str` slices.
//!
//! Internally, each `Rope` stores text as a segemented collection of utf8
//! strings.  The chunk-fetching methods and `Chunks` iterator provide direct
//! access to those strings (or "chunks") as `&str` slices, allowing client
//! code to work directly with the underlying utf8 data.
//!
//! The chunk-fetching methods and `str_utils` functions are the basic
//! building blocks that Ropey itself uses to build much of its functionality.
//! For example, the [`Rope::byte_to_char()`](struct.Rope.html#method.byte_to_char)
//! method can be reimplemented as a free function like this:
//!
//! ```no_run
//! use ropey::{
//!     Rope,
//!     str_utils::byte_to_char_idx
//! };
//!
//! fn byte_to_char(rope: &Rope, byte_idx: usize) -> usize {
//!     let (chunk, b, c, _) = rope.chunk_at_byte(byte_idx);
//!     c + byte_to_char_idx(chunk, byte_idx - b)
//! }
//! ```
//!
//! And this will be just as efficient as Ropey's implementation.
//!
//! The chunk-fetching methods in particular are among the fastest functions
//! that Ropey provides, generally operating in the sub-hundred nanosecond
//! range for medium-sized (~200kB) documents on recent-ish computer systems.
//!
//!
//! # A Note About Line Endings
//!
//! Some of Ropey's APIs use the concept of line breaks or lines of text.  In
//! all such APIs, Ropey treats the following unicode sequences as line
//! breaks:
//!
//! - `U+000A`          — LF (Line Feed)
//! - `U+000B`          — VT (Vertical Tab)
//! - `U+000C`          — FF (Form Feed)
//! - `U+000D`          — CR (Carriage Return)
//! - `U+0085`          — NEL (Next Line)
//! - `U+2028`          — Line Separator
//! - `U+2029`          — Paragraph Separator
//! - `U+000D` `U+000A` — CRLF (Carriage Return + Line Feed)
//!
//! Additionally, Ropey treats line breaks as being a part of the line that
//! they mark the end of.  That is to say, lines begin immediately _after_ a
//! line break.
//!
//! CRLF pairs are always treated as a single line break, and are never split
//! across chunks.  Note, however, that slicing can still split them.

#![allow(clippy::collapsible_if)]
#![allow(clippy::inline_always)]
#![allow(clippy::needless_return)]
#![allow(clippy::redundant_field_names)]
#![allow(clippy::type_complexity)]

extern crate smallvec;

mod crlf;
mod rope;
mod rope_builder;
mod slice;
mod tree;

pub mod iter;
pub mod str_utils;

pub use rope::Rope;
pub use rope_builder::RopeBuilder;
pub use slice::RopeSlice;
<commit_msg>Fix minor typo in documentation.<commit_after>//! Ropey is a utf8 text rope for Rust.  It is fast, robust, and can handle
//! huge texts and memory-incoherent edits with ease.
//!
//! Ropey's atomic unit of text is Unicode scalar values (or `char`s in Rust)
//! encoded as utf8.  All of Ropey's editing and slicing operations are done
//! in terms of char indices which prevents accidental creation of invalid
//! utf8 data.
//!
//! The library is made up of four main components:
//!
//! - [`Rope`](struct.Rope.html): the main rope type.
//! - [`RopeSlice`](struct.RopeSlice.html): an immutable view into part of a
//!   `Rope`.
//! - [`iter`](iter/index.html): iterators over `Rope`/`RopeSlice` data.
//! - [`RopeBuilder`](struct.RopeBuilder.html): an efficient incremental
//!   `Rope` builder.
//!
//!
//! # A Basic Example
//!
//! Let's say we want to open up a text file, replace the 516th line (the
//! writing was terrible!), and save it back to disk.  It's contrived, but will
//! give a good sampling of the APIs and how they work together.
//!
//! ```no_run
//! # use std::io::Result;
//! use std::fs::File;
//! use std::io::{BufReader, BufWriter};
//! use ropey::Rope;
//!
//! # fn do_stuff() -> Result<()> {
//! // Load a text file.
//! let mut text = Rope::from_reader(
//!     BufReader::new(File::open("my_great_book.txt")?)
//! )?;
//!
//! // Print the 516th line (zero-indexed) to see the terrible
//! // writing.
//! println!("{}", text.line(515));
//!
//! // Get the start/end char indices of the line.
//! let start_idx = text.line_to_char(515);
//! let end_idx = text.line_to_char(516);
//!
//! // Remove the line...
//! text.remove(start_idx..end_idx);
//!
//! // ...and replace it with something better.
//! text.insert(start_idx, "The flowers are... so... dunno.\n");
//!
//! // Print the changes, along with the previous few lines for context.
//! let start_idx = text.line_to_char(511);
//! let end_idx = text.line_to_char(516);
//! println!("{}", text.slice(start_idx..end_idx));
//!
//! // Write the file back out to disk.
//! text.write_to(
//!     BufWriter::new(File::create("my_great_book.txt")?)
//! )?;
//! # Ok(())
//! # }
//! # do_stuff().unwrap();
//! ```
//!
//! More examples can be found in the `examples` directory of the git
//! repository.  Many of those examples demonstrate doing non-trivial things
//! with Ropey such as grapheme handling, search-and-replace, and streaming
//! loading of non-utf8 text files.
//!
//!
//! # Low-level APIs
//!
//! Ropey also provides access to some of its low-level APIs, enabling client
//! code to efficiently work with a `Rope`'s data and implement new
//! functionality.  The most important of those API's are:
//!
//! - The [`chunk_at_*()`](struct.Rope.html#method.chunk_at_byte)
//!   chunk-fetching methods of `Rope` and `RopeSlice`.
//! - The [`Chunks`](iter/struct.Chunks.html) iterator.
//! - The functions in [`str_utils`](str_utils/index.html) for operating on
//!   `&str` slices.
//!
//! Internally, each `Rope` stores text as a segemented collection of utf8
//! strings.  The chunk-fetching methods and `Chunks` iterator provide direct
//! access to those strings (or "chunks") as `&str` slices, allowing client
//! code to work directly with the underlying utf8 data.
//!
//! The chunk-fetching methods and `str_utils` functions are the basic
//! building blocks that Ropey itself uses to build much of its functionality.
//! For example, the [`Rope::byte_to_char()`](struct.Rope.html#method.byte_to_char)
//! method can be reimplemented as a free function like this:
//!
//! ```no_run
//! use ropey::{
//!     Rope,
//!     str_utils::byte_to_char_idx
//! };
//!
//! fn byte_to_char(rope: &Rope, byte_idx: usize) -> usize {
//!     let (chunk, b, c, _) = rope.chunk_at_byte(byte_idx);
//!     c + byte_to_char_idx(chunk, byte_idx - b)
//! }
//! ```
//!
//! And this will be just as efficient as Ropey's implementation.
//!
//! The chunk-fetching methods in particular are among the fastest functions
//! that Ropey provides, generally operating in the sub-hundred nanosecond
//! range for medium-sized (~200kB) documents on recent-ish computer systems.
//!
//!
//! # A Note About Line Endings
//!
//! Some of Ropey's APIs use the concept of line breaks or lines of text.  In
//! all such APIs, Ropey treats the following unicode sequences as line
//! breaks:
//!
//! - `U+000A`          — LF (Line Feed)
//! - `U+000B`          — VT (Vertical Tab)
//! - `U+000C`          — FF (Form Feed)
//! - `U+000D`          — CR (Carriage Return)
//! - `U+0085`          — NEL (Next Line)
//! - `U+2028`          — Line Separator
//! - `U+2029`          — Paragraph Separator
//! - `U+000D` `U+000A` — CRLF (Carriage Return + Line Feed)
//!
//! Additionally, Ropey treats line breaks as being a part of the line that
//! they mark the end of.  That is to say, lines begin immediately _after_ a
//! line break.
//!
//! CRLF pairs are always treated as a single line break, and are never split
//! across chunks.  Note, however, that slicing can still split them.

#![allow(clippy::collapsible_if)]
#![allow(clippy::inline_always)]
#![allow(clippy::needless_return)]
#![allow(clippy::redundant_field_names)]
#![allow(clippy::type_complexity)]

extern crate smallvec;

mod crlf;
mod rope;
mod rope_builder;
mod slice;
mod tree;

pub mod iter;
pub mod str_utils;

pub use rope::Rope;
pub use rope_builder::RopeBuilder;
pub use slice::RopeSlice;
<|endoftext|>


<commit_before>//! `gel` is an extension of sebcrozet's `nalgebra` crate, designed to facilitate OpenGL
//! mathematics.

extern crate num;
extern crate nalgebra;
extern crate glium;
extern crate rustc_serialize;

use glium::uniforms::{
    AsUniformValue,
    UniformValue,
    UniformBlock,
};

pub use num::{
    One,
    Zero,
};

pub use nalgebra::*;
/// A trait for objects able to be extended.
pub trait Extend<N> {
    type Output;

    fn extend(&self, N) -> Self::Output;
}

/// A trait for objects able to be truncated.
pub trait Truncate {
    type Output;

    fn truncate(&self) -> Self::Output;
}

/// A trait for objects able to construct view matrices.
pub trait LookAt<N> {
    fn look_at(camera: &Vec3<N>, target: &Vec3<N>, up: &Vec3<N>) -> Self;
}

impl<N> Extend<N> for Vec0<N>
    where N: Copy
{
    type Output = Vec1<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec1::new(elem)
    }
}

impl<N> Extend<N> for Vec1<N>
    where N: Copy
{
    type Output = Vec2<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec2::new(self.x, elem)
    }
}

impl<N> Extend<N> for Vec2<N>
    where N: Copy
{
    type Output = Vec3<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec3::new(self.x, self.y, elem)
    }
}

impl<N> Extend<N> for Vec3<N>
    where N: Copy
{
    type Output = Vec4<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec4::new(self.x, self.y, self.z, elem)
    }
}

impl<N> Extend<N> for Vec4<N>
    where N: Copy
{
    type Output = Vec5<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec5::new(self.x, self.y, self.z, self.w, elem)
    }
}

impl<N> Extend<N> for Vec5<N>
    where N: Copy
{
    type Output = Vec6<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec6::new(self.x, self.y, self.z, self.w, self.a, elem)
    }
}

impl<N> Truncate for Vec1<N>
    where N: Copy
{
    type Output = Vec0<N>;

    fn truncate(&self) -> Self::Output {
        Vec0::new()
    }
}

impl<N> Truncate for Vec2<N>
    where N: Copy
{
    type Output = Vec1<N>;

    fn truncate(&self) -> Self::Output {
        Vec1::new(self.x)
    }
}

impl<N> Truncate for Vec3<N>
    where N: Copy
{
    type Output = Vec2<N>;

    fn truncate(&self) -> Self::Output {
        Vec2::new(self.x, self.y)
    }
}

impl<N> Truncate for Vec4<N>
    where N: Copy
{
    type Output = Vec3<N>;

    fn truncate(&self) -> Self::Output {
        Vec3::new(self.x, self.y, self.z)
    }
}

impl<N> Truncate for Vec5<N>
    where N: Copy
{
    type Output = Vec4<N>;

    fn truncate(&self) -> Self::Output {
        Vec4::new(self.x, self.y, self.z, self.w)
    }
}

impl<N> Truncate for Vec6<N>
    where N: Copy
{
    type Output = Vec5<N>;

    fn truncate(&self) -> Self::Output {
        Vec5::new(self.x, self.y, self.z, self.w, self.a)
    }
}

impl<N> Extend<N> for Pnt0<N>
    where N: Copy
{
    type Output = Pnt1<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt1::new(elem)
    }
}

impl<N> Extend<N> for Pnt1<N>
    where N: Copy
{
    type Output = Pnt2<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt2::new(self.x, elem)
    }
}

impl<N> Extend<N> for Pnt2<N>
    where N: Copy
{
    type Output = Pnt3<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt3::new(self.x, self.y, elem)
    }
}

impl<N> Extend<N> for Pnt3<N>
    where N: Copy
{
    type Output = Pnt4<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt4::new(self.x, self.y, self.z, elem)
    }
}

impl<N> Extend<N> for Pnt4<N>
    where N: Copy
{
    type Output = Pnt5<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt5::new(self.x, self.y, self.z, self.w, elem)
    }
}

impl<N> Extend<N> for Pnt5<N>
    where N: Copy
{
    type Output = Pnt6<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt6::new(self.x, self.y, self.z, self.w, self.a, elem)
    }
}

impl<N> Truncate for Pnt1<N>
    where N: Copy
{
    type Output = Pnt0<N>;

    fn truncate(&self) -> Self::Output {
        Pnt0::new()
    }
}

impl<N> Truncate for Pnt2<N>
    where N: Copy
{
    type Output = Pnt1<N>;

    fn truncate(&self) -> Self::Output {
        Pnt1::new(self.x)
    }
}

impl<N> Truncate for Pnt3<N>
    where N: Copy
{
    type Output = Pnt2<N>;

    fn truncate(&self) -> Self::Output {
        Pnt2::new(self.x, self.y)
    }
}

impl<N> Truncate for Pnt4<N>
    where N: Copy
{
    type Output = Pnt3<N>;

    fn truncate(&self) -> Self::Output {
        Pnt3::new(self.x, self.y, self.z)
    }
}

impl<N> Truncate for Pnt5<N>
    where N: Copy
{
    type Output = Pnt4<N>;

    fn truncate(&self) -> Self::Output {
        Pnt4::new(self.x, self.y, self.z, self.w)
    }
}

impl<N> Truncate for Pnt6<N>
    where N: Copy
{
    type Output = Pnt5<N>;

    fn truncate(&self) -> Self::Output {
        Pnt5::new(self.x, self.y, self.z, self.w, self.a)
    }
}

impl<N> LookAt<N> for Mat4<N>
    where N: BaseFloat
{
    fn look_at(camera: &Vec3<N>, target: &Vec3<N>, up: &Vec3<N>) -> Self {
        let zaxis = (*target - *camera).normalize();
        let xaxis = zaxis.cross(up).normalize();
        let yaxis = xaxis.cross(&zaxis);

        let mut result = Self::one();

        result.m11 = xaxis.x;
        result.m12 = xaxis.y;
        result.m13 = xaxis.z;
        result.m21 = yaxis.x;
        result.m22 = yaxis.y;
        result.m23 = yaxis.z;
        result.m31 = -zaxis.x;
        result.m32 = -zaxis.y;
        result.m33 = -zaxis.z;
        result.m14 = -(xaxis.dot(camera));
        result.m24 = -(yaxis.dot(camera));
        result.m34 = zaxis.dot(camera);

        result
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, RustcDecodable, RustcEncodable)]
pub struct Perspective<N> {
    mat: Mat4<N>,
}

impl<N> Perspective<N>
    where N: BaseFloat
{
    pub fn new(fov: N, aspect: N, znear: N, zfar: N) -> Perspective<N> {
        let one = N::one();
        let two = one + one;

        let tan_half_fov = (fov / two).tan();

        let mut mat = Mat4::zero();

        mat.m11 = one / (aspect * tan_half_fov);
        mat.m22 = one / (tan_half_fov);
        mat.m33 = -(zfar + znear) / (zfar - znear);
        mat.m43 = -one;
        mat.m34 = -(two * zfar * znear) / (zfar - znear);

        Perspective {
            mat: mat,
        }
    }

    pub fn aspect(&self) -> N {
        self.mat.m22 / self.mat.m11
    }

    pub fn set_aspect(&mut self, aspect: N) {
        self.mat.m11 = self.mat.m22 / aspect;
    }

    pub fn as_mat<'a>(&'a self) -> &'a Mat4<N> {
        &self.mat
    }

}

impl<N> Perspective<N>
    where N: BaseFloat + Clone
{
    pub fn to_mat(&self) -> Mat4<N> {
        self.mat.clone()
    }
}

impl AsUniformValue for Perspective<f32> {
    fn as_uniform_value(&self) -> UniformValue {
        let val = self.to_mat();
        UniformValue::Mat4(*val.as_array())
    }
}

impl UniformBlock for Perspective<f32> {
    fn matches(layout: &glium::program::BlockLayout, base_offset: usize)
        -> Result<(), glium::uniforms::LayoutMismatchError>
    {
        use glium::program::BlockLayout;
        use glium::uniforms::LayoutMismatchError;
        use glium::uniforms::UniformType;

        if let &BlockLayout::BasicType { ty, offset_in_buffer } = layout {
            if ty != UniformType::FloatMat4 {
                return Err(LayoutMismatchError::TypeMismatch {
                    expected: ty,
                    obtained: UniformType::FloatMat4,
                });
            }

            if offset_in_buffer != base_offset {
                return Err(LayoutMismatchError::OffsetMismatch {
                    expected: offset_in_buffer,
                    obtained: base_offset,
                });
            }

            Ok(())
        } else {
            Err(LayoutMismatchError::LayoutMismatch {
                expected: layout.clone(),
                obtained: BlockLayout::BasicType {
                    ty: UniformType::FloatMat4,
                    offset_in_buffer: base_offset,
                }
            })
        }
    }

    #[inline]
    fn build_layout(base_offset: usize) -> glium::program::BlockLayout {
        use glium::program::BlockLayout;
        use glium::uniforms::UniformType;

        BlockLayout::BasicType {
            ty: UniformType::FloatMat4,
            offset_in_buffer: base_offset,
        }
    }
}
pub fn radians<N>(n: N) -> N
    where N: BaseFloat
{
    n * (N::pi() / <N as Cast<f64>>::from(180.0))
}

pub fn degrees<N>(n: N) -> N
    where N: BaseFloat
{
    n * (<N as Cast<f64>>::from(180.0) / N::pi())
}

pub fn extend<T, N>(base: T, elem: N) -> T::Output
    where T: Extend<N>
{
    base.extend(elem)
}

pub fn truncate<T>(base: T) -> T::Output
    where T: Truncate
{
    base.truncate()
}

<commit_msg>new look at<commit_after>//! `gel` is an extension of sebcrozet's `nalgebra` crate, designed to facilitate OpenGL
//! mathematics.

extern crate num;
extern crate nalgebra;
extern crate glium;
extern crate rustc_serialize;

use glium::uniforms::{
    AsUniformValue,
    UniformValue,
    UniformBlock,
};

pub use num::{
    One,
    Zero,
};

pub use nalgebra::*;
/// A trait for objects able to be extended.
pub trait Extend<N> {
    type Output;

    fn extend(&self, N) -> Self::Output;
}

/// A trait for objects able to be truncated.
pub trait Truncate {
    type Output;

    fn truncate(&self) -> Self::Output;
}

/// A trait for objects able to construct view matrices.
pub trait LookAt<N> {
    fn look_at(camera: &Vec3<N>, target: &Vec3<N>, up: &Vec3<N>) -> Self;
}

impl<N> Extend<N> for Vec0<N>
    where N: Copy
{
    type Output = Vec1<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec1::new(elem)
    }
}

impl<N> Extend<N> for Vec1<N>
    where N: Copy
{
    type Output = Vec2<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec2::new(self.x, elem)
    }
}

impl<N> Extend<N> for Vec2<N>
    where N: Copy
{
    type Output = Vec3<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec3::new(self.x, self.y, elem)
    }
}

impl<N> Extend<N> for Vec3<N>
    where N: Copy
{
    type Output = Vec4<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec4::new(self.x, self.y, self.z, elem)
    }
}

impl<N> Extend<N> for Vec4<N>
    where N: Copy
{
    type Output = Vec5<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec5::new(self.x, self.y, self.z, self.w, elem)
    }
}

impl<N> Extend<N> for Vec5<N>
    where N: Copy
{
    type Output = Vec6<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Vec6::new(self.x, self.y, self.z, self.w, self.a, elem)
    }
}

impl<N> Truncate for Vec1<N>
    where N: Copy
{
    type Output = Vec0<N>;

    fn truncate(&self) -> Self::Output {
        Vec0::new()
    }
}

impl<N> Truncate for Vec2<N>
    where N: Copy
{
    type Output = Vec1<N>;

    fn truncate(&self) -> Self::Output {
        Vec1::new(self.x)
    }
}

impl<N> Truncate for Vec3<N>
    where N: Copy
{
    type Output = Vec2<N>;

    fn truncate(&self) -> Self::Output {
        Vec2::new(self.x, self.y)
    }
}

impl<N> Truncate for Vec4<N>
    where N: Copy
{
    type Output = Vec3<N>;

    fn truncate(&self) -> Self::Output {
        Vec3::new(self.x, self.y, self.z)
    }
}

impl<N> Truncate for Vec5<N>
    where N: Copy
{
    type Output = Vec4<N>;

    fn truncate(&self) -> Self::Output {
        Vec4::new(self.x, self.y, self.z, self.w)
    }
}

impl<N> Truncate for Vec6<N>
    where N: Copy
{
    type Output = Vec5<N>;

    fn truncate(&self) -> Self::Output {
        Vec5::new(self.x, self.y, self.z, self.w, self.a)
    }
}

impl<N> Extend<N> for Pnt0<N>
    where N: Copy
{
    type Output = Pnt1<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt1::new(elem)
    }
}

impl<N> Extend<N> for Pnt1<N>
    where N: Copy
{
    type Output = Pnt2<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt2::new(self.x, elem)
    }
}

impl<N> Extend<N> for Pnt2<N>
    where N: Copy
{
    type Output = Pnt3<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt3::new(self.x, self.y, elem)
    }
}

impl<N> Extend<N> for Pnt3<N>
    where N: Copy
{
    type Output = Pnt4<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt4::new(self.x, self.y, self.z, elem)
    }
}

impl<N> Extend<N> for Pnt4<N>
    where N: Copy
{
    type Output = Pnt5<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt5::new(self.x, self.y, self.z, self.w, elem)
    }
}

impl<N> Extend<N> for Pnt5<N>
    where N: Copy
{
    type Output = Pnt6<N>;

    fn extend(&self, elem: N) -> Self::Output {
        Pnt6::new(self.x, self.y, self.z, self.w, self.a, elem)
    }
}

impl<N> Truncate for Pnt1<N>
    where N: Copy
{
    type Output = Pnt0<N>;

    fn truncate(&self) -> Self::Output {
        Pnt0::new()
    }
}

impl<N> Truncate for Pnt2<N>
    where N: Copy
{
    type Output = Pnt1<N>;

    fn truncate(&self) -> Self::Output {
        Pnt1::new(self.x)
    }
}

impl<N> Truncate for Pnt3<N>
    where N: Copy
{
    type Output = Pnt2<N>;

    fn truncate(&self) -> Self::Output {
        Pnt2::new(self.x, self.y)
    }
}

impl<N> Truncate for Pnt4<N>
    where N: Copy
{
    type Output = Pnt3<N>;

    fn truncate(&self) -> Self::Output {
        Pnt3::new(self.x, self.y, self.z)
    }
}

impl<N> Truncate for Pnt5<N>
    where N: Copy
{
    type Output = Pnt4<N>;

    fn truncate(&self) -> Self::Output {
        Pnt4::new(self.x, self.y, self.z, self.w)
    }
}

impl<N> Truncate for Pnt6<N>
    where N: Copy
{
    type Output = Pnt5<N>;

    fn truncate(&self) -> Self::Output {
        Pnt5::new(self.x, self.y, self.z, self.w, self.a)
    }
}

impl<N> LookAt<N> for Mat4<N>
    where N: BaseFloat
{
    fn look_at(camera: &Vec3<N>, target: &Vec3<N>, up: &Vec3<N>) -> Self {
        let zaxis = (*target - *camera).normalize();
        let xaxis = zaxis.cross(up).normalize();
        let yaxis = xaxis.cross(&zaxis);

        let mut result = Self::one();

        result.m11 = xaxis.x;
        result.m12 = xaxis.y;
        result.m13 = xaxis.z;
        result.m21 = yaxis.x;
        result.m22 = yaxis.y;
        result.m23 = yaxis.z;
        result.m31 = -zaxis.x;
        result.m32 = -zaxis.y;
        result.m33 = -zaxis.z;
        result.m14 = -(xaxis.dot(camera));
        result.m24 = -(yaxis.dot(camera));
        result.m34 = zaxis.dot(camera);

        result
    }
}

impl<N> LookAt<N> for Rot3<N>
    where N: BaseFloat
{
    fn look_at(camera: &Vec3<N>, target: &Vec3<N>, up: &Vec3<N>) -> Self {
        let zaxis = (*target - *camera).normalize();
        let xaxis = zaxis.cross(up).normalize();
        let yaxis = xaxis.cross(&zaxis);

        let mat = Mat3::new(xaxis.x, xaxis.y, xaxis.z,
                            yaxis.x, yaxis.y, yaxis.z,
                            -zaxis.x, -zaxis.y, -zaxis.z);

        unsafe {
            Rot3::new_with_mat(mat)
        }
    }
}

impl<N> LookAt<N> for Iso3<N>
    where N: BaseFloat
{
    fn look_at(camera: &Vec3<N>, target: &Vec3<N>, up: &Vec3<N>) -> Self {
        let rotmat = LookAt::look_at(camera, target, up);
        Iso3::new_with_rotmat(*camera, rotmat)
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, RustcDecodable, RustcEncodable)]
pub struct Perspective<N> {
    mat: Mat4<N>,
}

impl<N> Perspective<N>
    where N: BaseFloat
{
    pub fn new(fov: N, aspect: N, znear: N, zfar: N) -> Perspective<N> {
        let one = N::one();
        let two = one + one;

        let tan_half_fov = (fov / two).tan();

        let mut mat = Mat4::zero();

        mat.m11 = one / (aspect * tan_half_fov);
        mat.m22 = one / (tan_half_fov);
        mat.m33 = -(zfar + znear) / (zfar - znear);
        mat.m43 = -one;
        mat.m34 = -(two * zfar * znear) / (zfar - znear);

        Perspective {
            mat: mat,
        }
    }

    pub fn aspect(&self) -> N {
        self.mat.m22 / self.mat.m11
    }

    pub fn set_aspect(&mut self, aspect: N) {
        self.mat.m11 = self.mat.m22 / aspect;
    }

    pub fn as_mat<'a>(&'a self) -> &'a Mat4<N> {
        &self.mat
    }

}

impl<N> Perspective<N>
    where N: BaseFloat + Clone
{
    pub fn to_mat(&self) -> Mat4<N> {
        self.mat.clone()
    }
}

impl AsUniformValue for Perspective<f32> {
    fn as_uniform_value(&self) -> UniformValue {
        let val = self.to_mat();
        UniformValue::Mat4(*val.as_array())
    }
}

impl UniformBlock for Perspective<f32> {
    fn matches(layout: &glium::program::BlockLayout, base_offset: usize)
        -> Result<(), glium::uniforms::LayoutMismatchError>
    {
        use glium::program::BlockLayout;
        use glium::uniforms::LayoutMismatchError;
        use glium::uniforms::UniformType;

        if let &BlockLayout::BasicType { ty, offset_in_buffer } = layout {
            if ty != UniformType::FloatMat4 {
                return Err(LayoutMismatchError::TypeMismatch {
                    expected: ty,
                    obtained: UniformType::FloatMat4,
                });
            }

            if offset_in_buffer != base_offset {
                return Err(LayoutMismatchError::OffsetMismatch {
                    expected: offset_in_buffer,
                    obtained: base_offset,
                });
            }

            Ok(())
        } else {
            Err(LayoutMismatchError::LayoutMismatch {
                expected: layout.clone(),
                obtained: BlockLayout::BasicType {
                    ty: UniformType::FloatMat4,
                    offset_in_buffer: base_offset,
                }
            })
        }
    }

    #[inline]
    fn build_layout(base_offset: usize) -> glium::program::BlockLayout {
        use glium::program::BlockLayout;
        use glium::uniforms::UniformType;

        BlockLayout::BasicType {
            ty: UniformType::FloatMat4,
            offset_in_buffer: base_offset,
        }
    }
}
pub fn radians<N>(n: N) -> N
    where N: BaseFloat
{
    n * (N::pi() / <N as Cast<f64>>::from(180.0))
}

pub fn degrees<N>(n: N) -> N
    where N: BaseFloat
{
    n * (<N as Cast<f64>>::from(180.0) / N::pi())
}

pub fn extend<T, N>(base: T, elem: N) -> T::Output
    where T: Extend<N>
{
    base.extend(elem)
}

pub fn truncate<T>(base: T) -> T::Output
    where T: Truncate
{
    base.truncate()
}

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