// Copyright 2015 The Servo Project Developers. See the COPYRIGHT

// file at the top-level directory of this distribution.

//

// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or

// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license

// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your

// option. This file may not be copied, modified, or distributed

// except according to those terms.

use phf_shared;

// FIXME(rust-lang/rust#18153): generate these from an enum

pub const DYNAMIC_TAG: u8 = 0b_00;

pub const INLINE_TAG: u8 = 0b_01; // len in upper nybble

pub const STATIC_TAG: u8 = 0b_10;

pub const TAG_MASK: u64 = 0b_11;

pub const ENTRY_ALIGNMENT: usize = 4; // Multiples have TAG_MASK bits unset, available for tagging.

pub const MAX_INLINE_LEN: usize = 7;

pub const STATIC_SHIFT_BITS: usize = 32;

pub fn pack_static(n: u32) -> u64 {

(STATIC_TAG as u64) | ((n as u64) << STATIC_SHIFT_BITS)

}

pub struct StaticAtomSet {

pub key: u64,

pub disps: &'static [(u32, u32)],

pub atoms: &'static [&'static str],

}

impl StaticAtomSet {

#[inline]

pub fn get_index_or_hash(&self, s: &str) -> Result<u32, u64> {

let hash = phf_shared::hash(s, self.key);

let index = phf_shared::get_index(hash, self.disps, self.atoms.len());

if self.atoms[index as usize] == s {

Ok(index)

} else {

Err(hash)

}

}

#[inline]

pub fn index(&self, i: u32) -> Option<&'static str> {

self.atoms.get(i as usize).map(|&s| s)

}

#[inline]

pub fn iter(&self) -> ::std::slice::Iter<&'static str> {

self.atoms.iter()

}

}