encoding-next 0.3.0

// This is a part of encoding-next.
// Copyright (c) 2013-2015, Kang Seonghoon.
// See README.md and LICENSE.txt for details.

//! Asymmetric or special encoding constructions required by the WHATWG Encoding standard.

use crate::codec;
use crate::types::*;

/// Replacement encoding used to solve a particular attack vector due to mismatching server and
/// client supports for encodings. It is rarely useful outside.
#[derive(Clone, Copy)]
pub struct EncoderOnlyUTF8Encoding;

impl Encoding for EncoderOnlyUTF8Encoding {
    fn name(&self) -> &'static str {
        "encoder-only-utf-8"
    }
    fn whatwg_name(&self) -> Option<&'static str> {
        Some("replacement")
    } // WHATWG compatibility
    fn raw_encoder(&self) -> Box<dyn RawEncoder> {
        codec::utf_8::UTF8Encoding.raw_encoder()
    }
    fn raw_decoder(&self) -> Box<dyn RawDecoder> {
        codec::error::ErrorEncoding.raw_decoder()
    }
}

/// Algorithmic mapping for `x-user-defined` encoding.
pub mod x_user_defined {
    #[inline]
    pub fn forward(code: u8) -> u16 {
        0xf700 | (code as u16)
    }

    #[inline]
    pub fn backward(code: u32) -> u8 {
        if (code & !0x7f) == 0xf780 {
            (code & 0xff) as u8
        } else {
            0
        }
    }
}