// SPDX-License-Identifier: Apache-2.0

use codicon::{Decoder, Encoder};
use lebicon::{Error, Leb128};

const UVALS: &[u64] = &[
    0,
    1,
    2,
    3,
    4,
    5,
    6,
    7,
    u8::max_value() as u64 - 1,
    u8::max_value() as u64,
    u8::max_value() as u64 + 1,
    u16::max_value() as u64 - 1,
    u16::max_value() as u64,
    u16::max_value() as u64 + 1,
    u32::max_value() as u64 - 1,
    u32::max_value() as u64,
    u32::max_value() as u64 + 1,
    u64::max_value() - 1,
    u64::max_value(),
];

#[test]
fn u64_decode_leb128() {
    use leb128;

    for i in UVALS {
        let mut b = Vec::new();
        let n = leb128::write::unsigned(&mut b, *i).unwrap();
        eprintln!("{:20}: {:?}", *i, b);
        let v = u64::decode(&mut &b[..n], Leb128).unwrap();
        assert_eq!(v, *i);
    }
}

#[test]
fn u64_encode_leb128() {
    use leb128;

    for i in UVALS {
        let mut b = Vec::new();
        i.encode(&mut b, Leb128).unwrap();
        eprintln!("{:20}: {:?}", *i, b);
        let v = leb128::read::unsigned(&mut &b[..]).unwrap();
        assert_eq!(v, *i);
    }
}

const SVALS: &[i64] = &[
    i64::min_value(),
    i64::min_value() + 1,
    i32::min_value() as i64 - 1,
    i32::min_value() as i64,
    i32::min_value() as i64 + 1,
    i16::min_value() as i64 - 1,
    i16::min_value() as i64,
    i16::min_value() as i64 + 1,
    i8::min_value() as i64 - 1,
    i8::min_value() as i64,
    i8::min_value() as i64 + 1,
    -3,
    -2,
    -1,
    0,
    1,
    2,
    3,
    i8::max_value() as i64 - 1,
    i8::max_value() as i64,
    i8::max_value() as i64 + 1,
    i16::max_value() as i64 - 1,
    i16::max_value() as i64,
    i16::max_value() as i64 + 1,
    i32::max_value() as i64 - 1,
    i32::max_value() as i64,
    i32::max_value() as i64 + 1,
    i64::max_value() - 1,
    i64::max_value(),
];

#[test]
fn i64_decode_leb128_i64() {
    use leb128;

    for i in SVALS {
        let mut b = Vec::new();
        let n = leb128::write::signed(&mut b, *i).unwrap();
        eprintln!("{:20}: {:?}", *i, b);
        let v = i64::decode(&mut &b[..n], Leb128).unwrap();
        assert_eq!(v, *i);
    }
}

#[test]
fn i64_encode_leb128() {
    use leb128;

    for i in SVALS {
        let mut b = Vec::new();
        i.encode(&mut b, Leb128).unwrap();
        eprintln!("{:20}: {:?}", *i, b);
        let v = leb128::read::signed(&mut &b[..]).unwrap();
        assert_eq!(v, *i);
    }
}

// http://dwarfstd.org/doc/DWARF4.pdf (p162)
const UDWARF: &'static [(u16, &'static [u8])] = &[
    (2, &[2]),
    (127, &[127]),
    (128, &[0 + 0x80, 1]),
    (129, &[1 + 0x80, 1]),
    (130, &[2 + 0x80, 1]),
    (12857, &[57 + 0x80, 100]),
];

#[test]
fn u16_decode_dwarf() {
    for (i, b) in UDWARF {
        eprintln!("{:20}: {:?}", *i, *b);
        assert_eq!(u16::decode(&mut &**b, Leb128).unwrap(), *i);
    }
}

#[test]
fn u16_encode_dwarf() {
    for (i, b) in UDWARF {
        let mut v = Vec::new();
        i.encode(&mut v, Leb128).unwrap();
        eprintln!("{:20}: {:?}", *i, *b);
        assert_eq!(&v[..], *b);
    }
}

// From http://dwarfstd.org/doc/DWARF4.pdf (p163)
const SDWARF: &'static [(i16, &'static [u8])] = &[
    (2, &[2]),
    (-2, &[0x7e]),
    (127, &[127 + 0x80, 0]),
    (-127, &[1 + 0x80, 0x7f]),
    (128, &[0 + 0x80, 1]),
    (-128, &[0 + 0x80, 0x7f]),
    (129, &[1 + 0x80, 1]),
    (-129, &[0x7f + 0x80, 0x7e]),
];

#[test]
fn i16_decode_dwarf() {
    for (i, b) in SDWARF {
        eprintln!("{:20}: {:?}", *i, *b);
        assert_eq!(i16::decode(&mut &**b, Leb128).unwrap(), *i);
    }
}

#[test]
fn i16_encode_dwarf() {
    for (i, b) in SDWARF {
        let mut v = Vec::new();
        i.encode(&mut v, Leb128).unwrap();
        eprintln!("{:20b}: {:?}", *i, *b);
        assert_eq!(&v[..], *b);
    }
}

fn overflow<T: Decoder<Leb128, Error = Error>>(buf: &[u8]) {
    match T::decode(&mut &buf[..], Leb128) {
        Ok(_) => panic!("Unexpected success!"),
        Err(e) => match e {
            Error::Overflow => (),
            _ => panic!("Unexpected error value!"),
        },
    }
}

#[test]
fn u8_overflow() {
    overflow::<u8>(&[128, 2]);
}

#[test]
fn u16_overflow() {
    overflow::<u16>(&[128, 128, 4]);
}

#[test]
fn u32_overflow() {
    overflow::<u32>(&[128, 128, 128, 128, 16]);
}

#[test]
fn u64_overflow() {
    overflow::<u64>(&[128, 128, 128, 128, 128, 128, 128, 128, 128, 2]);
}

#[test]
fn u128_overflow() {
    overflow::<u128>(&[
        128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 4,
    ]);
}

#[test]
fn i8_overflow() {
    overflow::<i8>(&[128, 1]);
    overflow::<i8>(&[128, 254]);
}

#[test]
fn i16_overflow() {
    overflow::<i8>(&[128, 128, 2]);
    overflow::<i8>(&[128, 128, 252]);
}

#[test]
fn i32_overflow() {
    overflow::<i8>(&[128, 128, 128, 128, 8]);
    overflow::<i8>(&[128, 128, 128, 128, 240]);
}

#[test]
fn i64_overflow() {
    overflow::<i8>(&[128, 128, 128, 128, 128, 128, 128, 128, 128, 1]);
    overflow::<i8>(&[128, 128, 128, 128, 128, 128, 128, 128, 128, 254]);
}

#[test]
fn i128_overflow() {
    overflow::<i128>(&[
        128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 2,
    ]);
    overflow::<i128>(&[
        128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128,
        252,
    ]);
}