1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138

// Copyright 2019 Joel Frank
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
pub mod error;
pub mod instructions;

use hex;
use std::collections::BTreeMap;
use std::io::Cursor;

use instructions::{assemble_instruction, disassemble_next_byte};

pub use error::DisassemblyError;
pub use instructions::Instruction;

#[derive(Clone, Debug)]
pub struct Disassembly {
    pub instructions: BTreeMap<usize, Instruction>,
}

impl Disassembly {
    pub fn from_bytes(bytes: &[u8]) -> Result<Self, DisassemblyError> {
        let instructions = disassemble_bytes(bytes)?;
        Ok(Self { instructions })
    }

    pub fn from_hex_str(input: &str) -> Result<Self, DisassemblyError> {
        let instructions = disassemble_hex_str(input)?;
        Ok(Self { instructions })
    }

    pub fn get(&self, addr: usize) -> Option<Instruction> {
        self.instructions.get(&addr).cloned()
    }
}

pub fn assemble_instructions(disassembly: Vec<Instruction>) -> Vec<u8> {
    let mut result = Vec::new();
    for disas in disassembly {
        result.extend(assemble_instruction(disas));
    }
    result
}

fn disassemble_hex_str(input: &str) -> Result<BTreeMap<usize, Instruction>, DisassemblyError> {
    let input = if input[0..2] == *"0x" {
        &input[2..]
    } else {
        input
    };
    let bytes = hex::decode(input)?;
    disassemble_bytes(&bytes)
}

fn disassemble_bytes(bytes: &[u8]) -> Result<BTreeMap<usize, Instruction>, DisassemblyError> {
    let mut instructions = BTreeMap::new();
    let mut cursor = Cursor::new(bytes);
    loop {
        let result = disassemble_next_byte(&mut cursor);
        match result {
            Err(DisassemblyError::IOError(..)) => break,
            Ok((offset, instruction)) => {
                instructions.insert(offset, instruction);
            }
            Err(err) => {
                return Err(err);
            }
        }
    }

    Ok(instructions)
}

#[cfg(test)]
mod tests {
    use super::*;
    use maplit::hashmap;
    use quickcheck::{quickcheck, TestResult};
    use std::iter::FromIterator;

    #[test]
    fn simple_programm() {
        let program = "0x608040526002610100";
        let program_bytes = vec![0x60, 0x80, 0x40, 0x52, 0x60, 0x02, 0x61, 0x01, 0x00];
        let disas = BTreeMap::from_iter(hashmap! {
            0 => Instruction::Push(vec!(0x80)),
            2 => Instruction::Blockhash,
            3 => Instruction::MStore,
            4 => Instruction::Push(vec!(0x2)),
            6 => Instruction::Push(vec!(0x1, 0x00)),
        });

        assert_eq!(disassemble_hex_str(program).unwrap(), disas);
        assert_eq!(disassemble_bytes(&program_bytes).unwrap(), disas);
    }

    fn disassemble_assemble(xs: &Vec<u8>) -> Result<Vec<u8>, DisassemblyError> {
        let rev = disassemble_bytes(xs);
        let rev: Vec<_> = rev?.values().cloned().collect();
        Ok(assemble_instructions(rev))
    }

    fn disassemble_assemble_is_same(xs: Vec<u8>) -> TestResult {
        match disassemble_assemble(&xs) {
            Ok(rev) => TestResult::from_bool(xs == rev),
            Err(..) => TestResult::discard(),
        }
    }

    #[test]
    fn fuzz_test() {
        quickcheck(disassemble_assemble_is_same as fn(Vec<u8>) -> TestResult);
    }

    #[test]
    fn regression_97_0_0() {
        let vec = vec![97, 0, 0];
        assert_eq!(disassemble_assemble(&vec), Ok(vec));
    }

    #[test]
    fn regression_96() {
        assert_eq!(
            disassemble_assemble(&vec![96]),
            Err(DisassemblyError::TooFewBytesForPush)
        );
    }
}