neo-decompiler 0.10.1

Neo N3 NEF decompiler: parse, disassemble, lift bytecode to high-level pseudocode and C# skeletons, with a CLI, JSON reports, and optional WebAssembly bindings.
Documentation 
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use crate::decompiler::ir::{BinOp, Literal, UnaryOp};
use crate::instruction::{Instruction, OpCode, Operand};

/// Resolve the syscall stack effect `(params popped, returns value?)` from the
/// embedded syscall hash. Unknown hashes are conservatively modelled as
/// `(0, true)` so a result slot is reserved.
pub(super) fn syscall_effect(instr: &Instruction) -> (usize, bool) {
    if let Some(Operand::Syscall(hash)) = &instr.operand {
        if let Some(info) = crate::syscalls::lookup(*hash) {
            return (info.param_count as usize, info.returns_value);
        }
    }
    (0, true)
}

/// Lower a push opcode with its operand to a literal, if it is one.
pub(super) fn literal_for_push(op: OpCode, instr: &Instruction) -> Option<Literal> {
    use OpCode::*;
    match op {
        Push0 => Some(Literal::Int(0)),
        Push1 => Some(Literal::Int(1)),
        Push2 => Some(Literal::Int(2)),
        Push3 => Some(Literal::Int(3)),
        Push4 => Some(Literal::Int(4)),
        Push5 => Some(Literal::Int(5)),
        Push6 => Some(Literal::Int(6)),
        Push7 => Some(Literal::Int(7)),
        Push8 => Some(Literal::Int(8)),
        Push9 => Some(Literal::Int(9)),
        Push10 => Some(Literal::Int(10)),
        Push11 => Some(Literal::Int(11)),
        Push12 => Some(Literal::Int(12)),
        Push13 => Some(Literal::Int(13)),
        Push14 => Some(Literal::Int(14)),
        Push15 => Some(Literal::Int(15)),
        Push16 => Some(Literal::Int(16)),
        PushM1 => Some(Literal::Int(-1)),
        PushT => Some(Literal::Bool(true)),
        PushF => Some(Literal::Bool(false)),
        PushNull => Some(Literal::Null),
        Pushint8 | Pushint16 | Pushint32 | Pushint64 => match &instr.operand {
            Some(Operand::I8(v)) => Some(Literal::Int(i64::from(*v))),
            Some(Operand::I16(v)) => Some(Literal::Int(i64::from(*v))),
            Some(Operand::I32(v)) => Some(Literal::Int(i64::from(*v))),
            Some(Operand::I64(v)) => Some(Literal::Int(*v)),
            _ => None,
        },
        Pushint128 | Pushint256 => match &instr.operand {
            Some(Operand::Bytes(b)) => Some(Literal::BigInt(hex::encode(b))),
            _ => None,
        },
        Pushdata1 | Pushdata2 | Pushdata4 => match &instr.operand {
            Some(Operand::Bytes(b)) => Some(Literal::Bytes(b.clone())),
            _ => None,
        },
        _ => None,
    }
}

/// Map a binary compute opcode to its IR operator, if applicable.
pub(super) fn binary_op_for(op: OpCode) -> Option<BinOp> {
    use OpCode::*;
    Some(match op {
        Add => BinOp::Add,
        Sub => BinOp::Sub,
        Mul => BinOp::Mul,
        Div => BinOp::Div,
        Mod => BinOp::Mod,
        Pow => BinOp::Pow,
        Shl => BinOp::Shl,
        Shr => BinOp::Shr,
        And => BinOp::And,
        Or => BinOp::Or,
        Xor => BinOp::Xor,
        Equal | Numequal => BinOp::Eq,
        Notequal | Numnotequal => BinOp::Ne,
        Lt => BinOp::Lt,
        Le => BinOp::Le,
        Gt => BinOp::Gt,
        Ge => BinOp::Ge,
        Booland => BinOp::LogicalAnd,
        Boolor => BinOp::LogicalOr,
        _ => return None,
    })
}

/// Map a unary compute opcode to its IR operator, if applicable.
pub(super) fn unary_op_for(op: OpCode) -> Option<UnaryOp> {
    use OpCode::*;
    Some(match op {
        Inc => UnaryOp::Inc,
        Dec => UnaryOp::Dec,
        Negate => UnaryOp::Neg,
        Abs => UnaryOp::Abs,
        Sign => UnaryOp::Sign,
        Not => UnaryOp::LogicalNot,
        Invert => UnaryOp::Not,
        _ => return None,
    })
}

/// A short mnemonic for call-placeholder expressions.
pub(super) fn mnemonic(op: OpCode) -> String {
    format!("{op:?}").to_lowercase()
}