Advance this code massively:
main.rs:
use clap::Parser;
use goblin::Object;
use log::{error, info};
use std::fs;
use std::path::PathBuf;

mod disassembler;

use disassembler::Disassembler;

/// Rust Binary Analyzer with Custom Disassembler
#[derive(Parser, Debug)]
#[command(author, version, about, long_about = None)]
struct Args {
    /// Path to the binary file to analyze
    #[arg(short, long, value_name = "FILE")]
    input: PathBuf,
    
    /// Optionally specify the architecture (currently only x86_64 is supported)
    #[arg(short, long, default_value = "x86_64")]
    arch: String,
}

fn main() {
    // Initialize the logger
    env_logger::init();

    // Parse command-line arguments
    let args = Args::parse();

    // Read the binary file
    let buffer = match fs::read(&args.input) {
        Ok(buf) => buf,
        Err(e) => {
            error!("Failed to read file {}: {}", args.input.display(), e);
            return;
        }
    };

    // Parse the binary using goblin
    match Object::parse(&buffer) {
        Ok(Object::Elf(elf)) => {
            info!("Parsed ELF binary");
            analyze_elf(&elf, &buffer, &args.arch);
        }
        Ok(Object::PE(pe)) => {
            info!("Parsed PE binary");
            analyze_pe(&pe, &buffer, &args.arch);
        }
        Ok(_) => {
            error!("Unsupported binary format");
        }
        Err(e) => {
            error!("Failed to parse binary: {}", e);
        }
    }
}

/// Analyze ELF binaries
fn analyze_elf(elf: &goblin::elf::Elf, buffer: &[u8], arch: &str) {
    // Initialize disassembler
    let disassembler = Disassembler::new(arch);

    // Iterate over executable sections
    for section in elf.section_headers.iter() {
        if section.is_executable() {
            let section_name = match elf.shdr_strtab.get_at(section.sh_name) {
                Some(name) => name.to_string(),
                None => "<unknown>".to_string(),
            };
            let section_addr = section.sh_addr;
            let section_size = section.sh_size as usize;
            let section_data = &buffer[section.sh_offset as usize..section.sh_offset as usize + section_size];

            info!("Disassembling section: {} (0x{:x} - 0x{:x})", section_name, section_addr, section_addr + section.sh_size);
            let instructions = disassembler.disassemble(section_data, section_addr);

            for instr in instructions {
                println!("{:#010x}: {}\t{:?}", instr.address, instr.mnemonic, instr.operands);
            }
        }
    }
}

/// Analyze PE binaries
fn analyze_pe(pe: &goblin::pe::PE, buffer: &[u8], arch: &str) {
    // Initialize disassembler
    let disassembler = Disassembler::new(arch);

    // Iterate over executable sections
    for section in pe.sections.iter() {
        if section.characteristics & goblin::pe::section_table::IMAGE_SCN_MEM_EXECUTE != 0 {
            let section_name = String::from_utf8_lossy(&section.name).trim_end_matches('\0').to_string();
            let section_addr = section.virtual_address as u64;
            let section_size = section.virtual_size as usize;
            let section_data = &buffer[section.pointer_to_raw_data as usize..section.pointer_to_raw_data as usize + section_size];

            info!("Disassembling section: {} (0x{:x} - 0x{:x})", section_name, section_addr, section_addr + section.virtual_size as u64);
            let instructions = disassembler.disassemble(section_data, section_addr);

            for instr in instructions {
                println!("{:#010x}: {}\t{:?}", instr.address, instr.mnemonic, instr.operands);
            }
        }
    }
}

disassembler/mod.rs:
pub mod decoder;
pub mod instruction;

use decoder::Decoder;
use instruction::{Instruction, Operand};

/// Disassembler engine
pub struct Disassembler {
    decoder: Decoder,
}

impl Disassembler {
    /// Create a new Disassembler for the specified architecture
    pub fn new(arch: &str) -> Self {
        match arch {
            "x86_64" => Disassembler {
                decoder: Decoder::new_x86_64(),
            },
            _ => {
                panic!("Unsupported architecture: {}", arch);
            }
        }
    }

    /// Disassemble a slice of bytes starting at a given address
    pub fn disassemble(&self, code: &[u8], start_address: u64) -> Vec<Instruction> {
        let mut instructions = Vec::new();
        let mut offset = 0;
        let code_len = code.len();
        let mut current_address = start_address;

        while offset < code_len {
            match self.decoder.decode(&code[offset..], current_address) {
                Ok(instr) => {
                    instructions.push(instr.clone());
                    let instr_len = instr.bytes.len();
                    if instr_len == 0 {
                        // Prevent infinite loop on zero-length instruction
                        break;
                    }
                    offset += instr_len;
                    current_address += instr_len as u64;
                }
                Err(e) => {
                    // Handle unknown opcode or decoding error as a single byte
                    instructions.push(Instruction {
                        mnemonic: "db".to_string(),
                        operands: vec![Operand::Immediate(code[offset] as u64)],
                        address: current_address,
                        bytes: vec![code[offset]],
                    });
                    offset += 1;
                    current_address += 1;
                }
            }
        }

        instructions
    }
}
disassembler/instruction.rs:
#[derive(Debug, Clone)]
pub enum Operand {
    Register(String),
    Immediate(u64),
    Memory {
        base: String,
        index: String,
        scale: i32,
        displacement: i64,
    },
    RelativeAddress(u64),
    Label(String), // For symbolic displacement or jump targets
    // Additional operand types can be added as needed
}

#[derive(Debug, Clone)]
pub struct Instruction {
    pub mnemonic: String,
    pub operands: Vec<Operand>,
    pub address: u64,
    pub bytes: Vec<u8>,
}

disassembler/decoder.rs:
use crate::disassembler::instruction::{Instruction, Operand};
use std::collections::HashMap;

/// Decoder for x86_64 architecture
pub struct Decoder {
    /// Opcode mapping: opcode bytes to [OpcodeInfo]
    opcode_map: HashMap<Vec<u8>, Vec<OpcodeInfo>>,
}

#[derive(Debug, Clone)]
struct OpcodeInfo {
    mnemonic: &'static str,
    opcode_length: usize, // Number of bytes in the opcode
    operands: Vec<OperandSpec>,
    has_modrm: bool,
    has_sib: bool,
    rex_required: bool,
    is_multibyte: bool, // Indicates if opcode uses prefixes like 0x0F
}

/// Specification for an operand in an instruction
#[derive(Debug, Clone)]
struct OperandSpec {
    operand_type: OperandType,
    size: OperandSize,
    // Additional fields can specify operand position or encoding details
}

/// Sizes of operands
#[derive(Debug, Clone, PartialEq)]
enum OperandSize {
    Byte,
    Word,
    Dword,
    Qword,
    // Other sizes can be added as needed
}

/// Types of operands for decoding purposes
#[derive(Debug, Clone)]
enum OperandType {
    Register,
    Immediate,
    Memory,
    RelativeAddress,
    // Additional types like Segment, Pointer, etc., can be added
}

impl Decoder {
    /// Initialize a new Decoder for x86_64
    pub fn new_x86_64() -> Self {
        let mut opcode_map: HashMap<Vec<u8>, Vec<OpcodeInfo>> = HashMap::new();

        // Example: Single-byte opcodes
        // NOP: 0x90
        opcode_map.insert(
            vec![0x90],
            vec![OpcodeInfo {
                mnemonic: "NOP",
                opcode_length: 1,
                operands: vec![],
                has_modrm: false,
                has_sib: false,
                rex_required: false,
                is_multibyte: false,
            }],
        );

        // RET: 0xC3
        opcode_map.insert(
            vec![0xC3],
            vec![OpcodeInfo {
                mnemonic: "RET",
                opcode_length: 1,
                operands: vec![],
                has_modrm: false,
                has_sib: false,
                rex_required: false,
                is_multibyte: false,
            }],
        );

        // MOV r64, imm32: 0xB8 + rd
        for rd in 0..8 {
            let opcode = vec![0xB8 + rd];
            opcode_map
                .entry(opcode.clone())
                .or_insert_with(Vec::new)
                .push(OpcodeInfo {
                    mnemonic: "MOV",
                    opcode_length: 1,
                    operands: vec![
                        OperandSpec {
                            operand_type: OperandType::Register,
                            size: OperandSize::Qword,
                        },
                        OperandSpec {
                            operand_type: OperandType::Immediate,
                            size: OperandSize::Dword,
                        },
                    ],
                    has_modrm: false,
                    has_sib: false,
                    rex_required: rd >= 4, // REX prefix needed for extended registers
                    is_multibyte: false,
                });
        }

        // CALL rel32: 0xE8
        opcode_map.insert(
            vec![0xE8],
            vec![OpcodeInfo {
                mnemonic: "CALL",
                opcode_length: 1,
                operands: vec![OperandSpec {
                    operand_type: OperandType::RelativeAddress,
                    size: OperandSize::Dword,
                }],
                has_modrm: false,
                has_sib: false,
                rex_required: false,
                is_multibyte: false,
            }],
        );

        // JMP rel8: 0xEB
        opcode_map.insert(
            vec![0xEB],
            vec![OpcodeInfo {
                mnemonic: "JMP",
                opcode_length: 1,
                operands: vec![OperandSpec {
                    operand_type: OperandType::RelativeAddress,
                    size: OperandSize::Byte,
                }],
                has_modrm: false,
                has_sib: false,
                rex_required: false,
                is_multibyte: false,
            }],
        );

        // ADD r/m64, r64: 0x01
        opcode_map.insert(
            vec![0x01],
            vec![OpcodeInfo {
                mnemonic: "ADD",
                opcode_length: 1,
                operands: vec![
                    OperandSpec {
                        operand_type: OperandType::Memory, // r/m64
                        size: OperandSize::Qword,
                    },
                    OperandSpec {
                        operand_type: OperandType::Register, // r64
                        size: OperandSize::Qword,
                    },
                ],
                has_modrm: true,
                has_sib: true, // Memory operand may have SIB
                rex_required: false,
                is_multibyte: false,
            }],
        );

        // More opcodes can be added here with similar structure...

        // Multi-byte opcodes (using 0x0F prefix)
        // Example: 0x0F 0xAF: IMUL r/m32, r32
        opcode_map.insert(
            vec![0x0F, 0xAF],
            vec![OpcodeInfo {
                mnemonic: "IMUL",
                opcode_length: 2,
                operands: vec![
                    OperandSpec {
                        operand_type: OperandType::Memory, // r/m32
                        size: OperandSize::Dword,
                    },
                    OperandSpec {
                        operand_type: OperandType::Register, // r32
                        size: OperandSize::Dword,
                    },
                ],
                has_modrm: true,
                has_sib: true,
                rex_required: false,
                is_multibyte: true,
            }],
        );

        // Initialize the Decoder with the opcode map
        Decoder { opcode_map }
    }

    /// Decode a single instruction from the given bytes starting at `address`
    pub fn decode(&self, bytes: &[u8], address: u64) -> Result<Instruction, DecodeError> {
        if bytes.is_empty() {
            return Err(DecodeError::IncompleteInstruction);
        }

        let mut offset = 0;
        let mut rex_prefix = RexPrefix::default();
        let mut prefixes = Vec::new();

        // Handle possible prefixes (REX, operand-size, address-size, segment overrides, etc.)
        while offset < bytes.len() {
            match bytes[offset] {
                0x40..=0x4F => {
                    // REX prefix
                    rex_prefix = RexPrefix::from_byte(bytes[offset])?;
                    prefixes.push(bytes[offset]);
                    offset += 1;
                }
                0xF0 | 0xF2 | 0xF3 | 0x2E | 0x36 | 0x3E | 0x26 | 0x64 | 0x65 | 0x66 | 0x67 => {
                    // Business other prefixes like LOCK, REP, segment overrides, etc.
                    prefixes.push(bytes[offset]);
                    offset += 1;
                }
                _ => break,
            }
        }

        // Attempt to match opcodes, starting with the longest possible
        let max_opcode_length = self
            .opcode_map
            .keys()
            .map(|k| k.len())
            .max()
            .unwrap_or(1);
        let mut matched_opcode_info: Option<(&OpcodeInfo, usize)> = None;

        // Search for the longest matching opcode
        for length in (1..=max_opcode_length).rev() {
            if offset + length > bytes.len() {
                continue;
            }
            let opcode_bytes = bytes[offset..offset + length].to_vec();
            if let Some(op_infos) = self.opcode_map.get(&opcode_bytes) {
                for op_info in op_infos {
                    // Check REX prefix requirements
                    if op_info.rex_required && !rex_prefix.is_present() {
                        continue;
                    }
                    matched_opcode_info = Some((op_info, length));
                    break;
                }
                if matched_opcode_info.is_some() {
                    break;
                }
            }
        }

        let (opcode_info, opcode_length) = match matched_opcode_info {
            Some(m) => m,
            None => return Err(DecodeError::UnknownOpcode),
        };

        offset += opcode_length;
        let mut operands = Vec::new();

        // Process operands
        for operand_spec in &opcode_info.operands {
            match operand_spec.operand_type {
                OperandType::Register => {
                    let reg = if opcode_info.has_modrm {
                        // Register is typically encoded in the ModR/M reg field
                        let reg_field = self.get_modrm_reg_field(bytes, offset)?;
                        self.decode_register_field(reg_field, &rex_prefix)?
                    } else {
                        // Otherwise, it might be encoded in the opcode
                        self.decode_register(&rex_prefix, opcode_info, &prefixes)?
                    };
                    operands.push(Operand::Register(reg));
                }
                OperandType::Immediate => {
                    let imm = self.read_immediate(bytes, offset, &operand_spec.size)?;
                    offset += operand_spec.size.bytes();
                    operands.push(Operand::Immediate(imm));
                }
                OperandType::RelativeAddress => {
                    let rel = self.read_immediate(bytes, offset, &operand_spec.size)? as i64;
                    let instr_size = offset as usize; // Total bytes read so far
                    let target = address
                        .wrapping_add(instr_size as u64)
                        .wrapping_add(rel as u64);
                    operands.push(Operand::RelativeAddress(target));
                    offset += operand_spec.size.bytes();
                }
                OperandType::Memory => {
                    if !opcode_info.has_modrm {
                        return Err(DecodeError::MissingModRM);
                    }
                    let (mem_operand, new_offset) = self.decode_memory_operand(bytes, offset, &rex_prefix)?;
                    operands.push(mem_operand);
                    offset = new_offset;
                }
            }
        }

        // Extract the bytes of the instruction
        let instr_bytes = bytes[..offset].to_vec();

        Ok(Instruction {
            mnemonic: opcode_info.mnemonic.to_string(),
            operands,
            address,
            bytes: instr_bytes,
        })
    }

    /// Decode the register operand based on REX prefix and opcode context
    fn decode_register(
        &self,
        rex: &RexPrefix,
        opcode_info: &OpcodeInfo,
        prefixes: &[u8],
    ) -> Result<String, DecodeError> {
        // Placeholder: In a complete implementation, decode based on opcode context
        // Here, we're returning 'rax' modified by REX.W for demonstration
        if rex.w {
            Ok("rax".to_string())
        } else {
            Ok("eax".to_string())
        }
    }

    /// Decode a register field from current instruction bytes
    fn decode_register_field(
        &self,
        reg_field: u8,
        rex: &RexPrefix,
    ) -> Result<String, DecodeError> {
        let extended = if rex.has_r_extension() { 8 } else { 0 };
        let registers = [
            "rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi",
            "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
        ];
        if (reg_field as usize) + extended >= registers.len() {
            return Err(DecodeError::InvalidRegister);
        }
        Ok(registers[(reg_field as usize) + extended].to_string())
    }

    /// Decode the ModR/M byte's reg field
    fn get_modrm_reg_field(&self, bytes: &[u8], offset: usize) -> Result<u8, DecodeError> {
        if offset >= bytes.len() {
            return Err(DecodeError::IncompleteInstruction);
        }
        let modrm = bytes[offset];
        Ok((modrm & 0b00111000) >> 3)
    }

    /// Decode the memory operand including ModR/M and SIB bytes
    fn decode_memory_operand(
        &self,
        bytes: &[u8],
        mut offset: usize,
        rex: &RexPrefix,
    ) -> Result<(Operand, usize), DecodeError> {
        if offset >= bytes.len() {
            return Err(DecodeError::IncompleteInstruction);
        }
        let modrm = bytes[offset];
        offset += 1;

        let mod_field = (modrm & 0b11000000) >> 6;
        let reg_field = (modrm & 0b00111000) >> 3;
        let rm_field = modrm & 0b00000111;

        // Decode SIB if needed
        let (base, index, scale, displacement, sib_offset) = if rm_field == 4 && mod_field != 3 {
            // SIB byte is present
            if offset >= bytes.len() {
                return Err(DecodeError::IncompleteInstruction);
            }
            let sib = bytes[offset];
            offset += 1;
            self.decode_sib(sib, rex)?
        } else {
            ("".to_string(), "".to_string(), 1, 0, 0)
        };

        // Decode displacement
        let displacement = match mod_field {
            0 => {
                if rm_field == 5 {
                    // disp32
                    if offset + 3 >= bytes.len() {
                        return Err(DecodeError::IncompleteInstruction);
                    }
                    let disp = i32::from_le_bytes([
                        bytes[offset],
                        bytes[offset + 1],
                        bytes[offset + 2],
                        bytes[offset + 3],
                    ]) as i64;
                    offset += 4;
                    disp
                } else {
                    0
                }
            }
            1 => {
                // disp8
                if offset >= bytes.len() {
                    return Err(DecodeError::IncompleteInstruction);
                }
                let disp = bytes[offset] as i8 as i64;
                offset += 1;
                disp
            }
            2 => {
                // disp32
                if offset + 3 >= bytes.len() {
                    return Err(DecodeError::IncompleteInstruction);
                }
                let disp = i32::from_le_bytes([
                    bytes[offset],
                    bytes[offset + 1],
                    bytes[offset + 2],
                    bytes[offset + 3],
                ]) as i64;
                offset += 4;
                disp
            }
            _ => 0,
        };

        // Decode base register
        let base_reg = if mod_field == 0 && rm_field == 5 {
            // No base, [disp32]
            String::from("")
        } else {
            self.decode_register_field(rm_field, rex)?
        };

        let mem_operand = Operand::Memory {
            base,
            index,
            scale,
            displacement,
        };

        Ok((mem_operand, offset))
    }

    /// Decode the SIB byte
    fn decode_sib(
        &self,
        sib: u8,
        rex: &RexPrefix,
    ) -> Result<(String, String, i32, i64, usize), DecodeError> {
        let scale = match (sib & 0b11000000) >> 6 {
            0 => 1,
            1 => 2,
            2 => 4,
            3 => 8,
            _ => 1, // Should not happen
        };
        let index = (sib & 0b00111000) >> 3;
        let base = sib & 0b00000111;

        let index_reg = if index == 4 {
            // No index
            "".to_string()
        } else {
            self.decode_sib_register(index, rex)?
        };

        let base_reg = if base == 5 && (self.is_no_base_required()) {
            // Special case: no base, disp32 follows
            "".to_string()
        } else {
            self.decode_register_field(base, rex)?
        };

        Ok((
            base_reg,
            index_reg,
            scale,
            0, // Placeholder for displacement if any
            0, // Placeholder for additional offset
        ))
    }

    /// Check if no base is required based on current decoding context
    fn is_no_base_required(&self) -> bool {
        // Placeholder: Logic to determine if no base is required
        false
    }

    /// Decode SIB register with REX considerations
    fn decode_sib_register(&self, reg: u8, rex: &RexPrefix) -> Result<String, DecodeError> {
        let extended = if rex.has_x_extension() { 8 } else { 0 };
        let registers = [
            "rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi",
            "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
        ];
        if (reg as usize) + extended >= registers.len() {
            return Err(DecodeError::InvalidRegister);
        }
        Ok(registers[(reg as usize) + extended].to_string())
    }

    /// Read immediate value from bytes based on operand size
    fn read_immediate(
        &self,
        bytes: &[u8],
        offset: usize,
        size: &OperandSize,
    ) -> Result<u64, DecodeError> {
        match size {
            OperandSize::Byte => {
                if offset >= bytes.len() {
                    return Err(DecodeError::IncompleteInstruction);
                }
                Ok(bytes[offset] as u64)
            }
            OperandSize::Word => {
                if offset + 1 >= bytes.len() {
                    return Err(DecodeError::IncompleteInstruction);
                }
                Ok(u16::from_le_bytes([bytes[offset], bytes[offset + 1]]) as u64)
            }
            OperandSize::Dword => {
                if offset + 3 >= bytes.len() {
                    return Err(DecodeError::IncompleteInstruction);
                }
                Ok(u32::from_le_bytes([
                    bytes[offset],
                    bytes[offset + 1],
                    bytes[offset + 2],
                    bytes[offset + 3],
                ]) as u64)
            }
            OperandSize::Qword => {
                if offset + 7 >= bytes.len() {
                    return Err(DecodeError::IncompleteInstruction);
                }
                Ok(u64::from_le_bytes([
                    bytes[offset],
                    bytes[offset + 1],
                    bytes[offset + 2],
                    bytes[offset + 3],
                    bytes[offset + 4],
                    bytes[offset + 5],
                    bytes[offset + 6],
                    bytes[offset + 7],
                ]))
            }
        }
    }
}

/// Structure representing the REX prefix
#[derive(Debug, Default)]
struct RexPrefix {
    w: bool, // 64-bit operand
    r: bool, // Extension of ModR/M reg field
    x: bool, // Extension of SIB index field
    b: bool, // Extension of ModR/M r/m field
}

impl OperandSize {
    fn bytes(&self) -> usize {
        match self {
            OperandSize::Byte => 1,
            OperandSize::Word => 2,
            OperandSize::Dword => 4,
            OperandSize::Qword => 8,
        }
    }
}

impl RexPrefix {
    /// Create REX prefix from a byte
    fn from_byte(byte: u8) -> Result<Self, DecodeError> {
        if byte & 0b11001111 != 0x40 {
            return Err(DecodeError::InvalidRexPrefix);
        }
        Ok(RexPrefix {
            w: byte & 0b00001000 != 0,
            r: byte & 0b00000100 != 0,
            x: byte & 0b00000010 != 0,
            b: byte & 0b00000001 != 0,
        })
    }

    /// Check if any REX field is present
    fn is_present(&self) -> bool {
        self.w || self.r || self.x || self.b
    }

    /// Extension for reg field
    fn has_r_extension(&self) -> bool {
        self.r
    }

    /// Extension for r/m or base field
    fn has_b_extension(&self) -> bool {
        self.b
    }

    /// Extension for index field in SIB
    fn has_x_extension(&self) -> bool {
        self.x
    }
}

/// Errors that can occur during decoding
#[derive(Debug)]
pub enum DecodeError {
    UnknownOpcode,
    IncompleteInstruction,
    InvalidRegister,
    MissingModRM,
    InvalidRexPrefix,
    InvalidSIB,
    // More error variants can be added as needed
}

impl std::fmt::Display for DecodeError {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        match &self {
            DecodeError::UnknownOpcode => write!(f, "Unknown opcode"),
            DecodeError::IncompleteInstruction => write!(f, "Incomplete instruction bytes"),
            DecodeError::InvalidRegister => write!(f, "Invalid register encoding"),
            DecodeError::MissingModRM => write!(f, "Missing ModR/M byte for instruction"),
            DecodeError::InvalidRexPrefix => write!(f, "Invalid REX prefix byte"),
            DecodeError::InvalidSIB => write!(f, "Invalid SIB byte"),
        }
    }
}

impl std::error::Error for DecodeError {}