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use std::collections::HashMap;
use std::mem::transmute;
use entry::Entry;
use helpers::find_subsequence;
#[cfg(feature = "optimize")]
use optimized_cache::OptimizedCache;
/// The default stub value
pub const STUB: usize = 0x13371337;
/// Manages the instructions.
pub struct Cache {
stub: usize,
cache: HashMap<String, Entry>,
#[cfg(feature = "optimize")]
optimized_cache: HashMap<OptimizedCache, Vec<u8>>
}
impl Cache {
/// Constructs a new `Cache`.
///
/// # Examples
///
/// ```
/// use machina::cache::Cache;
///
/// let cache = Cache::new();
/// ```
#[cfg(feature = "optimize")]
pub fn new() -> Cache {
Cache {
stub: STUB,
cache: HashMap::<String, Entry>::new(),
optimized_cache: HashMap::<OptimizedCache, Vec<u8>>::new(),
}
}
/// Constructs a new `Cache`.
///
/// # Examples
///
/// ```
/// use machina::cache::Cache;
///
/// let cache = Cache::new();
/// ```
#[cfg(not(feature = "optimize"))]
pub fn new() -> Cache {
Cache {
stub: STUB,
cache: HashMap::<String, Entry>::new(),
}
}
/// Sets the stub.
///
/// * `stub` - The new stub
///
/// # Examples
///
/// ```
/// use machina::cache::Cache;
///
/// let mut cache = Cache::new();
/// cache.set_stub(0x31313131);
/// ```
pub fn set_stub(&mut self, stub: usize) {
self.stub = stub;
}
/// Insert without stub
///
/// * `name` - The identifier
/// * `asm` - The bytes
///
/// # Examples
///
/// ```
/// use machina::cache::Cache;
///
/// let mut cache = Cache::new();
/// cache.insert("inc_rax".to_string(), vec![0x48, 0xff, 0xc0]);
/// ```
pub fn insert(&mut self, name: String, asm: Vec<u8>) {
self.cache.insert(name, Entry {
asm: asm,
stub: 0
});
}
/// Insert with stub
///
/// * `name` - The identifier
/// * `asm` - The bytes
///
/// # Examples
///
/// ```
/// use machina::cache::{Cache,STUB};
///
/// let mut cache = Cache::new();
/// cache.insert_with_stub("mov_rax_x".to_string(), vec![0x48, 0xc7, 0xc0, 0x37, 0x13, 0x37, 0x13]); // bytes with `STUB` (default: 0x13371337)
/// ```
pub fn insert_with_stub(&mut self, name: String, asm: Vec<u8>) {
self.cache.insert(name, Entry {
asm: asm,
stub: self.stub
});
}
/// Get without loading the stub
///
/// * `name` - The identifier
///
/// # Examples
///
/// ```
/// use machina::cache::Cache;
///
/// let mut cache = Cache::new();
/// cache.insert("inc_rax".to_string(), vec![0x48, 0xff, 0xc0]);
/// let _ = cache.get("inc_rax".to_string());
/// ```
pub fn get(&self, name: String) -> Vec<u8> {
self.cache.get(&name).unwrap().asm.to_owned()
}
/// Get with loading the stub
///
/// * `name` - The identifier
/// * `value` - The stub replacement
///
/// # Examples
///
/// ```
/// use machina::cache::{Cache,STUB};
///
/// let mut cache = Cache::new();
/// cache.insert_with_stub("mov_rax_x".to_string(), vec![0x48, 0xc7, 0xc0, 0x37, 0x13, 0x37, 0x13]); // bytes with STUB (default: 0x13371337)
/// let _ = cache.get_stub("mov_rax_x".to_string(), 0x69696969); // replace STUB with 0x69696969
/// ```
#[cfg(feature = "optimize")]
pub fn get_stub(&mut self, name: String, value: usize) -> Vec<u8> {
let other = OptimizedCache { name: (&name).to_string(), value };
let mut asm = self.cache.get(&name).unwrap().asm.to_owned();
let cached = self.check_cache(&other);
if cached.is_ok() {
cached.unwrap().to_owned()
} else {
let bytes: [u8; 4] = unsafe { transmute((self.stub as u32).to_le()) };
let actual_bytes: [u8; 4] = unsafe { transmute((value as u32).to_le()) };
let pos = find_subsequence(&asm, &bytes).unwrap();
asm[pos..pos + 4].clone_from_slice(&actual_bytes[(pos - pos)..(pos + 4 - pos)]);
self.optimized_cache.insert(other, asm.clone());
asm.to_owned()
}
}
/// Get with loading the stub
///
/// * `name` - The identifier
/// * `value` - The stub replacement
///
/// # Examples
///
/// ```
/// use machina::cache::{Cache,STUB};
///
/// let mut cache = Cache::new();
/// cache.insert_with_stub("mov_rax_x".to_string(), vec![0x48, 0xc7, 0xc0, 0x37, 0x13, 0x37, 0x13]); // bytes with STUB (default: 0x13371337)
/// let _ = cache.get_stub("mov_rax_x".to_string(), 0x69696969); // replace STUB with 0x69696969
/// ```
#[cfg(not(feature = "optimize"))]
pub fn get_stub(&mut self, name: String, value: usize) -> Vec<u8> {
let mut asm = self.cache.get(&name).unwrap().asm.to_owned();
let bytes: [u8; 4] = unsafe { transmute((self.stub as u32).to_le()) };
let actual_bytes: [u8; 4] = unsafe { transmute((value as u32).to_le()) };
let pos = find_subsequence(&asm, &bytes).unwrap();
asm[pos..pos + 4].clone_from_slice(&actual_bytes[(pos - pos)..(pos + 4 - pos)]);
asm.to_owned()
}
#[cfg(feature = "optimize")]
fn check_cache(&self, other: &OptimizedCache) -> Result<Vec<u8>, String> {
if let Some(cache) = self.optimized_cache.get(other) {
Ok(cache.to_owned())
} else {
Err("Not in cache.".to_string())
}
}
}