rust/src/memory.rs

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use byteorder::{ReadBytesExt, WriteBytesExt, LittleEndian, BigEndian, self};
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use std::collections::Bound::{Included, Excluded};
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use std::collections::{btree_map, BTreeMap, HashMap, HashSet, VecDeque};
use std::{fmt, iter, ptr};
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use rustc::hir::def_id::DefId;
use rustc::ty::{BareFnTy, ClosureTy, ClosureSubsts};
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use rustc::ty::subst::Substs;
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use rustc::ty::layout::{self, TargetDataLayout};
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use error::{EvalError, EvalResult};
use primval::PrimVal;
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////////////////////////////////////////////////////////////////////////////////
// Allocations and pointers
////////////////////////////////////////////////////////////////////////////////
#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq)]
pub struct AllocId(pub u64);
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impl fmt::Display for AllocId {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.0)
}
}
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#[derive(Debug)]
pub struct Allocation {
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/// The actual bytes of the allocation.
/// Note that the bytes of a pointer represent the offset of the pointer
pub bytes: Vec<u8>,
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/// Maps from byte addresses to allocations.
/// Only the first byte of a pointer is inserted into the map.
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pub relocations: BTreeMap<usize, AllocId>,
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/// Denotes undefined memory. Reading from undefined memory is forbidden in miri
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pub undef_mask: UndefMask,
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/// The alignment of the allocation to detect unaligned reads.
pub align: usize,
/// Whether the allocation may be modified.
/// Use the `freeze` method of `Memory` to ensure that an error occurs, if the memory of this
/// allocation is modified in the future.
pub immutable: bool,
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}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct Pointer {
pub alloc_id: AllocId,
pub offset: usize,
}
impl Pointer {
pub fn offset(self, i: isize) -> Self {
Pointer { offset: (self.offset as isize + i) as usize, ..self }
}
pub fn points_to_zst(&self) -> bool {
self.alloc_id == ZST_ALLOC_ID
}
fn zst_ptr() -> Self {
Pointer {
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alloc_id: ZST_ALLOC_ID,
offset: 0,
}
}
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}
#[derive(Debug, Clone, Hash, Eq, PartialEq)]
struct FunctionDefinition<'tcx> {
pub def_id: DefId,
pub kind: FunctionKind<'tcx>,
}
#[derive(Debug, Clone, Hash, Eq, PartialEq)]
enum FunctionKind<'tcx> {
Closure {
substs: ClosureSubsts<'tcx>,
ty: ClosureTy<'tcx>,
},
Function {
substs: &'tcx Substs<'tcx>,
ty: &'tcx BareFnTy<'tcx>,
}
}
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////////////////////////////////////////////////////////////////////////////////
// Top-level interpreter memory
////////////////////////////////////////////////////////////////////////////////
pub struct Memory<'a, 'tcx> {
/// Actual memory allocations (arbitrary bytes, may contain pointers into other allocations)
alloc_map: HashMap<AllocId, Allocation>,
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/// Number of virtual bytes allocated
memory_usage: usize,
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/// Maximum number of virtual bytes that may be allocated
memory_size: usize,
/// Function "allocations". They exist solely so pointers have something to point to, and
/// we can figure out what they point to.
functions: HashMap<AllocId, FunctionDefinition<'tcx>>,
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/// Inverse map of `functions` so we don't allocate a new pointer every time we need one
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function_alloc_cache: HashMap<FunctionDefinition<'tcx>, AllocId>,
next_id: AllocId,
pub layout: &'a TargetDataLayout,
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}
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const ZST_ALLOC_ID: AllocId = AllocId(0);
impl<'a, 'tcx> Memory<'a, 'tcx> {
pub fn new(layout: &'a TargetDataLayout, max_memory: usize) -> Self {
let mut mem = Memory {
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alloc_map: HashMap::new(),
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functions: HashMap::new(),
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function_alloc_cache: HashMap::new(),
next_id: AllocId(1),
layout: layout,
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memory_size: max_memory,
memory_usage: 0,
};
// alloc id 0 is reserved for ZSTs, this is an optimization to prevent ZST
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// (e.g. function items, (), [], ...) from requiring memory
let alloc = Allocation {
bytes: Vec::new(),
relocations: BTreeMap::new(),
undef_mask: UndefMask::new(0),
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align: 1,
immutable: false, // must be mutable, because sometimes we "move out" of a ZST
};
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mem.alloc_map.insert(ZST_ALLOC_ID, alloc);
// check that additional zst allocs work
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debug_assert!(mem.allocate(0, 1).unwrap().points_to_zst());
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debug_assert!(mem.get(ZST_ALLOC_ID).is_ok());
mem
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}
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pub fn allocations(&self) -> ::std::collections::hash_map::Iter<AllocId, Allocation> {
self.alloc_map.iter()
}
pub fn create_closure_ptr(&mut self, def_id: DefId, substs: ClosureSubsts<'tcx>, fn_ty: ClosureTy<'tcx>) -> Pointer {
self.create_fn_alloc(FunctionDefinition {
def_id: def_id,
kind: FunctionKind::Closure {
substs: substs,
ty: fn_ty,
}
})
}
pub fn create_fn_ptr(&mut self, def_id: DefId, substs: &'tcx Substs<'tcx>, fn_ty: &'tcx BareFnTy<'tcx>) -> Pointer {
self.create_fn_alloc(FunctionDefinition {
def_id: def_id,
kind: FunctionKind::Function {
substs: substs,
ty: fn_ty,
}
})
}
fn create_fn_alloc(&mut self, def: FunctionDefinition<'tcx>) -> Pointer {
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if let Some(&alloc_id) = self.function_alloc_cache.get(&def) {
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return Pointer {
alloc_id: alloc_id,
offset: 0,
};
}
let id = self.next_id;
debug!("creating fn ptr: {}", id);
self.next_id.0 += 1;
self.functions.insert(id, def.clone());
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self.function_alloc_cache.insert(def, id);
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Pointer {
alloc_id: id,
offset: 0,
}
}
pub fn allocate(&mut self, size: usize, align: usize) -> EvalResult<'tcx, Pointer> {
if size == 0 {
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return Ok(Pointer::zst_ptr());
}
assert!(align != 0);
if self.memory_size - self.memory_usage < size {
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return Err(EvalError::OutOfMemory {
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allocation_size: size,
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memory_size: self.memory_size,
memory_usage: self.memory_usage,
});
}
self.memory_usage += size;
let alloc = Allocation {
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bytes: vec![0; size],
relocations: BTreeMap::new(),
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undef_mask: UndefMask::new(size),
align: align,
immutable: false,
};
let id = self.next_id;
self.next_id.0 += 1;
self.alloc_map.insert(id, alloc);
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Ok(Pointer {
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alloc_id: id,
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offset: 0,
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})
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}
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// TODO(solson): Track which allocations were returned from __rust_allocate and report an error
// when reallocating/deallocating any others.
pub fn reallocate(&mut self, ptr: Pointer, new_size: usize, align: usize) -> EvalResult<'tcx, Pointer> {
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// TODO(solson): Report error about non-__rust_allocate'd pointer.
if ptr.offset != 0 {
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return Err(EvalError::Unimplemented(format!("bad pointer offset: {}", ptr.offset)));
}
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if ptr.points_to_zst() {
return self.allocate(new_size, align);
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}
let size = self.get(ptr.alloc_id)?.bytes.len();
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if new_size > size {
let amount = new_size - size;
self.memory_usage += amount;
let alloc = self.get_mut(ptr.alloc_id)?;
alloc.bytes.extend(iter::repeat(0).take(amount));
alloc.undef_mask.grow(amount, false);
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} else if size > new_size {
self.memory_usage -= size - new_size;
self.clear_relocations(ptr.offset(new_size as isize), size - new_size)?;
let alloc = self.get_mut(ptr.alloc_id)?;
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alloc.bytes.truncate(new_size);
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alloc.bytes.shrink_to_fit();
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alloc.undef_mask.truncate(new_size);
}
Ok(Pointer {
alloc_id: ptr.alloc_id,
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offset: 0,
})
}
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// TODO(solson): See comment on `reallocate`.
pub fn deallocate(&mut self, ptr: Pointer) -> EvalResult<'tcx, ()> {
if ptr.points_to_zst() {
return Ok(());
}
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if ptr.offset != 0 {
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// TODO(solson): Report error about non-__rust_allocate'd pointer.
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return Err(EvalError::Unimplemented(format!("bad pointer offset: {}", ptr.offset)));
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}
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if let Some(alloc) = self.alloc_map.remove(&ptr.alloc_id) {
self.memory_usage -= alloc.bytes.len();
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} else {
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debug!("deallocated a pointer twice: {}", ptr.alloc_id);
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// TODO(solson): Report error about erroneous free. This is blocked on properly tracking
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// already-dropped state since this if-statement is entered even in safe code without
// it.
}
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debug!("deallocated : {}", ptr.alloc_id);
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Ok(())
}
pub fn pointer_size(&self) -> usize {
self.layout.pointer_size.bytes() as usize
}
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pub fn endianess(&self) -> layout::Endian {
self.layout.endian
}
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pub fn check_align(&self, ptr: Pointer, align: usize) -> EvalResult<'tcx, ()> {
let alloc = self.get(ptr.alloc_id)?;
if alloc.align < align {
return Err(EvalError::AlignmentCheckFailed {
has: alloc.align,
required: align,
});
}
if ptr.offset % align == 0 {
Ok(())
} else {
Err(EvalError::AlignmentCheckFailed {
has: ptr.offset % align,
required: align,
})
}
}
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}
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/// Allocation accessors
impl<'a, 'tcx> Memory<'a, 'tcx> {
pub fn get(&self, id: AllocId) -> EvalResult<'tcx, &Allocation> {
match self.alloc_map.get(&id) {
Some(alloc) => Ok(alloc),
None => match self.functions.get(&id) {
Some(_) => Err(EvalError::DerefFunctionPointer),
None => Err(EvalError::DanglingPointerDeref),
}
}
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}
pub fn get_mut(&mut self, id: AllocId) -> EvalResult<'tcx, &mut Allocation> {
match self.alloc_map.get_mut(&id) {
Some(ref alloc) if alloc.immutable => Err(EvalError::ModifiedConstantMemory),
Some(alloc) => Ok(alloc),
None => match self.functions.get(&id) {
Some(_) => Err(EvalError::DerefFunctionPointer),
None => Err(EvalError::DanglingPointerDeref),
}
}
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}
pub fn get_closure(&self, id: AllocId) -> EvalResult<'tcx, (DefId, ClosureSubsts<'tcx>, ClosureTy<'tcx>)> {
debug!("reading closure fn ptr: {}", id);
match self.functions.get(&id) {
Some(&FunctionDefinition {
def_id,
kind: FunctionKind::Closure { ref substs, ref ty }
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}) => Ok((def_id, *substs, ty.clone())),
Some(&FunctionDefinition {
kind: FunctionKind::Function { .. }, ..
}) => Err(EvalError::CalledClosureAsFunction),
None => match self.alloc_map.get(&id) {
Some(_) => Err(EvalError::ExecuteMemory),
None => Err(EvalError::InvalidFunctionPointer),
}
}
}
pub fn get_fn(&self, id: AllocId) -> EvalResult<'tcx, (DefId, &'tcx Substs<'tcx>, &'tcx BareFnTy<'tcx>)> {
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debug!("reading fn ptr: {}", id);
match self.functions.get(&id) {
Some(&FunctionDefinition {
def_id,
kind: FunctionKind::Function { substs, ty }
}) => Ok((def_id, substs, ty)),
Some(&FunctionDefinition {
kind: FunctionKind::Closure { .. }, ..
}) => Err(EvalError::CalledClosureAsFunction),
None => match self.alloc_map.get(&id) {
Some(_) => Err(EvalError::ExecuteMemory),
None => Err(EvalError::InvalidFunctionPointer),
}
}
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}
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/// Print an allocation and all allocations it points to, recursively.
pub fn dump(&self, id: AllocId) {
let mut allocs_seen = HashSet::new();
let mut allocs_to_print = VecDeque::new();
allocs_to_print.push_back(id);
while let Some(id) = allocs_to_print.pop_front() {
allocs_seen.insert(id);
let prefix = format!("Alloc {:<5} ", format!("{}:", id));
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print!("{}", prefix);
let mut relocations = vec![];
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let alloc = match (self.alloc_map.get(&id), self.functions.get(&id)) {
(Some(a), None) => a,
(None, Some(_)) => {
// FIXME: print function name
println!("function pointer");
continue;
},
(None, None) => {
println!("(deallocated)");
continue;
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},
(Some(_), Some(_)) => bug!("miri invariant broken: an allocation id exists that points to both a function and a memory location"),
};
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for i in 0..alloc.bytes.len() {
if let Some(&target_id) = alloc.relocations.get(&i) {
if !allocs_seen.contains(&target_id) {
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allocs_to_print.push_back(target_id);
}
relocations.push((i, target_id));
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}
if alloc.undef_mask.is_range_defined(i, i + 1) {
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print!("{:02x} ", alloc.bytes[i]);
} else {
print!("__ ");
}
}
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println!("({} bytes)", alloc.bytes.len());
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if !relocations.is_empty() {
print!("{:1$}", "", prefix.len()); // Print spaces.
let mut pos = 0;
let relocation_width = (self.pointer_size() - 1) * 3;
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for (i, target_id) in relocations {
print!("{:1$}", "", (i - pos) * 3);
print!("{0:─^1$}", format!("({})", target_id), relocation_width);
pos = i + self.pointer_size();
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}
println!("");
}
}
}
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}
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/// Byte accessors
impl<'a, 'tcx> Memory<'a, 'tcx> {
fn get_bytes_unchecked(&self, ptr: Pointer, size: usize) -> EvalResult<'tcx, &[u8]> {
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let alloc = self.get(ptr.alloc_id)?;
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if ptr.offset + size > alloc.bytes.len() {
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return Err(EvalError::PointerOutOfBounds {
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ptr: ptr,
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size: size,
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allocation_size: alloc.bytes.len(),
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});
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}
Ok(&alloc.bytes[ptr.offset..ptr.offset + size])
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}
fn get_bytes_unchecked_mut(&mut self, ptr: Pointer, size: usize) -> EvalResult<'tcx, &mut [u8]> {
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let alloc = self.get_mut(ptr.alloc_id)?;
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if ptr.offset + size > alloc.bytes.len() {
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return Err(EvalError::PointerOutOfBounds {
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ptr: ptr,
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size: size,
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allocation_size: alloc.bytes.len(),
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});
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}
Ok(&mut alloc.bytes[ptr.offset..ptr.offset + size])
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}
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fn get_bytes(&self, ptr: Pointer, size: usize, align: usize) -> EvalResult<'tcx, &[u8]> {
self.check_align(ptr, align)?;
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if self.relocations(ptr, size)?.count() != 0 {
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return Err(EvalError::ReadPointerAsBytes);
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}
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self.check_defined(ptr, size)?;
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self.get_bytes_unchecked(ptr, size)
}
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fn get_bytes_mut(&mut self, ptr: Pointer, size: usize, align: usize) -> EvalResult<'tcx, &mut [u8]> {
self.check_align(ptr, align)?;
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self.clear_relocations(ptr, size)?;
self.mark_definedness(ptr, size, true)?;
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self.get_bytes_unchecked_mut(ptr, size)
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}
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}
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/// Reading and writing
impl<'a, 'tcx> Memory<'a, 'tcx> {
pub fn freeze(&mut self, alloc_id: AllocId) -> EvalResult<'tcx, ()> {
self.get_mut(alloc_id)?.immutable = true;
Ok(())
}
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pub fn copy(&mut self, src: Pointer, dest: Pointer, size: usize, align: usize) -> EvalResult<'tcx, ()> {
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self.check_relocation_edges(src, size)?;
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let src_bytes = self.get_bytes_unchecked(src, size)?.as_ptr();
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let dest_bytes = self.get_bytes_mut(dest, size, align)?.as_mut_ptr();
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// SAFE: The above indexing would have panicked if there weren't at least `size` bytes
// behind `src` and `dest`. Also, we use the overlapping-safe `ptr::copy` if `src` and
// `dest` could possibly overlap.
unsafe {
if src.alloc_id == dest.alloc_id {
ptr::copy(src_bytes, dest_bytes, size);
} else {
ptr::copy_nonoverlapping(src_bytes, dest_bytes, size);
}
}
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self.copy_undef_mask(src, dest, size)?;
self.copy_relocations(src, dest, size)?;
Ok(())
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}
pub fn read_bytes(&self, ptr: Pointer, size: usize) -> EvalResult<'tcx, &[u8]> {
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self.get_bytes(ptr, size, 1)
}
pub fn write_bytes(&mut self, ptr: Pointer, src: &[u8]) -> EvalResult<'tcx, ()> {
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let bytes = self.get_bytes_mut(ptr, src.len(), 1)?;
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bytes.clone_from_slice(src);
Ok(())
}
pub fn write_repeat(&mut self, ptr: Pointer, val: u8, count: usize) -> EvalResult<'tcx, ()> {
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let bytes = self.get_bytes_mut(ptr, count, 1)?;
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for b in bytes { *b = val; }
Ok(())
}
pub fn read_ptr(&self, ptr: Pointer) -> EvalResult<'tcx, Pointer> {
let size = self.pointer_size();
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self.check_defined(ptr, size)?;
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let endianess = self.endianess();
let bytes = self.get_bytes_unchecked(ptr, size)?;
let offset = read_target_uint(endianess, bytes).unwrap() as usize;
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let alloc = self.get(ptr.alloc_id)?;
match alloc.relocations.get(&ptr.offset) {
Some(&alloc_id) => Ok(Pointer { alloc_id: alloc_id, offset: offset }),
None => Err(EvalError::ReadBytesAsPointer),
}
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}
pub fn write_ptr(&mut self, dest: Pointer, ptr: Pointer) -> EvalResult<'tcx, ()> {
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self.write_usize(dest, ptr.offset as u64)?;
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self.get_mut(dest.alloc_id)?.relocations.insert(dest.offset, ptr.alloc_id);
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Ok(())
}
pub fn write_primval(&mut self, ptr: Pointer, val: PrimVal) -> EvalResult<'tcx, ()> {
let pointer_size = self.pointer_size();
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match val {
PrimVal::Bool(b) => self.write_bool(ptr, b),
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PrimVal::I8(n) => self.write_int(ptr, n as i64, 1),
PrimVal::I16(n) => self.write_int(ptr, n as i64, 2),
PrimVal::I32(n) => self.write_int(ptr, n as i64, 4),
PrimVal::I64(n) => self.write_int(ptr, n as i64, 8),
PrimVal::U8(n) => self.write_uint(ptr, n as u64, 1),
PrimVal::U16(n) => self.write_uint(ptr, n as u64, 2),
PrimVal::U32(n) => self.write_uint(ptr, n as u64, 4),
PrimVal::U64(n) => self.write_uint(ptr, n as u64, 8),
PrimVal::Char(c) => self.write_uint(ptr, c as u64, 4),
PrimVal::IntegerPtr(n) => self.write_uint(ptr, n as u64, pointer_size),
PrimVal::F32(f) => self.write_f32(ptr, f),
PrimVal::F64(f) => self.write_f64(ptr, f),
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PrimVal::FnPtr(p) |
PrimVal::AbstractPtr(p) => self.write_ptr(ptr, p),
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}
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}
pub fn read_bool(&self, ptr: Pointer) -> EvalResult<'tcx, bool> {
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let bytes = self.get_bytes(ptr, 1, self.layout.i1_align.abi() as usize)?;
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match bytes[0] {
0 => Ok(false),
1 => Ok(true),
_ => Err(EvalError::InvalidBool),
}
}
pub fn write_bool(&mut self, ptr: Pointer, b: bool) -> EvalResult<'tcx, ()> {
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let align = self.layout.i1_align.abi() as usize;
self.get_bytes_mut(ptr, 1, align)
.map(|bytes| bytes[0] = b as u8)
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}
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fn int_align(&self, size: usize) -> EvalResult<'tcx, usize> {
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match size {
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1 => Ok(self.layout.i8_align.abi() as usize),
2 => Ok(self.layout.i16_align.abi() as usize),
4 => Ok(self.layout.i32_align.abi() as usize),
8 => Ok(self.layout.i64_align.abi() as usize),
_ => bug!("bad integer size"),
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}
}
pub fn read_int(&self, ptr: Pointer, size: usize) -> EvalResult<'tcx, i64> {
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let align = self.int_align(size)?;
self.get_bytes(ptr, size, align).map(|b| read_target_int(self.endianess(), b).unwrap())
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}
pub fn write_int(&mut self, ptr: Pointer, n: i64, size: usize) -> EvalResult<'tcx, ()> {
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let align = self.int_align(size)?;
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let endianess = self.endianess();
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let b = self.get_bytes_mut(ptr, size, align)?;
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write_target_int(endianess, b, n).unwrap();
Ok(())
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}
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pub fn read_uint(&self, ptr: Pointer, size: usize) -> EvalResult<'tcx, u64> {
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let align = self.int_align(size)?;
self.get_bytes(ptr, size, align).map(|b| read_target_uint(self.endianess(), b).unwrap())
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}
pub fn write_uint(&mut self, ptr: Pointer, n: u64, size: usize) -> EvalResult<'tcx, ()> {
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let align = self.int_align(size)?;
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let endianess = self.endianess();
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let b = self.get_bytes_mut(ptr, size, align)?;
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write_target_uint(endianess, b, n).unwrap();
Ok(())
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}
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pub fn read_isize(&self, ptr: Pointer) -> EvalResult<'tcx, i64> {
self.read_int(ptr, self.pointer_size())
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}
pub fn write_isize(&mut self, ptr: Pointer, n: i64) -> EvalResult<'tcx, ()> {
let size = self.pointer_size();
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self.write_int(ptr, n, size)
}
pub fn read_usize(&self, ptr: Pointer) -> EvalResult<'tcx, u64> {
self.read_uint(ptr, self.pointer_size())
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}
pub fn write_usize(&mut self, ptr: Pointer, n: u64) -> EvalResult<'tcx, ()> {
let size = self.pointer_size();
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self.write_uint(ptr, n, size)
}
pub fn write_f32(&mut self, ptr: Pointer, f: f32) -> EvalResult<'tcx, ()> {
let endianess = self.endianess();
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let align = self.layout.f32_align.abi() as usize;
let b = self.get_bytes_mut(ptr, 4, align)?;
write_target_f32(endianess, b, f).unwrap();
Ok(())
}
pub fn write_f64(&mut self, ptr: Pointer, f: f64) -> EvalResult<'tcx, ()> {
let endianess = self.endianess();
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let align = self.layout.f64_align.abi() as usize;
let b = self.get_bytes_mut(ptr, 8, align)?;
write_target_f64(endianess, b, f).unwrap();
Ok(())
}
pub fn read_f32(&self, ptr: Pointer) -> EvalResult<'tcx, f32> {
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self.get_bytes(ptr, 4, self.layout.f32_align.abi() as usize)
.map(|b| read_target_f32(self.endianess(), b).unwrap())
}
pub fn read_f64(&self, ptr: Pointer) -> EvalResult<'tcx, f64> {
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self.get_bytes(ptr, 8, self.layout.f64_align.abi() as usize)
.map(|b| read_target_f64(self.endianess(), b).unwrap())
}
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}
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/// Relocations
impl<'a, 'tcx> Memory<'a, 'tcx> {
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fn relocations(&self, ptr: Pointer, size: usize)
-> EvalResult<'tcx, btree_map::Range<usize, AllocId>>
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{
let start = ptr.offset.saturating_sub(self.pointer_size() - 1);
let end = ptr.offset + size;
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Ok(self.get(ptr.alloc_id)?.relocations.range(Included(&start), Excluded(&end)))
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}
fn clear_relocations(&mut self, ptr: Pointer, size: usize) -> EvalResult<'tcx, ()> {
// Find all relocations overlapping the given range.
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let keys: Vec<_> = self.relocations(ptr, size)?.map(|(&k, _)| k).collect();
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if keys.is_empty() { return Ok(()); }
// Find the start and end of the given range and its outermost relocations.
let start = ptr.offset;
let end = start + size;
let first = *keys.first().unwrap();
let last = *keys.last().unwrap() + self.pointer_size();
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let alloc = self.get_mut(ptr.alloc_id)?;
// Mark parts of the outermost relocations as undefined if they partially fall outside the
// given range.
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if first < start { alloc.undef_mask.set_range(first, start, false); }
if last > end { alloc.undef_mask.set_range(end, last, false); }
// Forget all the relocations.
for k in keys { alloc.relocations.remove(&k); }
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Ok(())
}
fn check_relocation_edges(&self, ptr: Pointer, size: usize) -> EvalResult<'tcx, ()> {
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let overlapping_start = self.relocations(ptr, 0)?.count();
let overlapping_end = self.relocations(ptr.offset(size as isize), 0)?.count();
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if overlapping_start + overlapping_end != 0 {
return Err(EvalError::ReadPointerAsBytes);
}
Ok(())
}
fn copy_relocations(&mut self, src: Pointer, dest: Pointer, size: usize) -> EvalResult<'tcx, ()> {
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let relocations: Vec<_> = self.relocations(src, size)?
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.map(|(&offset, &alloc_id)| {
// Update relocation offsets for the new positions in the destination allocation.
(offset + dest.offset - src.offset, alloc_id)
})
.collect();
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self.get_mut(dest.alloc_id)?.relocations.extend(relocations);
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Ok(())
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}
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}
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/// Undefined bytes
impl<'a, 'tcx> Memory<'a, 'tcx> {
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// FIXME(solson): This is a very naive, slow version.
fn copy_undef_mask(&mut self, src: Pointer, dest: Pointer, size: usize) -> EvalResult<'tcx, ()> {
// The bits have to be saved locally before writing to dest in case src and dest overlap.
let mut v = Vec::with_capacity(size);
for i in 0..size {
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let defined = self.get(src.alloc_id)?.undef_mask.get(src.offset + i);
v.push(defined);
}
for (i, defined) in v.into_iter().enumerate() {
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self.get_mut(dest.alloc_id)?.undef_mask.set(dest.offset + i, defined);
}
Ok(())
}
fn check_defined(&self, ptr: Pointer, size: usize) -> EvalResult<'tcx, ()> {
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let alloc = self.get(ptr.alloc_id)?;
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if !alloc.undef_mask.is_range_defined(ptr.offset, ptr.offset + size) {
return Err(EvalError::ReadUndefBytes);
}
Ok(())
}
pub fn mark_definedness(&mut self, ptr: Pointer, size: usize, new_state: bool)
-> EvalResult<'tcx, ()>
{
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let mut alloc = self.get_mut(ptr.alloc_id)?;
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alloc.undef_mask.set_range(ptr.offset, ptr.offset + size, new_state);
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Ok(())
}
}
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////////////////////////////////////////////////////////////////////////////////
// Methods to access integers in the target endianess
////////////////////////////////////////////////////////////////////////////////
fn write_target_uint(endianess: layout::Endian, mut target: &mut [u8], data: u64) -> Result<(), byteorder::Error> {
let len = target.len();
match endianess {
layout::Endian::Little => target.write_uint::<LittleEndian>(data, len),
layout::Endian::Big => target.write_uint::<BigEndian>(data, len),
}
}
fn write_target_int(endianess: layout::Endian, mut target: &mut [u8], data: i64) -> Result<(), byteorder::Error> {
let len = target.len();
match endianess {
layout::Endian::Little => target.write_int::<LittleEndian>(data, len),
layout::Endian::Big => target.write_int::<BigEndian>(data, len),
}
}
fn read_target_uint(endianess: layout::Endian, mut source: &[u8]) -> Result<u64, byteorder::Error> {
match endianess {
layout::Endian::Little => source.read_uint::<LittleEndian>(source.len()),
layout::Endian::Big => source.read_uint::<BigEndian>(source.len()),
}
}
fn read_target_int(endianess: layout::Endian, mut source: &[u8]) -> Result<i64, byteorder::Error> {
match endianess {
layout::Endian::Little => source.read_int::<LittleEndian>(source.len()),
layout::Endian::Big => source.read_int::<BigEndian>(source.len()),
}
}
////////////////////////////////////////////////////////////////////////////////
// Methods to access floats in the target endianess
////////////////////////////////////////////////////////////////////////////////
fn write_target_f32(endianess: layout::Endian, mut target: &mut [u8], data: f32) -> Result<(), byteorder::Error> {
match endianess {
layout::Endian::Little => target.write_f32::<LittleEndian>(data),
layout::Endian::Big => target.write_f32::<BigEndian>(data),
}
}
fn write_target_f64(endianess: layout::Endian, mut target: &mut [u8], data: f64) -> Result<(), byteorder::Error> {
match endianess {
layout::Endian::Little => target.write_f64::<LittleEndian>(data),
layout::Endian::Big => target.write_f64::<BigEndian>(data),
}
}
fn read_target_f32(endianess: layout::Endian, mut source: &[u8]) -> Result<f32, byteorder::Error> {
match endianess {
layout::Endian::Little => source.read_f32::<LittleEndian>(),
layout::Endian::Big => source.read_f32::<BigEndian>(),
}
}
fn read_target_f64(endianess: layout::Endian, mut source: &[u8]) -> Result<f64, byteorder::Error> {
match endianess {
layout::Endian::Little => source.read_f64::<LittleEndian>(),
layout::Endian::Big => source.read_f64::<BigEndian>(),
}
}
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////////////////////////////////////////////////////////////////////////////////
// Undefined byte tracking
////////////////////////////////////////////////////////////////////////////////
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type Block = u64;
const BLOCK_SIZE: usize = 64;
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#[derive(Clone, Debug)]
pub struct UndefMask {
blocks: Vec<Block>,
len: usize,
}
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impl UndefMask {
fn new(size: usize) -> Self {
let mut m = UndefMask {
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blocks: vec![],
len: 0,
};
m.grow(size, false);
m
}
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/// Check whether the range `start..end` (end-exclusive) is entirely defined.
pub fn is_range_defined(&self, start: usize, end: usize) -> bool {
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if end > self.len { return false; }
for i in start..end {
if !self.get(i) { return false; }
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}
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true
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}
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fn set_range(&mut self, start: usize, end: usize, new_state: bool) {
let len = self.len;
if end > len { self.grow(end - len, new_state); }
self.set_range_inbounds(start, end, new_state);
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}
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fn set_range_inbounds(&mut self, start: usize, end: usize, new_state: bool) {
for i in start..end { self.set(i, new_state); }
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}
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fn get(&self, i: usize) -> bool {
let (block, bit) = bit_index(i);
(self.blocks[block] & 1 << bit) != 0
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}
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fn set(&mut self, i: usize, new_state: bool) {
let (block, bit) = bit_index(i);
if new_state {
self.blocks[block] |= 1 << bit;
} else {
self.blocks[block] &= !(1 << bit);
}
}
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fn grow(&mut self, amount: usize, new_state: bool) {
let unused_trailing_bits = self.blocks.len() * BLOCK_SIZE - self.len;
if amount > unused_trailing_bits {
let additional_blocks = amount / BLOCK_SIZE + 1;
self.blocks.extend(iter::repeat(0).take(additional_blocks));
}
let start = self.len;
self.len += amount;
self.set_range_inbounds(start, start + amount, new_state);
}
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fn truncate(&mut self, length: usize) {
self.len = length;
self.blocks.truncate(self.len / BLOCK_SIZE + 1);
self.blocks.shrink_to_fit();
}
}
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fn bit_index(bits: usize) -> (usize, usize) {
(bits / BLOCK_SIZE, bits % BLOCK_SIZE)
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}