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from typing import Any, Callable, Optional, TypeVar
from _pointers import run_stack_callback
from .base_pointers import BaseAllocatedPointer, IterDereferencable
from .util import handle
__all__ = ("StackAllocatedPointer", "acquire_stack_alloc", "stack_alloc")
T = TypeVar("T")
A = TypeVar("A", bound=BaseAllocatedPointer)
class StackAllocatedPointer(IterDereferencable[T], BaseAllocatedPointer[T]):
"""Pointer to memory allocated on the stack."""
def __init__(
self,
address: int,
size: int,
assigned: bool = False,
) -> None:
"""
Args:
address: Address of the allocated memory.
size: Size of the allocated memory.
assigned: Whether an object is currently inside the memory.
"""
self._address = address
self._size = size
self._freed = False
self._assigned = assigned
@property
def freed(self) -> bool:
return self._freed
@freed.setter
def freed(self, value: bool) -> None:
self._freed = value
@property
def address(self) -> Optional[int]:
return self._address
@address.setter
def address(self, value: int) -> None:
self._address = value
def __repr__(self) -> str:
return f"StackAllocatedPointer(address={self.address}, size={self.size})" # noqa
def __add__(self, amount: int):
return StackAllocatedPointer(
self.ensure() + amount,
self.size,
self.assigned,
)
def __sub__(self, amount: int):
return StackAllocatedPointer(
self.ensure() - amount,
self.size,
self.assigned,
)
def free(self) -> None:
raise ValueError(
"pointers to items on the stack may not be freed dynamically",
)
@handle
def stack_alloc(
size: int,
) -> Callable[
[Callable[[StackAllocatedPointer[Any]], T]], Callable[[], T]
]: # noqa
"""Get a callback with a pointer to stack allocated memory.
This function **is not** run automatically.
For that purpose, use `acquire_stack_alloc`.
Args:
size: Size of the allocation
"""
def decorator(
func: Callable[[StackAllocatedPointer[Any]], T],
) -> Callable[[], T]:
def wrapper():
return run_stack_callback(size, StackAllocatedPointer, func)
return wrapper
return decorator
def acquire_stack_alloc(
size: int,
) -> Callable[[Callable[[StackAllocatedPointer[Any]], T]], T]:
"""Execute a callback with a pointer to stack allocated memory.
Args:
size: Size of the allocation
"""
def decorator(func: Callable[[StackAllocatedPointer[Any]], T]) -> T:
def wrapper():
return run_stack_callback(size, StackAllocatedPointer, func)
return wrapper()
return decorator