# Copyright (c) 2013 Potential Ventures Ltd
# Copyright (c) 2013 SolarFlare Communications Inc
# All rights reserved.
#
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# modification, are permitted provided that the following conditions are met:
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of Potential Ventures Ltd,
# SolarFlare Communications Inc nor the
# names of its contributors may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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"""Collection of handy functions."""
import inspect
import math
import os
import sys
import traceback
import weakref
from decimal import Decimal
from enum import Enum
from functools import lru_cache
from numbers import Real
from typing import Any, Optional, Type, TypeVar, Union
from cocotb import simulator
def _get_simulator_precision():
# cache and replace this function
precision = simulator.get_precision()
global _get_simulator_precision
_get_simulator_precision = precision.__int__
return _get_simulator_precision()
# Simulator helper functions
[docs]
def get_sim_time(units: str = "step") -> int:
"""Retrieves the simulation time from the simulator.
Args:
units: String specifying the units of the result
(one of ``'step'``, ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``).
``'step'`` will return the raw simulation time.
.. versionchanged:: 2.0
Passing ``None`` as the *units* argument was removed, use ``'step'`` instead.
Returns:
The simulation time in the specified units.
.. versionchanged:: 1.6.0
Support ``'step'`` as the the *units* argument to mean "simulator time step".
"""
timeh, timel = simulator.get_sim_time()
result = timeh << 32 | timel
if units != "step":
result = get_time_from_sim_steps(result, units)
return result
def _ldexp10(frac, exp):
"""Like math.ldexp, but base 10"""
# using * or / separately prevents rounding errors if `frac` is a
# high-precision type
if exp > 0:
return frac * (10**exp)
else:
return frac / (10**-exp)
[docs]
def get_time_from_sim_steps(steps: int, units: str) -> int:
"""Calculates simulation time in the specified *units* from the *steps* based
on the simulator precision.
Args:
steps: Number of simulation steps.
units: String specifying the units of the result
(one of ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``).
Returns:
The simulation time in the specified units.
"""
return _ldexp10(steps, _get_simulator_precision() - _get_log_time_scale(units))
[docs]
def get_sim_steps(
time: Union[Real, Decimal], units: str = "step", *, round_mode: str = "error"
) -> int:
"""Calculates the number of simulation time steps for a given amount of *time*.
When *round_mode* is ``"error"``, a :exc:`ValueError` is thrown if the value cannot
be accurately represented in terms of simulator time steps.
When *round_mode* is ``"round"``, ``"ceil"``, or ``"floor"``, the corresponding
rounding function from the standard library will be used to round to a simulator
time step.
Args:
time: The value to convert to simulation time steps.
units: String specifying the units of the result
(one of ``'step'``, ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``).
``'step'`` means *time* is already in simulation time steps.
round_mode: String specifying how to handle time values that sit between time steps
(one of ``'error'``, ``'round'``, ``'ceil'``, ``'floor'``).
Returns:
The number of simulation time steps.
Raises:
ValueError: if the value cannot be represented accurately in terms of simulator
time steps when *round_mode* is ``"error"``.
.. versionchanged:: 1.5
Support ``'step'`` as the *units* argument to mean "simulator time step".
.. versionchanged:: 1.6
Support rounding modes.
"""
if units != "step":
result = _ldexp10(time, _get_log_time_scale(units) - _get_simulator_precision())
else:
result = time
if round_mode == "error":
result_rounded = math.floor(result)
if result_rounded != result:
precision = _get_simulator_precision()
raise ValueError(
f"Unable to accurately represent {time}({units}) with the simulator precision of 1e{precision}"
)
elif round_mode == "ceil":
result_rounded = math.ceil(result)
elif round_mode == "round":
result_rounded = round(result)
elif round_mode == "floor":
result_rounded = math.floor(result)
else:
raise ValueError(f"Invalid round_mode specifier: {round_mode}")
return result_rounded
def _get_log_time_scale(units):
"""Retrieves the ``log10()`` of the scale factor for a given time unit.
Args:
units (str): String specifying the units
(one of ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``).
Returns:
The ``log10()`` of the scale factor for the time unit.
"""
scale = {"fs": -15, "ps": -12, "ns": -9, "us": -6, "ms": -3, "sec": 0}
units_lwr = units.lower()
if units_lwr not in scale:
raise ValueError(f"Invalid unit ({units}) provided")
else:
return scale[units_lwr]
[docs]
class ParametrizedSingleton(type):
"""A metaclass that allows class construction to reuse an existing instance.
We use this so that :class:`RisingEdge(sig) <cocotb.triggers.RisingEdge>` and :class:`Join(coroutine) <cocotb.triggers.Join>` always return
the same instance, rather than creating new copies.
"""
def __init__(cls, *args, **kwargs):
# Attach a lookup table to this class.
# Weak such that if the instance is no longer referenced, it can be
# collected.
cls.__instances = weakref.WeakValueDictionary()
def __singleton_key__(cls, *args, **kwargs):
"""Convert the construction arguments into a normalized representation that
uniquely identifies this singleton.
"""
# Could default to something like this, but it would be slow
# return tuple(inspect.Signature(cls).bind(*args, **kwargs).arguments.items())
raise NotImplementedError
def __call__(cls, *args, **kwargs):
key = cls.__singleton_key__(*args, **kwargs)
try:
return cls.__instances[key]
except KeyError:
# construct the object as normal
self = super().__call__(*args, **kwargs)
cls.__instances[key] = self
return self
@property
def __signature__(cls):
return inspect.signature(cls.__singleton_key__)
[docs]
@lru_cache(maxsize=None)
def want_color_output():
"""Return ``True`` if colored output is possible/requested and not running in GUI.
Colored output can be explicitly requested by setting :envvar:`COCOTB_ANSI_OUTPUT` to ``1``.
"""
want_color = sys.stdout.isatty() # default to color for TTYs
if os.getenv("NO_COLOR") is not None:
want_color = False
if os.getenv("COCOTB_ANSI_OUTPUT", default="0") == "1":
want_color = True
if os.getenv("GUI", default="0") == "1":
want_color = False
return want_color
[docs]
def remove_traceback_frames(tb_or_exc, frame_names):
"""
Strip leading frames from a traceback
Args:
tb_or_exc (Union[traceback, BaseException, exc_info]):
Object to strip frames from. If an exception is passed, creates
a copy of the exception with a new shorter traceback. If a tuple
from `sys.exc_info` is passed, returns the same tuple with the
traceback shortened
frame_names (List[str]):
Names of the frames to strip, which must be present.
"""
# self-invoking overloads
if isinstance(tb_or_exc, BaseException):
exc = tb_or_exc
return exc.with_traceback(
remove_traceback_frames(exc.__traceback__, frame_names)
)
elif isinstance(tb_or_exc, tuple):
exc_type, exc_value, exc_tb = tb_or_exc
exc_tb = remove_traceback_frames(exc_tb, frame_names)
return exc_type, exc_value, exc_tb
# base case
else:
tb = tb_or_exc
for frame_name in frame_names:
assert tb.tb_frame.f_code.co_name == frame_name
tb = tb.tb_next
return tb
[docs]
def walk_coro_stack(coro):
"""Walk down the coroutine stack, starting at *coro*."""
while coro is not None:
try:
f = getattr(coro, "cr_frame")
coro = coro.cr_await
except AttributeError:
f = None
coro = None
if f is not None:
yield (f, f.f_lineno)
Self = TypeVar("Self")
[docs]
class DocEnum(Enum):
"""Like :class:`enum.Enum`, but allows documenting enum values.
Documentation for enum members can be optionally added by setting enum values to a tuple of the intended value and the docstring.
This adds the provided docstring to the ``__doc__`` field of the enum value.
.. code-block:: python3
class MyEnum(DocEnum):
\"\"\"Class documentation\"\"\"
VALUE1 = 1, "Value documentation"
VALUE2 = 2 # no documentation
Taken from :ref:`this StackOverflow answer <https://stackoverflow.com/questions/50473951/how-can-i-attach-documentation-to-members-of-a-python-enum/50473952#50473952>`
by :ref:`Eric Wieser <https://stackoverflow.com/users/102441/eric>`,
as recommended by the ``enum_tools`` documentation.
"""
def __new__(cls: Type[Self], value: Any, doc: Optional[str] = None) -> Self:
# super().__new__() assumes the value is already an enum value
# so we side step that and create a raw object and fill in _value_
self = object.__new__(cls)
self._value_ = value
if doc is not None:
self.__doc__ = doc
return self