Source code for cocotb.utils

from __future__ import print_function

# Copyright (c) 2013 Potential Ventures Ltd
# Copyright (c) 2013 SolarFlare Communications Inc
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"""Collection of handy functions."""

import ctypes
import math
import os
import sys
import weakref
import functools
import warnings

if "COCOTB_SIM" in os.environ:
    import simulator
    _LOG_SIM_PRECISION = simulator.get_precision()  # request once and cache
else:
    simulator = None
    _LOG_SIM_PRECISION = -15

# This is six.integer_types
if sys.version_info.major >= 3:
    integer_types = (int,)
else:
    integer_types = (int, long)  # noqa


def get_python_integer_types():
    warnings.warn(
        "This is an internal cocotb function, use six.integer_types instead",
        DeprecationWarning)
    return integer_types


# Simulator helper functions
[docs]def get_sim_time(units=None): """Retrieves the simulation time from the simulator. Args: units (str or None, optional): String specifying the units of the result (one of ``None``, ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``). ``None`` will return the raw simulation time. Returns: The simulation time in the specified units. """ timeh, timel = simulator.get_sim_time() result = (timeh << 32 | timel) if units is not None: result = get_time_from_sim_steps(result, units) return result
[docs]def get_time_from_sim_steps(steps, units): """Calculates simulation time in the specified *units* from the *steps* based on the simulator precision. Args: steps (int): Number of simulation steps. units (str): String specifying the units of the result (one of ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``). Returns: The simulation time in the specified units. """ result = steps * (10.0**(_LOG_SIM_PRECISION - _get_log_time_scale(units))) return result
[docs]def get_sim_steps(time, units=None): """Calculates the number of simulation time steps for a given amount of *time*. Args: time (int or float): The value to convert to simulation time steps. units (str or None, optional): String specifying the units of the result (one of ``None``, ``'fs'``, ``'ps'``, ``'ns'``, ``'us'``, ``'ms'``, ``'sec'``). ``None`` means time is already in simulation time steps. Returns: int: The number of simulation time steps. Raises: :exc:`ValueError`: If given *time* cannot be represented by simulator precision. """ result = time if units is not None: result = result * (10.0**(_get_log_time_scale(units) - _LOG_SIM_PRECISION)) err = int(result) - math.ceil(result) if err: raise ValueError("Unable to accurately represent {0}({1}) with the " "simulator precision of 1e{2}".format( time, units, _LOG_SIM_PRECISION)) return int(result)
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 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("Invalid unit ({0}) provided".format(units)) else: return scale[units_lwr] # Ctypes helper functions
[docs]def pack(ctypes_obj): """Convert a :mod:`ctypes` structure into a Python string. Args: ctypes_obj (ctypes.Structure): The ctypes structure to convert to a string. Returns: New Python string containing the bytes from memory holding *ctypes_obj*. """ return ctypes.string_at(ctypes.addressof(ctypes_obj), ctypes.sizeof(ctypes_obj))
[docs]def unpack(ctypes_obj, string, bytes=None): """Unpack a Python string into a :mod:`ctypes` structure. If the length of *string* is not the correct size for the memory footprint of the ctypes structure then the *bytes* keyword argument must be used. Args: ctypes_obj (ctypes.Structure): The ctypes structure to pack into. string (str): String to copy over the ctypes_obj memory space. bytes (int, optional): Number of bytes to copy. Defaults to ``None``, meaning the length of *string* is used. Raises: :exc:`ValueError`: If length of *string* and size of *ctypes_obj* are not equal. :exc:`MemoryError`: If *bytes* is longer than size of *ctypes_obj*. """ if bytes is None: if len(string) != ctypes.sizeof(ctypes_obj): raise ValueError("Attempt to unpack a string of size %d into a \ struct of size %d" % (len(string), ctypes.sizeof(ctypes_obj))) bytes = len(string) if bytes > ctypes.sizeof(ctypes_obj): raise MemoryError("Attempt to unpack %d bytes over an object \ of size %d" % (bytes, ctypes.sizeof(ctypes_obj))) ctypes.memmove(ctypes.addressof(ctypes_obj), string, bytes)
import cocotb.ANSI as ANSI def _sane_color(x): r = "" for i in x: j = ord(i) if (j < 32) or (j >= 127): r += "." else: r += i return r
[docs]def hexdump(x): """Hexdump a buffer. Args: x: Object that supports conversion via the ``str`` built-in. Returns: A string containing the hexdump. Example: .. code-block:: python print(hexdump('this somewhat long string')) .. code-block:: none 0000 74 68 69 73 20 73 6F 6D 65 77 68 61 74 20 6C 6F this somewhat lo 0010 6E 67 20 73 74 72 69 6E 67 ng string """ # adapted from scapy.utils.hexdump rs = "" x = str(x) l = len(x) i = 0 while i < l: rs += "%04x " % i for j in range(16): if i + j < l: rs += "%02X " % ord(x[i + j]) else: rs += " " if j % 16 == 7: rs += "" rs += " " rs += _sane_color(x[i:i + 16]) + "\n" i += 16 return rs
[docs]def hexdiffs(x, y): """Return a diff string showing differences between two binary strings. Args: x: Object that supports conversion via the ``str`` built-in. y: Object that supports conversion via the ``str`` built-in. Example: .. code-block:: python print(hexdiffs('this short thing', 'this also short')) .. code-block:: none 0000 746869732073686F 7274207468696E67 this short thing 0000 7468697320616C73 6F 2073686F7274 this also short """ # adapted from scapy.utils.hexdiff def sane(x): r = "" for i in x: j = ord(i) if (j < 32) or (j >= 127): r = r + "." else: r = r + i return r def highlight(string, colour=ANSI.COLOR_HILITE_HEXDIFF_DEFAULT): """Highlight only with ANSI output if it's requested and we are not in a GUI.""" want_ansi = os.getenv("COCOTB_ANSI_OUTPUT") and not os.getenv("GUI") if want_ansi is None: want_ansi = sys.stdout.isatty() # default to ANSI for TTYs else: want_ansi = want_ansi == '1' if want_ansi: return colour + string + ANSI.COLOR_DEFAULT else: return string rs = "" x = str(x)[::-1] y = str(y)[::-1] SUBST = 1 INSERT = 1 d = {} d[-1, -1] = 0, (-1, -1) for j in range(len(y)): d[-1, j] = d[-1, j - 1][0] + INSERT, (-1, j - 1) for i in range(len(x)): d[i, -1] = d[i - 1, -1][0] + INSERT, (i - 1, -1) for j in range(len(y)): for i in range(len(x)): d[i, j] = min((d[i-1, j-1][0] + SUBST*(x[i] != y[j]), (i-1, j-1)), (d[i - 1, j][0] + INSERT, (i - 1, j)), (d[i, j - 1][0] + INSERT, (i, j - 1))) backtrackx = [] backtracky = [] i = len(x) - 1 j = len(y) - 1 while not (i == j == -1): i2, j2 = d[i, j][1] backtrackx.append(x[i2+1:i+1]) backtracky.append(y[j2+1:j+1]) i, j = i2, j2 x = y = i = 0 colorize = { 0: lambda x: x, # noqa -1: lambda x: x, # noqa 1: lambda x: x} # noqa dox = 1 doy = 0 l = len(backtrackx) while i < l: separate = 0 linex = backtrackx[i:i+16] liney = backtracky[i:i+16] xx = sum(len(k) for k in linex) yy = sum(len(k) for k in liney) if dox and not xx: dox = 0 doy = 1 if dox and linex == liney: doy = 1 if dox: xd = y j = 0 while not linex[j]: j += 1 xd -= 1 if dox != doy: rs += highlight("%04x" % xd) + " " else: rs += highlight("%04x" % xd, colour=ANSI.COLOR_HILITE_HEXDIFF_1) + " " x += xx line = linex else: rs += " " if doy: yd = y j = 0 while not liney[j]: j += 1 yd -= 1 if doy - dox != 0: rs += " " + highlight("%04x" % yd) else: rs += highlight("%04x" % yd, colour=ANSI.COLOR_HILITE_HEXDIFF_1) y += yy line = liney else: rs += " " rs += " " cl = "" for j in range(16): if i + j < l: if line[j]: if linex[j] != liney[j]: rs += highlight("%02X" % ord(line[j]), colour=ANSI.COLOR_HILITE_HEXDIFF_2) else: rs += "%02X" % ord(line[j]) if linex[j] == liney[j]: cl += highlight(_sane_color(line[j]), colour=ANSI.COLOR_HILITE_HEXDIFF_3) else: cl += highlight(sane(line[j]), colour=ANSI.COLOR_HILITE_HEXDIFF_4) else: rs += " " cl += " " else: rs += " " if j == 7: rs += " " rs += " " + cl + '\n' if doy or not yy: doy = 0 dox = 1 i += 16 else: if yy: dox = 0 doy = 1 else: i += 16 return rs
# This is essentially six.exec_ if sys.version_info.major == 3: # this has to not be a syntax error in py2 import builtins exec_ = getattr(builtins, 'exec') else: # this has to not be a syntax error in py3 def exec_(_code_, _globs_=None, _locs_=None): """Execute code in a namespace.""" if _globs_ is None: frame = sys._getframe(1) _globs_ = frame.f_globals if _locs_ is None: _locs_ = frame.f_locals del frame elif _locs_ is None: _locs_ = _globs_ exec("""exec _code_ in _globs_, _locs_""") # this is six.with_metaclass, with a clearer docstring
[docs]def with_metaclass(meta, *bases): """This provides: .. code-block:: python class Foo(with_metaclass(Meta, Base1, Base2)): pass which is a unifying syntax for: .. code-block:: python # python 3 class Foo(Base1, Base2, metaclass=Meta): pass # python 2 class Foo(Base1, Base2): __metaclass__ = Meta """ # This requires a bit of explanation: the basic idea is to make a dummy # metaclass for one level of class instantiation that replaces itself with # the actual metaclass. class metaclass(type): def __new__(cls, name, this_bases, d): return meta(name, bases, d) @classmethod def __prepare__(cls, name, this_bases): return meta.__prepare__(name, bases) return type.__new__(metaclass, 'temporary_class', (), {})
# this is six.raise_from if sys.version_info[:2] == (3, 2): exec_("""def raise_from(value, from_value): try: if from_value is None: raise value raise value from from_value finally: value = None """) elif sys.version_info[:2] > (3, 2): exec_("""def raise_from(value, from_value): try: raise value from from_value finally: value = None """) else: def raise_from(value, from_value): raise value
[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. """ # Once we drop python 2, we can implement a default like the following, # which will work in 99% of cases: # 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(ParametrizedSingleton, cls).__call__(*args, **kwargs) cls.__instances[key] = self return self
# backport of Python 3.7's contextlib.nullcontext
[docs]class nullcontext(object): """Context manager that does no additional processing. Used as a stand-in for a normal context manager, when a particular block of code is only sometimes used with a normal context manager: >>> cm = optional_cm if condition else nullcontext() >>> with cm: >>> # Perform operation, using optional_cm if condition is True """ def __init__(self, enter_result=None): self.enter_result = enter_result def __enter__(self): return self.enter_result def __exit__(self, *excinfo): pass
[docs]def reject_remaining_kwargs(name, kwargs): """ Helper function to emulate python 3 keyword-only arguments. Use as:: def func(x1, **kwargs): a = kwargs.pop('a', 1) b = kwargs.pop('b', 2) reject_remaining_kwargs('func', kwargs) ... To emulate the Python 3 syntax:: def func(x1, *, a=1, b=2): ... """ if kwargs: # match the error message to what python 3 produces bad_arg = next(iter(kwargs)) raise TypeError( '{}() got an unexpected keyword argument {!r}'.format(name, bad_arg) )
[docs]class lazy_property(object): """ A property that is executed the first time, then cached forever. It does this by replacing itself on the instance, which works because unlike `@property` it does not define __set__. This should be used for expensive members of objects that are not always used. """ def __init__(self, fget): self.fget = fget # copy the getter function's docstring and other attributes functools.update_wrapper(self, fget) def __get__(self, obj, cls): if obj is None: return self value = self.fget(obj) setattr(obj, self.fget.__name__, value) return value
if __name__ == "__main__": import random a = "" for char in range(random.randint(250, 500)): a += chr(random.randint(0, 255)) b = a for error in range(random.randint(2, 9)): offset = random.randint(0, len(a)) b = b[:offset] + chr(random.randint(0, 255)) + b[offset+1:] diff = hexdiffs(a, b) print(diff) space = '\n' + (" " * 20) print(space.join(diff.split('\n')))