Source code for cocotb.utils

from __future__ import print_function, division

# 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


def get_python_integer_types():
    warnings.warn(
        "This is an internal cocotb function, use six.integer_types instead",
        DeprecationWarning)
    from cocotb import _py_compat
    return _py_compat.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
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, 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. """ return _ldexp10(steps, _LOG_SIM_PRECISION - _get_log_time_scale(units))
[docs]def get_sim_steps(time, units=None): """Calculates the number of simulation time steps for a given amount of *time*. Args: time (numbers.Number): 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 = _ldexp10(result, _get_log_time_scale(units) - _LOG_SIM_PRECISION) result_rounded = math.floor(result) if result_rounded != result: raise ValueError("Unable to accurately represent {0}({1}) with the " "simulator precision of 1e{2}".format( time, units, _LOG_SIM_PRECISION)) return int(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 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 :mod:`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 :mod:`ctypes` structure then the *bytes* keyword argument must be used. Args: ctypes_obj (ctypes.Structure): The :mod:`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: >>> print(hexdump('this somewhat long string')) 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 <BLANKLINE> """ # 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: >>> print(hexdiffs(0, 1)) 0000 30 0 0000 31 1 <BLANKLINE> >>> print(hexdiffs('a', 'b')) 0000 61 a 0000 62 b <BLANKLINE> >>> print(hexdiffs('this short thing', 'this also short')) 0000 746869732073686F 7274207468696E67 this short thing 0000 7468697320616C73 6F 2073686F7274 this also short <BLANKLINE> """ # 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 with ANSI colors if possible/requested and not running in GUI.""" if want_color_output(): 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
[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
[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
[docs]def want_color_output(): """Return ``True`` if colored output is possible/requested and not running in GUI.""" want_color = sys.stdout.isatty() # default to color for TTYs 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
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')))
[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 if sys.version_info < (3,): raise RuntimeError( "Cannot use remove_traceback_frames on exceptions in python 2. " "Call it directly on the traceback object instead.") 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