#  Copyright (c) 2001 Autonomous Zone Industries
#  Copyright (c) 2002-2007 Bryce "Zooko" Wilcox-O'Hearn
#  This file is licensed under the
#    GNU Lesser General Public License v2.1.
#    See the file COPYING or visit http://www.gnu.org/ for details.

"""
Benchmark a function for its behavior with respect to N...
"""

import math, operator, sys, time

if not hasattr(time, "realtime"):
    time.realtime = time.time

from assertutil import _assert

def makeg(func):
    def blah(n, func=func):
        for i in xrange(n):
            func()
    return blah

def rep_bench(func, n, initfunc=None, MAXREPS=5, MAXTIME=60.0):
    """
    Will run the func up to MAXREPS times, but won't start a new run if MAXTIME
    (wall-clock time) has already elapsed (unless MAXTIME is None).
    """
    starttime = time.realtime()
    print "N: %7d," % n,
    sys.stdout.flush()
    scores = []
    while ((len(scores) < MAXREPS) or (MAXREPS is None)) and ((MAXTIME is None) or ((time.realtime() - starttime) < MAXTIME)):
        if initfunc:
            initfunc(n)
        tl = bench_it(func, n)
        if tl < 0:
            raise AssertionError(tl)
        scores.append(tl)
    sum = reduce(operator.__add__, scores)
    ave = sum / len(scores)
    scores.sort()
    nw = min(int(math.log(len(scores)))+1, len(scores))
    worst = scores[-nw]
    best = scores[nw-1]
    if ave == 0:
        print "time: ave: %7.2f, %3dth-best: %7.2f, %3dth-worst: %7.2f (of %6d), ave rate: N/A" % (ave, nw, best, nw, worst, len(scores),)
    else:
        print "time: ave: %7.2f, %3dth-best: %7.2f, %3dth-worst: %7.2f (of %6d), reps/s: %6d, averate: %8.0f" % (ave, nw, best, nw, worst, len(scores), len(scores) / sum, (n * len(scores)) / sum,)
 
MARGINOFERROR = 10

worstemptymeasure = 0

def bench_it(func, n):
    st = time.realtime()
    func(n)
    sto = time.realtime()
    timeelapsed = sto - st
    global worstemptymeasure
    emsta = time.realtime()
    emstop = time.realtime()
    empty = emstop - emsta
    if empty > worstemptymeasure:
        worstemptymeasure = empty
    _assert(timeelapsed*MARGINOFERROR > worstemptymeasure, "Invoking func %s(%s) took only %0.20f seconds, but we cannot accurately measure times much less than %0.20f seconds.  Therefore we cannot produce good results here.  Try benchmarking a more time-consuming variant." % (func, n, timeelapsed, worstemptymeasure,))
    return timeelapsed

def bench(func, initfunc=None, TOPXP=21, MAXREPS=5, MAXTIME=60.0):
    BSIZES = []
    for i in range(TOPXP-6, TOPXP+1, 2):
        BSIZES.append(2 ** i)

    for BSIZE in BSIZES:
        rep_bench(func, BSIZE, initfunc=initfunc, MAXREPS=MAXREPS, MAXTIME=MAXTIME)