Limnoria/src/utils.py

#!/usr/bin/env python

###
# Copyright (c) 2002, Jeremiah Fincher
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#     this list of conditions, and the following disclaimer.
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#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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###

"""
Simple utility functions.
"""

from __future__ import generators

from fix import *

import sgmllib
import htmlentitydefs

class HtmlToText(sgmllib.SGMLParser):
    """Taken from some eff-bot code on c.l.p."""
    entitydefs = htmlentitydefs.entitydefs
    def __init__(self, tagReplace=' '):
        self.data = []
        self.tagReplace = tagReplace
        sgmllib.SGMLParser.__init__(self)

    def unknown_starttag(self, tag, attrib):
        self.data.append(self.tagReplace)

    def unknown_endtag(self, tag):
        self.data.append(self.tagReplace)

    def handle_data(self, data):
        self.data.append(data)

    def getText(self):
        text = ''.join(self.data).strip()
        return ' '.join(text.split()) # normalize whitespace

def htmlToText(s, tagReplace=' '):
    x = HtmlToText(tagReplace)
    x.feed(s)
    return x.getText()

def eachSubstring(s):
    for i in range(1, len(s)+1):
        yield s[:i]

def abbrev(strings):
    d = {}
    for s in strings:
        for abbreviation in eachSubstring(s):
            if abbreviation not in d:
                d[abbreviation] = s
            else:
                if abbreviation not in strings:
                    d[abbreviation] = None
    removals = []
    for key in d:
        if d[key] is None:
            removals.append(key)
    for key in removals:
        del d[key]
    return d

def timeElapsed(now, then, leadingZeroes=False, years=True, weeks=True,
                days=True, hours=True, minutes=True, seconds=True):
    assert days or hours or minutes or seconds, 'One flag must be True'
    elapsed = int(now - then)
    ret = []
    if years:
        yrs, elapsed = elapsed // 31536000, elapsed % 31536000
        if leadingZeroes or yrs:
            if yrs:
                leadingZeroes = True
            if yrs != 1:
                yrs = '%s years' % yrs
            else:
                yrs = '1 year'
            ret.append(yrs)
    if weeks:
        wks, elapsed = elapsed // 604800, elapsed % 604800
        if leadingZeroes or wks:
            if wks:
                leadingZeroes = True
            if wks != 1:
                wks = '%s weeks' % wks
            else:
                wks = '1 week'
            ret.append(wks)
    if days:
        ds, elapsed = elapsed // 86400, elapsed % 86400
        if leadingZeroes or ds:
            if ds:
                leadingZeroes = True
            if ds != 1:
                ds = '%s days' % ds
            else:
                ds = '1 day'
            ret.append(ds)
    if hours:
        hrs, elapsed = elapsed // 3600, elapsed % 3600
        if leadingZeroes or hrs:
            if hrs:
                leadingZeroes = True
            if hrs != 1:
                hrs = '%s hours' % hrs
            else:
                hrs = '1 hour'
            ret.append(hrs)
    if minutes or seconds:
        mins, secs = elapsed // 60, elapsed % 60
        if leadingZeroes or mins:
            if mins != 1:
                mins = '%s minutes' % mins
            else:
                mins = '1 minute'
            ret.append(mins)
        if seconds:
            if secs != 1:
                secs = '%s seconds' % secs
            else:
                secs = '1 second'
            ret.append(secs)
    if len(ret) == 0:
        raise ValueError, 'Time difference not great enough to be noted.'
    if len(ret) == 1:
        return ret[0]
    else:
        return ' and '.join([', '.join(ret[:-1]), ret[-1]])
        
def distance(s, t):
    n = len(s)
    m = len(t)
    if n == 0:
        return m
    elif m == 0:
        return n
    d = range(n+1)
    for i in range(len(d)):
        d[i] = range(m+1)
    for i in range(1, n+1):
        cs = s[i-1]
        for j in range(1, m+1):
            ct = t[j-1]
            if cs == ct:
                cost = 0
            else:
                cost = 1
            d[i][j] = min(d[i-1][j]+1, d[i][j-1]+1, d[i-1][j-1]+cost)
    return d[n][m]
    

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