git smudge filter to k&r style php code

phpfilter.py

#!/usr/bin/python
import sys
import re

CANTSMUDGE = '<?php //cantsmudgethis ?>'

class RewStream:
    def __init__(self, holdlines=0):
        self.holdlines = holdlines
        self.current = 0
        self.lines = []
    def write(self, line):
        self.lines.append([line,None])
    def read(self):
        if self.holdlines == None: holdlines = 0
        else: holdlines = self.holdlines
        for i in range(0, len(self.lines) - holdlines):
            if self.holdlines != None:
                self.current -= 1
                line = self.lines.pop(0)
                if line[1] == None: yield line[0]
                else: yield line[1]
    def getCurrent(self):
        if self.lines[self.current][1] == None: return self.lines[self.current][0]
        else: return self.lines[self.current][1]
    def setCurrent(self, line):
        self.lines[self.current][1] = line
    def seek(self, where):
        self.current += where
        return self.current > 0
    def seekback(self):
        seeked = 0
        while 1:
            seeked += 1
            s.seek(-1)
            if s.getCurrent() != '': break
        return seeked
    def revert(self):
        self.lines[self.current][1] = None

if sys.argv[1] == 'smudge':
    s = RewStream(None)
    cantsmudge = False
    for inp in sys.stdin:
        s.write(inp)
        if cantsmudge:
            while 1:
                s.revert()
                if not s.seek(-1):
                    s.setCurrent(CANTSMUDGE+s.getCurrent())
                    break
            break
        if '{' in s.getCurrent():
            if len(s.getCurrent()) >= 2 and s.getCurrent()[-2] != '\r' and re.match('^(    )*{$', s.getCurrent()):
                seeked = s.seekback()
                s.setCurrent(s.getCurrent()[:-1]+' {\n')
                s.seek(seeked)
                s.setCurrent('')
            else:
                cantsmudge = True
                print >> sys.stderr, [s.getCurrent()]
                continue
        if re.match('^(    )*else', s.getCurrent()):
            cur = re.sub('^(    )*', '', s.getCurrent())
            seeked = s.seekback()
            s.setCurrent(s.getCurrent()[:-1]+' '+cur)
            s.seek(seeked)
            s.setCurrent('')
        for outpl in s.read():
            sys.stdout.write(outpl)
        s.seek(1)

    for inp in sys.stdin: s.write(inp)
    s.holdlines = 0
    for outpl in s.read():
        sys.stdout.write(outpl)
else:
    s = RewStream(2)
    first = True
    cantsmudge = False
    for inp in sys.stdin:
        s.write(inp)
        if first:
            first = False
            if s.getCurrent().startswith(CANTSMUDGE):
                s.setCurrent(s.getCurrent()[len(CANTSMUDGE):])
                cantsmudge = True
        if not cantsmudge:
            if ' {' in s.getCurrent():
                m = re.match('^((?:    )*)', s.getCurrent())
                prefix = m.group(1)
                s.setCurrent(s.getCurrent().replace(' {', '\n'+prefix+'{'))
            if '} else' in s.getCurrent():
                m = re.match('^((?:    )*)', s.getCurrent())
                prefix = m.group(1)
                s.setCurrent(s.getCurrent().replace('} else', '}\n'+prefix+'else'))
        for outpl in s.read():
            sys.stdout.write(outpl)
        s.seek(1)
    s.holdlines = 0
    for outpl in s.read():
        sys.stdout.write(outpl)