# -*- Mode: Python; tab-width: 4 -*-

# [reworking of the version in Python-1.5.1/Demo/scripts/pi.py]

# Print digits of pi forever.
#
# The algorithm, using Python's 'long' integers ("bignums"), works
# with continued fractions, and was conceived by Lambert Meertens.
#
# See also the ABC Programmer's Handbook, by Geurts, Meertens & Pemberton,
# published by Prentice-Hall (UK) Ltd., 1990.

import string

StopException = "Stop!"

def go (file):
	try:
		k, a, b, a1, b1 = 2L, 4L, 1L, 12L, 4L
		while 1:
			# Next approximation
			p, q, k = k*k, 2L*k+1L, k+1L
			a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1
			# Print common digits
			d, d1 = a/b, a1/b1
			while d == d1:
				if file.write (str(int(d))):
					raise StopException
				a, a1 = 10L*(a%b), 10L*(a1%b1)
				d, d1 = a/b, a1/b1
	except StopException:
		return

class line_writer:
	
	"partition the endless line into 80-character ones"

	def __init__ (self, file, digit_limit=10000):
		self.file = file
		self.buffer = ''
		self.count = 0
		self.digit_limit = digit_limit

	def write (self, data):
		self.buffer = self.buffer + data
		if len(self.buffer) > 80:
			line, self.buffer = self.buffer[:80], self.buffer[80:]
			self.file.write (line+'\r\n')
			self.count = self.count + 80
		if self.count > self.digit_limit:
			return 1
		else:
			return 0

def main (env, stdin, stdout):
	parts = string.split (env['REQUEST_URI'], '/')
	if len(parts) >= 3:
		ndigits = string.atoi (parts[2])
	else:
		ndigits = 5000
	stdout.write ('Content-Type: text/plain\r\n\r\n')
	go (line_writer (stdout, ndigits))
