#!/usr/bin/env python

program = 'vdifd'
author  = 'Walter Brisken'
version = '0.3'
verdate = '20160610'

from os import system
from string import split
from sys import exit, argv


def usage():
	print '\n%s ver. %s  %s  %s\n' % (program, version, author, verdate)
	print 'A VDIF decoder for multi-thread, single channel VDIF data.  Uses vmux'
	print 'and m5d to do the heavy lifting.\n'
	print 'Usage : %s <infile> <frame size> <data rate> <threadlist> <n> [<offset> [<nbit>] ]\n' % program
	print '  <infile> is the name of the VDIF file\n'
	print '  <frame size> is the size of each input VDIF frame, inc. header (e.g., 5032)\n'
	print '  <data rate> is the stream data rate (Mbps)\n'
	print '  <n> is the number of samples per channel to decode\n'
	print '  <offset> optionally jump into input file by this many bytes\n'
	print '  <nbit> is number of bits per sample (default is 2)\n'
	print 'Note: Only works on 2-bit real data for now...\n'

if len(argv) < 6:
	usage()
	exit()

infile = argv[1]
framesize = int(argv[2])
datarate = int(argv[3])
threadlist = argv[4]
nt = len(split(threadlist, ','))
n = int(argv[5])
if len(argv) > 6:
	nbit = int(argv[6])
else:
	nbit = 2
if len(argv) > 7:
	offset = int(argv[7])
else:
	offset = 0

nc = 1
while(nc < nt):
	nc *= 2

outputpayload = nc*(framesize-32)
framespersecond = (datarate*1000000)/(nt*(framesize-32)*8)
outputdatarate = outputpayload*framespersecond*8/1000000

cmd = 'vmux %s %d %d %s - %d %d | m5d - VDIF_%d-%d-%d-%d %d' % (infile, framesize, framespersecond, threadlist, offset, nbit, outputpayload, outputdatarate, nc, nbit, n) 

print 'Executing: %s' % cmd
system(cmd)