#!/usr/bin/env python

# Copyright (c) 2011
#      Daniel O'Connor <darius@dons.net.au>.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#

import numpy
import re

headerre = re.compile(b'^(:[A-Z:]+ ).*')
insturlre = re.compile(b'([a-zA-Z0-9]+)://(([^:]+)?(:([^/]+)@))?([^:]+)(:(.+))?')

def query(d, q, timeout = None):
    d.write(q)
    return d.read(timeout)

def clean(data):
    # The instrument might return some header before the data (TEK 2024B does this)
    m = headerre.match(data)
    if m == None:
        return data
    else:
        hlen = len(m.groups()[0])
        return(data[hlen:])

def getdata(data, dtype = float):
    '''Get a single data item'''
    data = clean(data)
    return dtype(data)

def getbin(data):
    '''Fetch binary blob, strips ASCII length header and checks'''
    data = clean(data)

    if data[0] != ord('#'):
        raise ValueError('data length header incorrect')
    dlenlen = int(chr(data[1]))
    if dlenlen == 0:
        return numpy.array([])

    dlen = int(data[2:dlenlen + 2])
    if dlen == 0:
        return b''

    wanted = dlen + 2 + dlenlen
    # Chop off the trailing \n if necessary
    if len(data) == wanted + 1 and data[-1] == '\n':
        data = data[0:-1]

    if len(data) != wanted:
        raise ValueError('length mismatch, header says %d, actually got %d bytes' % (wanted, len(data)))

    return data[2 + dlenlen:]

def bindecode(data, dtype = numpy.float32):
    '''Decode binary data, returns numpy array'''

    return numpy.frombuffer(getbin(data), dtype = dtype)

def ascdecode(data, dtype = numpy.float32, sep = None):
    '''Decode ASCII data, returns numpy array'''

    data = clean(data)

    # Strip length off if present as we don't need it
    if data[0] == '#':
        l = int(data[1])
        data = data[l + 2:]

    # Take a guess at the separator
    if sep == None:
        if data.find(',', 0, 20) != -1:
            sep = ','
        else:
            sep = ' '
    return numpy.fromstring(data, dtype = dtype, sep = sep)
    

def instURL(url):
    m = insturlre.match(url)
    if m == None:
        raise ValueError('Unable to parse URL')
    proto, xxx, user, xxx, pwd, address, xxx, port = m.groups()
    if proto == 'rsib':
        import rsib
        return rsib.RSIBDevice(address, port)
    elif proto == 'usb':
        import usb488
        return usb488.USB488Device()
    elif proto == 'vxi':
        import vxi
        if port == None:
            port = 'inst0'
        return vxi.VXIDevice(address, device = port)
    elif proto == 'scpi':
        import scpisock
        return scpisock.SCPISockDevice(address, port)
    else:
        raise NotImplementedError("unknown protocol " + proto)