#!/usr/bin/env python

"""Parse and dump binary log generated by sdlog2
    
    Usage: python sdlog2_dump.py <log.bin>"""

__author__  = "Anton Babushkin"
__version__ = "0.1"

import struct, sys

class BufferUnderflow(Exception):
    pass

class SDLog2Parser:
    BLOCK_SIZE = 8192
    MSG_HEADER_LEN = 3
    MSG_HEAD1 = 0xA3
    MSG_HEAD2 = 0x95
    MSG_FORMAT_PACKET_LEN = 89
    MSG_TYPE_FORMAT = 0x80
    
    def __init__(self):
        return

    def reset(self):
        self.msg_formats = {}
        self.buffer = ""
        self.ptr = 0
    
    def process(self, fn):
        self.reset()
        f = open(fn, "r")
        while True:
            chunk = f.read(self.BLOCK_SIZE)
            if len(chunk) == 0:
                break
            self.buffer = self.buffer[self.ptr:] + chunk
            self.ptr = 0
            while self._bytes_left() >= self.MSG_HEADER_LEN:
                head1 = ord(self.buffer[self.ptr])
                head2 = ord(self.buffer[self.ptr+1])
                if (head1 != self.MSG_HEAD1 or head2 != self.MSG_HEAD2):
                    raise Exception("Invalid header: %02X %02X, must be %02X %02X" % (head1, head2, self.MSG_HEAD1, self.MSG_HEAD2))
                msg_type = ord(self.buffer[self.ptr+2])
                if msg_type == self.MSG_TYPE_FORMAT:
                    self._parse_msg_format()
                else:
                    msg_format = self.msg_formats[msg_type]
                    if msg_format == None:
                        raise Exception("Unknown msg type: %i" % msg_type)
                    msg_length = msg_format[0]
                    if self._bytes_left() < msg_length:
                        break
                    self._parse_msg(msg_format)
        f.close()

    def _bytes_left(self):
        return len(self.buffer) - self.ptr

    def _parse_msg_format(self):
        if self._bytes_left() < self.MSG_FORMAT_PACKET_LEN:
            raise BufferUnderflow("Data is too short: %i bytes, need %i" % (self._bytes_left(), self.MSG_FORMAT_PACKET_LEN))
        msg_type = ord(self.buffer[self.ptr+3])
        msg_length = ord(self.buffer[self.ptr+4])
        msg_name = self.buffer[self.ptr+5:self.ptr+9].strip('\0')
        msg_struct = self.buffer[self.ptr+9:self.ptr+25].strip('\0')
        msg_labels = self.buffer[self.ptr+25:self.ptr+89].strip('\0').split(",")
        print "MSG FORMAT: type = %i, length = %i, name = %s, format = %s, labels = %s" % (msg_type, msg_length, msg_name, msg_struct, str(msg_labels))
        self.msg_formats[msg_type] = (msg_length, msg_name, msg_struct, msg_labels)
        self.ptr += self.MSG_FORMAT_PACKET_LEN

    def _parse_msg(self, msg_format):
        msg_length = msg_format[0]
        msg_name = msg_format[1]
        msg_struct = "<" + msg_format[2]
        data = struct.unpack(msg_struct, self.buffer[self.ptr+self.MSG_HEADER_LEN:self.ptr+msg_length])
        print "MSG %s: %s" % (msg_name, str(data))
        self.ptr += msg_format[0]
    
def _main():
    if len(sys.argv) < 2:
        print "Usage:\npython sdlog2_dump.py <log.bin>"
        return
    fn = sys.argv[1]
    parser = SDLog2Parser()
    parser.process(fn)

if __name__ == "__main__":
    _main()