Building and reading canbus messages

Using Arduino Networking, Protocols, and Devices
1

Hi everybody, i'm working on a simple sketch that reads some canbus values and uses them for certain pat of my algorithm.
Right now i'm able to read che can messages but i can read only the RAW bytes of the can frames.
I would like to know if there is some ware a library that helps in retriving the data from the raw can bytes, for example:

My phisical signal, let's say Vehicle speed is on frame 167 start bit 51 13 bit lenght Big Endian and the scaling factor is 0,0625.
Right now i'm reading the bytes in wich my signal is and i bit shift the values of the individual bytes of the message 167 to rebuild the complete signal.
Would be great if there is a library in wich i can define the values of the signal and i can get it into a float variable, this will greately help in case i have a different vehicle with a different canbus message structure.
Thanks for any help.

2

This is the example:

+--------+--------+--------+--------+--------+--------+--------+--------+
|   0    |   1    |   2    |   3    |   4    |   5    |   6    |   7    |
+--------+--------+--------+--------+--------+--------+--------+--------+
|01234567|0123[color=red]4567|01234567|0[/color]1234567|01234567|01234567|01234567|01234567|
+--------+--------+--------+--------+--------+--------+--------+--------+
              ^             ^
              |Start Bit    |End Bit
Smaller Number 
+--------+--------+--------+--------+--------+--------+--------+--------+
|   0    |   1    |   2    |   3    |   4    |   5    |   6    |   7    |
+--------+--------+--------+--------+--------+--------+--------+--------+
|01234567|0123[color=red]1000|00000000|0[/color]1234567|01234567|01234567|01234567|01234567|
+--------+--------+--------+--------+--------+--------+--------+--------+
              ^             ^
              |Start Bit    |End Bit (Most Significative Bit)

Bigger Number 
+--------+--------+--------+--------+--------+--------+--------+--------+
|   0    |   1    |   2    |   3    |   4    |   5    |   6    |   7    |
+--------+--------+--------+--------+--------+--------+--------+--------+
|01234567|0123[color=red]1111|11111111|1[/color]1234567|01234567|01234567|01234567|01234567|
+--------+--------+--------+--------+--------+--------+--------+--------+
              ^             ^
              |Start Bit    |End Bit (Most Significative Bit)