Accessing a memory-mapped file using Python

问题

I am looking to take use of a memory mapped file from Guild Wars 2, which is designed to link into Mumble for positional audio. The file contains information on the characters coordinates and other useful information.

I have been able to access the coordinate information using this script,

import mmap
import struct

last=[]
while True:
    shmem = mmap.mmap(0, 20, "MumbleLink", mmap.ACCESS_READ)
    coord=struct.unpack("IL3f", shmem)[2:5]

    shmem.close()
    if last!=coord:
        print(coord)
        last = coord
        X = coord[2]
        Y = coord[0]
        Z = coord[1])

My problem is I am having difficulty working out how to get more information out of the file. How would I go about accessing other information that is stored, such as character name and camera position.

There is information on the file here:
https://forum-en.guildwars2.com/forum/community/api/Map-API-Mumble-Mashup http://mumble.sourceforge.net/Link

Any help would be greatly appreciated.

Cheers, Ed.

回答1:

You can try to map more than 20 bytes from the file in mmap call, say use 1024, unpack the whole thing according to the http://mumble.sourceforge.net/Link and then extract the name and camera position:

s = struct.unpack('IL3f3f3f512s3f')
name = s[11].decode('utf-16')
camera_pos_x,camera_pos_y,camera_pos_z = s[12:15]

回答2:

For the names, create a character name in the game and make sure it gets written to disk - perhaps by exiting the game.

Then use a binary file editor to search for the name. I'm partial to http://sourceforge.net/projects/bpe/ , but there are many of these.

Finding camera positions could prove more difficult. I'd probably start out by finding character names, and then search nearby for things that could be camera positions.

来源：https://stackoverflow.com/questions/20874804/accessing-a-memory-mapped-file-using-python

标签

python

struct

mmap

memory-mapped-files