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/dev/input/event* 的格式

发布于 2024-10-18 10:52:40 字数 99 浏览 2 评论 0原文

位于 /dev/input/event* 中的字符设备的“格式”是什么？

换句话说，如何解码字符流？如果有一个 Python 示例将不胜感激。

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蓬勃野心 2024-10-25 10:52:40

一个简单而原始的阅读器可以使用以下命令完成：

#!/usr/bin/python
import struct
import time
import sys

infile_path = "/dev/input/event" + (sys.argv[1] if len(sys.argv) > 1 else "0")

"""
FORMAT represents the format used by linux kernel input event struct
See https://github.com/torvalds/linux/blob/v5.5-rc5/include/uapi/linux/input.h#L28
Stands for: long int, long int, unsigned short, unsigned short, unsigned int
"""
FORMAT = 'llHHI'
EVENT_SIZE = struct.calcsize(FORMAT)

#open file in binary mode
in_file = open(infile_path, "rb")

event = in_file.read(EVENT_SIZE)

while event:
    (tv_sec, tv_usec, type, code, value) = struct.unpack(FORMAT, event)

    if type != 0 or code != 0 or value != 0:
        print("Event type %u, code %u, value %u at %d.%d" % \
            (type, code, value, tv_sec, tv_usec))
    else:
        # Events with code, type and value == 0 are "separator" events
        print("===========================================")

    event = in_file.read(EVENT_SIZE)

in_file.close()

A simple and raw reader can be just done using:

#!/usr/bin/python
import struct
import time
import sys

infile_path = "/dev/input/event" + (sys.argv[1] if len(sys.argv) > 1 else "0")

"""
FORMAT represents the format used by linux kernel input event struct
See https://github.com/torvalds/linux/blob/v5.5-rc5/include/uapi/linux/input.h#L28
Stands for: long int, long int, unsigned short, unsigned short, unsigned int
"""
FORMAT = 'llHHI'
EVENT_SIZE = struct.calcsize(FORMAT)

#open file in binary mode
in_file = open(infile_path, "rb")

event = in_file.read(EVENT_SIZE)

while event:
    (tv_sec, tv_usec, type, code, value) = struct.unpack(FORMAT, event)

    if type != 0 or code != 0 or value != 0:
        print("Event type %u, code %u, value %u at %d.%d" % \
            (type, code, value, tv_sec, tv_usec))
    else:
        # Events with code, type and value == 0 are "separator" events
        print("===========================================")

    event = in_file.read(EVENT_SIZE)

in_file.close()

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养猫人 2024-10-25 10:52:40

格式在 Documentation/input/input.txt 文件。基本上，您从文件中读取以下形式的结构：

struct input_event {
    struct timeval time;
    unsigned short type;
    unsigned short code;
    unsigned int value;
};

type 和 code 是 linux/input.h 中定义的值。例如，
类型可能是 EV_REL 表示鼠标的相对力矩，或 EV_KEY 表示
按键，code 是按键代码，或者 REL_X 或 ABS_X 表示按键
老鼠。

The format is described in the Documentation/input/input.txt file in the Linux source. Basically, you read structs of the following form from the file:

struct input_event {
    struct timeval time;
    unsigned short type;
    unsigned short code;
    unsigned int value;
};

type and code are values defined in linux/input.h. For example,
type might be EV_REL for relative moment of a mouse, or EV_KEY for
a keypress, and code is the keycode, or REL_X or ABS_X for a
mouse.

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树深时见影 2024-10-25 10:52:40

就在 Input.py 模块。您还需要 event.py< /a> 模块。

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梦回梦里 2024-10-25 10:52:40

python-evdev 包提供到事件设备接口的绑定。一个简短的用法示例是：

from evdev import InputDevice
from select import select

dev = InputDevice('/dev/input/event1')

while True:
   r,w,x = select([dev], [], [])
   for event in dev.read():
       print(event)

# event at 1337427573.061822, code 01, type 02, val 01
# event at 1337427573.061846, code 00, type 00, val 00

请记住，与迄今为止提到的非常方便的纯 Pythonic 模块不同， evdev 包含 C 扩展。构建它们需要安装 Python 开发和内核头文件。

The python-evdev package provides bindings to the event device interface. A short usage example would be:

from evdev import InputDevice
from select import select

dev = InputDevice('/dev/input/event1')

while True:
   r,w,x = select([dev], [], [])
   for event in dev.read():
       print(event)

# event at 1337427573.061822, code 01, type 02, val 01
# event at 1337427573.061846, code 00, type 00, val 00

Keep in mind that, unlike the very convenient, purely Pythonic modules mentioned so far, evdev contains C extensions. Building them requires having your Python development and kernel headers installed.

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