如何将Linux keycode从/dev/input/event*转换为Perl中的ASCII ?

I'm writing a Perl script that reads data from the infamous /dev/input/event* and I didn't find a way to translate the key codes generated by the kernel into ASCII.

我正在编写一个Perl脚本，它从臭名昭著的/dev/input/event*中读取数据，我没有找到将内核生成的关键代码转换为ASCII的方法。

I'm talking about the linux key codes in this table here and I can't seem to find something that would help me translate them without hardcoding an array into the script. Am I missing something?

我在这里讨论的是linux的关键代码，我似乎找不到可以帮助我翻译它们的东西，而不是把数组硬编码到脚本中。我遗漏了什么东西?

I'd like to skip the array part because it doesn't seem to be a good practice, so any idea? :)

我想跳过数组部分因为这看起来不是很好的练习，有什么想法吗?:)

3 个解决方案

#1

It's basically a map problem. You have to take a keycode and lookup its ASCII equivalent. What about the "array part" do you think is not a good practice?

这基本上是一个地图问题。您必须使用keycode并查找它的ASCII等效项。你认为“数组部分”不是一个好的实践吗?

I didn't see a module for this on CPAN, but that means that you have a chance to be the first to upload it. :)

我在CPAN上没有看到这个模块，但这意味着你有机会第一个上传它。:)

#2

Unfortunately, I don't program in Perl but here is a simple example written in C. Perhaps it might help you nevertheless.

不幸的是，我不使用Perl编程，但这里有一个简单的例子，也许它可以帮助您。

/*
 * Based on keytable.c by Mauro Carvalho Chehab
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>

#include <linux/input.h>

#include <string.h>
#include <linux/input.h>
#include <sys/ioctl.h>

#define KEY_RELEASE 0
#define KEY_PRESS 1
#define KEY_KEEPING_PRESSED 2

#include "parse.h"

void prtcode(int codes) {
    struct parse_key *p;

    for (p = keynames; p->name != NULL; p++) {
        if (p->value == (unsigned) codes) {
            printf("scancode %s (0x%02x)\n", p->name, codes);
            return;
        }
    }

    if (isprint(codes)) {
        printf("scancode '%c' (0x%02x)\n", codes, codes);
    } else {
        printf("scancode 0x%02x\n", codes);
    }
}

int main (int argc, char *argv[]) {
    int i, fd;
    struct input_event ev[64];

    if (argc != 2) {
        fprintf(stderr, "usage: %s event-device (/dev/input/eventX)\n", argv[0]);
        return 1;
    }

    if ((fd = open(argv[1], O_RDONLY)) < 0) {
        perror("Couldn't open input device");
        return 1;
    }

    while (1) {
        size_t rb = read(fd, ev, sizeof(ev));

        if (rb < (int) sizeof(struct input_event)) {
            perror("short read");
            return 1;
        }

        for (i = 0; i < (int) (rb / sizeof(struct input_event)); i++) {
            if (EV_KEY == ev[i].type) {
                if ((ev[i].value == KEY_PRESS) || (ev[i].value == KEY_KEEPING_PRESSED)) {
                    prtcode(ev[i].code);
                    printf("type %d code %d value %d\n", ev[i].type, ev[i].code, ev[i].value);
                    printf("\n");
                }
            }
        }
    }

    return 0;
}

For generating the parse.h, put this into your Makefile:

生成的解析。h，把这个放进你的Makefile:

parse.h: /usr/include/linux/input.h
    @echo generating parse.h
    @echo -en "struct parse_key {\n\tchar *name;\n\tunsigned int value;\n} " >parse.h
    @echo -en "keynames[] = {\n" >>parse.h

    @more /usr/include/linux/input.h |perl -n \
    -e 'if (m/^\#define\s+(KEY_[^\s]+)\s+(0x[\d\w]+|[\d]+)/) ' \
    -e '{ printf "\t{\"%s\", %s},\n",$$1,$$2; }' \
    -e 'if (m/^\#define\s+(BTN_[^\s]+)\s+(0x[\d\w]+|[\d]+)/) ' \
    -e '{ printf "\t{\"%s\", %s},\n",$$1,$$2; }' \
    >> parse.h
    @echo -en "\t{ NULL, 0}\n};\n" >>parse.h

Then, use it like this:

然后，像这样使用:

./keytable /dev/input/by-path/platform-i8042-serio-0-event-kbd

#3

Example 1 only gives you back the same key code values that are already coming from the linux kernel. For example you get KEY_A 0x1e for an 'a' key press. What you want is (and what i want) is the ascii conversion so if 'a' is pressed I want to see 0x61 for lower case and 0x41 for upper case.

示例1只提供了与linux内核相同的键值。例如，你得到KEY_A 0x1e作为“a”键。你想要的是(我想要的)是ascii转换，所以如果按下“a”，我想看到小写的0x61，大写的0x41。

#1