nls_utf8.c

可以在不启动LINUX的情况下直接访问EXT2和EXT3格式的磁盘

/*
 * Module for handling utf8 just like any other charset.
 * By Urban Widmark 2000
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/nls.h>
#include <linux/errno.h>

static unsigned char identity[256];

static int uni2char(wchar_t uni, unsigned char *out, int boundlen)
{
	int n;

	if ( (n = utf8_wctomb(out, uni, boundlen)) == -1) {
		*out = '?';
		return -EINVAL;
	}
	return n;
}

static int char2uni(const unsigned char *rawstring, int boundlen, wchar_t *uni)
{
	int n;

	if ( (n = utf8_mbtowc(uni, rawstring, boundlen)) == -1) {
		*uni = 0x003f;	/* ? */
		n = -EINVAL;
	}
	return n;
}

static struct nls_table table = {
	/* .charset */ "utf8",
    /* .alias */   0,
	/* .uni2char */ uni2char,
	/* .char2uni */ char2uni,
	/* .charset2lower */ identity,	/* no conversion */
	/* .charset2upper */ identity,
	/* .owner */ THIS_MODULE,
};

static int __init init_nls_utf8(void)
{
	int i;
	for (i=0; i<256; i++)
        identity[i] = (unsigned char) i;

        return register_nls(&table);
}

static void __exit exit_nls_utf8(void)
{
        unregister_nls(&table);
}

module_init(init_nls_utf8)
module_exit(exit_nls_utf8)
MODULE_LICENSE("Dual BSD/GPL");