nls_utf8.c

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/*
 * 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 (boundlen <= 0)
        return -ENAMETOOLONG;

    n = utf32_to_utf8(uni, out, boundlen);
    if (n < 0) {
        *out = '?';
        return -EINVAL;
    }
    return n;
}

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

    n = utf8_to_utf32(rawstring, boundlen, &u);
    if (n < 0 || u > MAX_WCHAR_T) {
        *uni = 0x003f;  /* ? */
        return -EINVAL;
    }
    *uni = (wchar_t) u;
    return n;
}

static struct nls_table table = {
    .charset    = "utf8",
    .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] = 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");