cmd/localedef/wide.c

	wide.c revision 723fee089c0a7e1bd9527b9a4b0f0abf5970336c
/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms version 1.0
 * of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
 */

/*
 * The functions in this file convert from the standard multibyte forms
 * to the wide character forms used internally by libc.  Unfortunately,
 * this approach means that we need a method for each and every encoding.
 */

#include <stdlib.h>
#include <wchar.h>
#include <string.h>
#include <sys/types.h>
#include "localedef.h"

static int towide_none(wchar_t *, const char *, int);
static int towide_utf8(wchar_t *, const char *, int);
static int towide_big5(wchar_t *, const char *, int);
static int towide_gbk(wchar_t *, const char *, int);
static int towide_gb2312(wchar_t *, const char *, int);
static int towide_gb18030(wchar_t *, const char *, int);
static int towide_mskanji(wchar_t *, const char *, int);
static int towide_euccn(wchar_t *, const char *, int);
static int towide_eucjp(wchar_t *, const char *, int);
static int towide_euckr(wchar_t *, const char *, int);
static int towide_euctw(wchar_t *, const char *, int);

static int tomb_none(char *, wchar_t);
static int tomb_utf8(char *, wchar_t);
static int tomb_mbs(char *, wchar_t);

static int (*_towide)(wchar_t *, const char *, int) = towide_none;
static int (*_tomb)(char *, wchar_t) = tomb_none;
static const char *_encoding = "NONE";
static int _nbits = 7;

/*
 * Table of supported encodings.  We only bother to list the multibyte
 * encodings here, because single byte locales are handed by "NONE".
 */
static struct {
    const char *name;
    /* the name that the underlying libc implemenation uses */
    const char *cname;
    /* the maximum number of bits required for priorities */
    int nbits;
    int (*towide)(wchar_t *, const char *, int);
    int (*tomb)(char *, wchar_t);
} mb_encodings[] = {
    /*
     * UTF8 values max out at 0x1fffff (although in theory there could
     * be later extensions, but it won't happen.)  This means we only need
     * 21 bits to be able to encode the entire range of priorities.
     */
    { "UTF-8",  "UTF-8",    21, towide_utf8, tomb_utf8 },
    { "UTF8",   "UTF-8",    21, towide_utf8, tomb_utf8 },
    { "utf8",   "UTF-8",    21, towide_utf8, tomb_utf8 },
    { "utf-8",  "UTF-8",    21, towide_utf8, tomb_utf8 },

    { "EUC-CN", "EUC-CN",   16, towide_euccn, tomb_mbs },
    { "eucCN",  "EUC-CN",   16, towide_euccn, tomb_mbs },
    /*
     * Becuase the 3-byte form of EUC-JP use the same leading byte,
     * only 17 bits required to provide unique priorities.  (The low
     * bit of that first byte is set.)  By setting this value low,
     * we can get by with only 3 bytes in the strxfrm expansion.
     */
    { "EUC-JP", "EUC-JP",   17, towide_eucjp, tomb_mbs },
    { "eucJP",  "EUC-JP",   17, towide_eucjp, tomb_mbs },

    { "EUC-KR", "EUC-KR",   16, towide_euckr, tomb_mbs },
    { "eucKR",  "EUC-KR",   16, towide_euckr, tomb_mbs },
    /*
     * EUC-TW uses 2 bytes most of the time, but 4 bytes if the
     * high order byte is 0x8E.  However, with 4 byte encodings,
     * the third byte will be A0-B0.  So we only need to consider
     * the lower order 24 bits for collation.
     */
    { "EUC-TW", "EUC-TW",   24, towide_euctw, tomb_mbs },
    { "eucTW",  "EUC-TW",   24, towide_euctw, tomb_mbs },

    { "MS_Kanji",   "MSKanji",  16, towide_mskanji, tomb_mbs },
    { "MSKanji",    "MSKanji",  16, towide_mskanji, tomb_mbs },
    { "PCK",    "MSKanji",  16, towide_mskanji, tomb_mbs },
    { "SJIS",   "MSKanji",  16, towide_mskanji, tomb_mbs },
    { "Shift_JIS",  "MSKanji",  16, towide_mskanji, tomb_mbs },

    { "BIG5",   "BIG5",     16, towide_big5, tomb_mbs },
    { "big5",   "BIG5",     16, towide_big5, tomb_mbs },
    { "Big5",   "BIG5",     16, towide_big5, tomb_mbs },

    { "GBK",    "GBK",      16, towide_gbk, tomb_mbs },

    /*
     * GB18030 can get away with just 31 bits.  This is because the
     * high order bit is always set for 4 byte values, and the
     * at least one of the other bits in that 4 byte value will
     * be non-zero.
     */
    { "GB18030",    "GB18030",  31, towide_gb18030, tomb_mbs },

    /*
     * This should probably be an aliase for euc-cn, or vice versa.
     */
    { "GB2312", "GB2312",   16, towide_gb2312, tomb_mbs },

    { "ASCII",  "ASCII",    7, towide_none, tomb_none },
    { "US-ASCII",   "ASCII",    7, towide_none, tomb_none },
    { "646",    "ASCII",    7, towide_none, tomb_none },

    { NULL, NULL },
};

static char *
show_mb(const char *mb)
{
    static char buf[64];

    /* ASCII stuff we just print */
    if (isascii(*mb) && isgraph(*mb)) {
        buf[0] = *mb;
        buf[1] = 0;
        return (buf);
    }
    buf[0] = 0;
    while (*mb != 0) {
        char scr[8];
        (void) snprintf(scr, sizeof (scr), "\\x%02x", *mb);
        (void) strlcat(buf, scr, sizeof (buf));
        mb++;
    }
    return (buf);
}

static char *widemsg;

void
werr(const char *fmt, ...)
{
    char    *msg;

    va_list va;
    va_start(va, fmt);
    (void) vasprintf(&msg, fmt, va);
    va_end(va);

    free(widemsg);
    widemsg = msg;
}

/*
 * This is used for 8-bit encodings.
 */
int
towide_none(wchar_t *c, const char *mb, int n)
{
    if (mb_cur_max != 1) {
        werr("invalid or unsupported multibyte locale");
        return (-1);
    }
    if (n < 1) {
        werr("no character data");
        return (-1);
    }
    *c = (uint8_t)*mb;
    return (1);
}

int
tomb_none(char *mb, wchar_t wc)
{
    if (mb_cur_max != 1) {
        werr("invalid or unsupported multibyte locale");
        return (-1);
    }
    *(uint8_t *)mb = (wc & 0xff);
    mb[1] = 0;
    return (1);
}

/*
 * UTF-8 stores wide characters in UTF-32 form.
 */
int
towide_utf8(wchar_t *wc, const char *mb, int n)
{
    wchar_t c;
    int nb;
    int lv; /* lowest legal value */
    int i;
    const uint8_t *s = (const uint8_t *)mb;

    if (n < 1) {
        werr("no utf8 data");
        return (-1);
    }
    c = *s;

    if ((c & 0x80) == 0) {
        /* 7-bit ASCII */
        *wc = c;
        return (1);
    } else if ((c & 0xe0) == 0xc0) {
        /* u80-u7ff - two bytes encoded */
        nb = 2;
        lv = 0x80;
        c &= ~0xe0;
    } else if ((c & 0xf0) == 0xe0) {
        /* u800-uffff - three bytes encoded */
        nb = 3;
        lv = 0x800;
        c &= ~0xf0;
    } else if ((c & 0xf8) == 0xf0) {
        /* u1000-u1fffff - four bytes encoded */
        nb = 4;
        lv = 0x1000;
        c &= ~0xf8;
    } else {
        /* 5 and 6 byte encodings are not legal unicode */
        werr("utf8 encoding too large (%s)", show_mb(mb));
        return (-1);
    }
    if (nb > n) {
        werr("incomplete utf8 sequence (%s)", show_mb(mb));
        return (-1);
    }

    for (i = 1; i < nb; i++) {
        if (((s[i]) & 0xc0) != 0x80) {
            werr("illegal utf8 byte (%x)", s[i]);
            return (-1);
        }
        c <<= 6;
        c |= (s[i] & 0x3f);
    }

    if (c < lv) {
        werr("illegal redundant utf8 encoding (%s)", show_mb(mb));
        return (-1);
    }
    *wc = c;
    return (nb);
}

int
tomb_utf8(char *mb, wchar_t wc)
{
    uint8_t *s = (uint8_t *)mb;
    uint8_t msk;
    int cnt;
    int i;

    if (wc <= 0x7f) {
        s[0] = wc & 0x7f;
        s[1] = 0;
        return (1);
    }
    if (wc <= 0x7ff) {
        cnt = 2;
        msk = 0xc0;
    } else if (wc <= 0xffff) {
        cnt = 3;
        msk = 0xe0;
    } else if (wc <= 0x1fffff) {
        cnt = 4;
        msk = 0xf0;
    } else {
        werr("illegal uf8 char (%x)", wc);
        return (-1);
    }
    for (i = cnt - 1; i; i--) {
        s[i] = (wc & 0x3f) | 0x80;
        wc >>= 6;
    }
    s[0] = (msk) | wc;
    s[cnt] = 0;
    return (cnt);
}

/*
 * Several encodings share a simplistic dual byte encoding.  In these
 * forms, they all indicate that a two byte sequence is to be used if
 * the first byte has its high bit set.  They all store this simple
 * encoding as a 16-bit value, although a great many of the possible
 * code points are not used in most character sets.  This gives a possible
 * set of just over 32,000 valid code points.
 *
 * 0x00 - 0x7f      - 1 byte encoding
 * 0x80 - 0x7fff    - illegal
 * 0x8000 - 0xffff  - 2 byte encoding
 */
static int
towide_dbcs(wchar_t *wc, const char *mb, int n)
{
    wchar_t c;

    c = *(uint8_t *)mb;

    if (n < 1) {
        werr("no character data");
        return (-1);
    }
    if ((c & 0x80) == 0) {
        /* 7-bit */
        *wc = c;
        return (1);
    }
    if (n < 2) {
        werr("incomplete character sequence (%s)", show_mb(mb));
        return (-1);
    }

    /* Store both bytes as a single 16-bit wide. */
    c <<= 8;
    c |= (uint8_t)(mb[1]);
    *wc = c;
    return (2);
}

/*
 * Most multibyte locales just convert the wide character to the multibyte
 * form by stripping leading null bytes, and writing the 32-bit quantity
 * in big-endian order.
 */
int
tomb_mbs(char *mb, wchar_t wc)
{
    uint8_t *s = (uint8_t *)mb;
    int     n = 0, c;

    if ((wc & 0xff000000U) != 0) {
        n = 4;
    } else if ((wc & 0x00ff0000U) != 0) {
        n = 3;
    } else if ((wc & 0x0000ff00U) != 0) {
        n = 2;
    } else {
        n = 1;
    }
    c = n;
    while (n) {
        n--;
        s[n] = wc & 0xff;
        wc >>= 8;
    }
    /* ensure null termination */
    s[c] = 0;
    return (c);
}


/*
 * big5 is a simple dual byte character set.
 */
int
towide_big5(wchar_t *wc, const char *mb, int n)
{
    return (towide_dbcs(wc, mb, n));
}

/*
 * GBK encodes wides in the same way that big5 does, the high order
 * bit of the first byte indicates a double byte character.
 */
int
towide_gbk(wchar_t *wc, const char *mb, int n)
{
    return (towide_dbcs(wc, mb, n));
}

/*
 * GB2312 is another DBCS.  Its cleaner than others in that the second
 * byte does not encode ASCII, but it supports characters.
 */
int
towide_gb2312(wchar_t *wc, const char *mb, int n)
{
    return (towide_dbcs(wc, mb, n));
}

/*
 * GB18030.  This encodes as 8, 16, or 32-bits.
 * 7-bit values are in 1 byte,  4 byte sequences are used when
 * the second byte encodes 0x30-39 and all other sequences are 2 bytes.
 */
int
towide_gb18030(wchar_t *wc, const char *mb, int n)
{
    wchar_t c;

    c = *(uint8_t *)mb;

    if (n < 1) {
        werr("no character data");
        return (-1);
    }
    if ((c & 0x80) == 0) {
        /* 7-bit */
        *wc = c;
        return (1);
    }
    if (n < 2) {
        werr("incomplete character sequence (%s)", show_mb(mb));
        return (-1);
    }

    /* pull in the second byte */
    c <<= 8;
    c |= (uint8_t)(mb[1]);

    if (((c & 0xff) >= 0x30) && ((c & 0xff) <= 0x39)) {
        if (n < 4) {
            werr("incomplete 4-byte character sequence (%s)",
                show_mb(mb));
            return (-1);
        }
        c <<= 8;
        c |= (uint8_t)(mb[2]);
        c <<= 8;
        c |= (uint8_t)(mb[3]);
        *wc = c;
        return (4);
    }

    *wc = c;
    return (2);
}

/*
 * MS-Kanji (aka SJIS) is almost a clean DBCS like the others, but it
 * also has a range of single byte characters above 0x80.  (0xa1-0xdf).
 */
int
towide_mskanji(wchar_t *wc, const char *mb, int n)
{
    wchar_t c;

    c = *(uint8_t *)mb;

    if (n < 1) {
        werr("no character data");
        return (-1);
    }
    if ((c < 0x80) || ((c > 0xa0) && (c < 0xe0))) {
        /* 7-bit */
        *wc = c;
        return (-1);
    }

    if (n < 2) {
        werr("incomplete character sequence (%s)", show_mb(mb));
        return (-1);
    }

    /* Store both bytes as a single 16-bit wide. */
    c <<= 8;
    c |= (uint8_t)(mb[1]);
    *wc = c;
    return (2);
}

/*
 * EUC forms.  EUC encodings are "variable".  FreeBSD carries some additional
 * variable data to encode these, but we're going to treat each as independent
 * instead.  Its the only way we can sensibly move forward.
 *
 * Note that the way in which the different EUC forms vary is how wide
 * CS2 and CS3 are and what the first byte of them is.
 */
static int
towide_euc_impl(wchar_t *wc, const char *mb, int n,
    uint8_t cs2, uint8_t cs2width, uint8_t cs3, uint8_t cs3width)
{
    int i;
    int width;
    wchar_t c;

    c = *(uint8_t *)mb;

    if (n < 1) {
        werr("no character data");
        return (-1);
    }

    /*
     * All variations of EUC encode 7-bit ASCII as one byte, and use
     * additional bytes for more than that.
     */
    if ((c & 0x80) == 0) {
        /* 7-bit */
        *wc = c;
        return (1);
    }

    /*
     * All EUC variants reserve 0xa1-0xff to identify CS1, which
     * is always two bytes wide.  Note that unused CS will be zero,
     * and that cannot be true because we know that the high order
     * bit must be set.
     */
    if (c >= 0xa1) {
        width = 2;
    } else if (c == cs2) {
        width = cs2width;
    } else if (c == cs3) {
        width = cs3width;
    }

    if (n < width) {
        werr("incomplete character sequence (%s)", show_mb(mb));
        return (-1);
    }

    for (i = 1; i < width; i++) {
        /* pull in the next byte */
        c <<= 8;
        c |= (uint8_t)(mb[i]);
    }

    *wc = c;
    return (width);
}

/*
 * EUC-CN encodes as follows:
 *
 * Code set 0 (ASCII):              0x21-0x7E
 * Code set 1 (CNS 11643-1992 Plane 1):     0xA1A1-0xFEFE
 * Code set 2:                  unused
 * Code set 3:                  unused
 */
int
towide_euccn(wchar_t *wc, const char *mb, int n)
{
    return (towide_euc_impl(wc, mb, n, 0x8e, 4, 0, 0));
}

/*
 * EUC-JP encodes as follows:
 *
 * Code set 0 (ASCII or JIS X 0201-1976 Roman): 0x21-0x7E
 * Code set 1 (JIS X 0208):         0xA1A1-0xFEFE
 * Code set 2 (half-width katakana):        0x8EA1-0x8EDF
 * Code set 3 (JIS X 0212-1990):        0x8FA1A1-0x8FFEFE
 */
int
towide_eucjp(wchar_t *wc, const char *mb, int n)
{
    return (towide_euc_impl(wc, mb, n, 0x8e, 2, 0x8f, 3));
}

/*
 * EUC-KR encodes as follows:
 *
 * Code set 0 (ASCII or KS C 5636-1993):    0x21-0x7E
 * Code set 1 (KS C 5601-1992):         0xA1A1-0xFEFE
 * Code set 2:                  unused
 * Code set 3:                  unused
 */
int
towide_euckr(wchar_t *wc, const char *mb, int n)
{
    return (towide_euc_impl(wc, mb, n, 0, 0, 0, 0));
}

/*
 * EUC-TW encodes as follows:
 *
 * Code set 0 (ASCII):              0x21-0x7E
 * Code set 1 (CNS 11643-1992 Plane 1):     0xA1A1-0xFEFE
 * Code set 2 (CNS 11643-1992 Planes 1-16): 0x8EA1A1A1-0x8EB0FEFE
 * Code set 3:                  unused
 */
int
towide_euctw(wchar_t *wc, const char *mb, int n)
{
    return (towide_euc_impl(wc, mb, n, 0x8e, 4, 0, 0));
}

/*
 * Public entry points.
 */

int
to_wide(wchar_t *wc, const char *mb)
{
    /* this won't fail hard */
    return (_towide(wc, mb, strlen(mb) + 1));
}

int
to_mb(char *mb, wchar_t wc)
{
    int rv;

    if ((rv = _tomb(mb, wc)) < 0) {
        errf(widemsg);
        free(widemsg);
        widemsg = NULL;
    }
    return (rv);
}

char *
to_mb_string(const wchar_t *wcs)
{
    char    *mbs;
    char    *ptr;
    int len;

    mbs = malloc((wcslen(wcs) * mb_cur_max) + 1);
    if (mbs == NULL) {
        errf("out of memory");
        return (NULL);
    }
    ptr = mbs;
    while (*wcs) {
        if ((len = to_mb(ptr, *wcs)) < 0) {
            INTERR;
            free(mbs);
            return (NULL);
        }
        wcs++;
        ptr += len;
    }
    *ptr = 0;
    return (mbs);
}

void
set_wide_encoding(const char *encoding)
{
    int i;

    _towide = towide_none;
    _tomb = tomb_none;
    _encoding = "NONE";
    _nbits = 8;

    for (i = 0; mb_encodings[i].name; i++) {
        if (strcasecmp(encoding, mb_encodings[i].name) == 0) {
            _towide = mb_encodings[i].towide;
            _tomb = mb_encodings[i].tomb;
            _encoding = mb_encodings[i].cname;
            _nbits = mb_encodings[i].nbits;
            break;
        }
    }
}

const char *
get_wide_encoding(void)
{
    return (_encoding);
}

int
max_wide(void)
{
    return ((int)((1U << _nbits) - 1));
}