/*
 * Ntdll locale definitions
 *
 * Copyright 2019, 2022 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#ifndef __NTDLL_LOCALE_PRIVATE_H
#define __NTDLL_LOCALE_PRIVATE_H

#include "windef.h"
#include "winbase.h"
#include "winnls.h"

/* NLS codepage file format:
 *
 * header:
 *   WORD      offset to cp2uni table in words
 *   WORD      CodePage
 *   WORD      MaximumCharacterSize
 *   BYTE[2]   DefaultChar
 *   WORD      UniDefaultChar
 *   WORD      TransDefaultChar
 *   WORD      TransUniDefaultChar
 *   BYTE[12]  LeadByte
 * cp2uni table:
 *   WORD      offset to uni2cp table in words
 *   WORD[256] cp2uni table
 *   WORD      glyph table size
 *   WORD[glyph_table_size] glyph table
 *   WORD      number of lead byte ranges
 *   WORD[256] lead byte offsets in words
 *   WORD[leadbytes][256] cp2uni table for lead bytes
 * uni2cp table:
 *   WORD      0 / 4
 *   BYTE[65536] / WORD[65536]  uni2cp table
 */

enum nls_section_type
{
    NLS_SECTION_SORTKEYS = 9,
    NLS_SECTION_CASEMAP = 10,
    NLS_SECTION_CODEPAGE = 11,
    NLS_SECTION_NORMALIZE = 12
};

/* NLS normalization file */
struct norm_table
{
    WCHAR   name[13];      /* 00 file name */
    USHORT  checksum[3];   /* 1a checksum? */
    USHORT  version[4];    /* 20 Unicode version */
    USHORT  form;          /* 28 normalization form */
    USHORT  len_factor;    /* 2a factor for length estimates */
    USHORT  unknown1;      /* 2c */
    USHORT  decomp_size;   /* 2e decomposition hash size */
    USHORT  comp_size;     /* 30 composition hash size */
    USHORT  unknown2;      /* 32 */
    USHORT  classes;       /* 34 combining classes table offset */
    USHORT  props_level1;  /* 36 char properties table level 1 offset */
    USHORT  props_level2;  /* 38 char properties table level 2 offset */
    USHORT  decomp_hash;   /* 3a decomposition hash table offset */
    USHORT  decomp_map;    /* 3c decomposition character map table offset */
    USHORT  decomp_seq;    /* 3e decomposition character sequences offset */
    USHORT  comp_hash;     /* 40 composition hash table offset */
    USHORT  comp_seq;      /* 42 composition character sequences offset */
    /* BYTE[]       combining class values */
    /* BYTE[0x2200] char properties index level 1 */
    /* BYTE[]       char properties index level 2 */
    /* WORD[]       decomposition hash table */
    /* WORD[]       decomposition character map */
    /* WORD[]       decomposition character sequences */
    /* WORD[]       composition hash table */
    /* WORD[]       composition character sequences */
};


/* locale.nls file */
struct locale_nls_header
{
    UINT ctypes;
    UINT unknown1;
    UINT unknown2;
    UINT unknown3;
    UINT locales;
    UINT charmaps;
    UINT geoids;
    UINT scripts;
};


static inline WCHAR casemap_ascii( WCHAR ch )
{
    if (ch >= 'a' && ch <= 'z') ch -= 'a' - 'A';
    return ch;
}


static inline int get_utf16( const WCHAR *src, unsigned int srclen, unsigned int *ch )
{
    if (IS_HIGH_SURROGATE( src[0] ))
    {
        if (srclen <= 1) return 0;
        if (!IS_LOW_SURROGATE( src[1] )) return 0;
        *ch = 0x10000 + ((src[0] & 0x3ff) << 10) + (src[1] & 0x3ff);
        return 2;
    }
    if (IS_LOW_SURROGATE( src[0] )) return 0;
    *ch = src[0];
    return 1;
}


static inline void put_utf16( WCHAR *dst, unsigned int ch )
{
    if (ch >= 0x10000)
    {
        ch -= 0x10000;
        dst[0] = 0xd800 | (ch >> 10);
        dst[1] = 0xdc00 | (ch & 0x3ff);
    }
    else dst[0] = ch;
}


static inline unsigned int decode_utf8_char( unsigned char ch, const char **str, const char *strend )
{
    /* number of following bytes in sequence based on first byte value (for bytes above 0x7f) */
    static const char utf8_length[128] =
    {
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 0x80-0x8f */
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 0x90-0x9f */
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 0xa0-0xaf */
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 0xb0-0xbf */
        0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* 0xc0-0xcf */
        1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, /* 0xd0-0xdf */
        2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, /* 0xe0-0xef */
        3,3,3,3,3,0,0,0,0,0,0,0,0,0,0,0  /* 0xf0-0xff */
    };

    /* first byte mask depending on UTF-8 sequence length */
    static const unsigned char utf8_mask[4] = { 0x7f, 0x1f, 0x0f, 0x07 };

    unsigned int len = utf8_length[ch - 0x80];
    unsigned int res = ch & utf8_mask[len];
    const char *end = *str + len;

    if (end > strend)
    {
        *str = end;
        return ~0;
    }
    switch (len)
    {
    case 3:
        if ((ch = end[-3] ^ 0x80) >= 0x40) break;
        res = (res << 6) | ch;
        (*str)++;
        if (res < 0x10) break;
    case 2:
        if ((ch = end[-2] ^ 0x80) >= 0x40) break;
        res = (res << 6) | ch;
        if (res >= 0x110000 >> 6) break;
        (*str)++;
        if (res < 0x20) break;
        if (res >= 0xd800 >> 6 && res <= 0xdfff >> 6) break;
    case 1:
        if ((ch = end[-1] ^ 0x80) >= 0x40) break;
        res = (res << 6) | ch;
        (*str)++;
        if (res < 0x80) break;
        return res;
    }
    return ~0;
}


static inline void init_codepage_table( USHORT *ptr, CPTABLEINFO *info )
{
    USHORT hdr_size = ptr[0];

    info->CodePage             = ptr[1];
    info->MaximumCharacterSize = ptr[2];
    info->DefaultChar          = ptr[3];
    info->UniDefaultChar       = ptr[4];
    info->TransDefaultChar     = ptr[5];
    info->TransUniDefaultChar  = ptr[6];
    memcpy( info->LeadByte, ptr + 7, sizeof(info->LeadByte) );
    ptr += hdr_size;

    info->WideCharTable = ptr + ptr[0] + 1;
    info->MultiByteTable = ++ptr;
    ptr += 256;
    if (*ptr++) ptr += 256;  /* glyph table */
    info->DBCSRanges = ptr;
    if (*ptr)  /* dbcs ranges */
    {
        info->DBCSCodePage = 1;
        info->DBCSOffsets  = ptr + 1;
    }
    else
    {
        info->DBCSCodePage = 0;
        info->DBCSOffsets  = NULL;
    }
}


static inline int compare_locale_names( const WCHAR *n1, const WCHAR *n2 )
{
    for (;;)
    {
        WCHAR ch1 = casemap_ascii( *n1++ );
        WCHAR ch2 = casemap_ascii( *n2++ );
        if (ch1 == '_') ch1 = '-';
        if (ch2 == '_') ch2 = '-';
        if (!ch1 || ch1 != ch2) return ch1 - ch2;
    }
}


static inline const NLS_LOCALE_LCNAME_INDEX *find_lcname_entry( const NLS_LOCALE_HEADER *header,
                                                                const WCHAR *name )
{
    const WCHAR *strings = (const WCHAR *)((char *)header + header->strings_offset);
    const NLS_LOCALE_LCNAME_INDEX *index = (const NLS_LOCALE_LCNAME_INDEX *)((char *)header + header->lcnames_offset);
    int min = 0, max = header->nb_lcnames - 1;

    if (!name) return NULL;
    while (min <= max)
    {
        int res, pos = (min + max) / 2;
        const WCHAR *str = strings + index[pos].name;
        res = compare_locale_names( name, str + 1 );
        if (res < 0) max = pos - 1;
        else if (res > 0) min = pos + 1;
        else return &index[pos];
    }
    return NULL;
}


static inline const NLS_LOCALE_LCID_INDEX *find_lcid_entry( const NLS_LOCALE_HEADER *header, LCID lcid )
{
    const NLS_LOCALE_LCID_INDEX *index = (const NLS_LOCALE_LCID_INDEX *)((char *)header + header->lcids_offset);
    int min = 0, max = header->nb_lcids - 1;

    while (min <= max)
    {
        int pos = (min + max) / 2;
        if (lcid < index[pos].id) max = pos - 1;
        else if (lcid > index[pos].id) min = pos + 1;
        else return &index[pos];
    }
    return NULL;
}


static inline const NLS_LOCALE_DATA *get_locale_data( const NLS_LOCALE_HEADER *header, UINT idx )
{
    ULONG offset = header->locales_offset + idx * header->locale_size;
    return (const NLS_LOCALE_DATA *)((const char *)header + offset);
}


static inline unsigned int cp_mbstowcs_size( const CPTABLEINFO *info, const char *str, unsigned int len )
{
    unsigned int res;

    if (!info->DBCSCodePage) return len;

    for (res = 0; len; len--, str++, res++)
    {
        if (info->DBCSOffsets[(unsigned char)*str] && len > 1)
        {
            str++;
            len--;
        }
    }
    return res;
}


static inline unsigned int cp_wcstombs_size( const CPTABLEINFO *info, const WCHAR *str, unsigned int len )
{
    if (info->DBCSCodePage)
    {
        WCHAR *uni2cp = info->WideCharTable;
        unsigned int res;

        for (res = 0; len; len--, str++, res++)
            if (uni2cp[*str] & 0xff00) res++;
        return res;
    }
    else return len;
}


static inline NTSTATUS utf8_wcstombs_size( const WCHAR *src, unsigned int srclen, unsigned int *reslen )
{
    unsigned int val, len;
    NTSTATUS status = STATUS_SUCCESS;

    for (len = 0; srclen; srclen--, src++)
    {
        if (*src < 0x80) len++;  /* 0x00-0x7f: 1 byte */
        else if (*src < 0x800) len += 2;  /* 0x80-0x7ff: 2 bytes */
        else
        {
            if (!get_utf16( src, srclen, &val ))
            {
                val = 0xfffd;
                status = STATUS_SOME_NOT_MAPPED;
            }
            if (val < 0x10000) len += 3; /* 0x800-0xffff: 3 bytes */
            else   /* 0x10000-0x10ffff: 4 bytes */
            {
                len += 4;
                src++;
                srclen--;
            }
        }
    }
    *reslen = len;
    return status;
}


static inline NTSTATUS utf8_mbstowcs_size( const char *src, unsigned int srclen, unsigned int *reslen )
{
    unsigned int res, len;
    NTSTATUS status = STATUS_SUCCESS;
    const char *srcend = src + srclen;

    for (len = 0; src < srcend; len++)
    {
        unsigned char ch = *src++;
        if (ch < 0x80) continue;
        if ((res = decode_utf8_char( ch, &src, srcend )) > 0x10ffff)
            status = STATUS_SOME_NOT_MAPPED;
        else
            if (res > 0xffff) len++;
    }
    *reslen = len;
    return status;
}


static inline unsigned int cp_mbstowcs( const CPTABLEINFO *info, WCHAR *dst, unsigned int dstlen,
                                        const char *src, unsigned int srclen )
{
    unsigned int i, ret;

    if (info->DBCSOffsets)
    {
        for (i = dstlen; srclen && i; i--, srclen--, src++, dst++)
        {
            USHORT off = info->DBCSOffsets[(unsigned char)*src];
            if (off && srclen > 1)
            {
                src++;
                srclen--;
                *dst = info->DBCSOffsets[off + (unsigned char)*src];
            }
            else *dst = info->MultiByteTable[(unsigned char)*src];
        }
        ret = dstlen - i;
    }
    else
    {
        ret = min( srclen, dstlen );
        for (i = 0; i < ret; i++) dst[i] = info->MultiByteTable[(unsigned char)src[i]];
    }
    return ret;
}


static inline unsigned int cp_wcstombs( const CPTABLEINFO *info, char *dst, unsigned int dstlen,
                                        const WCHAR *src, unsigned int srclen )
{
    unsigned int i, ret;

    if (info->DBCSCodePage)
    {
        const WCHAR *uni2cp = info->WideCharTable;

        for (i = dstlen; srclen && i; i--, srclen--, src++)
        {
            if (uni2cp[*src] & 0xff00)
            {
                if (i == 1) break;  /* do not output a partial char */
                i--;
                *dst++ = uni2cp[*src] >> 8;
            }
            *dst++ = (char)uni2cp[*src];
        }
        ret = dstlen - i;
    }
    else
    {
        const char *uni2cp = info->WideCharTable;
        ret = min( srclen, dstlen );
        for (i = 0; i < ret; i++) dst[i] = uni2cp[src[i]];
    }
    return ret;
}


static inline NTSTATUS utf8_mbstowcs( WCHAR *dst, unsigned int dstlen, unsigned int *reslen,
                                      const char *src, unsigned int srclen )
{
    unsigned int res;
    NTSTATUS status = STATUS_SUCCESS;
    const char *srcend = src + srclen;
    WCHAR *dstend = dst + dstlen;

    while ((dst < dstend) && (src < srcend))
    {
        unsigned char ch = *src++;
        if (ch < 0x80)  /* special fast case for 7-bit ASCII */
        {
            *dst++ = ch;
            continue;
        }
        if ((res = decode_utf8_char( ch, &src, srcend )) <= 0xffff)
        {
            *dst++ = res;
        }
        else if (res <= 0x10ffff)  /* we need surrogates */
        {
            res -= 0x10000;
            *dst++ = 0xd800 | (res >> 10);
            if (dst == dstend)
            {
                status = STATUS_BUFFER_TOO_SMALL;
                break;
            }
            *dst++ = 0xdc00 | (res & 0x3ff);
        }
        else
        {
            *dst++ = 0xfffd;
            status = STATUS_SOME_NOT_MAPPED;
        }
    }
    if (src < srcend) status = STATUS_BUFFER_TOO_SMALL;  /* overflow */
    *reslen = dstlen - (dstend - dst);
    return status;
}


static inline NTSTATUS utf8_wcstombs( char *dst, unsigned int dstlen, unsigned int *reslen,
                                      const WCHAR *src, unsigned int srclen )
{
    char *end;
    unsigned int val;
    NTSTATUS status = STATUS_SUCCESS;

    for (end = dst + dstlen; srclen; srclen--, src++)
    {
        WCHAR ch = *src;

        if (ch < 0x80)  /* 0x00-0x7f: 1 byte */
        {
            if (dst > end - 1) break;
            *dst++ = ch;
            continue;
        }
        if (ch < 0x800)  /* 0x80-0x7ff: 2 bytes */
        {
            if (dst > end - 2) break;
            dst[1] = 0x80 | (ch & 0x3f);
            ch >>= 6;
            dst[0] = 0xc0 | ch;
            dst += 2;
            continue;
        }
        if (!get_utf16( src, srclen, &val ))
        {
            val = 0xfffd;
            status = STATUS_SOME_NOT_MAPPED;
        }
        if (val < 0x10000)  /* 0x800-0xffff: 3 bytes */
        {
            if (dst > end - 3) break;
            dst[2] = 0x80 | (val & 0x3f);
            val >>= 6;
            dst[1] = 0x80 | (val & 0x3f);
            val >>= 6;
            dst[0] = 0xe0 | val;
            dst += 3;
        }
        else   /* 0x10000-0x10ffff: 4 bytes */
        {
            if (dst > end - 4) break;
            dst[3] = 0x80 | (val & 0x3f);
            val >>= 6;
            dst[2] = 0x80 | (val & 0x3f);
            val >>= 6;
            dst[1] = 0x80 | (val & 0x3f);
            val >>= 6;
            dst[0] = 0xf0 | val;
            dst += 4;
            src++;
            srclen--;
        }
    }
    if (srclen) status = STATUS_BUFFER_TOO_SMALL;
    *reslen = dstlen - (end - dst);
    return status;
}


#define HANGUL_SBASE  0xac00
#define HANGUL_LBASE  0x1100
#define HANGUL_VBASE  0x1161
#define HANGUL_TBASE  0x11a7
#define HANGUL_LCOUNT 19
#define HANGUL_VCOUNT 21
#define HANGUL_TCOUNT 28
#define HANGUL_NCOUNT (HANGUL_VCOUNT * HANGUL_TCOUNT)
#define HANGUL_SCOUNT (HANGUL_LCOUNT * HANGUL_NCOUNT)

static inline const WCHAR *get_decomposition( const struct norm_table *info, unsigned int ch,
                                              BYTE props, WCHAR *buffer, unsigned int *ret_len )
{
    const struct pair { WCHAR src; USHORT dst; } *pairs;
    const USHORT *hash_table = (const USHORT *)info + info->decomp_hash;
    const WCHAR *ret;
    unsigned int i, pos, end, len, hash;

    /* default to no decomposition */
    put_utf16( buffer, ch );
    *ret_len = 1 + (ch >= 0x10000);
    if (!props || props == 0x7f) return buffer;

    if (props == 0xff)  /* Hangul or invalid char */
    {
        if (ch >= HANGUL_SBASE && ch < HANGUL_SBASE + HANGUL_SCOUNT)
        {
            unsigned short sindex = ch - HANGUL_SBASE;
            unsigned short tindex = sindex % HANGUL_TCOUNT;
            buffer[0] = HANGUL_LBASE + sindex / HANGUL_NCOUNT;
            buffer[1] = HANGUL_VBASE + (sindex % HANGUL_NCOUNT) / HANGUL_TCOUNT;
            if (tindex) buffer[2] = HANGUL_TBASE + tindex;
            *ret_len = 2 + !!tindex;
            return buffer;
        }
        /* ignore other chars in Hangul range */
        if (ch >= HANGUL_LBASE && ch < HANGUL_LBASE + 0x100) return buffer;
        if (ch >= HANGUL_SBASE && ch < HANGUL_SBASE + 0x2c00) return buffer;
        return NULL;
    }

    hash = ch % info->decomp_size;
    pos = hash_table[hash];
    if (pos >> 13)
    {
        if (props != 0xbf) return buffer;
        ret = (const USHORT *)info + info->decomp_seq + (pos & 0x1fff);
        len = pos >> 13;
    }
    else
    {
        pairs = (const struct pair *)((const USHORT *)info + info->decomp_map);

        /* find the end of the hash bucket */
        for (i = hash + 1; i < info->decomp_size; i++) if (!(hash_table[i] >> 13)) break;
        if (i < info->decomp_size) end = hash_table[i];
        else for (end = pos; pairs[end].src; end++) ;

        for ( ; pos < end; pos++)
        {
            if (pairs[pos].src != (WCHAR)ch) continue;
            ret = (const USHORT *)info + info->decomp_seq + (pairs[pos].dst & 0x1fff);
            len = pairs[pos].dst >> 13;
            break;
        }
        if (pos >= end) return buffer;
    }

    if (len == 7) while (ret[len]) len++;
    if (!ret[0]) len = 0;  /* ignored char */
    *ret_len = len;
    return ret;
}


static inline BYTE rol( BYTE val, BYTE count )
{
    return (val << count) | (val >> (8 - count));
}


static inline BYTE get_char_props( const struct norm_table *info, unsigned int ch )
{
    const BYTE *level1 = (const BYTE *)((const USHORT *)info + info->props_level1);
    const BYTE *level2 = (const BYTE *)((const USHORT *)info + info->props_level2);
    BYTE off = level1[ch / 128];

    if (!off || off >= 0xfb) return rol( off, 5 );
    return level2[(off - 1) * 128 + ch % 128];
}


static inline BYTE get_combining_class( const struct norm_table *info, unsigned int c )
{
    const BYTE *classes = (const BYTE *)((const USHORT *)info + info->classes);
    BYTE class = get_char_props( info, c ) & 0x3f;

    if (class == 0x3f) return 0;
    return classes[class];
}


static inline BOOL reorderable_pair( const struct norm_table *info, unsigned int c1, unsigned int c2 )
{
    BYTE ccc1, ccc2;

    /* reorderable if ccc1 > ccc2 > 0 */
    ccc1 = get_combining_class( info, c1 );
    if (ccc1 < 2) return FALSE;
    ccc2 = get_combining_class( info, c2 );
    return ccc2 && (ccc1 > ccc2);
}

static inline void canonical_order_substring( const struct norm_table *info, WCHAR *str, unsigned int len )
{
    unsigned int i, ch1, ch2, len1, len2;
    BOOL swapped;

    do
    {
        swapped = FALSE;
        for (i = 0; i < len - 1; i += len1)
        {
            if (!(len1 = get_utf16( str + i, len - i, &ch1 ))) break;
            if (i + len1 >= len) break;
            if (!(len2 = get_utf16( str + i + len1, len - i - len1, &ch2 ))) break;
            if (reorderable_pair( info, ch1, ch2 ))
            {
                WCHAR tmp[2];
                memcpy( tmp, str + i, len1 * sizeof(WCHAR) );
                memcpy( str + i, str + i + len1, len2 * sizeof(WCHAR) );
                memcpy( str + i + len2, tmp, len1 * sizeof(WCHAR) );
                swapped = TRUE;
                i += len2 - len1;
            }
        }
    } while (swapped);
}


/* reorder the string into canonical order - D108/D109 */
static inline void canonical_order_string( const struct norm_table *info, WCHAR *str, unsigned int len )
{
    unsigned int ch, i, r, next = 0;

    for (i = 0; i < len; i += r)
    {
        if (!(r = get_utf16( str + i, len - i, &ch ))) return;
        if (i && !get_combining_class( info, ch ))
        {
            if (i > next + 1) /* at least two successive non-starters */
                canonical_order_substring( info, str + next, i - next );
            next = i + r;
        }
    }
    if (i > next + 1) canonical_order_substring( info, str + next, i - next );
}


static inline NTSTATUS decompose_string( const struct norm_table *info, const WCHAR *src, int src_len,
                                         WCHAR *dst, int *dst_len )
{
    BYTE props;
    int src_pos, dst_pos;
    unsigned int ch, len, decomp_len;
    WCHAR buffer[3];
    const WCHAR *decomp;

    for (src_pos = dst_pos = 0; src_pos < src_len; src_pos += len)
    {
        if (!(len = get_utf16( src + src_pos, src_len - src_pos, &ch )))
        {
            *dst_len = src_pos + IS_HIGH_SURROGATE( src[src_pos] );
            return STATUS_NO_UNICODE_TRANSLATION;
        }
        props = get_char_props( info, ch );
        if (!(decomp = get_decomposition( info, ch, props, buffer, &decomp_len )))
        {
            /* allow final null */
            if (!ch && src_pos == src_len - 1 && dst_pos < *dst_len)
            {
                dst[dst_pos++] = 0;
                break;
            }
            *dst_len = src_pos;
            return STATUS_NO_UNICODE_TRANSLATION;
        }
        if (dst_pos + decomp_len > *dst_len)
        {
            *dst_len += (src_len - src_pos) * info->len_factor;
            return STATUS_BUFFER_TOO_SMALL;
        }
        memcpy( dst + dst_pos, decomp, decomp_len * sizeof(WCHAR) );
        dst_pos += decomp_len;
    }

    canonical_order_string( info, dst, dst_pos );
    *dst_len = dst_pos;
    return STATUS_SUCCESS;
}


static inline unsigned int compose_hangul( unsigned int ch1, unsigned int ch2 )
{
    if (ch1 >= HANGUL_LBASE && ch1 < HANGUL_LBASE + HANGUL_LCOUNT)
    {
        int lindex = ch1 - HANGUL_LBASE;
        int vindex = ch2 - HANGUL_VBASE;
        if (vindex >= 0 && vindex < HANGUL_VCOUNT)
            return HANGUL_SBASE + (lindex * HANGUL_VCOUNT + vindex) * HANGUL_TCOUNT;
    }
    if (ch1 >= HANGUL_SBASE && ch1 < HANGUL_SBASE + HANGUL_SCOUNT)
    {
        int sindex = ch1 - HANGUL_SBASE;
        if (!(sindex % HANGUL_TCOUNT))
        {
            int tindex = ch2 - HANGUL_TBASE;
            if (tindex > 0 && tindex < HANGUL_TCOUNT) return ch1 + tindex;
        }
    }
    return 0;
}


static inline unsigned int compose_chars( const struct norm_table *info, unsigned int ch1, unsigned int ch2 )
{
    const USHORT *table = (const USHORT *)info + info->comp_hash;
    const WCHAR *chars = (const USHORT *)info + info->comp_seq;
    unsigned int hash, start, end, i, len, ch[3];

    hash = (ch1 + 95 * ch2) % info->comp_size;
    start = table[hash];
    end = table[hash + 1];
    while (start < end)
    {
        for (i = 0; i < 3; i++, start += len) len = get_utf16( chars + start, end - start, ch + i );
        if (ch[0] == ch1 && ch[1] == ch2) return ch[2];
    }
    return 0;
}


static inline unsigned int compose_string( const struct norm_table *info, WCHAR *str, unsigned int srclen )
{
    unsigned int i, ch, comp, len, start_ch = 0, last_starter = srclen;
    BYTE class, prev_class = 0;

    for (i = 0; i < srclen; i += len)
    {
        if (!(len = get_utf16( str + i, srclen - i, &ch ))) return 0;
        class = get_combining_class( info, ch );
        if (last_starter == srclen || (prev_class && prev_class >= class) ||
            (!(comp = compose_hangul( start_ch, ch )) &&
             !(comp = compose_chars( info, start_ch, ch ))))
        {
            if (!class)
            {
                last_starter = i;
                start_ch = ch;
            }
            prev_class = class;
        }
        else
        {
            int comp_len = 1 + (comp >= 0x10000);
            int start_len = 1 + (start_ch >= 0x10000);

            if (comp_len != start_len)
                memmove( str + last_starter + comp_len, str + last_starter + start_len,
                         (i - (last_starter + start_len)) * sizeof(WCHAR) );
            memmove( str + i + comp_len - start_len, str + i + len, (srclen - i - len) * sizeof(WCHAR) );
            srclen += comp_len - start_len - len;
            start_ch = comp;
            i = last_starter;
            len = comp_len;
            prev_class = 0;
            put_utf16( str + i, comp );
        }
    }
    return srclen;
}


#endif /* __NTDLL_LOCALE_PRIVATE_H */
