/* w32-iconv.c - iconv implementation for Windows.
 * Copyright (C) 2016 g10 Code GmbH
 *
 * This file is part of libgpg-error.
 *
 * libgpg-error 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.
 *
 * libgpg-error 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 program; if not, see <https://www.gnu.org/licenses/>.
 *
 **************************************************************
 * This code code is based on the file win_iconv.c as found
 * at https://github.com/win-iconv/win-iconv with the commit id
 * 8c23784e35327c9d85d22810b9e4a2cbd06ffe90, dated 2016-03-18.
 * Yukihiro Nakadaira <yukihiro.nakadaira@gmail.com> is the
 * original author.  The file win_iconv.c carried this notice:
 *--------------------------------------------------------------
 * iconv implementation using Win32 API to convert.
 *
 * This file is placed in the public domain.
 *---------------------------------------------------
 */

#if HAVE_CONFIG_H
#include <config.h>
#endif
#if !defined (_WIN32) && !defined (__CYGWIN32__)
#  error This module may only be build for Windows or Cygwin32
#endif

/* for WC_NO_BEST_FIT_CHARS */
#ifndef WINVER
# define WINVER 0x0500
#endif

#include <windows.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

#include "gpgrt-int.h"

#undef USE_MLANG_DLL

#define MB_CHAR_MAX 16

#define UNICODE_MODE_BOM_DONE   1
#define UNICODE_MODE_SWAPPED    2

#define FLAG_USE_BOM            1
#define FLAG_TRANSLIT           2 /* //TRANSLIT */
#define FLAG_IGNORE             4 /* //IGNORE */

typedef unsigned char uchar;
typedef unsigned short ushort;
typedef unsigned int uint;

typedef struct compat_t compat_t;
typedef struct csconv_t csconv_t;

typedef int* (*f_errno)(void);
typedef int (*f_mbtowc)(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize);
typedef int (*f_wctomb)(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize);
typedef int (*f_mblen)(csconv_t *cv, const uchar *buf, int bufsize);
typedef int (*f_flush)(csconv_t *cv, uchar *buf, int bufsize);

#define COMPAT_IN   1
#define COMPAT_OUT  2

/* unicode mapping for compatibility with other conversion table. */
struct compat_t {
    uint in;
    uint out;
    uint flag;
};

struct csconv_t {
    int codepage;
    int flags;
    f_mbtowc mbtowc;
    f_wctomb wctomb;
    f_mblen mblen;
    f_flush flush;
    DWORD mode;
    compat_t *compat;
};

struct _gpgrt_w32_iconv_s {
    f_errno _errno;
    csconv_t from;
    csconv_t to;
};

#if USE_MLANG_DLL
static int load_mlang(void);
#endif /*USE_MLANG_DLL*/

static int make_csconv(const char *name, csconv_t *cv);
static int name_to_codepage(const char *name);
static uint utf16_to_ucs4(const ushort *wbuf);
static void ucs4_to_utf16(uint wc, ushort *wbuf, int *wbufsize);
static int mbtowc_flags(int codepage);
static int must_use_null_useddefaultchar(int codepage);
static char *strrstr(const char *str, const char *token);
static char *xstrndup(const char *s, size_t n);
static int seterror(int err);

static int sbcs_mblen(csconv_t *cv, const uchar *buf, int bufsize);
static int dbcs_mblen(csconv_t *cv, const uchar *buf, int bufsize);
static int mbcs_mblen(csconv_t *cv, const uchar *buf, int bufsize);
static int utf8_mblen(csconv_t *cv, const uchar *buf, int bufsize);
#if USE_MLANG_DLL
static int eucjp_mblen(csconv_t *cv, const uchar *buf, int bufsize);
#endif /*USE_MLANG_DLL*/

static int kernel_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize);
static int kernel_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize);

#if USE_MLANG_DLL
static int mlang_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize);
static int mlang_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize);
#endif /*USE_MLANG_DLL*/

static int utf16_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize);
static int utf16_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize);
static int utf32_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize);
static int utf32_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize);

#if USE_MLANG_DLL
static int iso2022jp_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize);
static int iso2022jp_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize);
static int iso2022jp_flush(csconv_t *cv, uchar *buf, int bufsize);
#endif /*USE_MLANG_DLL*/

static struct {
    int codepage;
    const char *name;
} codepage_alias[] = {
    {65001, "CP65001"},
    {65001, "UTF8"},
    {65001, "UTF-8"},

    {1200, "CP1200"},
    {1200, "UTF16LE"},
    {1200, "UTF-16LE"},
    {1200, "UCS2LE"},
    {1200, "UCS-2LE"},
    {1200, "UCS-2-INTERNAL"},

    {1201, "CP1201"},
    {1201, "UTF16BE"},
    {1201, "UTF-16BE"},
    {1201, "UCS2BE"},
    {1201, "UCS-2BE"},
    {1201, "unicodeFFFE"},

    {12000, "CP12000"},
    {12000, "UTF32LE"},
    {12000, "UTF-32LE"},
    {12000, "UCS4LE"},
    {12000, "UCS-4LE"},

    {12001, "CP12001"},
    {12001, "UTF32BE"},
    {12001, "UTF-32BE"},
    {12001, "UCS4BE"},
    {12001, "UCS-4BE"},

    /*
     * Default is big endian.
     * See rfc2781 4.3 Interpreting text labelled as UTF-16.
     */
    {1201, "UTF16"},
    {1201, "UTF-16"},
    {1201, "UCS2"},
    {1201, "UCS-2"},
    {12001, "UTF32"},
    {12001, "UTF-32"},
    {12001, "UCS-4"},
    {12001, "UCS4"},

    /* copy from libiconv `iconv -l` */
    /* !IsValidCodePage(367) */
    {20127, "ANSI_X3.4-1968"},
    {20127, "ANSI_X3.4-1986"},
    {20127, "ASCII"},
    {20127, "CP367"},
    {20127, "IBM367"},
    {20127, "ISO-IR-6"},
    {20127, "ISO646-US"},
    {20127, "ISO_646.IRV:1991"},
    {20127, "US"},
    {20127, "US-ASCII"},
    {20127, "CSASCII"},

    /* !IsValidCodePage(819) */
    {1252, "CP819"},
    {1252, "IBM819"},
    {28591, "ISO-8859-1"},
    {28591, "ISO-IR-100"},
    {28591, "ISO8859-1"},
    {28591, "ISO_8859-1"},
    {28591, "ISO_8859-1:1987"},
    {28591, "L1"},
    {28591, "LATIN1"},
    {28591, "CSISOLATIN1"},

    {1250, "CP1250"},
    {1250, "MS-EE"},
    {1250, "WINDOWS-1250"},

    {1251, "CP1251"},
    {1251, "MS-CYRL"},
    {1251, "WINDOWS-1251"},

    {1252, "CP1252"},
    {1252, "MS-ANSI"},
    {1252, "WINDOWS-1252"},

    {1253, "CP1253"},
    {1253, "MS-GREEK"},
    {1253, "WINDOWS-1253"},

    {1254, "CP1254"},
    {1254, "MS-TURK"},
    {1254, "WINDOWS-1254"},

    {1255, "CP1255"},
    {1255, "MS-HEBR"},
    {1255, "WINDOWS-1255"},

    {1256, "CP1256"},
    {1256, "MS-ARAB"},
    {1256, "WINDOWS-1256"},

    {1257, "CP1257"},
    {1257, "WINBALTRIM"},
    {1257, "WINDOWS-1257"},

    {1258, "CP1258"},
    {1258, "WINDOWS-1258"},

    {850, "850"},
    {850, "CP850"},
    {850, "IBM850"},
    {850, "CSPC850MULTILINGUAL"},

    /* !IsValidCodePage(862) */
    {862, "862"},
    {862, "CP862"},
    {862, "IBM862"},
    {862, "CSPC862LATINHEBREW"},

    {866, "866"},
    {866, "CP866"},
    {866, "IBM866"},
    {866, "CSIBM866"},

    /* !IsValidCodePage(154) */
    {154, "CP154"},
    {154, "CYRILLIC-ASIAN"},
    {154, "PT154"},
    {154, "PTCP154"},
    {154, "CSPTCP154"},

    /* !IsValidCodePage(1133) */
    {1133, "CP1133"},
    {1133, "IBM-CP1133"},

    {874, "CP874"},
    {874, "WINDOWS-874"},

    /* !IsValidCodePage(51932) */
    {51932, "CP51932"},
    {51932, "MS51932"},
    {51932, "WINDOWS-51932"},
    {51932, "EUC-JP"},

    {932, "CP932"},
    {932, "MS932"},
    {932, "SHIFFT_JIS"},
    {932, "SHIFFT_JIS-MS"},
    {932, "SJIS"},
    {932, "SJIS-MS"},
    {932, "SJIS-OPEN"},
    {932, "SJIS-WIN"},
    {932, "WINDOWS-31J"},
    {932, "WINDOWS-932"},
    {932, "CSWINDOWS31J"},

    {50221, "CP50221"},
    {50221, "ISO-2022-JP"},
    {50221, "ISO-2022-JP-MS"},
    {50221, "ISO2022-JP"},
    {50221, "ISO2022-JP-MS"},
    {50221, "MS50221"},
    {50221, "WINDOWS-50221"},

    {936, "CP936"},
    {936, "GBK"},
    {936, "MS936"},
    {936, "WINDOWS-936"},

    {950, "CP950"},
    {950, "BIG5"},
    {950, "BIG5HKSCS"},
    {950, "BIG5-HKSCS"},

    {949, "CP949"},
    {949, "UHC"},
    {949, "EUC-KR"},

    {1361, "CP1361"},
    {1361, "JOHAB"},

    {437, "437"},
    {437, "CP437"},
    {437, "IBM437"},
    {437, "CSPC8CODEPAGE437"},

    {737, "CP737"},

    {775, "CP775"},
    {775, "IBM775"},
    {775, "CSPC775BALTIC"},

    {852, "852"},
    {852, "CP852"},
    {852, "IBM852"},
    {852, "CSPCP852"},

    /* !IsValidCodePage(853) */
    {853, "CP853"},

    {855, "855"},
    {855, "CP855"},
    {855, "IBM855"},
    {855, "CSIBM855"},

    {857, "857"},
    {857, "CP857"},
    {857, "IBM857"},
    {857, "CSIBM857"},

    /* !IsValidCodePage(858) */
    {858, "CP858"},

    {860, "860"},
    {860, "CP860"},
    {860, "IBM860"},
    {860, "CSIBM860"},

    {861, "861"},
    {861, "CP-IS"},
    {861, "CP861"},
    {861, "IBM861"},
    {861, "CSIBM861"},

    {863, "863"},
    {863, "CP863"},
    {863, "IBM863"},
    {863, "CSIBM863"},

    {864, "CP864"},
    {864, "IBM864"},
    {864, "CSIBM864"},

    {865, "865"},
    {865, "CP865"},
    {865, "IBM865"},
    {865, "CSIBM865"},

    {869, "869"},
    {869, "CP-GR"},
    {869, "CP869"},
    {869, "IBM869"},
    {869, "CSIBM869"},

    /* !IsValidCodePage(1152) */
    {1125, "CP1125"},

    /*
     * Code Page Identifiers
     * https://msdn.microsoft.com/en-us/library/dd317756.aspx
     */
    {37, "IBM037"}, /* IBM EBCDIC US-Canada */
    {437, "IBM437"}, /* OEM United States */
    {500, "IBM500"}, /* IBM EBCDIC International */
    {708, "ASMO-708"}, /* Arabic (ASMO 708) */
    /* 709 		Arabic (ASMO-449+, BCON V4) */
    /* 710 		Arabic - Transparent Arabic */
    {720, "DOS-720"}, /* Arabic (Transparent ASMO); Arabic (DOS) */
    {737, "ibm737"}, /* OEM Greek (formerly 437G); Greek (DOS) */
    {775, "ibm775"}, /* OEM Baltic; Baltic (DOS) */
    {850, "ibm850"}, /* OEM Multilingual Latin 1; Western European (DOS) */
    {852, "ibm852"}, /* OEM Latin 2; Central European (DOS) */
    {855, "IBM855"}, /* OEM Cyrillic (primarily Russian) */
    {857, "ibm857"}, /* OEM Turkish; Turkish (DOS) */
    {858, "IBM00858"}, /* OEM Multilingual Latin 1 + Euro symbol */
    {860, "IBM860"}, /* OEM Portuguese; Portuguese (DOS) */
    {861, "ibm861"}, /* OEM Icelandic; Icelandic (DOS) */
    {862, "DOS-862"}, /* OEM Hebrew; Hebrew (DOS) */
    {863, "IBM863"}, /* OEM French Canadian; French Canadian (DOS) */
    {864, "IBM864"}, /* OEM Arabic; Arabic (864) */
    {865, "IBM865"}, /* OEM Nordic; Nordic (DOS) */
    {866, "cp866"}, /* OEM Russian; Cyrillic (DOS) */
    {869, "ibm869"}, /* OEM Modern Greek; Greek, Modern (DOS) */
    {870, "IBM870"}, /* IBM EBCDIC Multilingual/ROECE (Latin 2); IBM EBCDIC Multilingual Latin 2 */
    {874, "windows-874"}, /* ANSI/OEM Thai (same as 28605, ISO 8859-15); Thai (Windows) */
    {875, "cp875"}, /* IBM EBCDIC Greek Modern */
    {932, "shift_jis"}, /* ANSI/OEM Japanese; Japanese (Shift-JIS) */
    {932, "shift-jis"}, /* alternative name for it */
    {936, "gb2312"}, /* ANSI/OEM Simplified Chinese (PRC, Singapore); Chinese Simplified (GB2312) */
    {949, "ks_c_5601-1987"}, /* ANSI/OEM Korean (Unified Hangul Code) */
    {950, "big5"}, /* ANSI/OEM Traditional Chinese (Taiwan; Hong Kong SAR, PRC); Chinese Traditional (Big5) */
    {950, "big5hkscs"}, /* ANSI/OEM Traditional Chinese (Hong Kong SAR); Chinese Traditional (Big5-HKSCS) */
    {950, "big5-hkscs"}, /* alternative name for it */
    {1026, "IBM1026"}, /* IBM EBCDIC Turkish (Latin 5) */
    {1047, "IBM01047"}, /* IBM EBCDIC Latin 1/Open System */
    {1140, "IBM01140"}, /* IBM EBCDIC US-Canada (037 + Euro symbol); IBM EBCDIC (US-Canada-Euro) */
    {1141, "IBM01141"}, /* IBM EBCDIC Germany (20273 + Euro symbol); IBM EBCDIC (Germany-Euro) */
    {1142, "IBM01142"}, /* IBM EBCDIC Denmark-Norway (20277 + Euro symbol); IBM EBCDIC (Denmark-Norway-Euro) */
    {1143, "IBM01143"}, /* IBM EBCDIC Finland-Sweden (20278 + Euro symbol); IBM EBCDIC (Finland-Sweden-Euro) */
    {1144, "IBM01144"}, /* IBM EBCDIC Italy (20280 + Euro symbol); IBM EBCDIC (Italy-Euro) */
    {1145, "IBM01145"}, /* IBM EBCDIC Latin America-Spain (20284 + Euro symbol); IBM EBCDIC (Spain-Euro) */
    {1146, "IBM01146"}, /* IBM EBCDIC United Kingdom (20285 + Euro symbol); IBM EBCDIC (UK-Euro) */
    {1147, "IBM01147"}, /* IBM EBCDIC France (20297 + Euro symbol); IBM EBCDIC (France-Euro) */
    {1148, "IBM01148"}, /* IBM EBCDIC International (500 + Euro symbol); IBM EBCDIC (International-Euro) */
    {1149, "IBM01149"}, /* IBM EBCDIC Icelandic (20871 + Euro symbol); IBM EBCDIC (Icelandic-Euro) */
    {1250, "windows-1250"}, /* ANSI Central European; Central European (Windows) */
    {1251, "windows-1251"}, /* ANSI Cyrillic; Cyrillic (Windows) */
    {1252, "windows-1252"}, /* ANSI Latin 1; Western European (Windows) */
    {1253, "windows-1253"}, /* ANSI Greek; Greek (Windows) */
    {1254, "windows-1254"}, /* ANSI Turkish; Turkish (Windows) */
    {1255, "windows-1255"}, /* ANSI Hebrew; Hebrew (Windows) */
    {1256, "windows-1256"}, /* ANSI Arabic; Arabic (Windows) */
    {1257, "windows-1257"}, /* ANSI Baltic; Baltic (Windows) */
    {1258, "windows-1258"}, /* ANSI/OEM Vietnamese; Vietnamese (Windows) */
    {1361, "Johab"}, /* Korean (Johab) */
    {10000, "macintosh"}, /* MAC Roman; Western European (Mac) */
    {10001, "x-mac-japanese"}, /* Japanese (Mac) */
    {10002, "x-mac-chinesetrad"}, /* MAC Traditional Chinese (Big5); Chinese Traditional (Mac) */
    {10003, "x-mac-korean"}, /* Korean (Mac) */
    {10004, "x-mac-arabic"}, /* Arabic (Mac) */
    {10005, "x-mac-hebrew"}, /* Hebrew (Mac) */
    {10006, "x-mac-greek"}, /* Greek (Mac) */
    {10007, "x-mac-cyrillic"}, /* Cyrillic (Mac) */
    {10008, "x-mac-chinesesimp"}, /* MAC Simplified Chinese (GB 2312); Chinese Simplified (Mac) */
    {10010, "x-mac-romanian"}, /* Romanian (Mac) */
    {10017, "x-mac-ukrainian"}, /* Ukrainian (Mac) */
    {10021, "x-mac-thai"}, /* Thai (Mac) */
    {10029, "x-mac-ce"}, /* MAC Latin 2; Central European (Mac) */
    {10079, "x-mac-icelandic"}, /* Icelandic (Mac) */
    {10081, "x-mac-turkish"}, /* Turkish (Mac) */
    {10082, "x-mac-croatian"}, /* Croatian (Mac) */
    {20000, "x-Chinese_CNS"}, /* CNS Taiwan; Chinese Traditional (CNS) */
    {20001, "x-cp20001"}, /* TCA Taiwan */
    {20002, "x_Chinese-Eten"}, /* Eten Taiwan; Chinese Traditional (Eten) */
    {20003, "x-cp20003"}, /* IBM5550 Taiwan */
    {20004, "x-cp20004"}, /* TeleText Taiwan */
    {20005, "x-cp20005"}, /* Wang Taiwan */
    {20105, "x-IA5"}, /* IA5 (IRV International Alphabet No. 5, 7-bit); Western European (IA5) */
    {20106, "x-IA5-German"}, /* IA5 German (7-bit) */
    {20107, "x-IA5-Swedish"}, /* IA5 Swedish (7-bit) */
    {20108, "x-IA5-Norwegian"}, /* IA5 Norwegian (7-bit) */
    {20127, "us-ascii"}, /* US-ASCII (7-bit) */
    {20261, "x-cp20261"}, /* T.61 */
    {20269, "x-cp20269"}, /* ISO 6937 Non-Spacing Accent */
    {20273, "IBM273"}, /* IBM EBCDIC Germany */
    {20277, "IBM277"}, /* IBM EBCDIC Denmark-Norway */
    {20278, "IBM278"}, /* IBM EBCDIC Finland-Sweden */
    {20280, "IBM280"}, /* IBM EBCDIC Italy */
    {20284, "IBM284"}, /* IBM EBCDIC Latin America-Spain */
    {20285, "IBM285"}, /* IBM EBCDIC United Kingdom */
    {20290, "IBM290"}, /* IBM EBCDIC Japanese Katakana Extended */
    {20297, "IBM297"}, /* IBM EBCDIC France */
    {20420, "IBM420"}, /* IBM EBCDIC Arabic */
    {20423, "IBM423"}, /* IBM EBCDIC Greek */
    {20424, "IBM424"}, /* IBM EBCDIC Hebrew */
    {20833, "x-EBCDIC-KoreanExtended"}, /* IBM EBCDIC Korean Extended */
    {20838, "IBM-Thai"}, /* IBM EBCDIC Thai */
    {20866, "koi8-r"}, /* Russian (KOI8-R); Cyrillic (KOI8-R) */
    {20871, "IBM871"}, /* IBM EBCDIC Icelandic */
    {20880, "IBM880"}, /* IBM EBCDIC Cyrillic Russian */
    {20905, "IBM905"}, /* IBM EBCDIC Turkish */
    {20924, "IBM00924"}, /* IBM EBCDIC Latin 1/Open System (1047 + Euro symbol) */
    {20932, "EUC-JP"}, /* Japanese (JIS 0208-1990 and 0121-1990) */
    {20936, "x-cp20936"}, /* Simplified Chinese (GB2312); Chinese Simplified (GB2312-80) */
    {20949, "x-cp20949"}, /* Korean Wansung */
    {21025, "cp1025"}, /* IBM EBCDIC Cyrillic Serbian-Bulgarian */
    /* 21027 		(deprecated) */
    {21866, "koi8-u"}, /* Ukrainian (KOI8-U); Cyrillic (KOI8-U) */
    {28591, "iso-8859-1"}, /* ISO 8859-1 Latin 1; Western European (ISO) */
    {28591, "iso8859-1"}, /* ISO 8859-1 Latin 1; Western European (ISO) */
    {28591, "iso_8859-1"},
    {28591, "iso_8859_1"},
    {28592, "iso-8859-2"}, /* ISO 8859-2 Central European; Central European (ISO) */
    {28592, "iso8859-2"}, /* ISO 8859-2 Central European; Central European (ISO) */
    {28592, "iso_8859-2"},
    {28592, "iso_8859_2"},
    {28593, "iso-8859-3"}, /* ISO 8859-3 Latin 3 */
    {28593, "iso8859-3"}, /* ISO 8859-3 Latin 3 */
    {28593, "iso_8859-3"},
    {28593, "iso_8859_3"},
    {28594, "iso-8859-4"}, /* ISO 8859-4 Baltic */
    {28594, "iso8859-4"}, /* ISO 8859-4 Baltic */
    {28594, "iso_8859-4"},
    {28594, "iso_8859_4"},
    {28595, "iso-8859-5"}, /* ISO 8859-5 Cyrillic */
    {28595, "iso8859-5"}, /* ISO 8859-5 Cyrillic */
    {28595, "iso_8859-5"},
    {28595, "iso_8859_5"},
    {28596, "iso-8859-6"}, /* ISO 8859-6 Arabic */
    {28596, "iso8859-6"}, /* ISO 8859-6 Arabic */
    {28596, "iso_8859-6"},
    {28596, "iso_8859_6"},
    {28597, "iso-8859-7"}, /* ISO 8859-7 Greek */
    {28597, "iso8859-7"}, /* ISO 8859-7 Greek */
    {28597, "iso_8859-7"},
    {28597, "iso_8859_7"},
    {28598, "iso-8859-8"}, /* ISO 8859-8 Hebrew; Hebrew (ISO-Visual) */
    {28598, "iso8859-8"}, /* ISO 8859-8 Hebrew; Hebrew (ISO-Visual) */
    {28598, "iso_8859-8"},
    {28598, "iso_8859_8"},
    {28599, "iso-8859-9"}, /* ISO 8859-9 Turkish */
    {28599, "iso8859-9"}, /* ISO 8859-9 Turkish */
    {28599, "iso_8859-9"},
    {28599, "iso_8859_9"},
    {28603, "iso-8859-13"}, /* ISO 8859-13 Estonian */
    {28603, "iso8859-13"}, /* ISO 8859-13 Estonian */
    {28603, "iso_8859-13"},
    {28603, "iso_8859_13"},
    {28605, "iso-8859-15"}, /* ISO 8859-15 Latin 9 */
    {28605, "iso8859-15"}, /* ISO 8859-15 Latin 9 */
    {28605, "iso_8859-15"},
    {28605, "iso_8859_15"},
    {29001, "x-Europa"}, /* Europa 3 */
    {38598, "iso-8859-8-i"}, /* ISO 8859-8 Hebrew; Hebrew (ISO-Logical) */
    {38598, "iso8859-8-i"}, /* ISO 8859-8 Hebrew; Hebrew (ISO-Logical) */
    {38598, "iso_8859-8-i"},
    {38598, "iso_8859_8-i"},
    {50220, "iso-2022-jp"}, /* ISO 2022 Japanese with no halfwidth Katakana; Japanese (JIS) */
    {50221, "csISO2022JP"}, /* ISO 2022 Japanese with halfwidth Katakana; Japanese (JIS-Allow 1 byte Kana) */
    {50222, "iso-2022-jp"}, /* ISO 2022 Japanese JIS X 0201-1989; Japanese (JIS-Allow 1 byte Kana - SO/SI) */
    {50225, "iso-2022-kr"}, /* ISO 2022 Korean */
    {50225, "iso2022-kr"}, /* ISO 2022 Korean */
    {50227, "x-cp50227"}, /* ISO 2022 Simplified Chinese; Chinese Simplified (ISO 2022) */
    /* 50229 		ISO 2022 Traditional Chinese */
    /* 50930 		EBCDIC Japanese (Katakana) Extended */
    /* 50931 		EBCDIC US-Canada and Japanese */
    /* 50933 		EBCDIC Korean Extended and Korean */
    /* 50935 		EBCDIC Simplified Chinese Extended and Simplified Chinese */
    /* 50936 		EBCDIC Simplified Chinese */
    /* 50937 		EBCDIC US-Canada and Traditional Chinese */
    /* 50939 		EBCDIC Japanese (Latin) Extended and Japanese */
    {51932, "euc-jp"}, /* EUC Japanese */
    {51936, "EUC-CN"}, /* EUC Simplified Chinese; Chinese Simplified (EUC) */
    {51949, "euc-kr"}, /* EUC Korean */
    /* 51950 		EUC Traditional Chinese */
    {52936, "hz-gb-2312"}, /* HZ-GB2312 Simplified Chinese; Chinese Simplified (HZ) */
    {54936, "GB18030"}, /* Windows XP and later: GB18030 Simplified Chinese (4 byte); Chinese Simplified (GB18030) */
    {57002, "x-iscii-de"}, /* ISCII Devanagari */
    {57003, "x-iscii-be"}, /* ISCII Bengali */
    {57004, "x-iscii-ta"}, /* ISCII Tamil */
    {57005, "x-iscii-te"}, /* ISCII Telugu */
    {57006, "x-iscii-as"}, /* ISCII Assamese */
    {57007, "x-iscii-or"}, /* ISCII Oriya */
    {57008, "x-iscii-ka"}, /* ISCII Kannada */
    {57009, "x-iscii-ma"}, /* ISCII Malayalam */
    {57010, "x-iscii-gu"}, /* ISCII Gujarati */
    {57011, "x-iscii-pa"}, /* ISCII Punjabi */

    {0, NULL}
};

/*
 * SJIS SHIFTJIS table              CP932 table
 * ---- --------------------------- --------------------------------
 *   5C U+00A5 YEN SIGN             U+005C REVERSE SOLIDUS
 *   7E U+203E OVERLINE             U+007E TILDE
 * 815C U+2014 EM DASH              U+2015 HORIZONTAL BAR
 * 815F U+005C REVERSE SOLIDUS      U+FF3C FULLWIDTH REVERSE SOLIDUS
 * 8160 U+301C WAVE DASH            U+FF5E FULLWIDTH TILDE
 * 8161 U+2016 DOUBLE VERTICAL LINE U+2225 PARALLEL TO
 * 817C U+2212 MINUS SIGN           U+FF0D FULLWIDTH HYPHEN-MINUS
 * 8191 U+00A2 CENT SIGN            U+FFE0 FULLWIDTH CENT SIGN
 * 8192 U+00A3 POUND SIGN           U+FFE1 FULLWIDTH POUND SIGN
 * 81CA U+00AC NOT SIGN             U+FFE2 FULLWIDTH NOT SIGN
 *
 * EUC-JP and ISO-2022-JP should be compatible with CP932.
 *
 * Kernel and MLang have different Unicode mapping table.  Make sure
 * which API is used.
 */
static compat_t cp932_compat[] = {
    {0x00A5, 0x005C, COMPAT_OUT},
    {0x203E, 0x007E, COMPAT_OUT},
    {0x2014, 0x2015, COMPAT_OUT},
    {0x301C, 0xFF5E, COMPAT_OUT},
    {0x2016, 0x2225, COMPAT_OUT},
    {0x2212, 0xFF0D, COMPAT_OUT},
    {0x00A2, 0xFFE0, COMPAT_OUT},
    {0x00A3, 0xFFE1, COMPAT_OUT},
    {0x00AC, 0xFFE2, COMPAT_OUT},
    {0, 0, 0}
};

static compat_t cp20932_compat[] = {
    {0x00A5, 0x005C, COMPAT_OUT},
    {0x203E, 0x007E, COMPAT_OUT},
    {0x2014, 0x2015, COMPAT_OUT},
    {0xFF5E, 0x301C, COMPAT_OUT|COMPAT_IN},
    {0x2225, 0x2016, COMPAT_OUT|COMPAT_IN},
    {0xFF0D, 0x2212, COMPAT_OUT|COMPAT_IN},
    {0xFFE0, 0x00A2, COMPAT_OUT|COMPAT_IN},
    {0xFFE1, 0x00A3, COMPAT_OUT|COMPAT_IN},
    {0xFFE2, 0x00AC, COMPAT_OUT|COMPAT_IN},
    {0, 0, 0}
};

static compat_t *cp51932_compat = cp932_compat;

/* cp20932_compat for kernel.  cp932_compat for mlang. */
static compat_t *cp5022x_compat = cp932_compat;

#if USE_MLANG_DLL
typedef HRESULT (WINAPI *CONVERTINETSTRING)(
    LPDWORD lpdwMode,
    DWORD dwSrcEncoding,
    DWORD dwDstEncoding,
    LPCSTR lpSrcStr,
    LPINT lpnSrcSize,
    LPBYTE lpDstStr,
    LPINT lpnDstSize
);
typedef HRESULT (WINAPI *CONVERTINETMULTIBYTETOUNICODE)(
    LPDWORD lpdwMode,
    DWORD dwSrcEncoding,
    LPCSTR lpSrcStr,
    LPINT lpnMultiCharCount,
    LPWSTR lpDstStr,
    LPINT lpnWideCharCount
);
typedef HRESULT (WINAPI *CONVERTINETUNICODETOMULTIBYTE)(
    LPDWORD lpdwMode,
    DWORD dwEncoding,
    LPCWSTR lpSrcStr,
    LPINT lpnWideCharCount,
    LPSTR lpDstStr,
    LPINT lpnMultiCharCount
);
typedef HRESULT (WINAPI *ISCONVERTINETSTRINGAVAILABLE)(
    DWORD dwSrcEncoding,
    DWORD dwDstEncoding
);
typedef HRESULT (WINAPI *LCIDTORFC1766A)(
    LCID Locale,
    LPSTR pszRfc1766,
    int nChar
);
typedef HRESULT (WINAPI *LCIDTORFC1766W)(
    LCID Locale,
    LPWSTR pszRfc1766,
    int nChar
);
typedef HRESULT (WINAPI *RFC1766TOLCIDA)(
    LCID *pLocale,
    LPSTR pszRfc1766
);
typedef HRESULT (WINAPI *RFC1766TOLCIDW)(
    LCID *pLocale,
    LPWSTR pszRfc1766
);
static CONVERTINETSTRING ConvertINetString;
static CONVERTINETMULTIBYTETOUNICODE ConvertINetMultiByteToUnicode;
static CONVERTINETUNICODETOMULTIBYTE ConvertINetUnicodeToMultiByte;
static ISCONVERTINETSTRINGAVAILABLE IsConvertINetStringAvailable;
static LCIDTORFC1766A LcidToRfc1766A;
static RFC1766TOLCIDA Rfc1766ToLcidA;
#endif /*USE_MLANG_DLL*/

#if USE_MLANG_DLL
static int
load_mlang(void)
{
    HMODULE h;
    if (ConvertINetString != NULL)
        return TRUE;
    h = LoadLibrary(TEXT("mlang.dll"));
    if (!h)
        return FALSE;
    ConvertINetString = (CONVERTINETSTRING)GetProcAddressA(h, "ConvertINetString");
    ConvertINetMultiByteToUnicode = (CONVERTINETMULTIBYTETOUNICODE)GetProcAddressA(h, "ConvertINetMultiByteToUnicode");
    ConvertINetUnicodeToMultiByte = (CONVERTINETUNICODETOMULTIBYTE)GetProcAddressA(h, "ConvertINetUnicodeToMultiByte");
    IsConvertINetStringAvailable = (ISCONVERTINETSTRINGAVAILABLE)GetProcAddressA(h, "IsConvertINetStringAvailable");
    LcidToRfc1766A = (LCIDTORFC1766A)GetProcAddressA(h, "LcidToRfc1766A");
    Rfc1766ToLcidA = (RFC1766TOLCIDA)GetProcAddressA(h, "Rfc1766ToLcidA");
    return TRUE;
}
#endif


static int
win_iconv_open(gpgrt_w32_iconv_t cd, const char *tocode, const char *fromcode)
{
    if (!make_csconv(fromcode, &cd->from) || !make_csconv(tocode, &cd->to))
        return FALSE;
    cd->_errno = _errno;
    return TRUE;
}

static size_t
win_iconv (gpgrt_w32_iconv_t cd,
           const char **inbuf, size_t *inbytesleft,
           char **outbuf, size_t *outbytesleft)
{
    ushort wbuf[MB_CHAR_MAX]; /* enough room for one character */
    int insize;
    int outsize;
    int wsize;
    DWORD frommode;
    DWORD tomode;
    uint wc;
    compat_t *cp;
    int i;

    if (inbuf == NULL || *inbuf == NULL)
    {
        if (outbuf != NULL && *outbuf != NULL && cd->to.flush != NULL)
        {
            tomode = cd->to.mode;
            outsize = cd->to.flush(&cd->to, (uchar *)*outbuf, *outbytesleft);
            if (outsize == -1)
            {
                if ((cd->to.flags & FLAG_IGNORE) && errno != E2BIG)
                {
                    outsize = 0;
                }
                else
                {
                    cd->to.mode = tomode;
                    return (size_t)(-1);
                }
            }
            *outbuf += outsize;
            *outbytesleft -= outsize;
        }
        cd->from.mode = 0;
        cd->to.mode = 0;
        return 0;
    }

    while (*inbytesleft != 0)
    {
        frommode = cd->from.mode;
        tomode = cd->to.mode;
        wsize = MB_CHAR_MAX;

        insize = cd->from.mbtowc(&cd->from, (const uchar *)*inbuf, *inbytesleft, wbuf, &wsize);
        if (insize == -1)
        {
            if (cd->to.flags & FLAG_IGNORE)
            {
                cd->from.mode = frommode;
                insize = 1;
                wsize = 0;
            }
            else
            {
                cd->from.mode = frommode;
                return (size_t)(-1);
            }
        }

        if (wsize == 0)
        {
            *inbuf += insize;
            *inbytesleft -= insize;
            continue;
        }

        if (cd->from.compat != NULL)
        {
            wc = utf16_to_ucs4(wbuf);
            cp = cd->from.compat;
            for (i = 0; cp[i].in != 0; ++i)
            {
                if ((cp[i].flag & COMPAT_IN) && cp[i].out == wc)
                {
                    ucs4_to_utf16(cp[i].in, wbuf, &wsize);
                    break;
                }
            }
        }

        if (cd->to.compat != NULL)
        {
            wc = utf16_to_ucs4(wbuf);
            cp = cd->to.compat;
            for (i = 0; cp[i].in != 0; ++i)
            {
                if ((cp[i].flag & COMPAT_OUT) && cp[i].in == wc)
                {
                    ucs4_to_utf16(cp[i].out, wbuf, &wsize);
                    break;
                }
            }
        }

        outsize = cd->to.wctomb(&cd->to, wbuf, wsize, (uchar *)*outbuf, *outbytesleft);
        if (outsize == -1)
        {
            if ((cd->to.flags & FLAG_IGNORE) && errno != E2BIG)
            {
                cd->to.mode = tomode;
                outsize = 0;
            }
            else
            {
                cd->from.mode = frommode;
                cd->to.mode = tomode;
                return (size_t)(-1);
            }
        }

        *inbuf += insize;
        *outbuf += outsize;
        *inbytesleft -= insize;
        *outbytesleft -= outsize;
    }

    return 0;
}

static int
make_csconv(const char *_name, csconv_t *cv)
{
    CPINFO cpinfo;
    int use_compat = TRUE;
    int flag = 0;
    char *name;
    char *p;

    name = xstrndup(_name, strlen(_name));
    if (name == NULL)
        return FALSE;

    /* check for option "enc_name//opt1//opt2" */
    while ((p = strrstr(name, "//")) != NULL)
    {
        if (_stricmp(p + 2, "nocompat") == 0)
            use_compat = FALSE;
        else if (_stricmp(p + 2, "translit") == 0)
            flag |= FLAG_TRANSLIT;
        else if (_stricmp(p + 2, "ignore") == 0)
            flag |= FLAG_IGNORE;
        *p = 0;
    }

    cv->mode = 0;
    cv->flags = flag;
    cv->mblen = NULL;
    cv->flush = NULL;
    cv->compat = NULL;
    cv->codepage = name_to_codepage(name);
    if (cv->codepage == 1200 || cv->codepage == 1201)
    {
        cv->mbtowc = utf16_mbtowc;
        cv->wctomb = utf16_wctomb;
        if (_stricmp(name, "UTF-16") == 0 || _stricmp(name, "UTF16") == 0 ||
          _stricmp(name, "UCS-2") == 0 || _stricmp(name, "UCS2") == 0 ||
	  _stricmp(name,"UCS-2-INTERNAL") == 0)
            cv->flags |= FLAG_USE_BOM;
    }
    else if (cv->codepage == 12000 || cv->codepage == 12001)
    {
        cv->mbtowc = utf32_mbtowc;
        cv->wctomb = utf32_wctomb;
        if (_stricmp(name, "UTF-32") == 0 || _stricmp(name, "UTF32") == 0 ||
          _stricmp(name, "UCS-4") == 0 || _stricmp(name, "UCS4") == 0)
            cv->flags |= FLAG_USE_BOM;
    }
    else if (cv->codepage == 65001)
    {
        cv->mbtowc = kernel_mbtowc;
        cv->wctomb = kernel_wctomb;
        cv->mblen = utf8_mblen;
    }
#if USE_MLANG_DLL
    else if ((cv->codepage == 50220 || cv->codepage == 50221 || cv->codepage == 50222) && load_mlang())
    {
        cv->mbtowc = iso2022jp_mbtowc;
        cv->wctomb = iso2022jp_wctomb;
        cv->flush = iso2022jp_flush;
    }
    else if (cv->codepage == 51932 && load_mlang())
    {
        cv->mbtowc = mlang_mbtowc;
        cv->wctomb = mlang_wctomb;
        cv->mblen = eucjp_mblen;
    }
#endif /*USE_MLANG_DLL*/
    else if (IsValidCodePage(cv->codepage)
	     && GetCPInfo(cv->codepage, &cpinfo) != 0)
    {
        cv->mbtowc = kernel_mbtowc;
        cv->wctomb = kernel_wctomb;
        if (cpinfo.MaxCharSize == 1)
            cv->mblen = sbcs_mblen;
        else if (cpinfo.MaxCharSize == 2)
            cv->mblen = dbcs_mblen;
        else
	    cv->mblen = mbcs_mblen;
    }
    else
    {
        /* not supported */
        free(name);
        errno = EINVAL;
        return FALSE;
    }

    if (use_compat)
    {
        switch (cv->codepage)
        {
        case 932: cv->compat = cp932_compat; break;
        case 20932: cv->compat = cp20932_compat; break;
        case 51932: cv->compat = cp51932_compat; break;
        case 50220: case 50221: case 50222: cv->compat = cp5022x_compat; break;
        }
    }

    free(name);

    return TRUE;
}

static int
name_to_codepage(const char *name)
{
    int i;

    if (*name == '\0' ||
	strcmp(name, "char") == 0)
        return GetACP();
    else if (strcmp(name, "wchar_t") == 0)
        return 1200;
    else if (_strnicmp(name, "cp", 2) == 0)
        return atoi(name + 2); /* CP123 */
    else if ('0' <= name[0] && name[0] <= '9')
        return atoi(name);     /* 123 */
    else if (_strnicmp(name, "xx", 2) == 0)
        return atoi(name + 2); /* XX123 for debug */

    for (i = 0; codepage_alias[i].name != NULL; ++i)
        if (_stricmp(name, codepage_alias[i].name) == 0)
            return codepage_alias[i].codepage;
    return -1;
}

/*
 * https://tools.ietf.org/html/rfc2781
 */
static uint
utf16_to_ucs4(const ushort *wbuf)
{
    uint wc = wbuf[0];
    if (0xD800 <= wbuf[0] && wbuf[0] <= 0xDBFF)
        wc = ((wbuf[0] & 0x3FF) << 10) + (wbuf[1] & 0x3FF) + 0x10000;
    return wc;
}

static void
ucs4_to_utf16(uint wc, ushort *wbuf, int *wbufsize)
{
    if (wc < 0x10000)
    {
        wbuf[0] = wc;
        *wbufsize = 1;
    }
    else
    {
        wc -= 0x10000;
        wbuf[0] = 0xD800 | ((wc >> 10) & 0x3FF);
        wbuf[1] = 0xDC00 | (wc & 0x3FF);
        *wbufsize = 2;
    }
}

/*
 * Check if codepage is one of those for which the dwFlags parameter
 * to MultiByteToWideChar() must be zero. Return zero or
 * MB_ERR_INVALID_CHARS.  The docs in Platform SDK for Windows
 * Server 2003 R2 claims that also codepage 65001 is one of these, but
 * that doesn't seem to be the case. The MSDN docs for MSVS2008 leave
 * out 65001 (UTF-8), and that indeed seems to be the case on XP, it
 * works fine to pass MB_ERR_INVALID_CHARS in dwFlags when converting
 * from UTF-8.
 */
static int
mbtowc_flags(int codepage)
{
    return (codepage == 50220 || codepage == 50221 ||
	    codepage == 50222 || codepage == 50225 ||
	    codepage == 50227 || codepage == 50229 ||
	    codepage == 52936 || codepage == 54936 ||
	    (codepage >= 57002 && codepage <= 57011) ||
	    codepage == 65000 || codepage == 42) ? 0 : MB_ERR_INVALID_CHARS;
}

/*
 * Check if codepage is one those for which the lpUsedDefaultChar
 * parameter to WideCharToMultiByte() must be NULL.  The docs in
 * Platform SDK for Windows Server 2003 R2 claims that this is the
 * list below, while the MSDN docs for MSVS2008 claim that it is only
 * for 65000 (UTF-7) and 65001 (UTF-8). This time the earlier Platform
 * SDK seems to be correct, at least for XP.
 */
static int
must_use_null_useddefaultchar(int codepage)
{
    return (codepage == 65000 || codepage == 65001 ||
            codepage == 50220 || codepage == 50221 ||
            codepage == 50222 || codepage == 50225 ||
            codepage == 50227 || codepage == 50229 ||
            codepage == 52936 || codepage == 54936 ||
            (codepage >= 57002 && codepage <= 57011) ||
            codepage == 42);
}

static char *
strrstr(const char *str, const char *token)
{
    int len = strlen(token);
    const char *p = str + strlen(str);

    while (str <= --p)
        if (p[0] == token[0] && strncmp(p, token, len) == 0)
            return (char *)p;
    return NULL;
}

static char *
xstrndup(const char *s, size_t n)
{
    char *p;

    p = (char *)malloc(n + 1);
    if (p == NULL)
        return NULL;
    memcpy(p, s, n);
    p[n] = '\0';
    return p;
}

static int
seterror(int err)
{
    _gpg_err_set_errno (err);
    return -1;
}


static int
sbcs_mblen(csconv_t *cv, const uchar *buf, int bufsize)
{
  (void)cv;
  (void)buf;
  (void)bufsize;
  return 1;
}

static int
dbcs_mblen(csconv_t *cv, const uchar *buf, int bufsize)
{
    int len = IsDBCSLeadByteEx(cv->codepage, buf[0]) ? 2 : 1;
    if (bufsize < len)
        return seterror(EINVAL);
    return len;
}

static int
mbcs_mblen(csconv_t *cv, const uchar *buf, int bufsize)
{
    int len = 0;

    if (cv->codepage == 54936) {
	if (buf[0] <= 0x7F) len = 1;
	else if (buf[0] >= 0x81 && buf[0] <= 0xFE &&
		 bufsize >= 2 &&
		 ((buf[1] >= 0x40 && buf[1] <= 0x7E) ||
		  (buf[1] >= 0x80 && buf[1] <= 0xFE))) len = 2;
	else if (buf[0] >= 0x81 && buf[0] <= 0xFE &&
		 bufsize >= 4 &&
		 buf[1] >= 0x30 && buf[1] <= 0x39) len = 4;
	else
	    return seterror(EINVAL);
	return len;
    }
    else
	return seterror(EINVAL);
}

static int
utf8_mblen(csconv_t *cv, const uchar *buf, int bufsize)
{
    int len = 0;

    (void) cv;

    if (buf[0] < 0x80) len = 1;
    else if ((buf[0] & 0xE0) == 0xC0) len = 2;
    else if ((buf[0] & 0xF0) == 0xE0) len = 3;
    else if ((buf[0] & 0xF8) == 0xF0) len = 4;
    else if ((buf[0] & 0xFC) == 0xF8) len = 5;
    else if ((buf[0] & 0xFE) == 0xFC) len = 6;

    if (len == 0)
        return seterror(EILSEQ);
    else if (bufsize < len)
        return seterror(EINVAL);
    return len;
}

#if USE_MLANG_DLL
static int
eucjp_mblen(csconv_t *cv, const uchar *buf, int bufsize)
{
    (void) cv;

    if (buf[0] < 0x80) /* ASCII */
        return 1;
    else if (buf[0] == 0x8E) /* JIS X 0201 */
    {
        if (bufsize < 2)
            return seterror(EINVAL);
        else if (!(0xA1 <= buf[1] && buf[1] <= 0xDF))
            return seterror(EILSEQ);
        return 2;
    }
    else if (buf[0] == 0x8F) /* JIS X 0212 */
    {
        if (bufsize < 3)
            return seterror(EINVAL);
        else if (!(0xA1 <= buf[1] && buf[1] <= 0xFE)
                || !(0xA1 <= buf[2] && buf[2] <= 0xFE))
            return seterror(EILSEQ);
        return 3;
    }
    else /* JIS X 0208 */
    {
        if (bufsize < 2)
            return seterror(EINVAL);
        else if (!(0xA1 <= buf[0] && buf[0] <= 0xFE)
                || !(0xA1 <= buf[1] && buf[1] <= 0xFE))
            return seterror(EILSEQ);
        return 2;
    }
}
#endif /*USE_MLANG_DLL*/

static int
kernel_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize)
{
    int len;

    len = cv->mblen(cv, buf, bufsize);
    if (len == -1)
        return -1;
    /* If converting from ASCII, reject 8bit
     * chars. MultiByteToWideChar() doesn't. Note that for ASCII we
     * know that the mblen function is sbcs_mblen() so len is 1.
     */
    if (cv->codepage == 20127 && buf[0] >= 0x80)
        return seterror(EILSEQ);
    *wbufsize = MultiByteToWideChar(cv->codepage, mbtowc_flags (cv->codepage),
            (const char *)buf, len, (wchar_t *)wbuf, *wbufsize);
    if (*wbufsize == 0)
        return seterror(EILSEQ);
    return len;
}

static int
kernel_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize)
{
    BOOL usedDefaultChar = 0;
    BOOL *p = NULL;
    int flags = 0;
    int len;

    if (bufsize == 0)
        return seterror(E2BIG);
    if (!must_use_null_useddefaultchar(cv->codepage))
    {
        p = &usedDefaultChar;
#ifdef WC_NO_BEST_FIT_CHARS
        if (!(cv->flags & FLAG_TRANSLIT))
            flags |= WC_NO_BEST_FIT_CHARS;
#endif
    }
    len = WideCharToMultiByte(cv->codepage, flags,
            (const wchar_t *)wbuf, wbufsize, (char *)buf, bufsize, NULL, p);
    if (len == 0)
    {
        if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
            return seterror(E2BIG);
        return seterror(EILSEQ);
    }
    else if (usedDefaultChar && !(cv->flags & FLAG_TRANSLIT))
        return seterror(EILSEQ);
    else if (cv->mblen(cv, buf, len) != len) /* validate result */
        return seterror(EILSEQ);
    return len;
}

/*
 * It seems that the mode (cv->mode) is fixnum.
 * For example, when converting iso-2022-jp(cp50221) to unicode:
 *      in ascii sequence: mode=0xC42C0000
 *   in jisx0208 sequence: mode=0xC42C0001
 * "C42C" is same for each convert session.
 * It should be: ((codepage-1)<<16)|state
 */
#if USE_MLANG_DLL
static int
mlang_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize)
{
    int len;
    int insize;
    HRESULT hr;

    len = cv->mblen(cv, buf, bufsize);
    if (len == -1)
        return -1;
    insize = len;
    hr = ConvertINetMultiByteToUnicode(&cv->mode, cv->codepage,
            (const char *)buf, &insize, (wchar_t *)wbuf, wbufsize);
    if (hr != S_OK || insize != len)
        return seterror(EILSEQ);
    return len;
}

static int
mlang_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize)
{
    char tmpbuf[MB_CHAR_MAX]; /* enough room for one character */
    int tmpsize = MB_CHAR_MAX;
    int insize = wbufsize;
    HRESULT hr;

    hr = ConvertINetUnicodeToMultiByte(&cv->mode, cv->codepage,
            (const wchar_t *)wbuf, &wbufsize, tmpbuf, &tmpsize);
    if (hr != S_OK || insize != wbufsize)
        return seterror(EILSEQ);
    else if (bufsize < tmpsize)
        return seterror(E2BIG);
    else if (cv->mblen(cv, (uchar *)tmpbuf, tmpsize) != tmpsize)
        return seterror(EILSEQ);
    memcpy(buf, tmpbuf, tmpsize);
    return tmpsize;
}
#endif /*USE_MLANG_DLL*/

static int
utf16_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize)
{
    int codepage = cv->codepage;

    /* swap endian: 1200 <-> 1201 */
    if (cv->mode & UNICODE_MODE_SWAPPED)
        codepage ^= 1;

    if (bufsize < 2)
        return seterror(EINVAL);
    if (codepage == 1200) /* little endian */
        wbuf[0] = (buf[1] << 8) | buf[0];
    else if (codepage == 1201) /* big endian */
        wbuf[0] = (buf[0] << 8) | buf[1];

    if ((cv->flags & FLAG_USE_BOM) && !(cv->mode & UNICODE_MODE_BOM_DONE))
    {
        cv->mode |= UNICODE_MODE_BOM_DONE;
        if (wbuf[0] == 0xFFFE)
        {
            cv->mode |= UNICODE_MODE_SWAPPED;
            *wbufsize = 0;
            return 2;
        }
        else if (wbuf[0] == 0xFEFF)
        {
            *wbufsize = 0;
            return 2;
        }
    }

    if (0xDC00 <= wbuf[0] && wbuf[0] <= 0xDFFF)
        return seterror(EILSEQ);
    if (0xD800 <= wbuf[0] && wbuf[0] <= 0xDBFF)
    {
        if (bufsize < 4)
            return seterror(EINVAL);
        if (codepage == 1200) /* little endian */
            wbuf[1] = (buf[3] << 8) | buf[2];
        else if (codepage == 1201) /* big endian */
            wbuf[1] = (buf[2] << 8) | buf[3];
        if (!(0xDC00 <= wbuf[1] && wbuf[1] <= 0xDFFF))
            return seterror(EILSEQ);
        *wbufsize = 2;
        return 4;
    }
    *wbufsize = 1;
    return 2;
}

static int
utf16_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize)
{
    if ((cv->flags & FLAG_USE_BOM) && !(cv->mode & UNICODE_MODE_BOM_DONE))
    {
        int r;

        cv->mode |= UNICODE_MODE_BOM_DONE;
        if (bufsize < 2)
            return seterror(E2BIG);
        if (cv->codepage == 1200) /* little endian */
            memcpy(buf, "\xFF\xFE", 2);
        else if (cv->codepage == 1201) /* big endian */
            memcpy(buf, "\xFE\xFF", 2);

        r = utf16_wctomb(cv, wbuf, wbufsize, buf + 2, bufsize - 2);
        if (r == -1)
            return -1;
        return r + 2;
    }

    if (bufsize < 2)
        return seterror(E2BIG);
    if (cv->codepage == 1200) /* little endian */
    {
        buf[0] = (wbuf[0] & 0x00FF);
        buf[1] = (wbuf[0] & 0xFF00) >> 8;
    }
    else if (cv->codepage == 1201) /* big endian */
    {
        buf[0] = (wbuf[0] & 0xFF00) >> 8;
        buf[1] = (wbuf[0] & 0x00FF);
    }
    if (0xD800 <= wbuf[0] && wbuf[0] <= 0xDBFF)
    {
        if (bufsize < 4)
            return seterror(E2BIG);
        if (cv->codepage == 1200) /* little endian */
        {
            buf[2] = (wbuf[1] & 0x00FF);
            buf[3] = (wbuf[1] & 0xFF00) >> 8;
        }
        else if (cv->codepage == 1201) /* big endian */
        {
            buf[2] = (wbuf[1] & 0xFF00) >> 8;
            buf[3] = (wbuf[1] & 0x00FF);
        }
        return 4;
    }
    return 2;
}

static int
utf32_mbtowc(csconv_t *cv, const uchar *buf, int bufsize, ushort *wbuf, int *wbufsize)
{
    int codepage = cv->codepage;
    uint wc = 0xD800;

    /* swap endian: 12000 <-> 12001 */
    if (cv->mode & UNICODE_MODE_SWAPPED)
        codepage ^= 1;

    if (bufsize < 4)
        return seterror(EINVAL);
    if (codepage == 12000) /* little endian */
        wc = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
    else if (codepage == 12001) /* big endian */
        wc = (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];

    if ((cv->flags & FLAG_USE_BOM) && !(cv->mode & UNICODE_MODE_BOM_DONE))
    {
        cv->mode |= UNICODE_MODE_BOM_DONE;
        if (wc == 0xFFFE0000)
        {
            cv->mode |= UNICODE_MODE_SWAPPED;
            *wbufsize = 0;
            return 4;
        }
        else if (wc == 0x0000FEFF)
        {
            *wbufsize = 0;
            return 4;
        }
    }

    if ((0xD800 <= wc && wc <= 0xDFFF) || 0x10FFFF < wc)
        return seterror(EILSEQ);
    ucs4_to_utf16(wc, wbuf, wbufsize);
    return 4;
}

static int
utf32_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize)
{
    uint wc;

    if ((cv->flags & FLAG_USE_BOM) && !(cv->mode & UNICODE_MODE_BOM_DONE))
    {
        int r;

        cv->mode |= UNICODE_MODE_BOM_DONE;
        if (bufsize < 4)
            return seterror(E2BIG);
        if (cv->codepage == 12000) /* little endian */
            memcpy(buf, "\xFF\xFE\x00\x00", 4);
        else if (cv->codepage == 12001) /* big endian */
            memcpy(buf, "\x00\x00\xFE\xFF", 4);

        r = utf32_wctomb(cv, wbuf, wbufsize, buf + 4, bufsize - 4);
        if (r == -1)
            return -1;
        return r + 4;
    }

    if (bufsize < 4)
        return seterror(E2BIG);
    wc = utf16_to_ucs4(wbuf);
    if (cv->codepage == 12000) /* little endian */
    {
        buf[0] = wc & 0x000000FF;
        buf[1] = (wc & 0x0000FF00) >> 8;
        buf[2] = (wc & 0x00FF0000) >> 16;
        buf[3] = (wc & 0xFF000000) >> 24;
    }
    else if (cv->codepage == 12001) /* big endian */
    {
        buf[0] = (wc & 0xFF000000) >> 24;
        buf[1] = (wc & 0x00FF0000) >> 16;
        buf[2] = (wc & 0x0000FF00) >> 8;
        buf[3] = wc & 0x000000FF;
    }
    return 4;
}

/*
 * 50220: ISO 2022 Japanese with no halfwidth Katakana; Japanese (JIS)
 * 50221: ISO 2022 Japanese with halfwidth Katakana; Japanese (JIS-Allow
 *        1 byte Kana)
 * 50222: ISO 2022 Japanese JIS X 0201-1989; Japanese (JIS-Allow 1 byte
 *        Kana - SO/SI)
 *
 * MultiByteToWideChar() and WideCharToMultiByte() behave differently
 * depending on Windows version.  On XP, WideCharToMultiByte() doesn't
 * terminate result sequence with ascii escape.  But Vista does.
 * Use MLang instead.
 */

#define ISO2022_MODE(cs, shift) (((cs) << 8) | (shift))
#define ISO2022_MODE_CS(mode) (((mode) >> 8) & 0xFF)
#define ISO2022_MODE_SHIFT(mode) ((mode) & 0xFF)

#define ISO2022_SI  0
#define ISO2022_SO  1

/* shift in */
static const char iso2022_SI_seq[] = "\x0F";
/* shift out */
static const char iso2022_SO_seq[] = "\x0E";

typedef struct iso2022_esc_t iso2022_esc_t;
struct iso2022_esc_t {
    const char *esc;
    int esc_len;
    int len;
    int cs;
};

#define ISO2022JP_CS_ASCII            0
#define ISO2022JP_CS_JISX0201_ROMAN   1
#define ISO2022JP_CS_JISX0201_KANA    2
#define ISO2022JP_CS_JISX0208_1978    3
#define ISO2022JP_CS_JISX0208_1983    4
#define ISO2022JP_CS_JISX0212         5

#if USE_MLANG_DLL
static iso2022_esc_t iso2022jp_esc[] = {
    {"\x1B\x28\x42", 3, 1, ISO2022JP_CS_ASCII},
    {"\x1B\x28\x4A", 3, 1, ISO2022JP_CS_JISX0201_ROMAN},
    {"\x1B\x28\x49", 3, 1, ISO2022JP_CS_JISX0201_KANA},
    {"\x1B\x24\x40", 3, 2, ISO2022JP_CS_JISX0208_1983}, /* unify 1978 with 1983 */
    {"\x1B\x24\x42", 3, 2, ISO2022JP_CS_JISX0208_1983},
    {"\x1B\x24\x28\x44", 4, 2, ISO2022JP_CS_JISX0212},
    {NULL, 0, 0, 0}
};
#endif /*USE_MLANG_DLL*/

#if USE_MLANG_DLL
static int
iso2022jp_mbtowc(csconv_t *cv, const uchar *buf, int bufsize,
                 ushort *wbuf, int *wbufsize)
{
    iso2022_esc_t *iesc = iso2022jp_esc;
    char tmp[MB_CHAR_MAX];
    int insize;
    HRESULT hr;
    DWORD dummy = 0;
    int len;
    int esc_len;
    int cs;
    int shift;
    int i;

    if (buf[0] == 0x1B)
    {
        for (i = 0; iesc[i].esc != NULL; ++i)
        {
            esc_len = iesc[i].esc_len;
            if (bufsize < esc_len)
            {
                if (strncmp((char *)buf, iesc[i].esc, bufsize) == 0)
                    return seterror(EINVAL);
            }
            else
            {
                if (strncmp((char *)buf, iesc[i].esc, esc_len) == 0)
                {
                    cv->mode = ISO2022_MODE(iesc[i].cs, ISO2022_SI);
                    *wbufsize = 0;
                    return esc_len;
                }
            }
        }
        /* not supported escape sequence */
        return seterror(EILSEQ);
    }
    else if (buf[0] == iso2022_SO_seq[0])
    {
        cv->mode = ISO2022_MODE(ISO2022_MODE_CS(cv->mode), ISO2022_SO);
        *wbufsize = 0;
        return 1;
    }
    else if (buf[0] == iso2022_SI_seq[0])
    {
        cv->mode = ISO2022_MODE(ISO2022_MODE_CS(cv->mode), ISO2022_SI);
        *wbufsize = 0;
        return 1;
    }

    cs = ISO2022_MODE_CS(cv->mode);
    shift = ISO2022_MODE_SHIFT(cv->mode);

    /* reset the mode for informal sequence */
    if (buf[0] < 0x20)
    {
        cs = ISO2022JP_CS_ASCII;
        shift = ISO2022_SI;
    }

    len = iesc[cs].len;
    if (bufsize < len)
        return seterror(EINVAL);
    for (i = 0; i < len; ++i)
        if (!(buf[i] < 0x80))
            return seterror(EILSEQ);
    esc_len = iesc[cs].esc_len;
    memcpy(tmp, iesc[cs].esc, esc_len);
    if (shift == ISO2022_SO)
    {
        memcpy(tmp + esc_len, iso2022_SO_seq, 1);
        esc_len += 1;
    }
    memcpy(tmp + esc_len, buf, len);

    if ((cv->codepage == 50220 || cv->codepage == 50221
                || cv->codepage == 50222) && shift == ISO2022_SO)
    {
        /* XXX: shift-out cannot be used for mbtowc (both kernel and
         * mlang) */
        esc_len = iesc[ISO2022JP_CS_JISX0201_KANA].esc_len;
        memcpy(tmp, iesc[ISO2022JP_CS_JISX0201_KANA].esc, esc_len);
        memcpy(tmp + esc_len, buf, len);
    }

    insize = len + esc_len;
    hr = ConvertINetMultiByteToUnicode(&dummy, cv->codepage,
            (const char *)tmp, &insize, (wchar_t *)wbuf, wbufsize);
    if (hr != S_OK || insize != len + esc_len)
        return seterror(EILSEQ);

    /* Check for conversion error.  Assuming defaultChar is 0x3F. */
    /* ascii should be converted from ascii */
    if (wbuf[0] == buf[0]
            && cv->mode != ISO2022_MODE(ISO2022JP_CS_ASCII, ISO2022_SI))
        return seterror(EILSEQ);

    /* reset the mode for informal sequence */
    if (cv->mode != ISO2022_MODE(cs, shift))
        cv->mode = ISO2022_MODE(cs, shift);

    return len;
}
#endif /*USE_MLANG_DLL*/


#if USE_MLANG_DLL
static int
iso2022jp_wctomb(csconv_t *cv, ushort *wbuf, int wbufsize, uchar *buf, int bufsize)
{
    iso2022_esc_t *iesc = iso2022jp_esc;
    char tmp[MB_CHAR_MAX];
    int tmpsize = MB_CHAR_MAX;
    int insize = wbufsize;
    HRESULT hr;
    DWORD dummy = 0;
    int len;
    int esc_len;
    int cs;
    int shift;
    int i;

    /*
     * MultiByte = [escape sequence] + character + [escape sequence]
     *
     * Whether trailing escape sequence is added depends on which API is
     * used (kernel or MLang, and its version).
     */
    hr = ConvertINetUnicodeToMultiByte(&dummy, cv->codepage,
            (const wchar_t *)wbuf, &wbufsize, tmp, &tmpsize);
    if (hr != S_OK || insize != wbufsize)
        return seterror(EILSEQ);
    else if (bufsize < tmpsize)
        return seterror(E2BIG);

    if (tmpsize == 1)
    {
        cs = ISO2022JP_CS_ASCII;
        esc_len = 0;
    }
    else
    {
        for (i = 1; iesc[i].esc != NULL; ++i)
        {
            esc_len = iesc[i].esc_len;
            if (strncmp(tmp, iesc[i].esc, esc_len) == 0)
            {
                cs = iesc[i].cs;
                break;
            }
        }
        if (iesc[i].esc == NULL)
            /* not supported escape sequence */
            return seterror(EILSEQ);
    }

    shift = ISO2022_SI;
    if (tmp[esc_len] == iso2022_SO_seq[0])
    {
        shift = ISO2022_SO;
        esc_len += 1;
    }

    len = iesc[cs].len;

    /* Check for converting error.  Assuming defaultChar is 0x3F. */
    /* ascii should be converted from ascii */
    if (cs == ISO2022JP_CS_ASCII && !(wbuf[0] < 0x80))
        return seterror(EILSEQ);
    else if (tmpsize < esc_len + len)
        return seterror(EILSEQ);

    if (cv->mode == ISO2022_MODE(cs, shift))
    {
        /* remove escape sequence */
        if (esc_len != 0)
            memmove(tmp, tmp + esc_len, len);
        esc_len = 0;
    }
    else
    {
        if (cs == ISO2022JP_CS_ASCII)
        {
            esc_len = iesc[ISO2022JP_CS_ASCII].esc_len;
            memmove(tmp + esc_len, tmp, len);
            memcpy(tmp, iesc[ISO2022JP_CS_ASCII].esc, esc_len);
        }
        if (ISO2022_MODE_SHIFT(cv->mode) == ISO2022_SO)
        {
            /* shift-in before changing to other mode */
            memmove(tmp + 1, tmp, len + esc_len);
            memcpy(tmp, iso2022_SI_seq, 1);
            esc_len += 1;
        }
    }

    if (bufsize < len + esc_len)
        return seterror(E2BIG);
    memcpy(buf, tmp, len + esc_len);
    cv->mode = ISO2022_MODE(cs, shift);
    return len + esc_len;
}
#endif /*USE_MLANG_DLL*/

#if USE_MLANG_DLL
static int
iso2022jp_flush(csconv_t *cv, uchar *buf, int bufsize)
{
    iso2022_esc_t *iesc = iso2022jp_esc;
    int esc_len;

    if (cv->mode != ISO2022_MODE(ISO2022JP_CS_ASCII, ISO2022_SI))
    {
        esc_len = 0;
        if (ISO2022_MODE_SHIFT(cv->mode) != ISO2022_SI)
            esc_len += 1;
        if (ISO2022_MODE_CS(cv->mode) != ISO2022JP_CS_ASCII)
            esc_len += iesc[ISO2022JP_CS_ASCII].esc_len;
        if (bufsize < esc_len)
            return seterror(E2BIG);

        esc_len = 0;
        if (ISO2022_MODE_SHIFT(cv->mode) != ISO2022_SI)
        {
            memcpy(buf, iso2022_SI_seq, 1);
            esc_len += 1;
        }
        if (ISO2022_MODE_CS(cv->mode) != ISO2022JP_CS_ASCII)
        {
            memcpy(buf + esc_len, iesc[ISO2022JP_CS_ASCII].esc,
                    iesc[ISO2022JP_CS_ASCII].esc_len);
            esc_len += iesc[ISO2022JP_CS_ASCII].esc_len;
        }
        return esc_len;
    }
    return 0;
}
#endif /*USE_MLANG_DLL*/


gpgrt_w32_iconv_t
gpgrt_w32_iconv_open (const char *tocode, const char *fromcode)
{
    gpgrt_w32_iconv_t cd;

    cd = calloc(1, sizeof *cd);
    if (!cd)
         return (gpgrt_w32_iconv_t)(-1);

    /* reset the errno to prevent reporting wrong error code.
     * 0 for unsorted error. */
    _gpg_err_set_errno (0);
    if (win_iconv_open(cd, tocode, fromcode))
        return cd;

    free(cd);

    return (gpgrt_w32_iconv_t)(-1);
}

int
gpgrt_w32_iconv_close (gpgrt_w32_iconv_t cd)
{
    if (cd)
    {
         free (cd);
    }

    return 0;
}

size_t
gpgrt_w32_iconv (gpgrt_w32_iconv_t cd,
                  const char **inbuf, size_t *inbytesleft,
                  char **outbuf, size_t *outbytesleft)
{
     size_t r;

     r = win_iconv (cd, inbuf, inbytesleft, outbuf, outbytesleft);
     _gpg_err_set_errno (*(cd->_errno()));
     return r;
}
