// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
 **********************************************************************
 *   Copyright (C) 1996-2016, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 **********************************************************************
 *
 * Provides functionality for mapping between
 * LCID and Posix IDs or ICU locale to codepage
 *
 * Note: All classes and code in this file are
 *       intended for internal use only.
 *
 * Methods of interest:
 *   unsigned long convertToLCID(const char*);
 *   const char* convertToPosix(unsigned long);
 *
 * Kathleen Wilson, 4/30/96
 *
 *  Date        Name        Description
 *  3/11/97     aliu        Fixed off-by-one bug in assignment operator. Added
 *                          setId() method and safety check against 
 *                          MAX_ID_LENGTH.
 * 04/23/99     stephen     Added C wrapper for convertToPosix.
 * 09/18/00     george      Removed the memory leaks.
 * 08/23/01     george      Convert to C
 */

#include "locmap.h"
#include "charstr.h"
#include "cstring.h"
#include "cmemory.h"
#include "ulocimp.h"
#include "unicode/uloc.h"

#if U_PLATFORM_HAS_WIN32_API && UCONFIG_USE_WINDOWS_LCID_MAPPING_API
#include <windows.h>
#include <winnls.h> // LCIDToLocaleName and LocaleNameToLCID
#endif

/*
 * Note:
 * The mapping from Win32 locale ID numbers to POSIX locale strings should
 * be the faster one.
 *
 * Windows LCIDs are defined at https://msdn.microsoft.com/en-us/library/cc233965.aspx
 * [MS-LCID] Windows Language Code Identifier (LCID) Reference
 */

namespace {

/*
////////////////////////////////////////////////
//
// Internal Classes for LCID <--> POSIX Mapping
//
/////////////////////////////////////////////////
*/

typedef struct ILcidPosixElement
{
    const uint32_t hostID;
    const char * const posixID;
} ILcidPosixElement;

typedef struct ILcidPosixMap
{
    const uint32_t numRegions;
    const struct ILcidPosixElement* const regionMaps;
} ILcidPosixMap;


/*
/////////////////////////////////////////////////
//
// Easy macros to make the LCID <--> POSIX Mapping
//
/////////////////////////////////////////////////
*/

/**
 * The standard one language/one country mapping for LCID.
 * The first element must be the language, and the following
 * elements are the language with the country.
 * @param hostID LCID in host format such as 0x044d
 * @param languageID posix ID of just the language such as 'de'
 * @param posixID posix ID of the language_TERRITORY such as 'de_CH'
 */
#define ILCID_POSIX_ELEMENT_ARRAY(hostID, languageID, posixID) \
constexpr ILcidPosixElement locmap_ ## languageID [] = { \
    {LANGUAGE_LCID(hostID), #languageID},     /* parent locale */ \
    {hostID, #posixID}, \
};

/**
 * Define a subtable by ID
 * @param id the POSIX ID, either a language or language_TERRITORY
 */
#define ILCID_POSIX_SUBTABLE(id) \
constexpr ILcidPosixElement locmap_ ## id [] =


/**
 * Create the map for the posixID. This macro supposes that the language string
 * name is the same as the global variable name, and that the first element
 * in the ILcidPosixElement is just the language.
 * @param _posixID the full POSIX ID for this entry.
 */
#define ILCID_POSIX_MAP(_posixID) \
    {UPRV_LENGTHOF(locmap_ ## _posixID), locmap_ ## _posixID}

/*
////////////////////////////////////////////
//
// Create the table of LCID to POSIX Mapping
// None of it should be dynamically created.
//
// Keep static locale variables inside the function so that
// it can be created properly during static init.
//
// Note: This table should be updated periodically. Check the [MS-LCID] Windows Language Code Identifier 
//       (LCID) Reference defined at https://msdn.microsoft.com/en-us/library/cc233965.aspx
//
//       Microsoft is moving away from LCID in favor of locale name as of Vista.  This table needs to be
//       maintained for support of older Windows version.
//       Update: Windows 7 (091130)
//
// Note: Microsoft assign a different LCID if a locale has a sorting variant. POSIX IDs below may contain
//       @collation=XXX, but no other keywords are allowed (at least for now). When uprv_convertToLCID() is
//       called from uloc_getLCID(), keywords other than collation are already removed. If we really need
//       to support other keywords in this mapping data, we must update the implementation.
////////////////////////////////////////////
*/

// TODO: For Windows ideally this table would be a list of exceptions rather than a complete list as 
// LocaleNameToLCID and LCIDToLocaleName provide 90% of these.

ILCID_POSIX_ELEMENT_ARRAY(0x0436, af, af_ZA)

ILCID_POSIX_SUBTABLE(ar) {
    {0x01,   "ar"},
    {0x3801, "ar_AE"},
    {0x3c01, "ar_BH"},
    {0x1401, "ar_DZ"},
    {0x0c01, "ar_EG"},
    {0x0801, "ar_IQ"},
    {0x2c01, "ar_JO"},
    {0x3401, "ar_KW"},
    {0x3001, "ar_LB"},
    {0x1001, "ar_LY"},
    {0x1801, "ar_MA"},
    {0x1801, "ar_MO"},
    {0x2001, "ar_OM"},
    {0x4001, "ar_QA"},
    {0x0401, "ar_SA"},
    {0x2801, "ar_SY"},
    {0x1c01, "ar_TN"},
    {0x2401, "ar_YE"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x044d, as, as_IN)
ILCID_POSIX_ELEMENT_ARRAY(0x045e, am, am_ET)
ILCID_POSIX_ELEMENT_ARRAY(0x047a, arn,arn_CL)

ILCID_POSIX_SUBTABLE(az) {
    {0x2c,   "az"},
    {0x082c, "az_Cyrl_AZ"},  /* Cyrillic based */
    {0x742c, "az_Cyrl"},  /* Cyrillic based */
    {0x042c, "az_Latn_AZ"}, /* Latin based */
    {0x782c, "az_Latn"}, /* Latin based */
    {0x042c, "az_AZ"} /* Latin based */
};

ILCID_POSIX_ELEMENT_ARRAY(0x046d, ba, ba_RU)
ILCID_POSIX_ELEMENT_ARRAY(0x0423, be, be_BY)

/*ILCID_POSIX_SUBTABLE(ber) {
    {0x5f,   "ber"},
    {0x045f, "ber_Arab_DZ"},
    {0x045f, "ber_Arab"},
    {0x085f, "ber_Latn_DZ"},
    {0x085f, "ber_Latn"}
};*/

ILCID_POSIX_ELEMENT_ARRAY(0x0402, bg, bg_BG)

ILCID_POSIX_SUBTABLE(bin) {
    {0x66, "bin"},
    {0x0466, "bin_NG"}
};

ILCID_POSIX_SUBTABLE(bn) {
    {0x45,   "bn"},
    {0x0845, "bn_BD"},
    {0x0445, "bn_IN"}
};

ILCID_POSIX_SUBTABLE(bo) {
    {0x51,   "bo"},
    {0x0851, "bo_BT"},
    {0x0451, "bo_CN"},
    {0x0c51, "dz_BT"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x047e, br, br_FR)

ILCID_POSIX_SUBTABLE(ca) {
    {0x03,   "ca"},
    {0x0403, "ca_ES"},
    {0x0803, "ca_ES_VALENCIA"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0483, co, co_FR)

ILCID_POSIX_SUBTABLE(chr) {
    {0x05c,  "chr"},
    {0x7c5c, "chr_Cher"},
    {0x045c, "chr_Cher_US"},
    {0x045c, "chr_US"}
};

// ICU has chosen different names for these.
ILCID_POSIX_SUBTABLE(ckb) {
    {0x92,   "ckb"},
    {0x7c92, "ckb_Arab"},
    {0x0492, "ckb_Arab_IQ"}
};

/* Declared as cs_CZ to get around compiler errors on z/OS, which defines cs as a function */
ILCID_POSIX_ELEMENT_ARRAY(0x0405, cs, cs_CZ)

ILCID_POSIX_ELEMENT_ARRAY(0x0452, cy, cy_GB)
ILCID_POSIX_ELEMENT_ARRAY(0x0406, da, da_DK)

// Windows doesn't know POSIX or BCP47 Unicode phonebook sort names
ILCID_POSIX_SUBTABLE(de) {
    {0x07,   "de"},
    {0x0c07, "de_AT"},
    {0x0807, "de_CH"},
    {0x0407, "de_DE"},
    {0x1407, "de_LI"},
    {0x1007, "de_LU"},
    {0x10407,"de_DE@collation=phonebook"},  /*This is really de_DE_PHONEBOOK on Windows*/
    {0x10407,"de@collation=phonebook"}  /*This is really de_DE_PHONEBOOK on Windows*/
};

ILCID_POSIX_ELEMENT_ARRAY(0x0465, dv, dv_MV)
ILCID_POSIX_ELEMENT_ARRAY(0x0408, el, el_GR)

// Windows uses an empty string for 'invariant'
ILCID_POSIX_SUBTABLE(en) {
    {0x09,   "en"},
    {0x0c09, "en_AU"},
    {0x2809, "en_BZ"},
    {0x1009, "en_CA"},
    {0x0809, "en_GB"},
    {0x3c09, "en_HK"},
    {0x3809, "en_ID"},
    {0x1809, "en_IE"},
    {0x4009, "en_IN"},
    {0x2009, "en_JM"},
    {0x4409, "en_MY"},
    {0x1409, "en_NZ"},
    {0x3409, "en_PH"},
    {0x4809, "en_SG"},
    {0x2C09, "en_TT"},
    {0x0409, "en_US"},
    {0x007f, "en_US_POSIX"}, /* duplicate for round-tripping */
    {0x2409, "en_029"},
    {0x1c09, "en_ZA"},
    {0x3009, "en_ZW"},
    {0x2409, "en_VI"},  /* Virgin Islands AKA Caribbean Islands (en_CB). On Windows8+ This is 0x1000 or dynamically assigned */
    {0x0409, "en_AS"},  /* Alias for en_US. Leave last.  On Windows8+ This is 0x1000 or dynamically assigned */
    {0x0409, "en_GU"},  /* Alias for en_US. Leave last.  On Windows8+ This is 0x1000 or dynamically assigned */
    {0x0409, "en_MH"},  /* Alias for en_US. Leave last.  On Windows8+ This is 0x1000 or dynamically assigned */
    {0x0409, "en_MP"},  /* Alias for en_US. Leave last.  On Windows8+ This is 0x1000 or dynamically assigned */
    {0x0409, "en_UM"}   /* Alias for en_US. Leave last.  On Windows8+ This is 0x1000 or dynamically assigned */
};

ILCID_POSIX_SUBTABLE(en_US_POSIX) {
    {0x007f, "en_US_POSIX"} /* duplicate for roundtripping */
};

// Windows doesn't know POSIX or BCP47 Unicode traditional sort names
ILCID_POSIX_SUBTABLE(es) {
    {0x0a,   "es"},
    {0x2c0a, "es_AR"},
    {0x400a, "es_BO"},
    {0x340a, "es_CL"},
    {0x240a, "es_CO"},
    {0x140a, "es_CR"},
    {0x5c0a, "es_CU"},
    {0x1c0a, "es_DO"},
    {0x300a, "es_EC"},
    {0x0c0a, "es_ES"},      /*Modern sort.*/
    {0x100a, "es_GT"},
    {0x480a, "es_HN"},
    {0x080a, "es_MX"},
    {0x4c0a, "es_NI"},
    {0x180a, "es_PA"},
    {0x280a, "es_PE"},
    {0x500a, "es_PR"},
    {0x3c0a, "es_PY"},
    {0x440a, "es_SV"},
    {0x540a, "es_US"},
    {0x380a, "es_UY"},
    {0x200a, "es_VE"},
    {0x580a, "es_419"},
    {0x040a, "es_ES@collation=traditional"},
    {0x040a, "es@collation=traditional"}        // Windows will treat this as es-ES@collation=traditional
};

ILCID_POSIX_ELEMENT_ARRAY(0x0425, et, et_EE)
ILCID_POSIX_ELEMENT_ARRAY(0x042d, eu, eu_ES)

/* ISO-639 doesn't distinguish between Persian and Dari.*/
ILCID_POSIX_SUBTABLE(fa) {
    {0x29,   "fa"},
    {0x0429, "fa_IR"},  /* Persian/Farsi (Iran) */
    {0x048c, "fa_AF"}   /* Persian/Dari (Afghanistan) */
};


/* duplicate for roundtripping */
ILCID_POSIX_SUBTABLE(fa_AF) {
    {0x8c,   "fa_AF"},  /* Persian/Dari (Afghanistan) */
    {0x048c, "fa_AF"}   /* Persian/Dari (Afghanistan) */
};

ILCID_POSIX_SUBTABLE(ff) {
    {0x67,   "ff"},
    {0x7c67, "ff_Latn"},
    {0x0867, "ff_Latn_SN"},
    {0x0467, "ff_NG"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x040b, fi, fi_FI)
ILCID_POSIX_ELEMENT_ARRAY(0x0464, fil,fil_PH)
ILCID_POSIX_ELEMENT_ARRAY(0x0438, fo, fo_FO)

ILCID_POSIX_SUBTABLE(fr) {
    {0x0c,   "fr"},
    {0x080c, "fr_BE"},
    {0x0c0c, "fr_CA"},
    {0x240c, "fr_CD"},
    {0x240c, "fr_CG"},
    {0x100c, "fr_CH"},
    {0x300c, "fr_CI"},
    {0x2c0c, "fr_CM"},
    {0x040c, "fr_FR"},
    {0x3c0c, "fr_HT"},
    {0x140c, "fr_LU"},
    {0x380c, "fr_MA"},
    {0x180c, "fr_MC"},
    {0x340c, "fr_ML"},
    {0x200c, "fr_RE"},
    {0x280c, "fr_SN"},
    {0xe40c, "fr_015"},
    {0x1c0c, "fr_029"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0467, fuv, fuv_NG)

ILCID_POSIX_ELEMENT_ARRAY(0x0462, fy, fy_NL)

ILCID_POSIX_SUBTABLE(ga) { /* Gaelic (Ireland) */
    {0x3c,   "ga"},
    {0x083c, "ga_IE"},
    {0x043c, "gd_GB"}
};

ILCID_POSIX_SUBTABLE(gd) { /* Gaelic (Scotland) */
    {0x91,   "gd"},
    {0x0491, "gd_GB"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0456, gl, gl_ES)
ILCID_POSIX_ELEMENT_ARRAY(0x0447, gu, gu_IN)
ILCID_POSIX_ELEMENT_ARRAY(0x0474, gn, gn_PY)
ILCID_POSIX_ELEMENT_ARRAY(0x0484, gsw,gsw_FR)

ILCID_POSIX_SUBTABLE(ha) {
    {0x68,   "ha"},
    {0x7c68, "ha_Latn"},
    {0x0468, "ha_Latn_NG"},
};

ILCID_POSIX_ELEMENT_ARRAY(0x0475, haw,haw_US)
ILCID_POSIX_ELEMENT_ARRAY(0x040d, he, he_IL)
ILCID_POSIX_ELEMENT_ARRAY(0x0439, hi, hi_IN)

/* This LCID is really four different locales.*/
ILCID_POSIX_SUBTABLE(hr) {
    {0x1a,   "hr"},
    {0x141a, "bs_Latn_BA"},  /* Bosnian, Bosnia and Herzegovina */
    {0x681a, "bs_Latn"},  /* Bosnian, Bosnia and Herzegovina */
    {0x141a, "bs_BA"},  /* Bosnian, Bosnia and Herzegovina */
    {0x781a, "bs"},     /* Bosnian */
    {0x201a, "bs_Cyrl_BA"},  /* Bosnian, Bosnia and Herzegovina */
    {0x641a, "bs_Cyrl"},  /* Bosnian, Bosnia and Herzegovina */
    {0x101a, "hr_BA"},  /* Croatian in Bosnia */
    {0x041a, "hr_HR"},  /* Croatian*/
    {0x2c1a, "sr_Latn_ME"},
    {0x241a, "sr_Latn_RS"},
    {0x181a, "sr_Latn_BA"}, /* Serbo-Croatian in Bosnia */
    {0x081a, "sr_Latn_CS"}, /* Serbo-Croatian*/
    {0x701a, "sr_Latn"},    /* It's 0x1a or 0x081a, pick one to make the test program happy. */
    {0x1c1a, "sr_Cyrl_BA"}, /* Serbo-Croatian in Bosnia */
    {0x0c1a, "sr_Cyrl_CS"}, /* Serbian*/
    {0x301a, "sr_Cyrl_ME"},
    {0x281a, "sr_Cyrl_RS"},
    {0x6c1a, "sr_Cyrl"},    /* It's 0x1a or 0x0c1a, pick one to make the test program happy. */
    {0x7c1a, "sr"}          /* In CLDR sr is sr_Cyrl. */
};

ILCID_POSIX_SUBTABLE(hsb) {
    {0x2E,   "hsb"},
    {0x042E, "hsb_DE"},
    {0x082E, "dsb_DE"},
    {0x7C2E, "dsb"},
};

ILCID_POSIX_ELEMENT_ARRAY(0x040e, hu, hu_HU)
ILCID_POSIX_ELEMENT_ARRAY(0x042b, hy, hy_AM)

ILCID_POSIX_SUBTABLE(ibb) {
    {0x69, "ibb"},
    {0x0469, "ibb_NG"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0421, id, id_ID)
ILCID_POSIX_ELEMENT_ARRAY(0x0470, ig, ig_NG)
ILCID_POSIX_ELEMENT_ARRAY(0x0478, ii, ii_CN)
ILCID_POSIX_ELEMENT_ARRAY(0x040f, is, is_IS)

ILCID_POSIX_SUBTABLE(it) {
    {0x10,   "it"},
    {0x0810, "it_CH"},
    {0x0410, "it_IT"}
};

ILCID_POSIX_SUBTABLE(iu) {
    {0x5d,   "iu"},
    {0x045d, "iu_Cans_CA"},
    {0x785d, "iu_Cans"},
    {0x085d, "iu_Latn_CA"},
    {0x7c5d, "iu_Latn"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x040d, iw, iw_IL)    /*Left in for compatibility*/
ILCID_POSIX_ELEMENT_ARRAY(0x0411, ja, ja_JP)
ILCID_POSIX_ELEMENT_ARRAY(0x0437, ka, ka_GE)
ILCID_POSIX_ELEMENT_ARRAY(0x043f, kk, kk_KZ)
ILCID_POSIX_ELEMENT_ARRAY(0x046f, kl, kl_GL)
ILCID_POSIX_ELEMENT_ARRAY(0x0453, km, km_KH)
ILCID_POSIX_ELEMENT_ARRAY(0x044b, kn, kn_IN)

ILCID_POSIX_SUBTABLE(ko) {
    {0x12,   "ko"},
    {0x0812, "ko_KP"},
    {0x0412, "ko_KR"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0457, kok, kok_IN)
ILCID_POSIX_ELEMENT_ARRAY(0x0471, kr,  kr_NG)

ILCID_POSIX_SUBTABLE(ks) {         /* We could add PK and CN too */
    {0x60,   "ks"},
    {0x0460, "ks_Arab_IN"},
    {0x0860, "ks_Deva_IN"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0440, ky, ky_KG)   /* Kyrgyz is spoken in Kyrgyzstan */

ILCID_POSIX_SUBTABLE(la) {
    {0x76,   "la"},
    {0x0476, "la_001"},
    {0x0476, "la_IT"}       /*Left in for compatibility*/
};

ILCID_POSIX_ELEMENT_ARRAY(0x046e, lb, lb_LU)
ILCID_POSIX_ELEMENT_ARRAY(0x0454, lo, lo_LA)
ILCID_POSIX_ELEMENT_ARRAY(0x0427, lt, lt_LT)
ILCID_POSIX_ELEMENT_ARRAY(0x0426, lv, lv_LV)
ILCID_POSIX_ELEMENT_ARRAY(0x0481, mi, mi_NZ)
ILCID_POSIX_ELEMENT_ARRAY(0x042f, mk, mk_MK)
ILCID_POSIX_ELEMENT_ARRAY(0x044c, ml, ml_IN)

ILCID_POSIX_SUBTABLE(mn) {
    {0x50,   "mn"},
    {0x0450, "mn_MN"},
    {0x7c50, "mn_Mong"},
    {0x0850, "mn_Mong_CN"},
    {0x0850, "mn_CN"},
    {0x7850, "mn_Cyrl"},
    {0x0c50, "mn_Mong_MN"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0458, mni,mni_IN)
ILCID_POSIX_ELEMENT_ARRAY(0x047c, moh,moh_CA)
ILCID_POSIX_ELEMENT_ARRAY(0x044e, mr, mr_IN)

ILCID_POSIX_SUBTABLE(ms) {
    {0x3e,   "ms"},
    {0x083e, "ms_BN"},   /* Brunei Darussalam*/
    {0x043e, "ms_MY"}    /* Malaysia*/
};

ILCID_POSIX_ELEMENT_ARRAY(0x043a, mt, mt_MT)
ILCID_POSIX_ELEMENT_ARRAY(0x0455, my, my_MM)

ILCID_POSIX_SUBTABLE(ne) {
    {0x61,   "ne"},
    {0x0861, "ne_IN"},   /* India*/
    {0x0461, "ne_NP"}    /* Nepal*/
};

ILCID_POSIX_SUBTABLE(nl) {
    {0x13,   "nl"},
    {0x0813, "nl_BE"},
    {0x0413, "nl_NL"}
};

/* The "no" locale split into nb and nn.  By default in ICU, "no" is nb.*/
// TODO: Not all of these are needed on Windows, but I don't know how ICU treats preferred ones here.
ILCID_POSIX_SUBTABLE(no) {
    {0x14,   "no"},     /* really nb_NO - actually Windows differentiates between neutral (no region) and specific (with region) */ 
    {0x7c14, "nb"},     /* really nb */
    {0x0414, "nb_NO"},  /* really nb_NO. Keep first in the 414 list. */
    {0x0414, "no_NO"},  /* really nb_NO */
    {0x0814, "nn_NO"},  /* really nn_NO. Keep first in the 814 list.  */
    {0x7814, "nn"},     /* It's 0x14 or 0x814, pick one to make the test program happy. */
    {0x0814, "no_NO_NY"}/* really nn_NO */
};

ILCID_POSIX_ELEMENT_ARRAY(0x046c, nso,nso_ZA)   /* TODO: Verify the ISO-639 code */
ILCID_POSIX_ELEMENT_ARRAY(0x0482, oc, oc_FR)

ILCID_POSIX_SUBTABLE(om) { /* TODO: Verify the country */
    {0x72,   "om"},
    {0x0472, "om_ET"},
    {0x0472, "gaz_ET"}
};

/* Declared as or_IN to get around compiler errors*/
ILCID_POSIX_SUBTABLE(or_IN) {
    {0x48,   "or"},
    {0x0448, "or_IN"},
};

ILCID_POSIX_SUBTABLE(pa) {
    {0x46,   "pa"},
    {0x0446, "pa_IN"},
    {0x0846, "pa_Arab_PK"},
    {0x0846, "pa_PK"}
};

ILCID_POSIX_SUBTABLE(pap) {
    {0x79, "pap"},
    {0x0479, "pap_029"},
    {0x0479, "pap_AN"}     /*Left in for compatibility*/
};

ILCID_POSIX_ELEMENT_ARRAY(0x0415, pl, pl_PL)
ILCID_POSIX_ELEMENT_ARRAY(0x0463, ps, ps_AF)

ILCID_POSIX_SUBTABLE(pt) {
    {0x16,   "pt"},
    {0x0416, "pt_BR"},
    {0x0816, "pt_PT"}
};

ILCID_POSIX_SUBTABLE(qu) {
    {0x6b,   "qu"},
    {0x046b, "qu_BO"},
    {0x086b, "qu_EC"},
    {0x0C6b, "qu_PE"},
    {0x046b, "quz_BO"},
    {0x086b, "quz_EC"},
    {0x0C6b, "quz_PE"}
};

ILCID_POSIX_SUBTABLE(quc) {
    {0x93,   "quc"},
    {0x0493, "quc_CO"},
    /*
        "quc_Latn_GT" is an exceptional case. Language ID of "quc"
        is 0x93, but LCID of "quc_Latn_GT" is 0x486, which should be
        under the group of "qut". "qut" is a retired ISO 639-3 language
        code for West Central Quiche, and merged to "quc".
        It looks Windows previously reserved "qut" for K'iche', but,
        decided to use "quc" when adding a locale for K'iche' (Guatemala).

        This data structure used here assumes language ID bits in
        LCID is unique for alphabetic language code. But this is not true
        for "quc_Latn_GT". If we don't have the data below, LCID look up
        by alphabetic locale ID (POSIX) will fail. The same entry is found
        under "qut" below, which is required for reverse look up.
    */
    {0x0486, "quc_Latn_GT"}
};

ILCID_POSIX_SUBTABLE(qut) {
    {0x86,   "qut"},
    {0x0486, "qut_GT"},
    /*
        See the note in "quc" above.
    */
    {0x0486, "quc_Latn_GT"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0417, rm, rm_CH)

ILCID_POSIX_SUBTABLE(ro) {
    {0x18,   "ro"},
    {0x0418, "ro_RO"},
    {0x0818, "ro_MD"}
};

// TODO: This is almost certainly 'wrong'.  0 in Windows is a synonym for LOCALE_USER_DEFAULT.
// More likely this is a similar concept to the Windows 0x7f Invariant locale ""
// (Except that it's not invariant in ICU)
ILCID_POSIX_SUBTABLE(root) {
    {0x00,   "root"}
};

ILCID_POSIX_SUBTABLE(ru) {
    {0x19,   "ru"},
    {0x0419, "ru_RU"},
    {0x0819, "ru_MD"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0487, rw, rw_RW)
ILCID_POSIX_ELEMENT_ARRAY(0x044f, sa, sa_IN)
ILCID_POSIX_ELEMENT_ARRAY(0x0485, sah,sah_RU)

ILCID_POSIX_SUBTABLE(sd) {
    {0x59,   "sd"},
    {0x0459, "sd_Deva_IN"},
    {0x0459, "sd_IN"},
    {0x0859, "sd_Arab_PK"},
    {0x0859, "sd_PK"},
    {0x7c59, "sd_Arab"}
};

ILCID_POSIX_SUBTABLE(se) {
    {0x3b,   "se"},
    {0x0c3b, "se_FI"},
    {0x043b, "se_NO"},
    {0x083b, "se_SE"},
    {0x783b, "sma"},
    {0x183b, "sma_NO"},
    {0x1c3b, "sma_SE"},
    {0x7c3b, "smj"},
    {0x703b, "smn"},
    {0x743b, "sms"},
    {0x103b, "smj_NO"},
    {0x143b, "smj_SE"},
    {0x243b, "smn_FI"},
    {0x203b, "sms_FI"},
};

ILCID_POSIX_ELEMENT_ARRAY(0x045b, si, si_LK)
ILCID_POSIX_ELEMENT_ARRAY(0x041b, sk, sk_SK)
ILCID_POSIX_ELEMENT_ARRAY(0x0424, sl, sl_SI)

ILCID_POSIX_SUBTABLE(so) {
    {0x77,   "so"},
    {0x0477, "so_SO"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x041c, sq, sq_AL)
ILCID_POSIX_ELEMENT_ARRAY(0x0430, st, st_ZA)

ILCID_POSIX_SUBTABLE(sv) {
    {0x1d,   "sv"},
    {0x081d, "sv_FI"},
    {0x041d, "sv_SE"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0441, sw, sw_KE)
ILCID_POSIX_ELEMENT_ARRAY(0x045A, syr, syr_SY)

ILCID_POSIX_SUBTABLE(ta) {
    {0x49,   "ta"},
    {0x0449, "ta_IN"},
    {0x0849, "ta_LK"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x044a, te, te_IN)

/* Cyrillic based by default */
ILCID_POSIX_SUBTABLE(tg) {
    {0x28,   "tg"},
    {0x7c28, "tg_Cyrl"},
    {0x0428, "tg_Cyrl_TJ"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x041e, th, th_TH)

ILCID_POSIX_SUBTABLE(ti) {
    {0x73,   "ti"},
    {0x0873, "ti_ER"},
    {0x0473, "ti_ET"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0442, tk, tk_TM)

ILCID_POSIX_SUBTABLE(tn) {
    {0x32,   "tn"},
    {0x0832, "tn_BW"},
    {0x0432, "tn_ZA"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x041f, tr, tr_TR)
ILCID_POSIX_ELEMENT_ARRAY(0x0431, ts, ts_ZA)
ILCID_POSIX_ELEMENT_ARRAY(0x0444, tt, tt_RU)

ILCID_POSIX_SUBTABLE(tzm) {
    {0x5f,   "tzm"},
    {0x7c5f, "tzm_Latn"},
    {0x085f, "tzm_Latn_DZ"},
    {0x105f, "tzm_Tfng_MA"},
    {0x045f, "tzm_Arab_MA"},
    {0x045f, "tmz"}
};

ILCID_POSIX_SUBTABLE(ug) {
    {0x80,   "ug"},
    {0x0480, "ug_CN"},
    {0x0480, "ug_Arab_CN"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x0422, uk, uk_UA)

ILCID_POSIX_SUBTABLE(ur) {
    {0x20,   "ur"},
    {0x0820, "ur_IN"},
    {0x0420, "ur_PK"}
};

ILCID_POSIX_SUBTABLE(uz) {
    {0x43,   "uz"},
    {0x0843, "uz_Cyrl_UZ"},  /* Cyrillic based */
    {0x7843, "uz_Cyrl"},  /* Cyrillic based */
    {0x0843, "uz_UZ"},  /* Cyrillic based */
    {0x0443, "uz_Latn_UZ"}, /* Latin based */
    {0x7c43, "uz_Latn"} /* Latin based */
};

ILCID_POSIX_SUBTABLE(ve) { /* TODO: Verify the country */
    {0x33,   "ve"},
    {0x0433, "ve_ZA"},
    {0x0433, "ven_ZA"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x042a, vi, vi_VN)
ILCID_POSIX_ELEMENT_ARRAY(0x0488, wo, wo_SN)
ILCID_POSIX_ELEMENT_ARRAY(0x0434, xh, xh_ZA)

ILCID_POSIX_SUBTABLE(yi) {
    {0x003d, "yi"},
    {0x043d, "yi_001"}
};

ILCID_POSIX_ELEMENT_ARRAY(0x046a, yo, yo_NG)

// Windows & ICU tend to different names for some of these
// TODO: Windows probably does not need all of these entries, but I don't know how the precedence works.
ILCID_POSIX_SUBTABLE(zh) {
    {0x0004, "zh_Hans"},
    {0x7804, "zh"},
    {0x0804, "zh_CN"},
    {0x0804, "zh_Hans_CN"},
    {0x0c04, "zh_Hant_HK"},
    {0x0c04, "zh_HK"},
    {0x1404, "zh_Hant_MO"},
    {0x1404, "zh_MO"},
    {0x1004, "zh_Hans_SG"},
    {0x1004, "zh_SG"},
    {0x0404, "zh_Hant_TW"},
    {0x7c04, "zh_Hant"},
    {0x0404, "zh_TW"},
    {0x30404,"zh_Hant_TW"},     /* Bopomofo order */
    {0x30404,"zh_TW"},          /* Bopomofo order */
    {0x20004,"zh@collation=stroke"},
    {0x20404,"zh_Hant@collation=stroke"},
    {0x20404,"zh_Hant_TW@collation=stroke"},
    {0x20404,"zh_TW@collation=stroke"},
    {0x20804,"zh_Hans@collation=stroke"},
    {0x20804,"zh_Hans_CN@collation=stroke"},
    {0x20804,"zh_CN@collation=stroke"}
    // TODO: Alternate collations for other LCIDs are missing, eg: 0x50804
};

ILCID_POSIX_ELEMENT_ARRAY(0x0435, zu, zu_ZA)

/* This must be static and grouped by LCID. */
constexpr ILcidPosixMap gPosixIDmap[] = {
    ILCID_POSIX_MAP(af),    /*  af  Afrikaans                 0x36 */
    ILCID_POSIX_MAP(am),    /*  am  Amharic                   0x5e */
    ILCID_POSIX_MAP(ar),    /*  ar  Arabic                    0x01 */
    ILCID_POSIX_MAP(arn),   /*  arn Araucanian/Mapudungun     0x7a */
    ILCID_POSIX_MAP(as),    /*  as  Assamese                  0x4d */
    ILCID_POSIX_MAP(az),    /*  az  Azerbaijani               0x2c */
    ILCID_POSIX_MAP(ba),    /*  ba  Bashkir                   0x6d */
    ILCID_POSIX_MAP(be),    /*  be  Belarusian                0x23 */
/*    ILCID_POSIX_MAP(ber),     ber Berber/Tamazight          0x5f */
    ILCID_POSIX_MAP(bg),    /*  bg  Bulgarian                 0x02 */
    ILCID_POSIX_MAP(bin),   /*  bin Edo                       0x66 */
    ILCID_POSIX_MAP(bn),    /*  bn  Bengali; Bangla           0x45 */
    ILCID_POSIX_MAP(bo),    /*  bo  Tibetan                   0x51 */
    ILCID_POSIX_MAP(br),    /*  br  Breton                    0x7e */
    ILCID_POSIX_MAP(ca),    /*  ca  Catalan                   0x03 */
    ILCID_POSIX_MAP(chr),   /*  chr Cherokee                  0x5c */
    ILCID_POSIX_MAP(ckb),   /*  ckb Sorani (Central Kurdish)  0x92 */
    ILCID_POSIX_MAP(co),    /*  co  Corsican                  0x83 */
    ILCID_POSIX_MAP(cs),    /*  cs  Czech                     0x05 */
    ILCID_POSIX_MAP(cy),    /*  cy  Welsh                     0x52 */
    ILCID_POSIX_MAP(da),    /*  da  Danish                    0x06 */
    ILCID_POSIX_MAP(de),    /*  de  German                    0x07 */
    ILCID_POSIX_MAP(dv),    /*  dv  Divehi                    0x65 */
    ILCID_POSIX_MAP(el),    /*  el  Greek                     0x08 */
    ILCID_POSIX_MAP(en),    /*  en  English                   0x09 */
    ILCID_POSIX_MAP(en_US_POSIX), /*    invariant             0x7f */
    ILCID_POSIX_MAP(es),    /*  es  Spanish                   0x0a */
    ILCID_POSIX_MAP(et),    /*  et  Estonian                  0x25 */
    ILCID_POSIX_MAP(eu),    /*  eu  Basque                    0x2d */
    ILCID_POSIX_MAP(fa),    /*  fa  Persian/Farsi             0x29 */
    ILCID_POSIX_MAP(fa_AF), /*  fa  Persian/Dari              0x8c */
    ILCID_POSIX_MAP(ff),    /*  ff  Fula                      0x67 */
    ILCID_POSIX_MAP(fi),    /*  fi  Finnish                   0x0b */
    ILCID_POSIX_MAP(fil),   /*  fil Filipino                  0x64 */
    ILCID_POSIX_MAP(fo),    /*  fo  Faroese                   0x38 */
    ILCID_POSIX_MAP(fr),    /*  fr  French                    0x0c */
    ILCID_POSIX_MAP(fuv),   /*  fuv Fulfulde - Nigeria        0x67 */
    ILCID_POSIX_MAP(fy),    /*  fy  Frisian                   0x62 */
    ILCID_POSIX_MAP(ga),    /*  *   Gaelic (Ireland,Scotland) 0x3c */
    ILCID_POSIX_MAP(gd),    /*  gd  Gaelic (United Kingdom)   0x91 */
    ILCID_POSIX_MAP(gl),    /*  gl  Galician                  0x56 */
    ILCID_POSIX_MAP(gn),    /*  gn  Guarani                   0x74 */
    ILCID_POSIX_MAP(gsw),   /*  gsw Alemanic/Alsatian/Swiss German 0x84 */
    ILCID_POSIX_MAP(gu),    /*  gu  Gujarati                  0x47 */
    ILCID_POSIX_MAP(ha),    /*  ha  Hausa                     0x68 */
    ILCID_POSIX_MAP(haw),   /*  haw Hawaiian                  0x75 */
    ILCID_POSIX_MAP(he),    /*  he  Hebrew (formerly iw)      0x0d */
    ILCID_POSIX_MAP(hi),    /*  hi  Hindi                     0x39 */
    ILCID_POSIX_MAP(hr),    /*  *   Croatian and others       0x1a */
    ILCID_POSIX_MAP(hsb),   /*  hsb Upper Sorbian             0x2e */
    ILCID_POSIX_MAP(hu),    /*  hu  Hungarian                 0x0e */
    ILCID_POSIX_MAP(hy),    /*  hy  Armenian                  0x2b */
    ILCID_POSIX_MAP(ibb),   /*  ibb Ibibio - Nigeria          0x69 */
    ILCID_POSIX_MAP(id),    /*  id  Indonesian (formerly in)  0x21 */
    ILCID_POSIX_MAP(ig),    /*  ig  Igbo                      0x70 */
    ILCID_POSIX_MAP(ii),    /*  ii  Sichuan Yi                0x78 */
    ILCID_POSIX_MAP(is),    /*  is  Icelandic                 0x0f */
    ILCID_POSIX_MAP(it),    /*  it  Italian                   0x10 */
    ILCID_POSIX_MAP(iu),    /*  iu  Inuktitut                 0x5d */
    ILCID_POSIX_MAP(iw),    /*  iw  Hebrew                    0x0d */
    ILCID_POSIX_MAP(ja),    /*  ja  Japanese                  0x11 */
    ILCID_POSIX_MAP(ka),    /*  ka  Georgian                  0x37 */
    ILCID_POSIX_MAP(kk),    /*  kk  Kazakh                    0x3f */
    ILCID_POSIX_MAP(kl),    /*  kl  Kalaallisut               0x6f */
    ILCID_POSIX_MAP(km),    /*  km  Khmer                     0x53 */
    ILCID_POSIX_MAP(kn),    /*  kn  Kannada                   0x4b */
    ILCID_POSIX_MAP(ko),    /*  ko  Korean                    0x12 */
    ILCID_POSIX_MAP(kok),   /*  kok Konkani                   0x57 */
    ILCID_POSIX_MAP(kr),    /*  kr  Kanuri                    0x71 */
    ILCID_POSIX_MAP(ks),    /*  ks  Kashmiri                  0x60 */
    ILCID_POSIX_MAP(ky),    /*  ky  Kyrgyz                    0x40 */
    ILCID_POSIX_MAP(lb),    /*  lb  Luxembourgish             0x6e */
    ILCID_POSIX_MAP(la),    /*  la  Latin                     0x76 */
    ILCID_POSIX_MAP(lo),    /*  lo  Lao                       0x54 */
    ILCID_POSIX_MAP(lt),    /*  lt  Lithuanian                0x27 */
    ILCID_POSIX_MAP(lv),    /*  lv  Latvian, Lettish          0x26 */
    ILCID_POSIX_MAP(mi),    /*  mi  Maori                     0x81 */
    ILCID_POSIX_MAP(mk),    /*  mk  Macedonian                0x2f */
    ILCID_POSIX_MAP(ml),    /*  ml  Malayalam                 0x4c */
    ILCID_POSIX_MAP(mn),    /*  mn  Mongolian                 0x50 */
    ILCID_POSIX_MAP(mni),   /*  mni Manipuri                  0x58 */
    ILCID_POSIX_MAP(moh),   /*  moh Mohawk                    0x7c */
    ILCID_POSIX_MAP(mr),    /*  mr  Marathi                   0x4e */
    ILCID_POSIX_MAP(ms),    /*  ms  Malay                     0x3e */
    ILCID_POSIX_MAP(mt),    /*  mt  Maltese                   0x3a */
    ILCID_POSIX_MAP(my),    /*  my  Burmese                   0x55 */
/*    ILCID_POSIX_MAP(nb),    //  no  Norwegian                 0x14 */
    ILCID_POSIX_MAP(ne),    /*  ne  Nepali                    0x61 */
    ILCID_POSIX_MAP(nl),    /*  nl  Dutch                     0x13 */
/*    ILCID_POSIX_MAP(nn),    //  no  Norwegian                 0x14 */
    ILCID_POSIX_MAP(no),    /*  *   Norwegian                 0x14 */
    ILCID_POSIX_MAP(nso),   /*  nso Sotho, Northern (Sepedi dialect) 0x6c */
    ILCID_POSIX_MAP(oc),    /*  oc  Occitan                   0x82 */
    ILCID_POSIX_MAP(om),    /*  om  Oromo                     0x72 */
    ILCID_POSIX_MAP(or_IN), /*  or  Oriya                     0x48 */
    ILCID_POSIX_MAP(pa),    /*  pa  Punjabi                   0x46 */
    ILCID_POSIX_MAP(pap),   /*  pap Papiamentu                0x79 */
    ILCID_POSIX_MAP(pl),    /*  pl  Polish                    0x15 */
    ILCID_POSIX_MAP(ps),    /*  ps  Pashto                    0x63 */
    ILCID_POSIX_MAP(pt),    /*  pt  Portuguese                0x16 */
    ILCID_POSIX_MAP(qu),    /*  qu  Quechua                   0x6B */
    ILCID_POSIX_MAP(quc),   /*  quc K'iche                    0x93 */
    ILCID_POSIX_MAP(qut),   /*  qut K'iche                    0x86 */
    ILCID_POSIX_MAP(rm),    /*  rm  Raeto-Romance/Romansh     0x17 */
    ILCID_POSIX_MAP(ro),    /*  ro  Romanian                  0x18 */
    ILCID_POSIX_MAP(root),  /*  root                          0x00 */
    ILCID_POSIX_MAP(ru),    /*  ru  Russian                   0x19 */
    ILCID_POSIX_MAP(rw),    /*  rw  Kinyarwanda               0x87 */
    ILCID_POSIX_MAP(sa),    /*  sa  Sanskrit                  0x4f */
    ILCID_POSIX_MAP(sah),   /*  sah Yakut                     0x85 */
    ILCID_POSIX_MAP(sd),    /*  sd  Sindhi                    0x59 */
    ILCID_POSIX_MAP(se),    /*  se  Sami                      0x3b */
/*    ILCID_POSIX_MAP(sh),    //  sh  Serbo-Croatian            0x1a */
    ILCID_POSIX_MAP(si),    /*  si  Sinhalese                 0x5b */
    ILCID_POSIX_MAP(sk),    /*  sk  Slovak                    0x1b */
    ILCID_POSIX_MAP(sl),    /*  sl  Slovenian                 0x24 */
    ILCID_POSIX_MAP(so),    /*  so  Somali                    0x77 */
    ILCID_POSIX_MAP(sq),    /*  sq  Albanian                  0x1c */
/*    ILCID_POSIX_MAP(sr),    //  sr  Serbian                   0x1a */
    ILCID_POSIX_MAP(st),    /*  st  Sutu                      0x30 */
    ILCID_POSIX_MAP(sv),    /*  sv  Swedish                   0x1d */
    ILCID_POSIX_MAP(sw),    /*  sw  Swahili                   0x41 */
    ILCID_POSIX_MAP(syr),   /*  syr Syriac                    0x5A */
    ILCID_POSIX_MAP(ta),    /*  ta  Tamil                     0x49 */
    ILCID_POSIX_MAP(te),    /*  te  Telugu                    0x4a */
    ILCID_POSIX_MAP(tg),    /*  tg  Tajik                     0x28 */
    ILCID_POSIX_MAP(th),    /*  th  Thai                      0x1e */
    ILCID_POSIX_MAP(ti),    /*  ti  Tigrigna                  0x73 */
    ILCID_POSIX_MAP(tk),    /*  tk  Turkmen                   0x42 */
    ILCID_POSIX_MAP(tn),    /*  tn  Tswana                    0x32 */
    ILCID_POSIX_MAP(tr),    /*  tr  Turkish                   0x1f */
    ILCID_POSIX_MAP(ts),    /*  ts  Tsonga                    0x31 */
    ILCID_POSIX_MAP(tt),    /*  tt  Tatar                     0x44 */
    ILCID_POSIX_MAP(tzm),   /*  tzm Tamazight                 0x5f */
    ILCID_POSIX_MAP(ug),    /*  ug  Uighur                    0x80 */
    ILCID_POSIX_MAP(uk),    /*  uk  Ukrainian                 0x22 */
    ILCID_POSIX_MAP(ur),    /*  ur  Urdu                      0x20 */
    ILCID_POSIX_MAP(uz),    /*  uz  Uzbek                     0x43 */
    ILCID_POSIX_MAP(ve),    /*  ve  Venda                     0x33 */
    ILCID_POSIX_MAP(vi),    /*  vi  Vietnamese                0x2a */
    ILCID_POSIX_MAP(wo),    /*  wo  Wolof                     0x88 */
    ILCID_POSIX_MAP(xh),    /*  xh  Xhosa                     0x34 */
    ILCID_POSIX_MAP(yi),    /*  yi  Yiddish                   0x3d */
    ILCID_POSIX_MAP(yo),    /*  yo  Yoruba                    0x6a */
    ILCID_POSIX_MAP(zh),    /*  zh  Chinese                   0x04 */
    ILCID_POSIX_MAP(zu),    /*  zu  Zulu                      0x35 */
};

constexpr uint32_t gLocaleCount = UPRV_LENGTHOF(gPosixIDmap);

/**
 * Do not call this function. It is called by hostID.
 * The function is not private because this struct must stay as a C struct,
 * and this is an internal class.
 */
int32_t
idCmp(const char* id1, const char* id2)
{
    int32_t diffIdx = 0;
    while (*id1 == *id2 && *id1 != 0) {
        diffIdx++;
        id1++;
        id2++;
    }
    return diffIdx;
}

/**
 * Searches for a Windows LCID
 *
 * @param posixID the Posix style locale id.
 * @param status gets set to U_ILLEGAL_ARGUMENT_ERROR when the Posix ID has
 *               no equivalent Windows LCID.
 * @return the LCID
 */
uint32_t
getHostID(const ILcidPosixMap *this_0, const char* posixID, UErrorCode& status)
{
    if (U_FAILURE(status)) { return locmap_root->hostID; }
    int32_t bestIdx = 0;
    int32_t bestIdxDiff = 0;
    int32_t posixIDlen = (int32_t)uprv_strlen(posixID);
    uint32_t idx;

    for (idx = 0; idx < this_0->numRegions; idx++ ) {
        int32_t sameChars = idCmp(posixID, this_0->regionMaps[idx].posixID);
        if (sameChars > bestIdxDiff && this_0->regionMaps[idx].posixID[sameChars] == 0) {
            if (posixIDlen == sameChars) {
                /* Exact match */
                return this_0->regionMaps[idx].hostID;
            }
            bestIdxDiff = sameChars;
            bestIdx = idx;
        }
    }
    /* We asked for something unusual, like en_ZZ, and we try to return the number for the same language. */
    /* We also have to make sure that sid and si and similar string subsets don't match. */
    if ((posixID[bestIdxDiff] == '_' || posixID[bestIdxDiff] == '@')
        && this_0->regionMaps[bestIdx].posixID[bestIdxDiff] == 0)
    {
        status = U_USING_FALLBACK_WARNING;
        return this_0->regionMaps[bestIdx].hostID;
    }

    /*no match found */
    status = U_ILLEGAL_ARGUMENT_ERROR;
    return locmap_root->hostID;
}

const char*
getPosixID(const ILcidPosixMap *this_0, uint32_t hostID)
{
    uint32_t i;
    for (i = 0; i < this_0->numRegions; i++)
    {
        if (this_0->regionMaps[i].hostID == hostID)
        {
            return this_0->regionMaps[i].posixID;
        }
    }

    /* If you get here, then no matching region was found,
       so return the language id with the wild card region. */
    return this_0->regionMaps[0].posixID;
}

/*
//////////////////////////////////////
//
// LCID --> POSIX
//
/////////////////////////////////////
*/
#if U_PLATFORM_HAS_WIN32_API && UCONFIG_USE_WINDOWS_LCID_MAPPING_API
/*
 * Various language tags needs to be changed:
 * quz -> qu
 * prs -> fa
 */
void FIX_LANGUAGE_ID_TAG(char* buffer, int32_t len) {
    if (len >= 3) {
        if (buffer[0] == 'q' && buffer[1] == 'u' && buffer[2] == 'z') {
            buffer[2] = 0;
            uprv_strcat(buffer, buffer+3);
        } else if (buffer[0] == 'p' && buffer[1] == 'r' && buffer[2] == 's') {
            buffer[0] = 'f'; buffer[1] = 'a'; buffer[2] = 0;
            uprv_strcat(buffer, buffer+3);
        }
    }
}
#endif

}  // namespace

U_CAPI int32_t
uprv_convertToPosix(uint32_t hostid, char *posixID, int32_t posixIDCapacity, UErrorCode* status)
{
    uint16_t langID;
    uint32_t localeIndex;
    UBool bLookup = true;
    const char *pPosixID = nullptr;

#if U_PLATFORM_HAS_WIN32_API && UCONFIG_USE_WINDOWS_LCID_MAPPING_API
    static_assert(ULOC_FULLNAME_CAPACITY > LOCALE_NAME_MAX_LENGTH, "Windows locale names have smaller length than ICU locale names.");

    char locName[LOCALE_NAME_MAX_LENGTH] = {};

    // Note: Windows primary lang ID 0x92 in LCID is used for Central Kurdish and
    // GetLocaleInfo() maps such LCID to "ku". However, CLDR uses "ku" for
    // Northern Kurdish and "ckb" for Central Kurdish. For this reason, we cannot
    // use the Windows API to resolve locale ID for this specific case.
    if ((hostid & 0x3FF) != 0x92) {
        int32_t tmpLen = 0;
        char16_t windowsLocaleName[LOCALE_NAME_MAX_LENGTH] = {};

        // Note: LOCALE_ALLOW_NEUTRAL_NAMES was enabled in Windows7+, prior versions did not handle neutral (no-region) locale names.
        tmpLen = LCIDToLocaleName(hostid, (PWSTR)windowsLocaleName, UPRV_LENGTHOF(windowsLocaleName), LOCALE_ALLOW_NEUTRAL_NAMES);
        if (tmpLen > 1) {
            int32_t i = 0;
            // Only need to look up in table if have _, eg for de-de_phoneb type alternate sort.
            bLookup = false;
            for (i = 0; i < UPRV_LENGTHOF(locName); i++)
            {
                locName[i] = (char)(windowsLocaleName[i]);

                // Windows locale name may contain sorting variant, such as "es-ES_tradnl".
                // In such cases, we need special mapping data found in the hardcoded table
                // in this source file.
                if (windowsLocaleName[i] == L'_')
                {
                    // Keep the base locale, without variant
                    // TODO: Should these be mapped from _phoneb to @collation=phonebook, etc.?
                    locName[i] = '\0';
                    tmpLen = i;
                    bLookup = true;
                    break;
                }
                else if (windowsLocaleName[i] == L'-')
                {
                    // Windows names use -, ICU uses _
                    locName[i] = '_';
                }
                else if (windowsLocaleName[i] == L'\0')
                {
                    // No point in doing more work than necessary
                    break;
                }
            }
            // TODO: Need to understand this better, why isn't it an alias?
            FIX_LANGUAGE_ID_TAG(locName, tmpLen);
            pPosixID = locName;
        }
    }
#endif

    if (bLookup) {
        const char *pCandidate = nullptr;
        langID = LANGUAGE_LCID(hostid);

        for (localeIndex = 0; localeIndex < gLocaleCount; localeIndex++) {
            if (langID == gPosixIDmap[localeIndex].regionMaps->hostID) {
                pCandidate = getPosixID(&gPosixIDmap[localeIndex], hostid);
                break;
            }
        }

        /* On Windows, when locale name has a variant, we still look up the hardcoded table.
           If a match in the hardcoded table is longer than the Windows locale name without
           variant, we use the one as the result */
        if (pCandidate && (pPosixID == nullptr || uprv_strlen(pCandidate) > uprv_strlen(pPosixID))) {
            pPosixID = pCandidate;
        }
    }

    if (pPosixID) {
        int32_t resLen = static_cast<int32_t>(uprv_strlen(pPosixID));
        int32_t copyLen = resLen <= posixIDCapacity ? resLen : posixIDCapacity;
        uprv_memcpy(posixID, pPosixID, copyLen);
        if (resLen < posixIDCapacity) {
            posixID[resLen] = 0;
            if (*status == U_STRING_NOT_TERMINATED_WARNING) {
                *status = U_ZERO_ERROR;
            }
        } else if (resLen == posixIDCapacity) {
            *status = U_STRING_NOT_TERMINATED_WARNING;
        } else {
            *status = U_BUFFER_OVERFLOW_ERROR;
        }
        return resLen;
    }

    /* no match found */
    *status = U_ILLEGAL_ARGUMENT_ERROR;
    return 0;
}

/*
//////////////////////////////////////
//
// POSIX --> LCID
// This should only be called from uloc_getLCID.
// The locale ID must be in canonical form.
//
/////////////////////////////////////
*/
U_CAPI uint32_t
uprv_convertToLCIDPlatform(const char* localeID, UErrorCode* status)
{
    if (U_FAILURE(*status)) {
        return 0;
    }

    // The purpose of this function is to leverage the Windows platform name->lcid
    // conversion functionality when available.
#if U_PLATFORM_HAS_WIN32_API && UCONFIG_USE_WINDOWS_LCID_MAPPING_API
    int32_t len;
    icu::CharString baseName;
    const char * mylocaleID = localeID;

    // Check any for keywords.
    if (uprv_strchr(localeID, '@'))
    {
        icu::CharString collVal = ulocimp_getKeywordValue(localeID, "collation", *status);
        if (U_SUCCESS(*status) && !collVal.isEmpty())
        {
            // If it contains the keyword collation, return 0 so that the LCID lookup table will be used.
            return 0;
        }
        else
        {
            // If the locale ID contains keywords other than collation, just use the base name.
            baseName = ulocimp_getBaseName(localeID, *status);
            if (U_SUCCESS(*status) && !baseName.isEmpty())
            {
                mylocaleID = baseName.data();
            }
        }
    }

    // this will change it from de_DE@collation=phonebook to de-DE-u-co-phonebk form
    icu::CharString asciiBCP47Tag = ulocimp_toLanguageTag(mylocaleID, false, *status);

    if (U_SUCCESS(*status))
    {
        // Need it to be UTF-16, not 8-bit
        wchar_t bcp47Tag[LOCALE_NAME_MAX_LENGTH] = {};
        int32_t i;
        for (i = 0; i < UPRV_LENGTHOF(bcp47Tag); i++)
        {
            if (asciiBCP47Tag[i] == '\0')
            {
                break;
            }
            else
            {
                // Copy the character
                bcp47Tag[i] = static_cast<wchar_t>(asciiBCP47Tag[i]);
            }
        }

        if (i < (UPRV_LENGTHOF(bcp47Tag) - 1))
        {
            // Ensure it's null terminated
            bcp47Tag[i] = L'\0';
            LCID lcid = LocaleNameToLCID(bcp47Tag, LOCALE_ALLOW_NEUTRAL_NAMES);
            if (lcid > 0)
            {
                // Found LCID from windows, return that one, unless its completely ambiguous
                // LOCALE_USER_DEFAULT and transients are OK because they will round trip
                // for this process.
                if (lcid != LOCALE_CUSTOM_UNSPECIFIED)
                {
                    return lcid;
                }
            }
        }
    }
#else
    (void) localeID; // Suppress unused variable warning.
#endif

    // Nothing found, or not implemented.
    return 0;
}

U_CAPI uint32_t
uprv_convertToLCID(const char *langID, const char* posixID, UErrorCode* status)
{
    if (U_FAILURE(*status) ||
            langID == nullptr ||
            posixID == nullptr ||
            uprv_strlen(langID) < 2 ||
            uprv_strlen(posixID) < 2) {
        return locmap_root->hostID;
    }

    // This function does the table lookup when native platform name->lcid conversion isn't available,
    // or for locales that don't follow patterns the platform expects.
    uint32_t   low    = 0;
    uint32_t   high   = gLocaleCount;
    uint32_t   mid;
    uint32_t   oldmid = 0;
    int32_t    compVal;

    uint32_t   value         = 0;
    uint32_t   fallbackValue = (uint32_t)-1;
    UErrorCode myStatus;
    uint32_t   idx;

    /*Binary search for the map entry for normal cases */

    while (high > low)  /*binary search*/{

        mid = (high+low) >> 1; /*Finds median*/

        if (mid == oldmid) 
            break;

        compVal = uprv_strcmp(langID, gPosixIDmap[mid].regionMaps->posixID);
        if (compVal < 0){
            high = mid;
        }
        else if (compVal > 0){
            low = mid;
        }
        else /*we found it*/{
            return getHostID(&gPosixIDmap[mid], posixID, *status);
        }
        oldmid = mid;
    }

    /*
     * Sometimes we can't do a binary search on posixID because some LCIDs
     * go to different locales.  We hit one of those special cases.
     */
    for (idx = 0; idx < gLocaleCount; idx++ ) {
        myStatus = U_ZERO_ERROR;
        value = getHostID(&gPosixIDmap[idx], posixID, myStatus);
        if (myStatus == U_ZERO_ERROR) {
            return value;
        }
        else if (myStatus == U_USING_FALLBACK_WARNING) {
            fallbackValue = value;
        }
    }

    if (fallbackValue != (uint32_t)-1) {
        *status = U_USING_FALLBACK_WARNING;
        return fallbackValue;
    }

    /* no match found */
    *status = U_ILLEGAL_ARGUMENT_ERROR;
    return locmap_root->hostID;   /* return international (root) */
}
