/***
* winapinls.cpp - helper functions for Win32 NLS Apis
*
*       Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
*       Contains functions to work with Win32 NLS-specific APIs
*
*******************************************************************************/

#include <awint.h>

#if _STL_WIN32_WINNT < _WIN32_WINNT_VISTA

#include <nlsdownlevel.h>
#include <ctype.h>
#include <stdlib.h>

/*
 * __wcsnicmp_ascii
 * Implements wcsncpmp for ASCII chars only.
 * We can't use wcsncmp in this context because we may end up trying to modify
 * locale data structs or even calling the same function in NLS code.
 */
extern "C" int __wcsnicmp_ascii(__in const wchar_t* string1, __in const wchar_t* string2, __in size_t count)
{
    wchar_t f,l;
    int result = 0;

    if(count)
    {
        /* validation section */
        do {
            f = __ascii_towlower(*string1);
            l = __ascii_towlower(*string2);
            string1++;
            string2++;
        } while ( (--count) && f && (f == l) );

        result = (int)(f-l);
    }

    return result;
}

/*
 *  Maps input locale name to the index on LcidToLocaleNameTable
 */
extern "C" int GetTableIndexFromLocaleName(__in const wchar_t* localeName)
{
    const LOCALENAMEINDEX *localeNamesIndex = LocaleNameToIndexTable;
    int bottom = 0;
    int top = _countof(LocaleNameToIndexTable) - 1;

    while (bottom <= top)
    {
        int middle = (bottom + top) / 2;
        int testIndex = __wcsnicmp_ascii(localeName, localeNamesIndex[middle].name, LOCALE_NAME_MAX_LENGTH);

        if (testIndex == 0)
            return localeNamesIndex[middle].index;

        if (testIndex < 0)
            top = middle - 1;
        else
            bottom = middle + 1;
    }

    return -1;
}


/*
* Maps input LCID to an index in LcidToLocaleNameTable
*/
extern "C" int GetTableIndexFromLcid(__in LCID lcid)
{

    int bottom = 0;
    int top = _countof(LcidToLocaleNameTable) - 1;

    while (bottom <= top)
    {
        int middle = (bottom + top) / 2;
        int testIndex = lcid - LcidToLocaleNameTable[middle].lcid;

        if (testIndex == 0)
            return middle;

        if (testIndex < 0)
            top = middle - 1;
        else
            bottom = middle + 1;
    }

    return -1;
}

/*******************************************************************************
*__crtDownlevelLocaleNameToLCID() - Maps the locale name to Lcid on Windows XP.
*
*******************************************************************************/
extern "C" LCID __cdecl __crtDownlevelLocaleNameToLCID(
    LPCWSTR localeName)
{
    int index;

    if (localeName == NULL)
        return 0;

    index = GetTableIndexFromLocaleName(localeName);

    if (index < 0 || (index >= _countof(LcidToLocaleNameTable)))
        return 0;

    return LcidToLocaleNameTable[index].lcid;
}

/*******************************************************************************
*__crtDownlevelLCIDToLocaleName() - Maps the Lcid to locale name on Windows XP.
*
*******************************************************************************/
extern "C" int __cdecl __crtDownlevelLCIDToLocaleName(
    LCID lcid,
    LPWSTR outLocaleName,
    int cchLocaleName)
{
    size_t           count;
    const wchar_t*   buffer;
    int              index;

    if (lcid == 0                           ||
        lcid == LOCALE_USER_DEFAULT         ||
        lcid == LOCALE_SYSTEM_DEFAULT)
    {
        return 0;
    }

    if ((outLocaleName == NULL && cchLocaleName>0) || cchLocaleName < 0)
    {
        return 0;
    }

    index = GetTableIndexFromLcid(lcid);
    if (index < 0)
        return 0;

    buffer = LcidToLocaleNameTable[index].localeName;
    count = wcsnlen(buffer, LOCALE_NAME_MAX_LENGTH);

    if (cchLocaleName > 0)
    {
        if ((int)count >= cchLocaleName)
            return 0;

        wcscpy_s(outLocaleName, cchLocaleName, buffer);
    }

    return (int) count + 1;
}

/*******************************************************************************
*__crtCompareStringEx() - Wrapper for CompareStringEx().
*
*******************************************************************************/
extern "C" int __cdecl __crtCompareStringEx(
    LPCWSTR lpLocaleName,
    DWORD dwCmpFlags,
    LPCWSTR lpString1,
    int cchCount1,
    LPCWSTR lpString2,
    int cchCount2)
{
    // use CompareStringEx if it is available (only on Vista+)...
    IFDYNAMICGETCACHEDFUNCTION(KERNEL32, PFNCOMPARESTRINGEX, CompareStringEx, pfCompareStringEx)
    {
        return (*pfCompareStringEx)(lpLocaleName, dwCmpFlags, lpString1, cchCount1, lpString2, cchCount2, NULL, NULL, 0);
    }

    // ...otherwise fall back to using CompareString.
    return CompareStringW(__crtDownlevelLocaleNameToLCID(lpLocaleName), dwCmpFlags, lpString1, cchCount1, lpString2, cchCount2);
}

/*******************************************************************************
*__crtLCMapStringEx() - Wrapper for LCMapStringEx().
*
*******************************************************************************/
extern "C"  int __cdecl __crtLCMapStringEx(
    LPCWSTR lpLocaleName,
    DWORD dwMapFlags,
    LPCWSTR lpSrcStr,
    int cchSrc,
    LPWSTR lpDestStr,
    int cchDest)
{
    // use LCMapStringEx if it is available (only on Vista+)...
    IFDYNAMICGETCACHEDFUNCTION(KERNEL32, PFNLCMAPSTRINGEX, LCMapStringEx, pfLCMapStringEx)
    {
        return (*pfLCMapStringEx)(lpLocaleName, dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest, NULL, NULL, 0);
    }

    // ...otherwise fall back to using LCMapString.
    return LCMapStringW(__crtDownlevelLocaleNameToLCID(lpLocaleName), dwMapFlags, lpSrcStr, cchSrc, lpDestStr, cchDest);
}


/*******************************************************************************
*__crtGetLocaleInfoEx() - Wrapper for GetLocaleInfoEx().
*
*******************************************************************************/
extern "C" int __cdecl __crtGetLocaleInfoEx(
    LPCWSTR const lpLocaleName,
    LCTYPE  const LCType,
    LPWSTR  const lpLCData,
    int     const cchData
    )
{
    IFDYNAMICGETCACHEDFUNCTION(KERNEL32, PFNGETLOCALEINFOEX, GetLocaleInfoEx, pfGetLocaleInfoEx)
    {
        return pfGetLocaleInfoEx(lpLocaleName, LCType, lpLCData, cchData);
    }

    return GetLocaleInfoW(__crtDownlevelLocaleNameToLCID(lpLocaleName), LCType, lpLCData, cchData);
}

#endif // _STL_WIN32_WINNT < _WIN32_WINNT_VISTA