wctomb.cpp File Reference

#include <corecrt_internal.h>
#include <corecrt_internal_mbstring.h>
#include <corecrt_internal_ptd_propagation.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stdlib.h>

Include dependency graph for wctomb.cpp:

Go to the source code of this file.

Functions
int __cdecl	_wctomb_internal (int *const return_value, char *const destination, size_t const destination_count, wchar_t const wchar, __crt_cached_ptd_host &ptd)
int __cdecl	_wctomb_s_l (int *const return_value, char *const destination, size_t const destination_count, wchar_t const wchar, _locale_t const locale)
errno_t __cdecl	wctomb_s (int *const return_value, char *const destination, size_t const destination_count, wchar_t const wchar)
int __cdecl	_wctomb_l (char *const destination, wchar_t const wchar, _locale_t const locale)
	__pragma (warning(push)) __pragma(warning(disable

Function Documentation

__pragma()

__pragma

(

warning(push)

)

Definition at line 197 of file wctomb.cpp.

                        :__WARNING_POTENTIAL_BUFFER_OVERFLOW_HIGH_PRIORITY)) // 26015
 
extern "C" int __cdecl wctomb(
    char*   const destination,
    wchar_t const wchar
    )
{
    __crt_cached_ptd_host ptd;
 
    int return_value{};
    errno_t const e = _wctomb_internal(&return_value, destination, MB_CUR_MAX, wchar, ptd);
    if (e != 0)
    {
        return -1;
    }
 
    return return_value;
}

_wctomb_internal()

int __cdecl _wctomb_internal	(	int *const	return_value,
		char *const	destination,
		size_t const	destination_count,
		wchar_t const	wchar,
		__crt_cached_ptd_host &	ptd
	)

Definition at line 30 of file wctomb.cpp.

{
    // Did the caller request if this is a state dependent encoding?
    if (!destination && destination_count > 0)
    {
        // Indicate do not have state-dependent encodings:
        if (return_value != nullptr)
            *return_value = 0;
 
        return 0;
    }
 
    if (return_value)
        *return_value = -1;
 
    // We need to cast destination_count to int, so we make sure we are not
    // going to truncate destination_count:
    _UCRT_VALIDATE_RETURN_ERRCODE(ptd, destination_count <= INT_MAX, EINVAL);
    _locale_t const locale = ptd.get_locale();
 
    if (locale->locinfo->_public._locale_lc_codepage == CP_UTF8)
    {
        // Unlike c16rtomb. wctomb/wcrtomb have no ability to process a partial code point.
        // So, we could call c16rtomb and check for a lone surrogate or other error, or for simplicity
        // We can instead just call c32rtomb and check for any error. I choose the latter.
        mbstate_t state{};
        int result = static_cast<int>(__crt_mbstring::__c32rtomb_utf8(destination, static_cast<char32_t>(wchar), &state, ptd));
        if (return_value != nullptr)
        {
            *return_value = result;
        }
        if (result <= 4)
        {
            return 0;
        }
        else
        {
            return ptd.get_errno().value_or(0);
        }
    }
 
    // Check for C-locale behavior, which merely casts it to char (if in range)
    // for ASCII-ish behavior.
    if (!locale->locinfo->locale_name[LC_CTYPE])
    {
        // See if the WCHAR is > ASCII-ish range
        if (wchar > 255)  // Validate high byte
        {
            // Too big, can't convert, clear buffer and return error
            if (destination != nullptr && destination_count > 0)
            {
                memset(destination, 0, destination_count);
            }
 
            return ptd.get_errno().set(EILSEQ);
        }
 
        // ASCII-ish, just cast to a (char)
        if (destination != nullptr)
        {
            _UCRT_VALIDATE_RETURN_ERRCODE(ptd, destination_count > 0, ERANGE);
            *destination = static_cast<char>(wchar);
        }
 
        if (return_value != nullptr)
        {
            // casting one WCHAR emits a single char
            *return_value = 1;
        }
 
        // We're done
        return 0;
    }
    else
    {
        BOOL default_used{};
        int const size = __acrt_WideCharToMultiByte(
            locale->locinfo->_public._locale_lc_codepage,
            0,
            &wchar,
            1,
            destination,
            static_cast<int>(destination_count),
            nullptr,
            &default_used);
 
        if (size == 0 || default_used)
        {
            if (size == 0 && GetLastError() == ERROR_INSUFFICIENT_BUFFER)
            {
                if (destination && destination_count > 0)
                {
                    memset(destination, 0, destination_count);
                }
 
                _UCRT_VALIDATE_RETURN_ERRCODE(ptd, ("Buffer too small", 0), ERANGE);
            }
 
            return ptd.get_errno().set(EILSEQ);
        }
 
        if (return_value)
        {
            *return_value = size;
        }
 
        return 0;
    }
 
    // The last thing was an if/else, so we already returned.
}

Referenced by __pragma(), _fputwc_nolock_internal(), _wctomb_l(), _wctomb_s_l(), __crt_stdio_output::output_processor< Character, OutputAdapter, ProcessorBase >::type_case_c_tchar(), wctomb_s(), and __crt_stdio_output::output_processor< Character, OutputAdapter, ProcessorBase >::write_stored_string_tchar().

_wctomb_l()

int __cdecl _wctomb_l	(	char *const	destination,
		wchar_t const	wchar,
		_locale_t const	locale
	)

Definition at line 171 of file wctomb.cpp.

{
    __crt_cached_ptd_host ptd(locale);
 
    int return_value{};
    errno_t const e = _wctomb_internal(
        &return_value,
        destination,
        ptd.get_locale()->locinfo->_public._locale_mb_cur_max,
        wchar,
        ptd);
 
    if (e != 0)
    {
        return -1;
    }
 
    return return_value;
}

_wctomb_s_l()

int __cdecl _wctomb_s_l	(	int *const	return_value,
		char *const	destination,
		size_t const	destination_count,
		wchar_t const	wchar,
		_locale_t const	locale
	)

Definition at line 148 of file wctomb.cpp.

{
    __crt_cached_ptd_host ptd(locale);
    return _wctomb_internal(return_value, destination, destination_count, wchar, ptd);
}

wctomb_s()

errno_t __cdecl wctomb_s	(	int *const	return_value,
		char *const	destination,
		size_t const	destination_count,
		wchar_t const	wchar
	)

Definition at line 160 of file wctomb.cpp.

{
    __crt_cached_ptd_host ptd;
    return _wctomb_internal(return_value, destination, destination_count, wchar, ptd);
}

Referenced by _cgets_s(), ungetwc_text_mode_nolock(), and __crt_stdio_input::input_processor< Character, InputAdapter >::write_character().