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https://github.com/Chuyu-Team/VC-LTL5.git
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mingkuang
145 lines
3.7 KiB
C++
145 lines
3.7 KiB
C++
//
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// _mbslen.cpp
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// Defines the mbstrlen functions, which return the number of multibyte
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// characters in a multibyte string, excluding the null terminator. This
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// function is locale-dependent. If the string contains invalid multibyte
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// characters, -1 is returned and errno is set to EILSEQ.
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//
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// There are two variations of these functions: mbstrnlen (note the 'n'),
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// which takes a max_size, which is the maximum number of bytes to scan
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// in the string. These variations also validate their arguments. The
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// variations without the 'n' (mbstrlen) stop only when the null terminator
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// is reached and do not validate their arguments.
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//
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#include <corecrt_internal.h>
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#include <stdlib.h>
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#include <locale.h>
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_Check_return_
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_Post_satisfies_((return <= _String_length_(string) && return <= max_size) || return == (size_t)-1)
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static size_t __cdecl common_mbstrlen_l(
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char const* const string,
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size_t const max_size,
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_locale_t const locale
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)
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{
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//_LocaleUpdate locale_update(locale);
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int _locale_mb_cur_max;
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unsigned int _locale_lc_codepage;
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if (locale)
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{
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_locale_mb_cur_max = locale->locinfo->_locale_mb_cur_max;
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_locale_lc_codepage = locale->locinfo->_locale_lc_codepage;
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}
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else
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{
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_locale_mb_cur_max = __mb_cur_max;
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_locale_lc_codepage = ___lc_codepage_func();
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}
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_ASSERTE(
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_locale_mb_cur_max == 1 ||
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_locale_mb_cur_max == 2);
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// Handle single byte character sets:
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if (_locale_mb_cur_max == 1)
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{
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return strnlen(string, max_size);
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}
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// Verify that all of the multibyte characters are valid:
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if (__acrt_MultiByteToWideChar(
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_locale_lc_codepage,
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MB_PRECOMPOSED | MB_ERR_INVALID_CHARS,
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string,
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static_cast<int>(max_size),
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nullptr,
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0
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) == 0)
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{
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// There was a bad multibyte character:
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errno = EILSEQ;
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return static_cast<size_t>(-1);
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}
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// Count multibyte characters:
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size_t n = 0; // Number of multibyte characters read
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size_t size = 0; // Number of bytes read
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for (char const* it = string; size < max_size && *it; ++n, ++it, ++size)
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{
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if (_isleadbyte_fast_internal(static_cast<unsigned char>(*it), locale))
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{
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++size;
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if (size >= max_size)
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break;
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++it;
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if (*it == '\0')
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break;
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}
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}
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return size >= max_size ? max_size : n;
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}
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#if WindowsTargetPlatformMinVersion < WindowsTargetPlatformWindows6
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extern "C" size_t __cdecl _mbstrlen_l(
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char const* const string,
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_locale_t const locale
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)
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{
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return common_mbstrlen_l(string, _CRT_UNBOUNDED_BUFFER_SIZE, locale);
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}
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_LCRT_DEFINE_IAT_SYMBOL(_mbstrlen_l);
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#endif
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#if 0
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extern "C" size_t __cdecl _mbstrlen(char const* const string)
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{
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if (!__acrt_locale_changed())
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{
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return strlen(string);
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}
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else
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{
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return _mbstrlen_l(string, nullptr);
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}
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}
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#endif
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#if WindowsTargetPlatformMinVersion < WindowsTargetPlatformWindows6
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extern "C" size_t __cdecl _mbstrnlen_l(
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char const* const string,
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size_t const max_size,
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_locale_t const locale
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)
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{
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_VALIDATE_RETURN(string != nullptr, EINVAL, static_cast<size_t>(-1));
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_VALIDATE_RETURN(max_size <= INT_MAX, EINVAL, static_cast<size_t>(-1));
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return common_mbstrlen_l(string, max_size, locale);
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}
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_LCRT_DEFINE_IAT_SYMBOL(_mbstrnlen_l);
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#endif
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#if WindowsTargetPlatformMinVersion < WindowsTargetPlatformWindows6
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extern "C" size_t __cdecl _mbstrnlen(
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char const* const string,
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size_t const max_size
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)
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{
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return _mbstrnlen_l(string, max_size, nullptr);
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}
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_LCRT_DEFINE_IAT_SYMBOL(_mbstrnlen);
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#endif |