huwcampbell.com
Reactos
1//
2// ismbstr.cpp
3//
4// Copyright (c) Microsoft Corporation. All rights reserved.
5//
6// Defines _ismbstrail, which is the context-sensitive MBCS trail-byte function.
7// While much less efficient than _ismbbtrail, it is also much more sophisticated.
8// It determines whether a given sub-string pointer points to a trail byte or not,
9// taking into account the context of the string.
10//
11// These functions return -1 if the pointer points to a trail byte; 0 if it does
12// not.
13//
14// These functions are intended for use with single/double byte character sets (DBCS)
15// and are meaningless for UTF-8 which has more than just a lead/trail byte pair.
16// for UTF-8 these functions always return FALSE.
17//
18#ifndef _MBCS
19 #error This file should only be compiled with _MBCS defined
20#endif
21
22#define _ALLOW_OLD_VALIDATE_MACROS
23#include <corecrt_internal_mbstring.h>
24#include <locale.h>
25
26
27
28extern "C" int __cdecl _ismbstrail_l(
29 unsigned char const* string,
30 unsigned char const* current,
31 _locale_t const locale
32 )
33{
34 _VALIDATE_RETURN(string != nullptr, EINVAL, 0);
35 _VALIDATE_RETURN(current != nullptr, EINVAL, 0);
36
37 _LocaleUpdate locale_update(locale);
38
39 if (locale_update.GetLocaleT()->mbcinfo->ismbcodepage == 0)
40 return 0;
41
42 while (string <= current && *string)
43 {
44 if (_ismbblead_l((*string), locale_update.GetLocaleT()))
45 {
46 if (++string == current) // check trail byte
47 return -1;
48
49 if (*string == 0)
50 return 0;
51 }
52 ++string;
53 }
54
55 return 0;
56}
57
58extern "C" int __cdecl _ismbstrail(
59 unsigned char const* const string,
60 unsigned char const* const current
61 )
62{
63 return _ismbstrail_l(string, current, nullptr);
64}