| /*** | |
| *mbsnbset.c - Sets first n bytes of string to given character (MBCS) | |
| * | |
| * Copyright (c) Microsoft Corporation. All rights reserved. | |
| * | |
| *Purpose: | |
| * Sets first n bytes of string to given character (MBCS) | |
| * | |
| *******************************************************************************/ | |
| /*** | |
| * _mbsnbset - Sets first n bytes of string to given character (MBCS) | |
| * | |
| *Purpose: | |
| * Sets the first n bytes of string to the supplied | |
| * character value. If the length of string is less than n, | |
| * the length of string is used in place of n. Handles | |
| * MBCS chars correctly. | |
| * | |
| * There are several factors that make this routine complicated: | |
| * (1) The fill value may be 1 or 2 bytes long. | |
| * (2) The fill operation may end by hitting the count value | |
| * or by hitting the end of the string. | |
| * (3) A null terminating char is NOT placed at the end of | |
| * the string. | |
| * | |
| * Cases to be careful of (both of these can occur at once): | |
| * (1) Leaving an "orphaned" trail byte in the string (e.g., | |
| * overwriting a lead byte but not the corresponding trail byte). | |
| * (2) Writing only the 1st byte of a 2-byte fill value because the | |
| * end of string was encountered. | |
| * | |
| *Entry: | |
| * unsigned char *string = string to modify | |
| * unsigned int val = value to fill string with | |
| * size_t count = count of characters to fill | |
| * | |
| * | |
| *Exit: | |
| * Returns string = now filled with char val | |
| * | |
| *Uses: | |
| * | |
| *Exceptions: | |
| * Input parameters are validated. Refer to the validation section of the function. | |
| * | |
| *******************************************************************************/ | |
| extern "C" unsigned char * __cdecl _mbsnbset_l( | |
| unsigned char *string, | |
| unsigned int val, | |
| size_t count, | |
| _locale_t plocinfo | |
| ) | |
| { | |
| unsigned char *start = string; | |
| unsigned char highval, lowval; | |
| _LocaleUpdate _loc_update(plocinfo); | |
| _BEGIN_SECURE_CRT_DEPRECATION_DISABLE | |
| if (_loc_update.GetLocaleT()->mbcinfo->ismbcodepage == 0) | |
| return (unsigned char *)_strnset((char *)string, val, count); | |
| _END_SECURE_CRT_DEPRECATION_DISABLE | |
| /* validation section */ | |
| _VALIDATE_RETURN(string != nullptr || count == 0, EINVAL, nullptr); | |
| /* | |
| * leadbyte flag indicates if the last byte we overwrote was | |
| * a lead byte or not. | |
| */ | |
| highval = static_cast<unsigned char>(val >> 8); | |
| if (highval) | |
| { | |
| /* double byte value */ | |
| lowval = (unsigned char)(val & 0x00ff); | |
| if(lowval=='\0') | |
| { | |
| _ASSERTE(("invalid MBCS pair passed to mbsnbset",0)); | |
| /* Ideally we would return nullptr here and signal an error | |
| condition. But since this function has no other | |
| error modes, there would be a good chance of crashing | |
| the caller. So instead we fill the string with spaces | |
| to ensure that no information leaks through | |
| unexpectedly. Anyway, we do set errno to EINVAL. | |
| */ | |
| errno = EINVAL; | |
| lowval=highval=' '; | |
| } | |
| while ((count--) && *string) { | |
| /* pad with ' ' if no room for both bytes -- odd len */ | |
| if ((!count--) || (!*(string+1))) { | |
| *string = ' '; | |
| break; | |
| } | |
| *string++ = highval; | |
| *string++ = lowval; | |
| } | |
| } | |
| else { | |
| /* single byte value */ | |
| while (count-- && *string) { | |
| *string++ = (unsigned char)val; | |
| } | |
| } | |
| return( start ); | |
| } | |
| extern "C" unsigned char * (__cdecl _mbsnbset)( | |
| unsigned char *string, | |
| unsigned int val, | |
| size_t count | |
| ) | |
| { | |
| _BEGIN_SECURE_CRT_DEPRECATION_DISABLE | |
| return _mbsnbset_l(string, val, count, nullptr); | |
| _END_SECURE_CRT_DEPRECATION_DISABLE | |
| } | |