/*** *a_cmp.c - A version of CompareString. * * Copyright (c) 1993-1997, Microsoft Corporation. All rights reserved. * *Purpose: * Use either CompareStringA or CompareStringW depending on which is * available * *******************************************************************************/ #include #include #include #include #include #include #include #define USE_W 1 #define USE_A 2 /*** *int __cdecl strncnt - count characters in a string, up to n. * *Purpose: * Internal local support function. Counts characters in string before NULL. * If NULL not found in n chars, then return n. * *Entry: * const char *string - start of string * int n - byte count * *Exit: * returns number of bytes from start of string to * NULL (exclusive), up to n. * *Exceptions: * *******************************************************************************/ static int __cdecl strncnt ( const char *string, int cnt ) { int n = cnt; char *cp = (char *)string; while (n-- && *cp) cp++; if (!*cp) return cp - string; return cnt; } /*** *int __cdecl __crtCompareStringA - Get type information about an ANSI string. * *Purpose: * Internal support function. Assumes info in ANSI string format. Tries * to use NLS API call CompareStringA if available and uses CompareStringW * if it must. If neither are available it fails and returns 0. * *Entry: * LCID Locale - locale context for the comparison. * DWORD dwCmpFlags - see NT\Chicago docs * LPCSTR lpStringn - multibyte string to be compared * int cchCountn - char (byte) count (NOT including NULL) * (-1 if NULL terminated) * int code_page - for MB/WC conversion. If 0, use __lc_codepage * *Exit: * Success: 1 - if lpString1 < lpString2 * 2 - if lpString1 == lpString2 * 3 - if lpString1 > lpString2 * Failure: 0 * *Exceptions: * *******************************************************************************/ int __cdecl __crtCompareStringA( LCID Locale, DWORD dwCmpFlags, LPCSTR lpString1, int cchCount1, LPCSTR lpString2, int cchCount2, int code_page ) { static int f_use = 0; /* * Look for unstubbed 'preferred' flavor. Otherwise use available flavor. * Must actually call the function to ensure it's not a stub. * (Always try wide version first so WinNT can process codepage correctly.) */ if (0 == f_use) { if (0 != CompareStringW(0, 0, L"\0", 1, L"\0", 1)) f_use = USE_W; else if (0 != CompareStringA(0, 0, "\0", 1, "\0", 1)) f_use = USE_A; else return 0; } /* * CompareString will compare past NULL. Must find NULL if in string * before cchCountn chars. */ if (cchCount1 > 0) cchCount1 = strncnt(lpString1, cchCount1); if (cchCount2 > 0) cchCount2 = strncnt(lpString2, cchCount2); /* Use "A" version */ if (USE_A == f_use) { return CompareStringA( Locale, dwCmpFlags, lpString1, cchCount1, lpString2, cchCount2 ); } /* Use "W" version */ if (USE_W == f_use) { int buff_size1; int buff_size2; wchar_t *wbuffer1; wchar_t *wbuffer2; /* * Use __lc_codepage for conversion if code_page not specified */ if (0 == code_page) code_page = __lc_codepage; /* * Special case: at least one count is zero */ if (!cchCount1 || !cchCount2) { unsigned char *cp; // char pointer CPINFO lpCPInfo; // struct for use with GetCPInfo /* both strings zero */ if (cchCount1 == cchCount2) return 2; /* string 1 greater */ if (cchCount2 > 1) return 1; /* string 2 greater */ if (cchCount1 > 1) return 3; /* * one has zero count, the other has a count of one * - if the one count is a naked lead byte, the strings are equal * - otherwise it is a single character and they are unequal */ if (GetCPInfo(code_page, &lpCPInfo) == FALSE) return 0; _ASSERTE(cchCount1==0 && cchCount2==1 || cchCount1==1 && cchCount2==0); /* string 1 has count of 1 */ if (cchCount1 > 0) { if (lpCPInfo.MaxCharSize < 2) return 3; for ( cp = (unsigned char *)lpCPInfo.LeadByte ; cp[0] && cp[1] ; cp += 2 ) if ( (*(unsigned char *)lpString1 >= cp[0]) && (*(unsigned char *)lpString1 <= cp[1]) ) return 2; return 3; } /* string 2 has count of 1 */ if (cchCount2 > 0) { if (lpCPInfo.MaxCharSize < 2) return 1; for ( cp = (unsigned char *)lpCPInfo.LeadByte ; cp[0] && cp[1] ; cp += 2 ) if ( (*(unsigned char *)lpString2 >= cp[0]) && (*(unsigned char *)lpString2 <= cp[1]) ) return 2; return 1; } } /* * Convert strings and return the requested information. */ /* find out how big a buffer we need (includes NULL if any) */ if ( 0 == (buff_size1 = MultiByteToWideChar( code_page, MB_PRECOMPOSED | MB_ERR_INVALID_CHARS, lpString1, cchCount1, NULL, 0 )) ) return 0; /* allocate enough space for chars */ __try { wbuffer1 = (wchar_t *)_alloca( buff_size1 * sizeof(wchar_t) ); } __except( EXCEPTION_EXECUTE_HANDLER ) { wbuffer1 = NULL; } if ( wbuffer1 == NULL ) return 0; /* do the conversion */ if ( 0 == MultiByteToWideChar( code_page, MB_PRECOMPOSED, lpString1, cchCount1, wbuffer1, buff_size1 ) ) return 0; /* find out how big a buffer we need (includes NULL if any) */ if ( 0 == (buff_size2 = MultiByteToWideChar( code_page, MB_PRECOMPOSED | MB_ERR_INVALID_CHARS, lpString2, cchCount2, NULL, 0 )) ) return 0; /* allocate enough space for chars */ __try { wbuffer2 = (wchar_t *)_alloca( buff_size2 * sizeof(wchar_t) ); } __except( EXCEPTION_EXECUTE_HANDLER ) { wbuffer2 = NULL; } if ( wbuffer2 == NULL ) return 0; /* do the conversion */ if ( 0 == MultiByteToWideChar( code_page, MB_PRECOMPOSED, lpString2, cchCount2, wbuffer2, buff_size2 ) ) return 0; return CompareStringW( Locale, dwCmpFlags, wbuffer1, buff_size1, wbuffer2, buff_size2 ); } else /* f_use is neither USE_A nor USE_W */ return 0; }