a_str.c

C标准库源代码

/***
*a_str.c - A version of GetStringType.
*
*       Copyright (c) 1993-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
*       Use either GetStringTypeA or GetStringTypeW depending on which is
*       unstubbed.
*
*******************************************************************************/

#include <cruntime.h>
#include <internal.h>
#include <stdlib.h>
#include <setlocal.h>
#include <locale.h>
#include <awint.h>
#include <dbgint.h>

#define USE_W   1
#define USE_A   2

/***
*int __cdecl __crtGetStringTypeA - Get type information about an ANSI string.
*
*Purpose:
*       Internal support function. Assumes info in ANSI string format. Tries
*       to use NLS API call GetStringTypeA if available and uses GetStringTypeW
*       if it must. If neither are available it fails and returns FALSE.
*
*Entry:
*       DWORD    dwInfoType  - see NT\Chicago docs
*       LPCSTR   lpSrcStr    - char (byte) string for which character types
*                              are requested
*       int      cchSrc      - char (byte) count of lpSrcStr (including NULL
*                              if any)
*       LPWORD   lpCharType  - word array to receive character type information
*                              (must be twice the size of lpSrcStr)
*       int      code_page   - for MB/WC conversion. If 0, use __lc_codepage
*       int      lcid        - for A call, specify LCID, If 0, use
*                              __lc_handle[LC_CTYPE].
*       BOOL     bError      - TRUE if MB_ERR_INVALID_CHARS set on call to
*                              MultiByteToWideChar when GetStringTypeW used.
*
*Exit:
*       Success: TRUE
*       Failure: FALSE
*
*Exceptions:
*
*******************************************************************************/

BOOL __cdecl __crtGetStringTypeA(
        DWORD    dwInfoType,
        LPCSTR   lpSrcStr,
        int      cchSrc,
        LPWORD   lpCharType,
        int      code_page,
        int      lcid,
        BOOL     bError
        )
{
        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)
        {
            unsigned short dummy;

            if (0 != GetStringTypeW(CT_CTYPE1, L"\0", 1, &dummy))
                f_use = USE_W;

            else if (0 != GetStringTypeA(0, CT_CTYPE1, "\0", 1, &dummy))
                f_use = USE_A;

            else
                return FALSE;
        }

        /* Use "A" version */

        if (USE_A == f_use)
        {
            if (0 == lcid)
                lcid = __lc_handle[LC_CTYPE];

            return GetStringTypeA(lcid, dwInfoType, lpSrcStr, cchSrc, lpCharType);
        }

        /* Use "W" version */

        if (USE_W == f_use)
        {
            int retval;
            int buff_size;
            wchar_t *wbuffer;

            /*
             * Convert string and return the requested information. Note that
             * we are converting to a wide character string so there is not a
             * one-to-one correspondence between number of multibyte chars in the
             * input string and the number of wide chars in the buffer. However,
             * there had *better be* a one-to-one correspondence between the
             * number of multibyte characters and the number of WORDs in the
             * return buffer.
             */

            /*
             * Use __lc_codepage for conversion if code_page not specified
             */

            if (0 == code_page)
                code_page = __lc_codepage;

            /* find out how big a buffer we need */
            if ( 0 == (buff_size = MultiByteToWideChar( code_page,
                                                        bError ?
                                                            MB_PRECOMPOSED |
                                                            MB_ERR_INVALID_CHARS
                                                            : MB_PRECOMPOSED,
                                                        lpSrcStr,
                                                        cchSrc,
                                                        NULL,
                                                        0 )) )
                return FALSE;

            /* allocate enough space for wide chars */
            __try {
                wbuffer = (wchar_t *)_alloca( sizeof(wchar_t) * buff_size );
                (void)memset( wbuffer, 0, sizeof(wchar_t) * buff_size );
            }
            __except( EXCEPTION_EXECUTE_HANDLER ) {
                wbuffer = NULL;
            }

            if ( wbuffer == NULL )
                return FALSE;

            /* do the conversion */
            if ( 0 == (retval = MultiByteToWideChar( code_page,
                                                     MB_PRECOMPOSED,
                                                     lpSrcStr,
                                                     cchSrc,
                                                     wbuffer,
                                                     buff_size )) )
                return FALSE;

            /* obtain result */
            return GetStringTypeW(dwInfoType, wbuffer, retval, lpCharType);
        }
        else   /* f_use is neither USE_A nor USE_W */
            return FALSE;
}