path: root/src/pal/src/safecrt/vswprint.c

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

/***
*vswprint.c - print formatted data into a string from var arg list
*
*Purpose:
*       defines vswprintf(), _vswprintf_c and _vsnwprintf() - print formatted output to
*       a string, get the data from an argument ptr instead of explicit
*       arguments.
*
*******************************************************************************/


#include <string.h>
#include <errno.h>
#include <limits.h>
#include "internal_securecrt.h"

#include "mbusafecrt_internal.h"

typedef int (*WOUTPUTFN)(miniFILE *, const wchar_t *, va_list);

static int _vswprintf_helper( WOUTPUTFN outfn, wchar_t *string, size_t count, const wchar_t *format, va_list ap );
static int _vscwprintf_helper (WOUTPUTFN outfn, const wchar_t *format, va_list ap );

/***
*ifndef _COUNT_
*int _vswprintf(string, format, ap) - print formatted data to string from arg ptr
*else
*ifndef _SWPRINTFS_ERROR_RETURN_FIX
*int _vsnwprintf(string, cnt, format, ap) - print formatted data to string from arg ptr
*else
*int _vswprintf_c(string, cnt, format, ...) - print formatted data to string
*endif
*endif
*
*Purpose:
*       Prints formatted data, but to a string and gets data from an argument
*       pointer.
*       Sets up a FILE so file i/o operations can be used, make string look
*       like a huge buffer to it, but _flsbuf will refuse to flush it if it
*       fills up. Appends '\0' to make it a true string.
*
*       Allocate the 'fake' _iob[] entryit statically instead of on
*       the stack so that other routines can assume that _iob[] entries are in
*       are in DGROUP and, thus, are near.
*
*ifdef _COUNT_
*ifndef _SWPRINTFS_ERROR_RETURN_FIX
*       The _vsnwprintf() flavor takes a count argument that is
*       the max number of bytes that should be written to the
*       user's buffer.
*       We don't expose this function directly in the headers.
*else
*       The _vswprintf_c() flavor does the same thing as the _snwprintf
*       above, but, it also fixes an issue in the return value in the case
*       when there isn't enough space to write the null terminator
*       We don't fix this issue in _vsnwprintf because of backward
*       compatibility. In new code, however, _vsnwprintf is #defined to
*       _vswprintf_c so users get the fix.
*
*endif
*
*       Multi-thread: (1) Since there is no stream, this routine must never try
*       to get the stream lock (i.e., there is no stream lock either).  (2)
*       Also, since there is only one statically allocated 'fake' iob, we must
*       lock/unlock to prevent collisions.
*
*Entry:
*       wchar_t *string - place to put destination string
*ifdef _COUNT_
*       size_t count - max number of bytes to put in buffer
*endif
*       wchar_t *format - format string, describes format of data
*       va_list ap - varargs argument pointer
*
*Exit:
*       returns number of wide characters in string
*       returns -2 if the string has been truncated (only in _vsnprintf_helper)
*       returns -1 in other error cases
*
*Exceptions:
*
*******************************************************************************/

int __cdecl _vswprintf_helper (
        WOUTPUTFN woutfn,
        wchar_t *string,
        size_t count,
        const wchar_t *format,
        va_list ap
        )
{
        miniFILE str;
        miniFILE *outfile = &str;
        int retval;

        _VALIDATE_RETURN( (format != NULL), EINVAL, -1);

        _VALIDATE_RETURN( (count == 0) || (string != NULL), EINVAL, -1 );

        outfile->_flag = _IOWRT|_IOSTRG;
        outfile->_ptr = outfile->_base = (char *) string;

        if(count>(INT_MAX/sizeof(wchar_t)))
        {
           /* old-style functions allow any large value to mean unbounded */
           outfile->_cnt = INT_MAX;
        }
        else
        {
            outfile->_cnt = (int)(count*sizeof(wchar_t));
        }

        retval = woutfn(outfile, format, ap );

        if(string==NULL)
        {
            return retval;
        }

        if((retval >= 0) && (_putc_nolock('\0',outfile) != EOF) && (_putc_nolock('\0',outfile) != EOF))
            return(retval);

        string[count - 1] = 0;
        if (outfile->_cnt < 0)
        {
            /* the buffer was too small; we return -2 to indicate truncation */
            return -2;
        }
        return -1;
}

int __cdecl _vswprintf_s (
        wchar_t *string,
        size_t sizeInWords,
        const wchar_t *format,
        va_list ap
        )
{
    int retvalue = -1;

    /* validation section */
    _VALIDATE_RETURN(format != NULL, EINVAL, -1);
    _VALIDATE_RETURN(string != NULL && sizeInWords > 0, EINVAL, -1);

    retvalue = _vswprintf_helper(_woutput_s, string, sizeInWords, format, ap);
    if (retvalue < 0)
    {
        string[0] = 0;
        _SECURECRT__FILL_STRING(string, sizeInWords, 1);
    }
    if (retvalue == -2)
    {
        _VALIDATE_RETURN(("Buffer too small" && 0), ERANGE, -1);
    }
    if (retvalue >= 0)
    {
        _SECURECRT__FILL_STRING(string, sizeInWords, retvalue + 1);
    }

    return retvalue;
}

int __cdecl _vsnwprintf_s (
        wchar_t *string,
        size_t sizeInWords,
        size_t count,
        const wchar_t *format,
        va_list ap
        )
{
    int retvalue = -1;
    errno_t save_errno = 0;

    /* validation section */
    _VALIDATE_RETURN(format != NULL, EINVAL, -1);
    if (count == 0 && string == NULL && sizeInWords == 0)
    {
        /* this case is allowed; nothing to do */
        return 0;
    }
    _VALIDATE_RETURN(string != NULL && sizeInWords > 0, EINVAL, -1);

    if (sizeInWords > count)
    {
        save_errno = errno;
        retvalue = _vswprintf_helper(_woutput_s, string, count + 1, format, ap);
        if (retvalue == -2)
        {
            /* the string has been truncated, return -1 */
            _SECURECRT__FILL_STRING(string, sizeInWords, count + 1);
            if (errno == ERANGE)
            {
                errno = save_errno;
            }
            return -1;
        }
    }
    else /* sizeInWords <= count */
    {
        save_errno = errno;
        retvalue = _vswprintf_helper(_woutput_s, string, sizeInWords, format, ap);
        string[sizeInWords - 1] = 0;
        /* we allow truncation if count == _TRUNCATE */
        if (retvalue == -2 && count == _TRUNCATE)
        {
            if (errno == ERANGE)
            {
                errno = save_errno;
            }
            return -1;
        }
    }

    if (retvalue < 0)
    {
        string[0] = 0;
        _SECURECRT__FILL_STRING(string, sizeInWords, 1);
        if (retvalue == -2)
        {
            _VALIDATE_RETURN(("Buffer too small" && 0), ERANGE, -1);
        }
        return -1;
    }

    _SECURECRT__FILL_STRING(string, sizeInWords, retvalue + 1);

    return (retvalue < 0 ? -1 : retvalue);
}

/***
* _vscwprintf() - counts the number of character needed to print the formatted
* data
*
*Purpose:
*       Counts the number of characters in the fotmatted data.
*
*Entry:
*       wchar_t *format - format string, describes format of data
*       va_list ap - varargs argument pointer
*
*Exit:
*       returns number of characters needed to print formatted data.
*
*Exceptions:
*
*******************************************************************************/

#ifndef _COUNT_

int __cdecl _vscwprintf_helper (
        WOUTPUTFN woutfn,
        const wchar_t *format,
        va_list ap
        )
{
        miniFILE str;
        miniFILE *outfile = &str;
        int retval;

        _VALIDATE_RETURN( (format != NULL), EINVAL, -1);

        outfile->_cnt = INT_MAX; //MAXSTR;
        outfile->_flag = _IOWRT|_IOSTRG;
        outfile->_ptr = outfile->_base = NULL;

        retval = woutfn(outfile, format, ap);
        return(retval);
}

int __cdecl _vscwprintf (
        const wchar_t *format,
        va_list ap
        )
{
        return _vscwprintf_helper(_woutput_s, format, ap);
}

#endif  /* _COUNT_ */