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50 lines
1.9 KiB
C
50 lines
1.9 KiB
C
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/*
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* Handy secure string adapter functions for mbedTLS,
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* converting from `StringCchVPrintfEx` to `_vsnprintf_s`.
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*
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* Copyright 2015 Ismael Ferreras Morezuelas <swyterzone+ros@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include <windef.h>
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#include <strsafe.h>
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int _vsnprintf_s(char *buffer, size_t sizeOfBuffer, size_t count, const char *format, va_list argptr)
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{
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size_t cchRemaining;
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HRESULT ret = StringCchVPrintfEx(buffer, sizeOfBuffer, NULL, &cchRemaining, 0, format, argptr);
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// EXAMPLE //////////////////////////
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// -------- > Size of provided buffer in chars (8).
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// ABC0____ > Buffer contents after StringCchVPrintfEx gets called.
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// --- > What we actually need to return (3).
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// ----- > Remaining chars in buffer, including post string NULL, returned by StringCchVPrintfEx (5).
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/* _vsnprintf_s returns the number of characters written, not including
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the terminating null, or a negative value if an output error occurs. */
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switch (ret)
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{
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case S_OK:
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return (sizeOfBuffer - cchRemaining);
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case STRSAFE_E_INVALID_PARAMETER:
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case STRSAFE_E_INSUFFICIENT_BUFFER:
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default:
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return -1;
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}
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}
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