Thanks to Owen Shepherd of the Public Domain C Library for helping design and formalize these interfaces.
66 lines
2 KiB
C++
66 lines
2 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdio/vsnprintf.cpp
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Prints a formatted string to a limited string.
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*******************************************************************************/
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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typedef struct vsnprintf_struct
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{
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char* str;
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size_t size;
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size_t produced;
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size_t written;
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} vsnprintf_t;
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static size_t StringPrintCallback(void* user, const char* string,
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size_t stringlen)
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{
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vsnprintf_t* info = (vsnprintf_t*) user;
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if ( info->produced < info->size )
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{
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size_t available = info->size - info->produced;
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size_t possible = (stringlen < available) ? stringlen : available;
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memcpy(info->str + info->produced, string, possible);
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info->written += possible;
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}
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info->produced += stringlen;
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return stringlen;
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}
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extern "C"
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int vsnprintf(char* restrict str, size_t size, const char* restrict format,
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va_list list)
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{
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vsnprintf_t info;
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info.str = str;
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info.size = size ? size-1 : 0;
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info.produced = 0;
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info.written = 0;
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int result = vcbprintf(&info, StringPrintCallback, format, list);
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if ( size )
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info.str[info.written] = '\0';
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return result;
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}
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