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sortix--sortix/libc/stdio/vsnprintf.cpp
2015-12-12 16:53:42 +01:00

63 lines
1.9 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014, 2015.
This file is part of the Sortix C Library.
The Sortix C Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
The Sortix C Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
stdio/vsnprintf.cpp
Prints a formatted string to the supplied buffer.
*******************************************************************************/
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
struct vsnprintf
{
char* str;
size_t size;
size_t written;
};
static size_t vsnprintf_callback(void* ctx, const char* string, size_t length)
{
struct vsnprintf* info = (struct vsnprintf*) ctx;
if ( 1 <= info->size && info->written < info->size )
{
size_t available = info->size - info->written;
size_t possible = length < available ? length : available;
memcpy(info->str + info->written, string, possible);
info->written += possible;
}
return length;
}
extern "C"
int vsnprintf(char* restrict str,
size_t size,
const char* restrict format,
va_list list)
{
struct vsnprintf info;
info.str = str;
info.size = size ? size - 1 : 0;
info.written = 0;
int result = vcbprintf(&info, vsnprintf_callback, format, list);
if ( 1 <= size )
info.str[info.written] = '\0';
return result;
}