Files
MaxScale/maxutils/maxbase/src/format.cc
Esa Korhonen a1e1ac0012 Move string_printf to maxbase
Can be used in tests.
2018-11-29 12:21:40 +02:00

100 lines
2.1 KiB
C++

/*
* Copyright (c) 2018 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2022-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include <maxbase/format.hh>
#include <cmath>
#include <cstdio>
#include <maxbase/assert.h>
#include <maxbase/log.hh>
namespace
{
const char* get_binary_size_suffix(int i)
{
switch (i)
{
case 0:
return "B";
case 1:
return "KiB";
case 2:
return "MiB";
case 3:
return "GiB";
case 4:
return "TiB";
case 5:
return "PiB";
case 6:
return "EiB";
case 7:
return "ZiB";
default:
return "YiB";
}
}
}
namespace maxbase
{
std::string to_binary_size(int64_t size)
{
// Calculate log1024(size) and round it up
int idx = floor(log(size) / log(1024));
double num = size / pow(1024, idx);
char buf[200]; // Enough for all possible values
snprintf(buf, sizeof(buf), "%.2lf%s", num, get_binary_size_suffix(idx));
return buf;
}
std::string string_printf(const char* format, ...)
{
/* Use 'vsnprintf' for the formatted printing. It outputs the optimal buffer length - 1. */
va_list args;
va_start(args, format);
int characters = vsnprintf(NULL, 0, format, args);
va_end(args);
std::string rval;
if (characters < 0)
{
// Encoding (programmer) error.
mxb_assert(!true);
MXB_ERROR("Could not format the string %s.", format);
}
else if (characters > 0)
{
// 'characters' does not include the \0-byte.
int total_size = characters + 1;
rval.reserve(total_size);
rval.resize(characters); // The final "length" of the string
va_start(args, format);
// Write directly to the string internal array, avoiding any temporary arrays.
vsnprintf(&rval[0], total_size, format, args);
va_end(args);
}
return rval;
}
}