tmux-mem-cpu-load/linux/memory.cc
2015-01-18 20:02:46 +01:00

106 lines
3.2 KiB
C++

/* vim: tabstop=2 shiftwidth=2 expandtab textwidth=80 linebreak wrap
*
* Copyright 2012 Matthew McCormick
* Copyright 2015 Pawel 'l0ner' Soltys
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <sstream>
#include <fstream>
#include <sys/sysinfo.h>
#include "memory.h"
#include "../luts.h"
#include "../conversions.h"
std::string mem_string( bool use_colors = false )
{
using std::string;
using std::ifstream;
using std::stoi;
std::ostringstream oss;
string line, substr;
size_t substr_start;
size_t substr_len;
unsigned int total_mem, used_mem;
/* Since linux uses some RAM for disk caching, the actuall used ram is lower
* than what sysinfo(), top or free reports. htop reports the usage in a
* correct way. The memory used for caching doesn't count as used, since it
* can be freed in any moment. Usually it hapens automatically, when an
* application requests memory.
* In order to calculate the ram that's actually used we need to use the
* following formula:
* total_ram - free_ram - buffered_ram - cached_ram
*
* example data, junk removed, with comments added:
*
* MemTotal: 61768 kB old
* MemFree: 1436 kB old
* MemAvailable ????? kB ??
* MemShared: 0 kB old (now always zero; not calculated)
* Buffers: 1312 kB old
* Cached: 20932 kB old
* SwapTotal: 122580 kB old
* SwapFree: 60352 kB old
*/
ifstream memory_info("/proc/meminfo");
while( getline( memory_info, line ) )
{
substr_start = 0;
substr_len = line.find_first_of( ':' );
substr = line.substr( substr_start, substr_len );
substr_start = line.find_first_not_of( " ", substr_len + 1 );
substr_len = line.find_first_of( 'k' ) - substr_start;
if( substr.compare( "MemTotal" ) == 0 )
{
// get total memory
total_mem = stoi( line.substr( substr_start, substr_len ) );
}
else if( substr.compare( "MemFree" ) == 0 )
{
used_mem = total_mem - stoi( line.substr( substr_start, substr_len ) );
}
else if( substr.compare( "Buffers" ) == 0 ||
substr.compare( "Cached" ) == 0 )
{
used_mem -= stoi( line.substr( substr_start, substr_len ) );
}
}
if( use_colors )
{
oss << mem_lut[(100 * used_mem) / total_mem];
}
// we want megabytes on output, but since the values already come as
// kilobytes we need to divide them by 1024 only once, thus we use
// KILOBYTES
oss << convert_unit(used_mem, MEGABYTES, KILOBYTES) << '/'
<< convert_unit(total_mem, MEGABYTES, KILOBYTES) << "MB";
if( use_colors )
{
oss << "#[fg=default,bg=default]";
}
return oss.str();
}