/************************************************************************
 ************************************************************************
    FAUST compiler
    Copyright (C) 2003-2014 GRAME, Centre National de Creation Musicale
    ---------------------------------------------------------------------
    This program 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 2.1 of the License, or
    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 ************************************************************************
 ************************************************************************/

// Author: Nick Strupat
// Date: October 29, 2010
// Returns the cache line size (in bytes) of the processor, or 0 on failure

#if defined(__APPLE__)

#include <sys/sysctl.h>
size_t cache_line_size()
{
    size_t line_size        = 0;
    size_t sizeof_line_size = sizeof(line_size);
    sysctlbyname("hw.cachelinesize", &line_size, &sizeof_line_size, 0, 0);
    return line_size;
}

#elif defined(__MINGW32__)

// MinGW doesn't have GetLogicalProcessorInformation() and friends in its
// libraries.
#include <stdlib.h>
size_t cache_line_size()
{
    return 0;
}

#elif defined(WIN32)

#include <stdlib.h>
#include <windows.h>
size_t cache_line_size()
{
    size_t                                line_size   = 0;
    DWORD                                 buffer_size = 0;
    DWORD                                 i           = 0;
    SYSTEM_LOGICAL_PROCESSOR_INFORMATION* buffer      = 0;

    GetLogicalProcessorInformation(0, &buffer_size);
    buffer = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION*)malloc(buffer_size);
    GetLogicalProcessorInformation(&buffer[0], &buffer_size);

    for (i = 0; i != buffer_size / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION); ++i) {
        if (buffer[i].Relationship == RelationCache && buffer[i].Cache.Level == 1) {
            line_size = buffer[i].Cache.LineSize;
            break;
        }
    }

    free(buffer);
    return line_size;
}

#elif defined(linux)

#include <stdio.h>
size_t cache_line_size()
{
    FILE* p        = 0;
    p              = fopen("/sys/devices/system/cpu/cpu0/cache/index0/coherency_line_size", "r");
    unsigned int i = 0;
    if (p) {
        fscanf(p, "%d", &i);
        fclose(p);
    }
    return i;
}

#else
#warning Unrecognized platform
#include <cstddef>
size_t cache_line_size()
{
    return 0;
}
#endif
