mirror of
https://git.tukaani.org/xz.git
synced 2024-04-04 12:36:23 +02:00
67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
|
///////////////////////////////////////////////////////////////////////////////
|
||
|
|
//
|
||
|
|
/// \file physmem.h
|
||
|
|
/// \brief Get the amount of physical memory
|
||
|
|
//
|
||
|
|
// This code has been put into the public domain.
|
||
|
|
//
|
||
|
|
// This 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.
|
||
|
|
//
|
||
|
|
///////////////////////////////////////////////////////////////////////////////
|
||
|
|
|
||
|
|
#ifndef PHYSMEM_H
|
||
|
|
#define PHYSMEM_H
|
||
|
|
|
||
|
|
#if defined(HAVE_PHYSMEM_SYSCTL) || defined(HAVE_NCPU_SYSCTL)
|
||
|
|
# ifdef HAVE_SYS_PARAM_H
|
||
|
|
# include <sys/param.h>
|
||
|
|
# endif
|
||
|
|
# ifdef HAVE_SYS_SYSCTL_H
|
||
|
|
# include <sys/sysctl.h>
|
||
|
|
# endif
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
/// \brief Get the amount of physical memory in bytes
|
||
|
|
///
|
||
|
|
/// \return Amount of physical memory in bytes. On error, zero is
|
||
|
|
/// returned.
|
||
|
|
static inline uint64_t
|
||
|
|
physmem(void)
|
||
|
|
{
|
||
|
|
uint64_t ret = 0;
|
||
|
|
|
||
|
|
#if defined(HAVE_PHYSMEM_SYSCONF)
|
||
|
|
const long pagesize = sysconf(_SC_PAGESIZE);
|
||
|
|
const long pages = sysconf(_SC_PHYS_PAGES);
|
||
|
|
if (pagesize != -1 || pages != -1)
|
||
|
|
// According to docs, pagesize * pages can overflow.
|
||
|
|
// Simple case is 32-bit box with 4 GiB or more RAM,
|
||
|
|
// which may report exactly 4 GiB of RAM, and "long"
|
||
|
|
// being 32-bit will overflow. Casting to uint64_t
|
||
|
|
// hopefully avoids overflows in the near future.
|
||
|
|
ret = (uint64_t)(pagesize) * (uint64_t)(pages);
|
||
|
|
|
||
|
|
#elif defined(HAVE_PHYSMEM_SYSCTL)
|
||
|
|
int name[2] = { CTL_HW, HW_PHYSMEM };
|
||
|
|
unsigned long mem;
|
||
|
|
size_t mem_ptr_size = sizeof(mem);
|
||
|
|
if (!sysctl(name, 2, &mem, &mem_ptr_size, NULL, NULL)) {
|
||
|
|
// Some systems use unsigned int as the "return value".
|
||
|
|
// This makes a difference on 64-bit boxes.
|
||
|
|
if (mem_ptr_size != sizeof(mem)) {
|
||
|
|
if (mem_ptr_size == sizeof(unsigned int))
|
||
|
|
ret = *(unsigned int *)(&mem);
|
||
|
|
} else {
|
||
|
|
ret = mem;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif
|