mirror of https://git.tukaani.org/xz.git
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
///////////////////////////////////////////////////////////////////////////////
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//
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/// \file physmem.h
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/// \brief Get the amount of physical memory
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#ifndef PHYSMEM_H
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#define PHYSMEM_H
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#if defined(HAVE_PHYSMEM_SYSCONF)
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# include <unistd.h>
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#elif defined(HAVE_PHYSMEM_SYSCTL)
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# ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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# endif
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# ifdef HAVE_SYS_SYSCTL_H
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# include <sys/sysctl.h>
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# endif
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#elif defined(HAVE_PHYSMEM_SYSINFO)
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# include <sys/sysinfo.h>
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#elif defined(_WIN32)
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# ifndef _WIN32_WINNT
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# define _WIN32_WINNT 0x0500
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# endif
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# include <windows.h>
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#elif defined(__DJGPP__)
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# include <dpmi.h>
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#endif
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/// \brief Get the amount of physical memory in bytes
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///
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/// \return Amount of physical memory in bytes. On error, zero is
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/// returned.
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static inline uint64_t
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physmem(void)
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{
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uint64_t ret = 0;
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#if defined(HAVE_PHYSMEM_SYSCONF)
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const long pagesize = sysconf(_SC_PAGESIZE);
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const long pages = sysconf(_SC_PHYS_PAGES);
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if (pagesize != -1 || pages != -1)
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// According to docs, pagesize * pages can overflow.
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// Simple case is 32-bit box with 4 GiB or more RAM,
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// which may report exactly 4 GiB of RAM, and "long"
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// being 32-bit will overflow. Casting to uint64_t
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// hopefully avoids overflows in the near future.
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ret = (uint64_t)(pagesize) * (uint64_t)(pages);
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#elif defined(HAVE_PHYSMEM_SYSCTL)
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int name[2] = { CTL_HW, HW_PHYSMEM };
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union {
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unsigned long ul;
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unsigned int ui;
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} mem;
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size_t mem_ptr_size = sizeof(mem.ul);
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if (!sysctl(name, 2, &mem.ul, &mem_ptr_size, NULL, NULL)) {
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// Some systems use unsigned int as the "return value".
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// This makes a difference on 64-bit boxes.
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if (mem_ptr_size == sizeof(mem.ul))
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ret = mem.ul;
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else if (mem_ptr_size == sizeof(mem.ui))
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ret = mem.ui;
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}
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#elif defined(HAVE_PHYSMEM_SYSINFO)
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struct sysinfo si;
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if (sysinfo(&si) == 0)
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ret = (uint64_t)(si.totalram) * si.mem_unit;
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#elif defined(_WIN32)
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if ((GetVersion() & 0xFF) >= 5) {
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// Windows 2000 and later have GlobalMemoryStatusEx() which
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// supports reporting values greater than 4 GiB. To keep the
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// code working also on older Windows versions, use
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// GlobalMemoryStatusEx() conditionally.
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HMODULE kernel32 = GetModuleHandle("kernel32.dll");
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if (kernel32 != NULL) {
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BOOL (WINAPI *gmse)(LPMEMORYSTATUSEX) = GetProcAddress(
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kernel32, "GlobalMemoryStatusEx");
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if (gmse != NULL) {
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MEMORYSTATUSEX meminfo;
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meminfo.dwLength = sizeof(meminfo);
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if (gmse(&meminfo))
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ret = meminfo.ullTotalPhys;
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}
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}
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}
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if (ret == 0) {
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// GlobalMemoryStatus() is supported by Windows 95 and later,
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// so it is fine to link against it unconditionally. Note that
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// GlobalMemoryStatus() has no return value.
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MEMORYSTATUS meminfo;
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meminfo.dwLength = sizeof(meminfo);
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GlobalMemoryStatus(&meminfo);
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ret = meminfo.dwTotalPhys;
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}
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#elif defined(__DJGPP__)
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__dpmi_free_mem_info meminfo;
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if (__dpmi_get_free_memory_information(&meminfo) == 0
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&& meminfo.total_number_of_physical_pages
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!= (unsigned long)(-1))
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ret = (uint64_t)(meminfo.total_number_of_physical_pages)
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* 4096;
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#endif
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return ret;
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}
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#endif
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