cpucount.c

   1 #include "cpucount.h"
   2
   3 #ifndef BSD
   4 #  ifndef __linux__
   5 // FreeBSD
   6 #    ifdef __FreeBSD__
   7 #      undef BSD
   8 #      define BSD
   9 #    endif
  10 // OpenBSD
  11 #    ifdef __OpenBSD__
  12 #      undef BSD
  13 #      define BSD
  14 #    endif
  15 // NetBSD
  16 #    ifdef __NetBSD__
  17 #      undef BSD
  18 #      define BSD
  19 #    endif
  20 // DragonFly
  21 #    ifdef __DragonFly__
  22 #      undef BSD
  23 #      define BSD
  24 #    endif
  25 #  endif // __linux__
  26 // sys/param.h may have its own define
  27 #  ifdef BSD
  28 #    undef BSD
  29 #    include <sys/param.h>
  30 #    define SYS_PARAM_INCLUDED
  31 #    ifndef BSD
  32 #      define BSD
  33 #    endif
  34 #  endif
  35 #endif // BSD
  36
  37 #ifdef BSD
  38 #  ifndef SYS_PARAM_INCLUDED
  39 #    include <sys/param.h>
  40 #  endif
  41 #  include <sys/sysctl.h>
  42 #endif
  43
  44 #include <string.h>
  45
  46 #ifndef _WIN32
  47 #include <unistd.h>
  48 #else
  49 #define UNICODE 1
  50 #include <windows.h>
  51 #endif
  52
  53 #ifdef __linux__
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <strings.h>
  57 static int parsecpuinfo(void)
  58 {
  59         unsigned char cpubitmap[128];
  60
  61         memset(cpubitmap,0,sizeof(cpubitmap));
  62
  63         FILE *f = fopen("/proc/cpuinfo","r");
  64         if (!f)
  65                 return -1;
  66
  67         char buf[8192];
  68         while (fgets(buf,sizeof(buf),f)) {
  69                 // we don't like newlines
  70                 for (char *p = buf;*p;++p) {
  71                         if (*p == '\n') {
  72                                 *p = 0;
  73                                 break;
  74                         }
  75                 }
  76                 // split ':'
  77                 char *v = 0;
  78                 for (char *p = buf;*p;++p) {
  79                         if (*p == ':') {
  80                                 *p = 0;
  81                                 v = p + 1;
  82                                 break;
  83                         }
  84                 }
  85                 // key padding
  86                 size_t kl = strlen(buf);
  87                 while (kl > 0 && (buf[kl - 1] == '\t' || buf[kl - 1] == ' ')) {
  88                         --kl;
  89                         buf[kl] = 0;
  90                 }
  91                 // space before value
  92                 if (v) {
  93                         while (*v && (*v == ' ' || *v == '\t'))
  94                                 ++v;
  95                 }
  96                 // check what we need
  97                 if (strcasecmp(buf,"processor") == 0 && v) {
  98                         char *endp = 0;
  99                         long n = strtol(v,&endp,10);
 100                         if (endp && endp > v && n >= 0 && (size_t)n < sizeof(cpubitmap) * 8)
 101                                 cpubitmap[n / 8] |= 1 << (n % 8);
 102                 }
 103         }
 104
 105         fclose(f);
 106
 107         // count bits in bitmap
 108         int ncpu = 0;
 109         for (size_t n = 0;n < sizeof(cpubitmap) * 8;++n)
 110                 if (cpubitmap[n / 8] & (1 << (n % 8)))
 111                         ++ncpu;
 112
 113         return ncpu;
 114 }
 115 #endif
 116
 117 int cpucount(void)
 118 {
 119         int ncpu;
 120 #ifdef _SC_NPROCESSORS_ONLN
 121         ncpu = (int)sysconf(_SC_NPROCESSORS_ONLN);
 122         if (ncpu > 0)
 123                 return ncpu;
 124 #endif
 125 #ifdef __linux__
 126         // try parsing /proc/cpuinfo
 127         // NOTE seems cygwin can provide this too, idk if need tho
 128         ncpu = parsecpuinfo();
 129         if (ncpu > 0)
 130                 return ncpu;
 131 #endif
 132 #ifdef BSD
 133         const int ctlname[2] = {CTL_HW,HW_NCPU};
 134         size_t ctllen = sizeof(ncpu);
 135         if (sysctl(ctlname,2,&ncpu,&ctllen,0,0) < 0)
 136                 ncpu = -1;
 137         if (ncpu > 0)
 138                 return ncpu;
 139 #endif
 140 #ifdef _WIN32
 141         SYSTEM_INFO sysinfo;
 142         GetSystemInfo(&sysinfo);
 143         ncpu = (int)sysinfo.dwNumberOfProcessors;
 144         if (ncpu > 0)
 145                 return ncpu;
 146 #endif
 147         (void) ncpu;
 148         return -1;
 149 }