【Darwin学习笔记】之获取系统处理器数量的方法

阅读Darwin源码的时候看到这个方法，感觉挺有用处，且考虑了多种平台下的实现方式，直接贴代码，以后说不定会用到~

单一种平台下的实现方法可能很容易，但是把这些个系统都收集在一起，在一个函数中实现还是极好的

【转载请注明出处】：http://blog.csdn.net/longlong530

UInt32 OS::GetNumProcessors()
{
#if (__Win32__)
SYSTEM_INFO theSystemInfo;
::GetSystemInfo(&theSystemInfo);

return (UInt32)theSystemInfo.dwNumberOfProcessors;
#endif

#if (__MacOSX__ || __FreeBSD__)
int numCPUs = 1;
size_t len = sizeof(numCPUs);
int mib[2];
mib[ 0] = CTL_HW;
mib[ 1] = HW_NCPU;
( void) ::sysctl(mib,2,&numCPUs,&len,NULL,0);
if (numCPUs < 1)
numCPUs = 1;
return (UInt32) numCPUs;
#endif

#if(__linux__ || __linuxppc__)

char cpuBuffer[8192] = "";
StrPtrLen cpuInfoBuf(cpuBuffer, sizeof(cpuBuffer));
FILE *cpuFile = ::fopen( "/proc/cpuinfo", "r" );
if (cpuFile)
{ cpuInfoBuf.Len = ::fread(cpuInfoBuf.Ptr, sizeof(char), cpuInfoBuf.Len, cpuFile);
::fclose(cpuFile);
}

StringParser cpuInfoFileParser(&cpuInfoBuf);
StrPtrLen line;
StrPtrLen word;
UInt32 numCPUs = 0;

while( cpuInfoFileParser.GetDataRemaining() != 0 )
{
cpuInfoFileParser.GetThruEOL(&line); // Read each line
StringParser lineParser(&line);
lineParser.ConsumeWhitespace(); //skip over leading whitespace

if (lineParser.GetDataRemaining() == 0) // must be an empty line
continue;

lineParser.ConsumeUntilWhitespace(&word);

if ( word.Equal("processor") ) // found a processor as first word in line
{ numCPUs ++;
}
}

if (numCPUs == 0)
numCPUs = 1;

return numCPUs;
#endif

#if(__solaris__)
{
UInt32 numCPUs = 0;
char linebuff[512] = "";
StrPtrLen line(linebuff, sizeof(linebuff));
StrPtrLen word;

FILE *p = ::popen( "uname -X","r");
while((::fgets(linebuff, sizeof(linebuff -1), p)) > 0)
{
StringParser lineParser(&line);
lineParser.ConsumeWhitespace(); //skip over leading whitespace

if (lineParser.GetDataRemaining() == 0) // must be an empty line
continue;

lineParser.ConsumeUntilWhitespace(&word);

if ( word.Equal("NumCPU")) // found a tag as first word in line
{
lineParser.GetThru( NULL,'=');
lineParser.ConsumeWhitespace(); //skip over leading whitespace
lineParser.ConsumeUntilWhitespace(&word); //read the number of cpus
if (word.Len > 0)
:: sscanf(word.Ptr, "%"_U32BITARG_"", &numCPUs);

break;
}
}
if (numCPUs == 0)
numCPUs = 1;

::pclose(p);

return numCPUs;
}
#endif

#if(__sgi__)
UInt32 numCPUs = 0;

numCPUs = sysconf(_SC_NPROC_ONLN);

return numCPUs;
#endif


return 1;
}

PS:  函数摘自Darwin源码：\StreamServer\CommonUtilitiesLib\OS.cpp