Implement System for Win32

src/crystal/system/win32/cpucount.cr

@@ -0,0 +1,8 @@
+require "c/sysinfoapi"
+
+module Crystal::System
+  def self.cpu_count
+    LibC.GetNativeSystemInfo(out system_info)
+    system_info.dwNumberOfProcessors
+  end
+end

src/crystal/system/win32/hostname.cr

@@ -0,0 +1,16 @@
+require "c/sysinfoapi"
+
+module Crystal::System
+  def self.hostname
+    retry_wstr_buffer do |buffer, small_buf|
+      name_size = buffer.size.to_u
+      if LibC.GetComputerNameExW(LibC::COMPUTER_NAME_FORMAT::ComputerNameDnsHostname, buffer, pointerof(name_size)) != 0
+        break String.from_utf16(buffer[0, name_size])
+      elsif small_buf && name_size > 0
+        next name_size
+      else
+        raise WinError.new("GetComputerNameExW")
+      end
+    end
+  end
+end

src/lib_c/x86_64-windows-msvc/c/sysinfoapi.cr

@@ -0,0 +1,45 @@
+require "c/winnt"
+require "c/win_def"
+require "c/int_safe"
+
+lib LibC
+  fun GetNativeSystemInfo(system_info : SYSTEM_INFO*)
+
+  struct PROCESSOR_INFO
+    wProcessorArchitecture : WORD
+    wReserved : WORD
+  end
+
+  union OEM_PROCESSOR_INFO
+    dwOemId : DWORD
+    processorInfo : PROCESSOR_INFO
+  end
+
+  struct SYSTEM_INFO
+    oemProcessorInfo : OEM_PROCESSOR_INFO
+    dwPageSize : DWORD
+    lpMinimumApplicationAddress : Void*
+    lpMaximumApplicationAddress : Void*
+    dwActiveProcessorMask : DWORD*
+    dwNumberOfProcessors : DWORD
+    dwProcessorType : DWORD
+    dwAllocationGranularity : DWORD
+    wProcessorLevel : WORD
+    wProcessorRevision : WORD
+  end
+
+  fun GetComputerNameExW(computer_name_format : COMPUTER_NAME_FORMAT,
+                         machine_name : LPWSTR,
+                         machine_name_size : DWORD*) : BOOLEAN
+
+  enum COMPUTER_NAME_FORMAT
+    ComputerNameNetBIOS
+    ComputerNameDnsHostname
+    ComputerNameDnsDomain
+    ComputerNameDnsFullyQualified
+    ComputerNamePhysicalNetBIOS
+    ComputerNamePhysicalDnsHostname
+    ComputerNamePhysicalDomain
+    ComputerNamePhysicalDnsFullyQualified
+  end
+end