ios: Add diagstreambuf

Signed-off-by: Simon Rozman <simon@rozman.si>

UnitTests/ios.cpp

@@ -55,5 +55,53 @@ namespace UnitTests
 			Assert::IsTrue(f.good());
 			Assert::IsTrue(val == data[_countof(data) - 2]);
 		}
+
+		TEST_METHOD(diagstream)
+		{
+			constexpr size_t n = 3;
+
+			{
+				unique_ptr<ofstream> f[n];
+				vector<ofstream*> fv(n);
+				for (size_t i = 0; i < n; ++i)
+				{
+					WCHAR path[MAX_PATH];
+					ExpandEnvironmentStringsW(stdex::sprintf(L"%%temp%%\\file%zu.dat", NULL, i).c_str(), path, _countof(path));
+					f[i].reset(new ofstream(path, ios_base::out | ios_base::binary));
+					fv[i] = f[i].get();
+				}
+				stdex::odiagstream d(fv.begin(), fv.end(), 8);
+				srand(0);
+				auto write_some_random = [](_Inout_ ostream& f, _In_ size_t amount)
+				{
+					for (size_t i = 0; i < amount; ++i) {
+						auto r = static_cast<uint32_t>(rand());
+						f.write(reinterpret_cast<const char*>(&r), sizeof(r) / sizeof(char));
+					}
+				};
+				write_some_random(d, 15);
+				d.seekp(3);
+				write_some_random(d, 2);
+				d.seekp(28);
+				write_some_random(d, 7);
+			}
+
+			{
+				unique_ptr<ifstream> f[n];
+				vector<ifstream*> fv(n);
+				for (size_t i = 0; i < n; ++i)
+				{
+					WCHAR path[MAX_PATH];
+					ExpandEnvironmentStringsW(stdex::sprintf(L"%%temp%%\\file%zu.dat", NULL, i).c_str(), path, _countof(path));
+					f[i].reset(new ifstream(path, ios_base::in | ios_base::binary));
+					fv[i] = f[i].get();
+				}
+				stdex::idiagstream d(fv.begin(), fv.end(), 8);
+				do {
+					uint32_t r;
+					d.read(reinterpret_cast<char*>(&r), sizeof(r) / sizeof(char));
+				} while (!d.eof());
+			}
+		}
 	};
 }

UnitTests/pch.h

@@ -24,3 +24,5 @@
 #include <stdex/vector_queue.hpp>
 
 #include <CppUnitTest.h>
+
+#include <cstdlib>