[UCRT] Import Microsoft.Windows.SDK.CRTSource version 10.0.22621.3

Imported from https://www.nuget.org/packages/Microsoft.Windows.SDK.CRTSource/10.0.22621.3
License: MIT

sdk/lib/ucrt/stdio/openfile.cpp

@@ -0,0 +1,77 @@
+//
+// openfile.cpp
+//
+//      Copyright (c) Microsoft Corporation.  All rights reserved.
+//
+// Functions that open a file as a stdio stream, with mode and share flag.
+//
+#include <corecrt_internal_stdio.h>
+#include <sys/stat.h>
+
+
+
+// Opens a file with a string mode and file sharing flag.  This function defines
+// the common logic shared by other stdio open functions.  It parses the mode
+// string, per the rules described in the above parser, then opens the file via
+// the lowio library.
+//
+// Returns the new FILE* on success; returns nullptr on failure.
+template <typename Character>
+static FILE* __cdecl common_openfile(
+    Character const*   const file_name,
+    Character const*   const mode,
+    int                const share_flag,
+    __crt_stdio_stream const stream
+    ) throw()
+{
+    typedef __acrt_stdio_char_traits<Character> stdio_traits;
+
+    _ASSERTE(file_name != nullptr);
+    _ASSERTE(mode      != nullptr);
+    _ASSERTE(stream.valid());
+
+    __acrt_stdio_stream_mode const parsed_mode = __acrt_stdio_parse_mode(mode);
+    if (!parsed_mode._success)
+        return nullptr;
+
+    int fh;
+    if (stdio_traits::tsopen_s(&fh, file_name, parsed_mode._lowio_mode, share_flag, _S_IREAD | _S_IWRITE) != 0)
+        return nullptr;
+
+    // Ensure that streams get flushed during pre-termination:
+    #ifndef CRTDLL
+    _cflush++;
+    #endif
+
+    // Initialize the stream:
+    stream.set_flags(parsed_mode._stdio_mode);
+    stream->_cnt      = 0;
+    stream->_tmpfname = nullptr;
+    stream->_base     = nullptr;
+    stream->_ptr      = nullptr;
+    stream->_file     = fh;
+
+    return stream.public_stream();
+}
+
+
+
+extern "C" FILE* __cdecl _openfile(
+    char const* const file_name,
+    char const* const mode,
+    int         const share_flag,
+    FILE*       const public_stream
+    )
+{
+    return common_openfile(file_name, mode, share_flag, __crt_stdio_stream(public_stream));
+}
+
+extern "C" FILE* __cdecl _wopenfile(
+    wchar_t const* const file_name,
+    wchar_t const* const mode,
+    int            const share_flag,
+    FILE*          const public_stream
+    )
+{
+    return common_openfile(file_name, mode, share_flag, __crt_stdio_stream(public_stream));
+}