1 #ifndef AL_FSTREAM_H
2 #define AL_FSTREAM_H
3 
4 #ifdef _WIN32
5 
6 #define WIN32_LEAN_AND_MEAN
7 #include <windows.h>
8 
9 #include <array>
10 #include <string>
11 #include <fstream>
12 
13 
14 namespace al {
15 
16 // Windows' std::ifstream fails with non-ANSI paths since the standard only
17 // specifies names using const char* (or std::string). MSVC has a non-standard
18 // extension using const wchar_t* (or std::wstring?) to handle Unicode paths,
19 // but not all Windows compilers support it. So we have to make our own istream
20 // that accepts UTF-8 paths and forwards to Unicode-aware I/O functions.
21 class filebuf final : public std::streambuf {
22     std::array<char_type,4096> mBuffer;
23     HANDLE mFile{INVALID_HANDLE_VALUE};
24 
25     int_type underflow() override;
26     pos_type seekoff(off_type offset, std::ios_base::seekdir whence, std::ios_base::openmode mode) override;
27     pos_type seekpos(pos_type pos, std::ios_base::openmode mode) override;
28 
29 public:
30     filebuf() = default;
31     ~filebuf() override;
32 
33     bool open(const wchar_t *filename, std::ios_base::openmode mode);
34     bool open(const char *filename, std::ios_base::openmode mode);
35 
is_open()36     bool is_open() const noexcept { return mFile != INVALID_HANDLE_VALUE; }
37 
38     void close();
39 };
40 
41 // Inherit from std::istream to use our custom streambuf
42 class ifstream final : public std::istream {
43     filebuf mStreamBuf;
44 
45 public:
46     ifstream(const wchar_t *filename, std::ios_base::openmode mode = std::ios_base::in);
47     ifstream(const std::wstring &filename, std::ios_base::openmode mode = std::ios_base::in)
48       : ifstream(filename.c_str(), mode) { }
49     ifstream(const char *filename, std::ios_base::openmode mode = std::ios_base::in);
50     ifstream(const std::string &filename, std::ios_base::openmode mode = std::ios_base::in)
51       : ifstream(filename.c_str(), mode) { }
52     ~ifstream() override;
53 
is_open()54     bool is_open() const noexcept { return mStreamBuf.is_open(); }
55 
close()56     void close() { mStreamBuf.close(); }
57 };
58 
59 } // namespace al
60 
61 #else /* _WIN32 */
62 
63 #include <fstream>
64 
65 namespace al {
66 
67 using filebuf = std::filebuf;
68 using ifstream = std::ifstream;
69 
70 } // namespace al
71 
72 #endif /* _WIN32 */
73 
74 #endif /* AL_FSTREAM_H */
75