Use ifstream's wchar_t constructors on Windows

MinGW seems to have added them a while ago, so that greatly simplifies things.

3 files changed, 20 insertions, 173 deletions

diff --git a/common/alfstream.cpp b/common/alfstream.cpp
index 3beda833..8991ce03 100644
--- a/common/alfstream.cpp
+++ b/common/alfstream.cpp
@@ -9,141 +9,17 @@
 
 namespace al {
 
-auto filebuf::underflow() -> int_type
-{
-    if(mFile != INVALID_HANDLE_VALUE && gptr() == egptr())
-    {
-        // Read in the next chunk of data, and set the pointers on success
-        DWORD got{};
-        if(ReadFile(mFile, mBuffer.data(), static_cast<DWORD>(mBuffer.size()), &got, nullptr))
-            setg(mBuffer.data(), mBuffer.data(), mBuffer.data()+got);
-    }
-    if(gptr() == egptr())
-        return traits_type::eof();
-    return traits_type::to_int_type(*gptr());
-}
-
-auto filebuf::seekoff(off_type offset, std::ios_base::seekdir whence, std::ios_base::openmode mode) -> pos_type
-{
-    if(mFile == INVALID_HANDLE_VALUE || (mode&std::ios_base::out) || !(mode&std::ios_base::in))
-        return traits_type::eof();
-
-    LARGE_INTEGER fpos{};
-    switch(whence)
-    {
-        case std::ios_base::beg:
-            fpos.QuadPart = offset;
-            if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_BEGIN))
-                return traits_type::eof();
-            break;
-
-        case std::ios_base::cur:
-            // If the offset remains in the current buffer range, just
-            // update the pointer.
-            if((offset >= 0 && offset < off_type(egptr()-gptr())) ||
-                (offset < 0 && -offset <= off_type(gptr()-eback())))
-            {
-                // Get the current file offset to report the correct read
-                // offset.
-                fpos.QuadPart = 0;
-                if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_CURRENT))
-                    return traits_type::eof();
-                setg(eback(), gptr()+offset, egptr());
-                return fpos.QuadPart - off_type(egptr()-gptr());
-            }
-            // Need to offset for the file offset being at egptr() while
-            // the requested offset is relative to gptr().
-            offset -= off_type(egptr()-gptr());
-            fpos.QuadPart = offset;
-            if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_CURRENT))
-                return traits_type::eof();
-            break;
-
-        case std::ios_base::end:
-            fpos.QuadPart = offset;
-            if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_END))
-                return traits_type::eof();
-            break;
-
-        default:
-            return traits_type::eof();
-    }
-    setg(nullptr, nullptr, nullptr);
-    return fpos.QuadPart;
-}
-
-auto filebuf::seekpos(pos_type pos, std::ios_base::openmode mode) -> pos_type
-{
-    // Simplified version of seekoff
-    if(mFile == INVALID_HANDLE_VALUE || (mode&std::ios_base::out) || !(mode&std::ios_base::in))
-        return traits_type::eof();
-
-    LARGE_INTEGER fpos{};
-    fpos.QuadPart = pos;
-    if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_BEGIN))
-        return traits_type::eof();
-
-    setg(nullptr, nullptr, nullptr);
-    return fpos.QuadPart;
-}
-
-filebuf::~filebuf()
-{ close(); }
-
-bool filebuf::open(const wchar_t *filename, std::ios_base::openmode mode)
-{
-    if((mode&std::ios_base::out) || !(mode&std::ios_base::in))
-        return false;
-    HANDLE f{CreateFileW(filename, GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING,
-        FILE_ATTRIBUTE_NORMAL, nullptr)};
-    if(f == INVALID_HANDLE_VALUE) return false;
-
-    if(mFile != INVALID_HANDLE_VALUE)
-        CloseHandle(mFile);
-    mFile = f;
-
-    setg(nullptr, nullptr, nullptr);
-    return true;
-}
-bool filebuf::open(const char *filename, std::ios_base::openmode mode)
-{
-    std::wstring wname{utf8_to_wstr(filename)};
-    return open(wname.c_str(), mode);
-}
-
-void filebuf::close()
-{
-    if(mFile != INVALID_HANDLE_VALUE)
-        CloseHandle(mFile);
-    mFile = INVALID_HANDLE_VALUE;
-}
-
-
-ifstream::ifstream(const wchar_t *filename, std::ios_base::openmode mode)
-  : std::istream{nullptr}
-{
-    init(&mStreamBuf);
-
-    // Set the failbit if the file failed to open.
-    if((mode&std::ios_base::out) || !mStreamBuf.open(filename, mode|std::ios_base::in))
-        clear(failbit);
-}
-
 ifstream::ifstream(const char *filename, std::ios_base::openmode mode)
-  : std::istream{nullptr}
-{
-    init(&mStreamBuf);
+  : std::ifstream{utf8_to_wstr(filename).c_str(), mode}
+{ }
 
-    // Set the failbit if the file failed to open.
-    if((mode&std::ios_base::out) || !mStreamBuf.open(filename, mode|std::ios_base::in))
-        clear(failbit);
+void ifstream::open(const char *filename, std::ios_base::openmode mode)
+{
+    std::wstring wstr{utf8_to_wstr(filename)};
+    std::ifstream::open(wstr.c_str(), mode);
 }
 
-/* This is only here to ensure the compiler doesn't define an implicit
- * destructor, which it tries to automatically inline and subsequently complain
- * it can't inline without excessive code growth.
- */
-ifstream::~ifstream() { }
+ifstream::~ifstream() = default;
 
 } // namespace al
 
diff --git a/common/alfstream.h b/common/alfstream.h
index 353fd2de..62b2e12c 100644
--- a/common/alfstream.h
+++ b/common/alfstream.h
@@ -3,57 +3,29 @@
 
 #ifdef _WIN32
 
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-
-#include <array>
 #include <string>
 #include <fstream>
 
 
 namespace al {
 
-// Windows' std::ifstream fails with non-ANSI paths since the standard only
-// specifies names using const char* (or std::string). MSVC has a non-standard
-// extension using const wchar_t* (or std::wstring?) to handle Unicode paths,
-// but not all Windows compilers support it. So we have to make our own istream
-// that accepts UTF-8 paths and forwards to Unicode-aware I/O functions.
-class filebuf final : public std::streambuf {
-    std::array<char_type,4096> mBuffer;
-    HANDLE mFile{INVALID_HANDLE_VALUE};
-
-    int_type underflow() override;
-    pos_type seekoff(off_type offset, std::ios_base::seekdir whence, std::ios_base::openmode mode) override;
-    pos_type seekpos(pos_type pos, std::ios_base::openmode mode) override;
-
+// Inherit from std::ifstream to accept UTF-8 filenames
+class ifstream final : public std::ifstream {
 public:
-    filebuf() = default;
-    ~filebuf() override;
+    explicit ifstream(const char *filename, std::ios_base::openmode mode=std::ios_base::in);
+    explicit ifstream(const std::string &filename, std::ios_base::openmode mode=std::ios_base::in)
+        : ifstream{filename.c_str(), mode} { }
 
-    bool open(const wchar_t *filename, std::ios_base::openmode mode);
-    bool open(const char *filename, std::ios_base::openmode mode);
+    explicit ifstream(const wchar_t *filename, std::ios_base::openmode mode=std::ios_base::in)
+        : std::ifstream{filename, mode} { }
+    explicit ifstream(const std::wstring &filename, std::ios_base::openmode mode=std::ios_base::in)
+        : ifstream{filename.c_str(), mode} { }
 
-    bool is_open() const noexcept { return mFile != INVALID_HANDLE_VALUE; }
-
-    void close();
-};
+    void open(const char *filename, std::ios_base::openmode mode=std::ios_base::in);
+    void open(const std::string &filename, std::ios_base::openmode mode=std::ios_base::in)
+    { open(filename.c_str(), mode); }
 
-// Inherit from std::istream to use our custom streambuf
-class ifstream final : public std::istream {
-    filebuf mStreamBuf;
-
-public:
-    ifstream(const wchar_t *filename, std::ios_base::openmode mode = std::ios_base::in);
-    ifstream(const std::wstring &filename, std::ios_base::openmode mode = std::ios_base::in)
-      : ifstream(filename.c_str(), mode) { }
-    ifstream(const char *filename, std::ios_base::openmode mode = std::ios_base::in);
-    ifstream(const std::string &filename, std::ios_base::openmode mode = std::ios_base::in)
-      : ifstream(filename.c_str(), mode) { }
     ~ifstream() override;
-
-    bool is_open() const noexcept { return mStreamBuf.is_open(); }
-
-    void close() { mStreamBuf.close(); }
 };
 
 } // namespace al
@@ -64,7 +36,6 @@ public:
 
 namespace al {
 
-using filebuf = std::filebuf;
 using ifstream = std::ifstream;
 
 } // namespace al
diff --git a/core/ambdec.cpp b/core/ambdec.cpp
index 4e4c7e1e..db8f45ab 100644
--- a/core/ambdec.cpp
+++ b/core/ambdec.cpp
@@ -15,7 +15,7 @@
 #include "albit.h"
 #include "alfstream.h"
 #include "alspan.h"
-#include "core/logging.h"
+#include "opthelpers.h"
 
 
 namespace {