common/alfstream.cpp

   1
   2 #include "config.h"
   3
   4 #include "alfstream.h"
   5
   6 #include "strutils.h"
   7
   8 #ifdef _WIN32
   9
  10 namespace al {
  11
  12 auto filebuf::underflow() -> int_type
  13 {
  14     if(mFile != INVALID_HANDLE_VALUE && gptr() == egptr())
  15     {
  16         // Read in the next chunk of data, and set the pointers on success
  17         DWORD got{};
  18         if(ReadFile(mFile, mBuffer.data(), static_cast<DWORD>(mBuffer.size()), &got, nullptr))
  19             setg(mBuffer.data(), mBuffer.data(), mBuffer.data()+got);
  20     }
  21     if(gptr() == egptr())
  22         return traits_type::eof();
  23     return traits_type::to_int_type(*gptr());
  24 }
  25
  26 auto filebuf::seekoff(off_type offset, std::ios_base::seekdir whence, std::ios_base::openmode mode) -> pos_type
  27 {
  28     if(mFile == INVALID_HANDLE_VALUE || (mode&std::ios_base::out) || !(mode&std::ios_base::in))
  29         return traits_type::eof();
  30
  31     LARGE_INTEGER fpos{};
  32     switch(whence)
  33     {
  34         case std::ios_base::beg:
  35             fpos.QuadPart = offset;
  36             if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_BEGIN))
  37                 return traits_type::eof();
  38             break;
  39
  40         case std::ios_base::cur:
  41             // If the offset remains in the current buffer range, just
  42             // update the pointer.
  43             if((offset >= 0 && offset < off_type(egptr()-gptr())) ||
  44                 (offset < 0 && -offset <= off_type(gptr()-eback())))
  45             {
  46                 // Get the current file offset to report the correct read
  47                 // offset.
  48                 fpos.QuadPart = 0;
  49                 if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_CURRENT))
  50                     return traits_type::eof();
  51                 setg(eback(), gptr()+offset, egptr());
  52                 return fpos.QuadPart - off_type(egptr()-gptr());
  53             }
  54             // Need to offset for the file offset being at egptr() while
  55             // the requested offset is relative to gptr().
  56             offset -= off_type(egptr()-gptr());
  57             fpos.QuadPart = offset;
  58             if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_CURRENT))
  59                 return traits_type::eof();
  60             break;
  61
  62         case std::ios_base::end:
  63             fpos.QuadPart = offset;
  64             if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_END))
  65                 return traits_type::eof();
  66             break;
  67
  68         default:
  69             return traits_type::eof();
  70     }
  71     setg(nullptr, nullptr, nullptr);
  72     return fpos.QuadPart;
  73 }
  74
  75 auto filebuf::seekpos(pos_type pos, std::ios_base::openmode mode) -> pos_type
  76 {
  77     // Simplified version of seekoff
  78     if(mFile == INVALID_HANDLE_VALUE || (mode&std::ios_base::out) || !(mode&std::ios_base::in))
  79         return traits_type::eof();
  80
  81     LARGE_INTEGER fpos{};
  82     fpos.QuadPart = pos;
  83     if(!SetFilePointerEx(mFile, fpos, &fpos, FILE_BEGIN))
  84         return traits_type::eof();
  85
  86     setg(nullptr, nullptr, nullptr);
  87     return fpos.QuadPart;
  88 }
  89
  90 filebuf::~filebuf()
  91 {
  92     if(mFile != INVALID_HANDLE_VALUE)
  93         CloseHandle(mFile);
  94     mFile = INVALID_HANDLE_VALUE;
  95 }
  96
  97 bool filebuf::open(const wchar_t *filename, std::ios_base::openmode mode)
  98 {
  99     if((mode&std::ios_base::out) || !(mode&std::ios_base::in))
 100         return false;
 101     HANDLE f{CreateFileW(filename, GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING,
 102         FILE_ATTRIBUTE_NORMAL, nullptr)};
 103     if(f == INVALID_HANDLE_VALUE) return false;
 104
 105     if(mFile != INVALID_HANDLE_VALUE)
 106         CloseHandle(mFile);
 107     mFile = f;
 108
 109     setg(nullptr, nullptr, nullptr);
 110     return true;
 111 }
 112 bool filebuf::open(const char *filename, std::ios_base::openmode mode)
 113 {
 114     std::wstring wname{utf8_to_wstr(filename)};
 115     return open(wname.c_str(), mode);
 116 }
 117
 118
 119 ifstream::ifstream(const wchar_t *filename, std::ios_base::openmode mode)
 120   : std::istream{nullptr}
 121 {
 122     init(&mStreamBuf);
 123
 124     // Set the failbit if the file failed to open.
 125     if((mode&std::ios_base::out) || !mStreamBuf.open(filename, mode|std::ios_base::in))
 126         clear(failbit);
 127 }
 128
 129 ifstream::ifstream(const char *filename, std::ios_base::openmode mode)
 130   : std::istream{nullptr}
 131 {
 132     init(&mStreamBuf);
 133
 134     // Set the failbit if the file failed to open.
 135     if((mode&std::ios_base::out) || !mStreamBuf.open(filename, mode|std::ios_base::in))
 136         clear(failbit);
 137 }
 138
 139 /* This is only here to ensure the compiler doesn't define an implicit
 140  * destructor, which it tries to automatically inline and subsequently complain
 141  * it can't inline without excessive code growth.
 142  */
 143 ifstream::~ifstream() { }
 144
 145 } // namespace al
 146
 147 #endif