source/io/seekable.cpp

   1 #ifndef WIN32
   2 #define _LARGEFILE64_SOURCE
   3 #else
   4 #include <windows.h>
   5 #endif
   6 #include <stdexcept>
   7 #include <msp/core/systemerror.h>
   8 #include "handle.h"
   9 #include "handle_private.h"
  10 #include "seekable.h"
  11
  12 using namespace std;
  13
  14 namespace {
  15
  16 using namespace Msp::IO;
  17
  18 int sys_seek_type(SeekType st)
  19 {
  20 #ifdef WIN32
  21         if(st==S_BEG)
  22                 return FILE_BEGIN;
  23         else if(st==S_CUR)
  24                 return FILE_CURRENT;
  25         else if(st==S_END)
  26                 return FILE_END;
  27 #else
  28         if(st==S_BEG)
  29                 return SEEK_SET;
  30         else if(st==S_CUR)
  31                 return SEEK_CUR;
  32         else if(st==S_END)
  33                 return SEEK_END;
  34 #endif
  35
  36         throw invalid_argument("sys_seek_type");
  37 }
  38
  39 } // namespace
  40
  41
  42 namespace Msp {
  43 namespace IO {
  44
  45 SeekOffset sys_seek(Handle &handle, SeekOffset offset, SeekType type)
  46 {
  47 #ifdef WIN32
  48         LONG high = offset>>32;
  49         DWORD ret = SetFilePointer(*handle, offset, &high, sys_seek_type(type));
  50         if(ret==INVALID_SET_FILE_POINTER)
  51         {
  52                 DWORD err = GetLastError();
  53                 if(err!=NO_ERROR)
  54                         throw system_error("SetFilePointer");
  55         }
  56
  57         return (SeekOffset(high)<<32) | ret;
  58 #else
  59         off64_t ret = lseek64(*handle, offset, sys_seek_type(type));
  60         if(ret==(off64_t)-1)
  61                 throw system_error("lseek64");
  62
  63         return ret;
  64 #endif
  65 }
  66
  67 } // namespace IO
  68 } // namespace Msp