source/io/seekable.cpp

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