source/io/seekable.cpp

   1 #ifndef WIN32
   2 #define _LARGEFILE64_SOURCE
   3 #include <cerrno>
   4 #include <unistd.h>
   5 #else
   6 #include <windows.h>
   7 #endif
   8 #include <msp/core/systemerror.h>
   9 #include <msp/strings/format.h>
  10 #include "handle.h"
  11 #include "handle_private.h"
  12 #include "seekable.h"
  13
  14 using namespace std;
  15
  16 namespace {
  17
  18 using namespace Msp::IO;
  19
  20 int sys_seek_type(SeekType st)
  21 {
  22 #ifdef WIN32
  23         if(st==S_BEG)
  24                 return FILE_BEGIN;
  25         else if(st==S_CUR)
  26                 return FILE_CURRENT;
  27         else if(st==S_END)
  28                 return FILE_END;
  29 #else
  30         if(st==S_BEG)
  31                 return SEEK_SET;
  32         else if(st==S_CUR)
  33                 return SEEK_CUR;
  34         else if(st==S_END)
  35                 return SEEK_END;
  36 #endif
  37
  38         throw invalid_argument("sys_seek_type");
  39 }
  40
  41 } // namespace
  42
  43
  44 namespace Msp {
  45 namespace IO {
  46
  47 bad_seek::bad_seek(SeekOffset offset, SeekType type):
  48         runtime_error(type==S_BEG ? lexical_cast<string>(offset) :
  49                 type==S_CUR ? format("CUR%+d", offset) :
  50                 type==S_END ? format("END%+d", offset) :
  51                 format("SeekType(%d)", type))
  52 { }
  53
  54
  55 SeekOffset sys_seek(Handle &handle, SeekOffset offset, SeekType type)
  56 {
  57 #ifdef WIN32
  58         LONG high = offset>>32;
  59         DWORD ret = SetFilePointer(*handle, offset, &high, sys_seek_type(type));
  60         if(ret==INVALID_SET_FILE_POINTER)
  61         {
  62                 DWORD err = GetLastError();
  63                 if(err!=NO_ERROR)
  64                         throw system_error("SetFilePointer");
  65         }
  66
  67         return (SeekOffset(high)<<32) | ret;
  68 #else
  69         off64_t ret = lseek64(*handle, offset, sys_seek_type(type));
  70         if(ret==(off64_t)-1)
  71         {
  72                 if(errno==EINVAL)
  73                         throw bad_seek(offset, type);
  74                 else
  75                         throw system_error("lseek64");
  76         }
  77
  78         return ret;
  79 #endif
  80 }
  81
  82 } // namespace IO
  83 } // namespace Msp