libcxx/test/std/input.output/file.streams/fstreams/filebuf.virtuals/seekoff.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <fstream>
  10
  11 // pos_type seekoff(off_type off, ios_base::seekdir way,
  12 //                  ios_base::openmode which = ios_base::in | ios_base::out);
  13 // pos_type seekpos(pos_type sp,
  14 //                  ios_base::openmode which = ios_base::in | ios_base::out);
  15
  16 #include <fstream>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20
  21 int main(int, char**)
  22 {
  23     {
  24         char buf[10];
  25         typedef std::filebuf::pos_type pos_type;
  26         std::filebuf f;
  27         f.pubsetbuf(buf, sizeof(buf));
  28         assert(f.open("seekoff.dat", std::ios_base::in | std::ios_base::out
  29                                                        | std::ios_base::trunc) != 0);
  30         assert(f.is_open());
  31         f.sputn("abcdefghijklmnopqrstuvwxyz", 26);
  32         LIBCPP_ASSERT(buf[0] == 'v');
  33         pos_type p = f.pubseekoff(-15, std::ios_base::cur);
  34         assert(p == 11);
  35         assert(f.sgetc() == 'l');
  36         f.pubseekoff(0, std::ios_base::beg);
  37         assert(f.sgetc() == 'a');
  38         f.pubseekoff(-1, std::ios_base::end);
  39         assert(f.sgetc() == 'z');
  40         assert(f.pubseekpos(p) == p);
  41         assert(f.sgetc() == 'l');
  42     }
  43     std::remove("seekoff.dat");
  44
  45 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  46     {
  47         wchar_t buf[10];
  48         typedef std::filebuf::pos_type pos_type;
  49         std::wfilebuf f;
  50         f.pubsetbuf(buf, sizeof(buf)/sizeof(buf[0]));
  51         assert(f.open("seekoff.dat", std::ios_base::in | std::ios_base::out
  52                                                        | std::ios_base::trunc) != 0);
  53         assert(f.is_open());
  54         f.sputn(L"abcdefghijklmnopqrstuvwxyz", 26);
  55         LIBCPP_ASSERT(buf[0] == L'v');
  56         pos_type p = f.pubseekoff(-15, std::ios_base::cur);
  57         assert(p == 11);
  58         assert(f.sgetc() == L'l');
  59         f.pubseekoff(0, std::ios_base::beg);
  60         assert(f.sgetc() == L'a');
  61         f.pubseekoff(-1, std::ios_base::end);
  62         assert(f.sgetc() == L'z');
  63         assert(f.pubseekpos(p) == p);
  64         assert(f.sgetc() == L'l');
  65     }
  66     std::remove("seekoff.dat");
  67 #endif
  68
  69   return 0;
  70 }