diff options
Diffstat (limited to 'tests/fdstream')
| -rw-r--r-- | tests/fdstream/driver.cxx | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/tests/fdstream/driver.cxx b/tests/fdstream/driver.cxx index 675a66e..01da9fb 100644 --- a/tests/fdstream/driver.cxx +++ b/tests/fdstream/driver.cxx @@ -482,6 +482,286 @@ main (int argc, const char* argv[]) #endif + // Test setting and getting position via the non-standard fdbuf interface. + // + // Seek for read. + // + { + to_file (f, "012\n3\n4567", fdopen_mode::truncate); + + ifdstream is (f); + + fdbuf* buf (dynamic_cast<fdbuf*> (is.rdbuf ())); + assert (buf != nullptr); + + char c; + for (size_t i (0); i < 7; ++i) + is.get (c); + + uint64_t p (buf->tellg ()); + assert (p == 7); + + is.get (c); + assert (c == '5'); + + buf->seekg (p); + assert (buf->tellg () == p); + + is.get (c); + assert (c == '5'); + + // Can't seek beyond the end of the stream. + // + try + { + buf->seekg (20); + assert (false); + } + catch (const ios::failure&) {} + } + + // Seek for write. + // + { + // Let's test replacing the '3' fragment with 'XYZ' in the following file. + // + to_file (f, "012\n3\n4567", fdopen_mode::truncate); + + auto_fd fd; + string suffix; + size_t p (4); // Logical position of the fragment being replaced. + + { + ifdstream is (f, fdopen_mode::in | fdopen_mode::out); + + fdbuf* buf (dynamic_cast<fdbuf*> (is.rdbuf ())); + assert (buf != nullptr); + + // Read till the end of the fragment. + // + char c; + for (size_t i (0); i < p + 1; ++i) + is.get (c); + + assert (c == '3'); + + // Read the suffix. + // + suffix = is.read_text (); + assert (suffix == "\n4567"); + + // Seek to the beginning of the fragment and detach the file descriptor. + // + buf->seekg (p); + fd = is.release (); + } + + // Rewrite the fragment. + // + // Note that on Windows in the text mode the logical position differs from + // the file descriptor position, so we need to query the later one to + // truncate the file. + // + fdtruncate (fd.get (), fdseek (fd.get (), 0, fdseek_mode::cur)); + + ofdstream os (move (fd), ofdstream::badbit | ofdstream::failbit, p); + + os << "XYZ" << suffix; + os.close (); + + assert (from_file (f) == "012\nXYZ\n4567"); + } + + // Test setting and getting position via the standard [io]stream interface. + // + to_file (f, "0123456789", fdopen_mode::truncate); + + // Seek for read. + // + { + ifdstream is (f); + + char c; + is.get (c); + + is.seekg (5, ios::beg); + is.get (c); + assert (c == '5'); + + is.seekg (2, ios::cur); + + assert (static_cast<streamoff> (is.tellg ()) == 8); + + const fdbuf* buf (dynamic_cast<const fdbuf*> (is.rdbuf ())); + assert (buf != nullptr && buf->tellg () == 8); + + assert (from_stream (is) == "89"); + } + + // Seek for write. + // + { + ofdstream os (f, fdopen_mode::out); + os.seekp (4, ios::beg); + os << "ABC"; + os.seekp (-4, ios::end); + os << "XYZ"; + os.seekp (-8, ios::cur); + os << 'C'; + + assert (static_cast<streamoff> (os.tellp ()) == 2); + + const fdbuf* buf (dynamic_cast<const fdbuf*> (os.rdbuf ())); + assert (buf != nullptr && buf->tellp () == 2); + + os.close (); + assert (from_file (f) == "0C23ABXYZ9"); + } + +#ifdef _WIN32 + + // Test handling newline characters on Windows while setting and getting + // position via the standard [io]stream interface. + // + // Save the string in the text mode, so the newline character is translated + // into the 0xD, 0xA character sequence on Windows. + // + to_file (f, "01234\n56789", fdopen_mode::truncate); + + // Seek for read in the text mode. + // + { + ifdstream is (f); + + char c; + is.get (c); + + is.seekg (2, ios::cur); + is.get (c); + + assert (c == '3'); + + is.seekg (4, ios::cur); + + assert (static_cast<streamoff> (is.tellg ()) == 8); + assert (from_stream (is) == "6789"); + } + + // Seek for read in the binary mode. + // + { + ifdstream is (f, ios::binary); + + char c; + is.get (c); + + is.seekg (2, ios::cur); + is.get (c); + + assert (c == '3'); + + is.seekg (4, ios::cur); + + assert (static_cast<streamoff> (is.tellg ()) == 8); + + const fdbuf* buf (dynamic_cast<const fdbuf*> (is.rdbuf ())); + assert (buf != nullptr && buf->tellp () == 8); + + assert (from_stream (is) == "6789"); + } + + // Research the positioning misbehavior of std::ifstream object opened + // in the text mode on Windows. + // +#if 0 + + to_file (f, "012\r\n3\n4567", fdopen_mode::truncate | fdopen_mode::binary); + + { + ifstream is (f.string ()); +// ifdstream is (f); + + char c1; + for (size_t i (0); i < 2; ++i) + is.get (c1); + + is.seekg (6, ios::cur); + + streamoff p1 (is.tellg ()); + + is.get (c1); + + cout << "c1: '" << c1 << "' pos " << p1 << endl; + + char c2; + is.seekg (8, ios::beg); + + streamoff p2 (is.tellg ()); + is.get (c2); + + cout << "c2: '" << c2 << "' pos " << p2 << endl; + + // One could expect the positions and characters to match, but: + // + // VC's ifstream and ifdstream end up with: + // + // c1: '4' pos 7 + // c2: '5' pos 8 + // + // MinGW's ifstream ends up with: + // + // c1: '6' pos 9 + // c2: '5' pos 8 + // + // These assertions fail for all implementations: + // + // assert (p1 == p2); + // assert (c1 == c2); + } + + { + ifstream is (f.string ()); +// ifdstream is (f); + + char c1; + for (size_t i (0); i < 2; ++i) + is.get (c1); + + auto p1 (is.tellg ()); + is.get (c1); + + cout << "c1: '" << c1 << "' pos " << p1 << endl; + + is.seekg (p1, ios::beg); + + auto p2 (is.tellg ()); + + char c2; + is.get (c2); + + cout << "c2: '" << c2 << "' pos " << p2 << endl; + + // One could expect the positions and characters to match, but: + // + // VC's ifstream and ifdstream end up with: + // + // c1: '2' pos 1 + // c2: '1' pos 1 + // + // MinGW's ifstream ends up with: + // + // c1: '2' pos 3 + // c2: '\n' pos 3 + // + // This assertion fails for all implementations: + // + // assert (c1 == c2); + } + +#endif + +#endif + // Test pipes. // // Here we rely on buffering being always enabled for pipes. |