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authorKaren Arutyunov <karen@codesynthesis.com>2018-12-09 01:18:10 +0300
committerKaren Arutyunov <karen@codesynthesis.com>2018-12-15 17:27:56 +0300
commit5bff24a8862f61e40f827591be5c81228efab4c6 (patch)
treecf509c18ecae91150ac51d1eea036dfa1d30eb5d /tests
parentcc8b52be1e02802ef82ff474721d78815ab4e63a (diff)
Add support for fdstream positioning
Diffstat (limited to 'tests')
-rw-r--r--tests/fdstream/driver.cxx280
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.