diff options
| author | Carl Hetherington <cth@carlh.net> | 2020-10-07 01:02:47 +0200 |
|---|---|---|
| committer | Carl Hetherington <cth@carlh.net> | 2020-10-13 18:51:11 +0200 |
| commit | e5277d4042b896c4b50c694fba0f1afb47337f45 (patch) | |
| tree | 774c47252813040503a256105466d249114c44b0 | |
| parent | a6f1c4deaf0ddbf0197b286d0d5f1a107a487deb (diff) | |
Fix errors when over-reading a "large" amount from FileGroups on
Windows. I haven't been able to find any conclusive explanation for
why this stuff happens;
https://stackoverflow.com/questions/7241168/safe-maximum-number-of-records-read-by-fread
is one possible lead.
| -rw-r--r-- | src/lib/file_group.cc | 13 | ||||
| -rw-r--r-- | src/lib/file_group.h | 1 |
2 files changed, 13 insertions, 1 deletions
diff --git a/src/lib/file_group.cc b/src/lib/file_group.cc index 3e8a7b79c..9863a21cb 100644 --- a/src/lib/file_group.cc +++ b/src/lib/file_group.cc @@ -37,6 +37,7 @@ using std::cout; FileGroup::FileGroup () : _current_path (0) , _current_file (0) + , _current_size (0) { } @@ -45,6 +46,7 @@ FileGroup::FileGroup () FileGroup::FileGroup (boost::filesystem::path p) : _current_path (0) , _current_file (0) + , _current_size (0) { _paths.push_back (p); ensure_open_path (0); @@ -95,6 +97,7 @@ FileGroup::ensure_open_path (size_t p) const if (_current_file == 0) { throw OpenFileError (_paths[_current_path], errno, OpenFileError::READ); } + _current_size = boost::filesystem::file_size (_paths[_current_path]); } int64_t @@ -155,7 +158,15 @@ FileGroup::read (uint8_t* buffer, int amount) const { int read = 0; while (true) { - int const this_time = fread (buffer + read, 1, amount - read, _current_file); + int64_t to_read = amount - read; +#ifdef DCPOMATIC_WINDOWS + /* If we over-read from the file by too much on Windows we get a errno=22 rather than an feof condition, + * for unknown reasons. So if we're going to over-read, we need to do it by a little bit, so that feof + * still gets triggered but there is no errno=22. + */ + to_read = std::min(to_read, static_cast<int64_t>(_current_size - _ftelli64(_current_file) + 1)); +#endif + int const this_time = fread (buffer + read, 1, to_read, _current_file); read += this_time; if (read == amount) { /* Done */ diff --git a/src/lib/file_group.h b/src/lib/file_group.h index 800d9a059..21499f563 100644 --- a/src/lib/file_group.h +++ b/src/lib/file_group.h @@ -52,6 +52,7 @@ private: /** Index of path that we are currently reading from */ mutable size_t _current_path; mutable FILE* _current_file; + mutable size_t _current_size; }; #endif |