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Merge pull request #9047 from JosJuice/wia-header-heuristic 

DiscIO: Adjust WIA/RVZ header size heuristic
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LC 2020-09-01 17:58:51 -04:00 committed by GitHub
parent 936702bd04 bdd28c0edf
commit db067104ed
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1 changed files with 10 additions and 5 deletions
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15
Source/Core/DiscIO/WIABlob.cpp
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@ -1770,19 +1770,24 @@ WIARVZFileReader<RVZ>::Convert(BlobReader* infile, const VolumeDisc* infile_volu
const size_t raw_data_entries_size = raw_data_entries.size() * sizeof(RawDataEntry);
const size_t group_entries_size = group_entries.size() * sizeof(GroupEntry);
// Conservative estimate for how much space will be taken up by headers.
// The compression methods None and Purge have very predictable overhead,
// and the other methods are able to compress group entries well
// An estimate for how much space will be taken up by headers.
// We will reserve this much space at the beginning of the file, and if the headers don't
// fit on that space, we will need to write them at the end of the file instead.
const u64 headers_size_upper_bound = [&] {
// 0x100 is added to account for compression overhead (in particular for Purge).
u64 upper_bound = sizeof(WIAHeader1) + sizeof(WIAHeader2) + partition_entries_size +
raw_data_entries_size + 0x100;
// RVZ's added data in GroupEntry usually compresses well
// RVZ's added data in GroupEntry usually compresses well, so we'll assume the compression ratio
// for RVZ GroupEntries is 9 / 16 or better. This constant is somehwat arbitrarily chosen, but
// no games were found that get a worse compression ratio than that. There are some games that
// get a worse ratio than 1 / 2, such as Metroid: Other M (PAL) with the default settings.
if (RVZ && compression_type > WIARVZCompressionType::Purge)
upper_bound += group_entries_size / 2;
upper_bound += static_cast<u64>(group_entries_size) * 9 / 16;
else
upper_bound += group_entries_size;
// This alignment is also somewhat arbitrary.
return Common::AlignUp(upper_bound, VolumeWii::BLOCK_TOTAL_SIZE);
}();