EBML::minSize() chose the size length for an element's data size with
<= at each limit, so a size of exactly 2^(7n) - 1 (127, 16383, 2097151,
...) was rendered in n bytes with every value bit set. That is the
reserved "unknown size" value (RFC 8794 section 6.2), so a reader no
longer knows where the element ends. A tag value of exactly 127 bytes,
for example, saves without error but reads back as an empty string.
minSize() also returned 0 for any size from 0x7FFFFFFFF (32 GiB) up, so
renderVINT() wrote a size of zero bytes. Sizes up to 2^56 - 2 now use
size lengths 6 to 8; larger sizes still return 0, as no size length can
hold them.
testElementSizeLength checks minSize() on either side of the limit of
each size length from 1 to 8 bytes. testSaveElementSizeAtLengthLimit
saves titles of 126 to 128 and 16382 to 16384 bytes to no-tags.mka and
reads them back.
Ryan FrancesconiandGitHub
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