... Though in the only place where these summaries are used, which is
Sequence::GetWaveDisplay, we ignore the correctly reported error code anyway.
Also RAII in management of relevant memory buffers and mutexes.
... also replace explicit mutex locking with RAII and atomics.
This is a part of the big project that handles failure to write block files, as
from disk exhaustion. ODDecodeBlockFile::WriteODDecodeBlockFile is the one
place calling WriteSimpleBlockFile but not (as in SimpleBlockFile constructor)
throwing an exception.
It is called only when attempting to recover files at open time, or in worker
threads in an EXPERIMENTAL code branch.
... whenever they really describe the size of a buffer that fits in memory, or
of a block file (which is never now more than a megabyte and so could be fit in
memory all at once), or a part thereof.
... A non-narrowing conversion out to long long is a necessity, but the
conversions to float and double are simply conveniences.
Conversion from floating is explicit, to avoid unintended consequences with
arithmetic operators, when later sampleCount ceases to be an alias for an
integral type.
Some conversions are not made explicit, where I expect to change the type of
the variable later to have mere size_t width.
... And in some places where a library uses signed types, assert that
the reported number is not negative.
What led me to this, is that there are many places where a size_t value for
an allocation is the product of a number of channels and some other number.
...They may never have been large enough to matter, but some seek offsets into
files were written as 64 bits but read back as only 32. It ought to be
consistent.
... for functions in final classes.
override is like const -- it's not necessary, but it helps the compiler to
catch mistakes.
There may be some overriding functions not explicitly declared virtual and I did
not identify such cases, in which I might also add override.
... Should have no effect on generated code, except perhaps some slight faster
virtual function calls. Mostly useful as documentation of design intent.
Tried to mark every one of our classes that inherits from another, or is a
base for others, or has abstract virtual functions, and a few others besides.
