class DumpFile

Map the file in if possible, falling back to reading via stdio.

Returns true if the probed bytes indicate a compressed file. The buffer

is expected to be at least kHeaderProbeSize to be able to match anything.

Return a new DumpFile that decompresses part of this one by doing

ReadEphemeral calls on it. The new DumpFile's lifetime must not exceed

this object's lifetime. The underlying object should not be used for

ReadEphemeral while the decompressor object is being used.

Return the size of the file. This may not be known for a streaming input,

in which case this value acts only as an upper bound.

Reduce resources when no more reading will be done but the object is kept

alive for ReadPermanent results.

Read a range of the file, yielding a pointer that's valid as long as this

object lives. When not doing mmap, this has to copy it all in memory.

Read a range of the file, yielding a pointer that's only guaranteed to be

valid until the next ReadEphemeral (or ReadProbe) call on the same object.

This does ReadEphemeral (and so it invalidates past ReadEphemeral results

and vice versa), but if the dump file ends before the whole range, just

return a shorter range rather than the "truncated dump" error.

Read a range of the file, yielding a Buffer object whose lifetime is tied

to the lifetime of this DumpFile object. The given range is the minimum

range that must be read. If less is available, failure is returned

(possibly using the "truncated dump" error). More may be returned if it

is conveniently at hand.