decoder output buffer would receive a wrong size.
In previous version, ZSTD_decompressStream() would blindly trust the caller that pos <= size.
In this version, this condition is actively checked,
and the function returns an error code if this condition is not respected.
This check could also be done with an assert(),
but since this is a user-facing interface, it seems better to keep this check at runtime.
* Maximum window size in 32-bit mode is 1GB, since allocations for 2GB fail
on my Mac.
* Maximum window size in 64-bit mode is 2GB, since that is the largest
power of 2 that works with the overflow prevention.
* Allow `--long=windowLog` to set the window log, along with
`--zstd=wlog=#`. These options also set the window size during
decompression, but don't override `--memory=#` if it is set.
* Present a helpful error message when the window size is too large during
decompression.
* The long range matcher defaults to a hash log 7 less than the window log,
which keeps it at 20 for window log 27.
* Keep the default long range matcher window size and the default maximum
window size at 27 for the API and CLI.
* Add tests that use the maximum window size and hash size for compression
and decompression.
ZSTD_estimateCDictSize() now uses same arguments as ZSTD_createCDict()
ZSTD_estimateCDictSize_advanced() uses same arguments as ZSTD_createCDict_advanced()
--no-big-tests is typically used in combination with qemu-user-static
qemu-user-static allocated 4 GB of RAM upfront.
On 2 GB VM, this can degenerate into a crash.
It's not a problem as long as memory is not used.
But with multi-threading enabled, memory fragmentation kicks in,
so the amoung of RAM effectively touched increases,
and can pass beyond the 2 GB limit of the VM.
In single-threaded mode, there is no such issue :
memory requirement is smaller, and remains well-located,
so very little fragmentation is expected.
This modification should make `qemu-arm-static zstreamtests --newapi --no-big-tests`
work fine on Travis CI.
