Testing validity of the data without the actual decompression

[nyurik]

My sqlite-compression extension needs to support gzip testing in addition to compression/decompression. Currently I do it with decode(data).is_ok(), but that causes a lot of unnecessary memory allocation and possibly other steps. Is there a way to efficiently validate the content of the gzip stream without allocating/re-allocating output buffers?

[Byron]

I don't think there is an official 'validate' call in Gzip, and thus would think decompression is the only way to validate a Gzip stream.
However, it should be possible to decode the stream in chunks and reuse a smaller buffer until done, which then could easily live on the stack. Unfortunately the INFLATE algorithm still allocates a lot during normal operation, making this only a partial fix.