Boost C++ Libraries

Update the compression level and strategy.

Synopsis

void
params(
    z_params& zs,
    int level,
    Strategy strategy,
    error_code& ec);

Description

This function dynamically updates the compression level and compression strategy. The interpretation of level and strategy is as in reset. This can be used to switch between compression and straight copy of the input data, or to switch to a different kind of input data requiring a different strategy. If the compression level is changed, the input available so far is compressed with the old level (and may be flushed); the new level will take effect only at the next call of write.

Before the call of params, the stream state must be set as for a call of write, since the currently available input may have to be compressed and flushed. In particular, zs.avail_out must be non-zero.

Return Value

Z_OK if success, Z_STREAM_ERROR if the source stream state was inconsistent or if a parameter was invalid, error::need_buffers if zs.avail_out was zero.