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Gz
Gz.deflate
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Method Gz.deflate()->create()
- Method
create
void Gz.deflate(int(-9..9)|void level, int|void strategy, int(8..15)|void window_size)
- Description
This function can also be used to re-initialize a Gz.deflate object
so it can be re-used.
- Parameter level
Indicates the level of effort spent to make the data compress
well. Zero means no packing, 2-3 is considered 'fast', 6 is
default and higher is considered 'slow' but gives better
packing.
If the argument is negative, no headers will be emitted. This is
needed to produce ZIP-files, as an example. The negative value
is then negated, and handled as a positive value.
- Parameter strategy
The strategy to be used when compressing the data. One of the
following.
DEFAULT_STRATEGY | The default strategy as selected in the zlib library.
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FILTERED | This strategy is intented for data created by a filter or
predictor and will put more emphasis on huffman encoding and
less on LZ string matching. This is between DEFAULT_STRATEGY
and HUFFMAN_ONLY.
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RLE | This strategy is even closer to the HUFFMAN_ONLY in that it
only looks at the latest byte in the window, i.e. a window
size of 1 byte is sufficient for decompression. This mode is
not available in all zlib versions.
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HUFFMAN_ONLY | This strategy will turn of string matching completely, only
doing huffman encoding. Window size doesn't matter in this
mode and the data can be decompressed with a zero size window.
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FIXED | In this mode dynamic huffman codes are disabled, allowing for
a simpler decoder for special applications. This mode is not
available in all zlib versions.
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- Parameter window_size
Defines the size of the LZ77 window from 256 bytes to 32768
bytes, expressed as 2^x.
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