(PHP 7)
deflate_init — Initialize an incremental deflate context
$encoding
[, array $options = array()
] )
Initializes an incremental deflate context using the specified
encoding.
Note that the window option here only sets the window size
of the algorithm, differently from the zlib filters where the same parameter
also sets the encoding to use; the encoding must be set with the
encoding parameter.
Limitation: there is currently no way to set the header information on a GZIP compressed stream, which are set as follows: GZIP signature (\x1f\x8B); compression method (\x08 == DEFLATE); 6 zero bytes; the operating system set to the current system (\x00 = Windows, \x03 = Unix, etc.)
encoding
One of the ZLIB_ENCODING_* constants.
optionsAn associative array which may contain the following elements:
The compression level in range -1..9; defaults to -1.
The compression memory level in range 1..9; defaults to 8.
The zlib window size (logarithmic) in range 8..15; defaults to 15.
One of ZLIB_FILTERED,
ZLIB_HUFFMAN_ONLY, ZLIB_RLE,
ZLIB_FIXED or
ZLIB_DEFAULT_STRATEGY (the default).
A string or an array of strings of the preset dictionary (default: no preset dictionary).
Returns a deflate context resource (zlib.deflate) on
success, 或者在失败时返回 FALSE.
If an invalid option is passed to options or the
context couldn't be created, an error of level E_WARNING
is generated.