deflate_init
(PHP 7)
deflate_init — Initialize an incremental deflate context
说明
$encoding [,
array $options = array() ] ) :
resource
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.)
参数
-
encoding -
One of the
ZLIB_ENCODING_*constants. -
options -
An associative array which may contain the following elements:
- level
-
The compression level in range -1..9; defaults to -1.
- memory
-
The compression memory level in range 1..9; defaults to 8.
- window
-
The zlib window size (logarithmic) in range 8..15; defaults to 15.
- strategy
-
One of
ZLIB_FILTERED,ZLIB_HUFFMAN_ONLY,ZLIB_RLE,ZLIB_FIXEDorZLIB_DEFAULT_STRATEGY(the default). - dictionary
-
A string or an array of strings of the preset dictionary (default: no preset dictionary).
返回值
Returns a deflate context resource (zlib.deflate) on success, 或者在失败时返回 FALSE.
错误／异常
If an invalid option is passed to options or the context couldn't be created, an error of level E_WARNING is generated.
参见
- deflate_add() - Incrementally deflate data
- inflate_init() - Initialize an incremental inflate context
