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Diffstat (limited to 'deflateInit.3')
| -rw-r--r--[l---------] | deflateInit.3 | 164 |
1 files changed, 163 insertions, 1 deletions
diff --git a/deflateInit.3 b/deflateInit.3 index 7d7a5e2..477e05a 120000..100644 --- a/deflateInit.3 +++ b/deflateInit.3 @@ -1 +1,163 @@ -deflate.3 \ No newline at end of file +.Dd November 9, 2018 +.Dt DEFLATEINIT 3 +.Os +. +.Sh NAME +.Nm deflateInit +.Nd initialize deflate stream +. +.Sh LIBRARY +.Lb libz +. +.Sh SYNOPSIS +.In zlib.h +. +.Ft typedef voidpf +.Fo (*alloc_func) +.Fa "voidpf opaque" +.Fa "uInt items" +.Fa "uInt size" +.Fc +. +.Ft typedef void +.Fo (*free_func) +.Fa "voidpf opaque" +.Fa "voidpf address" +.Fc +. +.Bd -literal +typedef struct z_stream_s { + z_const Bytef *next_in; + uInt avail_in; + uLong total_in; + + Bytef *next_out; + uInt avail_out; + uLong total_out; + + z_const char *msg; + struct internal_state FAR *state; + + alloc_func zalloc; + free_func zfree; + voidpf opaque; + + int data_type; + uLong adler; + uLong reserved; +} z_stream; +.Ed +. +.Pp +.Vt typedef z_stream FAR *z_streamp; +. +.Ft int +.Fn deflateInit "z_streamp strm" "int level" +. +.Sh DESCRIPTION +Initializes the internal stream state for compression. +The fields +.Fa zalloc , +.Fa zfree +and +.Fa opaque +must be initialized before by the caller. +If +.Fa zalloc +and +.Fa zfree +are set to +.Dv Z_NULL , +.Fn deflateInit +updates them to use default allocation functions. +.Fn deflateInit +does not perform any compression: +this will be done by +.Xr deflate 3 . +. +.Pp +The compression +.Fa level +must be +.Dv Z_DEFAULT_COMPRESSION , +or between 0 and 9: +1 gives best speed, +9 gives best compression, +0 gives no compression at all +(the input data is simply copied a block at a time). +.Dv Z_DEFAULT_COMPRESSION +requests a default compromise between speed and compression +(currently equivalent to level 6). +. +.Pp +The fields of +.Vt z_stream +are as follows: +. +.Bl -tag -width "data_type" +.It Fa next_in +next input byte +.It Fa avail_in +number of bytes available at +.Fa next_in +.It Fa total_in +total number of input bytes read so far +.It Fa next_out +next output byte will go here +.It Fa avail_out +remaining free space at +.Fa next_out +.It Fa total_out +total number of bytes output so far +.It Fa msg +last error message, +.Dv NULL +if no error +.It Fa state +not visible by applications +.It Fa zalloc +used to allocate the internal state +.It Fa zfree +used to free the internal state +.It Fa opaque +private data object passed to +.Fa zalloc +and +.Fa zfree +.It data_type +best guess about the data type: +binary or text for +.Xr deflate 3 , +or the decoding state for +.Xr inflate 3 +.It adler +Adler-32 or CRC-32 value of the uncompressed data +.It reserved +reserved for future use +.El +. +.Sh RETURN VALUES +.Fn deflateInit +returns +.Dv Z_OK +if success, +.Dv Z_MEM_ERROR +if there was not enough memory, +.Dv Z_STREAM_ERROR +if +.Fa level +is not a valid compression level, +or +.Dv Z_VERSION_ERROR +if the zlib library version +.Pq Xr zlibVersion 3 +is incompatible with the version assumed by the caller +.Pq Dv ZLIB_VERSION . +.Fa msg +is set to null +if there is no error message. +. +.Sh SEE ALSO +.Xr deflate 3 , +.Xr deflateEnd 3 , +.Xr deflateInit2 3 |