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author | June McEnroe <june@causal.agency> | 2018-11-08 21:40:50 -0500 |
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committer | June McEnroe <june@causal.agency> | 2020-12-27 22:10:42 -0500 |
commit | 470523cdad6c92d3b88a82f5e476cd4a4c61bcd2 (patch) | |
tree | 8217a4f88c46cc5f2792e17025d7044d2d0b2d28 /inflateGetHeader.3 | |
download | zlib-man-pages-470523cdad6c92d3b88a82f5e476cd4a4c61bcd2.tar.gz zlib-man-pages-470523cdad6c92d3b88a82f5e476cd4a4c61bcd2.zip |
Convert zlib.h comments to mdoc
Diffstat (limited to 'inflateGetHeader.3')
-rw-r--r-- | inflateGetHeader.3 | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/inflateGetHeader.3 b/inflateGetHeader.3 new file mode 100644 index 0000000..f77670f --- /dev/null +++ b/inflateGetHeader.3 @@ -0,0 +1,170 @@ +.Dd January 15, 2017 +.Dt INFLATEGETHEADER 3 +.Os +. +.Sh NAME +.Nm inflateGetHeader +.Nd get gzip header +. +.Sh LIBRARY +.Lb libz +. +.Sh SYNOPSIS +.In zlib.h +.Ft int +.Fn inflateGetHeader "z_streamp strm" "gz_headerp head" +. +.Sh DESCRIPTION +.Fn inflateGetHeader +requests that gzip header information +be stored in the provided +.Vt gz_header +structure. +.Fn inflateGetHeader +may be called after +.Xr inflateInit2 3 +or +.Xr inflateReset 3 , +and before the first call of +.Xr inflate 3 . +As +.Xr inflate 3 +processes the gzip stream, +.Fa head->done +is zero until the header is completed, +at which time +.Fa head->done +is set to one. +If a zlib stream is being decoded, +then +.Fa head->done +is set to -1 to indicate that +there will be no gzip header information forthcoming. +Note that +.Dv Z_BLOCK +or +.Dv Z_TREES +can be used to force +.Xr inflate 3 +to return immediately after +header processing is complete +and before any actual data is decompressed. +. +.Pp +The +.Fa text , +.Fa time , +.Fa xflags , +and +.Fa os +fields are filled in with the gzip header contents. +.Fa hcrc +is set to true if there is a header CRC. +.Po +The header CRC was valid if +.Fa done +is set to one. +.Pc \& +If +.Fa extra +is not +.Dv Z_NULL , +then +.Fa extra_max +contains the maximum number of bytes to write to +.Fa extra . +Once +.Fa done +is true, +.Fa extra_len +contains the actual extra field length, +and +.Fa extra +contains the extra field, +or that field truncated if +.Fa extra_max +is less than +.Fa extra_len . +If +.Fa name +is not +.Dv Z_NULL , +then up to +.Fa name_max +characters are written there, +terminated with a zero +unless the length is greater than +.Fa name_max . +If +.Fa comment +is not +.Dv Z_NULL , +then up to +.Fa comm_max +characters are written there, +terminated with a zero +unless the length is greater than +.Fa comm_max . +When any of +.Fa extra , +.Fa name , +or +.Fa comment +are not +.Dv Z_NULL +and the respective field +is not present in the header, +then that field is set to +.Dv Z_NULL +to signal its absence. +This allows the use of +.Xr deflateSetHeader 3 +with the returned structure +to duplicate the header. +However if those fields are set to allocated memory, +then the application will need to +save those pointers elsewhere +so that they can be eventually feed. +. +.Pp +If +.Fn inflateGetHeader +is not used, +then the header information is simply discarded. +The header is always checked for validity, +including the header CRC if present. +.Xr inflateReset 3 +will reset the process to discard the header information. +The application would need to call +.Fn inflateGetHeader +again to retrieve the header from the next gzip stream. +. +.Pp +The +.Vt gz_headerp +type is documented in +.Xr deflateSetHeader 3 . +. +.Sh RETURN VALUES +.Fn inflateGetHeader +returns +.Dv Z_OK +if success, +or +.Dv Z_STREAM_ERROR +if the source stream state was inconsistent. +. +.Sh SEE ALSO +.Xr gzip 1 , +.Xr deflateSetHeader 3 , +.Xr inflateInit2 3 +. +.Sh HISTORY +This manual page was converted from +.In zlib.h +to mdoc format by +.An C. McEnroe Aq Mt june@causal.agency . +. +.Sh AUTHORS +.An Jean-loup Gailly Aq Mt jloup@gzip.org +.An Mark Adler Aq Mt madler@alumni.caltech.edu |