| Line 31... |
Line 31... |
| 31 |
}
|
31 |
}
|
| 32 |
|
32 |
|
| 33 |
\details{
|
33 |
\details{
|
| 34 |
\code{type = "none"} passes the input through unchanged, but may be
|
34 |
\code{type = "none"} passes the input through unchanged, but may be
|
| 35 |
useful if \code{type} is a variable.
|
35 |
useful if \code{type} is a variable.
|
| 36 |
|
36 |
|
| 37 |
\code{type = "unknown"} attempts to detect the type of compression
|
37 |
\code{type = "unknown"} attempts to detect the type of compression
|
| 38 |
applied (if any): this will always succeed for \command{bzip2}
|
38 |
applied (if any): this will always succeed for \command{bzip2}
|
| 39 |
compression, and will succeed for other forms if there is a suitable
|
39 |
compression, and will succeed for other forms if there is a suitable
|
| 40 |
header. It will auto-detect the \sQuote{magic} header
|
40 |
header. It will auto-detect the \sQuote{magic} header
|
| 41 |
(\code{"\x1f\x8b"}) added to files by the \command{gzip} program (and
|
41 |
(\code{"\x1f\x8b"}) added to files by the \command{gzip} program (and
|
| Line 48... |
Line 48... |
| 48 |
file with \command{xz -9e} (including adding the \sQuote{magic}
|
48 |
file with \command{xz -9e} (including adding the \sQuote{magic}
|
| 49 |
header): decompression should cope with the contents of any file
|
49 |
header): decompression should cope with the contents of any file
|
| 50 |
compressed with \command{xz} version 4.999 and some versions of
|
50 |
compressed with \command{xz} version 4.999 and some versions of
|
| 51 |
\command{lzma}. There are other versions, in particular \sQuote{raw}
|
51 |
\command{lzma}. There are other versions, in particular \sQuote{raw}
|
| 52 |
streams, that are not currently handled.
|
52 |
streams, that are not currently handled.
|
| 53 |
|
53 |
|
| 54 |
All the types of compression can expand the input: for \code{"gzip"}
|
54 |
All the types of compression can expand the input: for \code{"gzip"}
|
| 55 |
and \code{"bzip"} the maximum expansion is known and so
|
55 |
and \code{"bzip"} the maximum expansion is known and so
|
| 56 |
\code{memCompress} can always allocate sufficient space. For
|
56 |
\code{memCompress} can always allocate sufficient space. For
|
| 57 |
\code{"xz"} it is possible (but extremely unlikely) that compression
|
57 |
\code{"xz"} it is possible (but extremely unlikely) that compression
|
| 58 |
will fail if the output would have been too large.
|
58 |
will fail if the output would have been too large.
|
| Line 62... |
Line 62... |
| 62 |
A raw vector or a character string (if \code{asChar = TRUE}).
|
62 |
A raw vector or a character string (if \code{asChar = TRUE}).
|
| 63 |
}
|
63 |
}
|
| 64 |
|
64 |
|
| 65 |
\seealso{
|
65 |
\seealso{
|
| 66 |
\link{connections}.
|
66 |
\link{connections}.
|
| 67 |
|
67 |
|
| 68 |
\url{http://en.wikipedia.org/wiki/Data_compression} for background on
|
68 |
\url{http://en.wikipedia.org/wiki/Data_compression} for background on
|
| 69 |
data compression, \url{http://zlib.net/},
|
69 |
data compression, \url{http://zlib.net/},
|
| 70 |
\url{http://en.wikipedia.org/wiki/Gzip}, \url{http://www.bzip.org/},
|
70 |
\url{http://en.wikipedia.org/wiki/Gzip}, \url{http://www.bzip.org/},
|
| 71 |
\url{http://en.wikipedia.org/wiki/Bzip2}, \url{http://tukaani.org/xz/}
|
71 |
\url{http://en.wikipedia.org/wiki/Bzip2}, \url{http://tukaani.org/xz/}
|
| 72 |
and \url{http://en.wikipedia.org/wiki/Xz} for references about the
|
72 |
and \url{http://en.wikipedia.org/wiki/Xz} for references about the
|
The R Project SVN
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