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std.zlib
Compress/decompress data using the zlib library.
Examples:
If you have a small buffer you can use compress and
uncompress directly.
import std.zlib; auto src = "the quick brown fox jumps over the lazy dog\r the quick brown fox jumps over the lazy dog\r"; ubyte[] dst; ubyte[] result; dst = compress(src); result = cast(ubyte[]) uncompress(dst); assert(result == src);When the data to be compressed doesn't fit in one buffer, use Compress and UnCompress.
import std.zlib; import std.stdio; import std.conv : to; import std.algorithm.iteration : map; UnCompress decmp = new UnCompress; foreach (chunk; stdin.byChunk(4096).map!(x => decmp.uncompress(x))) { chunk.to!string.write; }
References Wikipedia
License:
Authors:
Source std/zlib.d
- class
ZlibException
: object.Exception; - Errors throw a ZlibException.
- uint
adler32
(uintadler
, const(void)[]buf
); Compute the Adler-32 checksum of a buffer's worth of data.
Parameters:uint adler
the starting checksum for the computation. Use 1 for a new checksum. Use the output of this function for a cumulative checksum. const(void)[] buf
buffer containing input data Returns:A uint checksum for the provided input data and starting checksumSee Also:Examples:static ubyte[] data = [1,2,3,4,5,6,7,8,9,10]; uint adler = adler32(0u, data); writeln(adler); // 0xdc0037
- uint
crc32
(uintcrc
, const(void)[]buf
); Compute the CRC32 checksum of a buffer's worth of data.
Parameters:uint crc
the starting checksum for the computation. Use 0 for a new checksum. Use the output of this function for a cumulative checksum. const(void)[] buf
buffer containing input data Returns:A uint checksum for the provided input data and starting checksum- ubyte[]
compress
(const(void)[]srcbuf
, intlevel
);
ubyte[]compress
(const(void)[]srcbuf
); Compress data
Parameters:const(void)[] srcbuf
buffer containing the data to compress int level
compression level. Legal values are -1 .. 9, with -1 indicating the default level (6), 0 indicating no compression, 1 being the least compression and 9 being the most. Returns:the compressed data- void[]
uncompress
(const(void)[]srcbuf
, size_tdestlen
= 0u, intwinbits
= 15); - Decompresses the data in srcbuf[].Parameters:
const(void)[] srcbuf
buffer containing the compressed data. size_t destlen
size of the uncompressed data. It need not be accurate, but the decompression will be faster if the exact size is supplied. int winbits
the base two logarithm of the maximum window size. Returns:the decompressed data. - enum
HeaderFormat
: int; - the header format the compressed stream is wrapped in
deflate
- a standard zlib header
gzip
- a gzip file format header
determineFromData
- used when decompressing. Try to automatically detect the stream format by looking at the data
- class
Compress
; - Used when the data to be compressed is not all in one buffer.
- this(int
level
, HeaderFormatheader
= HeaderFormat.deflate);
this(HeaderFormatheader
= HeaderFormat.deflate); - Constructor.Parameters:
int level
compression level. Legal values are 1 .. 9, with 1 being the least compression and 9 being the most. The default value is 6. HeaderFormat header
sets the compression type to one of the options available in HeaderFormat. Defaults to HeaderFormat.deflate. See Also: - const(void)[]
compress
(const(void)[]buf
); - Compress the data in buf and return the compressed data.Parameters:
const(void)[] buf
data to compress Returns:the compressed data. The buffers returned from successive calls to this should be concatenated together. - void[]
flush
(intmode
= Z_FINISH); - Compress and return any remaining data. The returned data should be appended to that returned by compress().Parameters:
int mode
one of the following: - Z_SYNC_FLUSH
- Syncs up flushing to the next byte boundary. Used when more data is to be compressed later on.
- Z_FULL_FLUSH
- Syncs up flushing to the next byte boundary. Used when more data is to be compressed later on, and the decompressor needs to be restartable at this point.
- Z_FINISH
- (default) Used when finished compressing the data.
- class
UnCompress
; - Used when the data to be decompressed is not all in one buffer.
- this(uint
destbufsize
);
this(HeaderFormatformat
= HeaderFormat.determineFromData); - Construct. destbufsize is the same as for D.zlib.uncompress().
- const(void)[]
uncompress
(const(void)[]buf
); - Decompress the data in buf and return the decompressed data. The buffers returned from successive calls to this should be concatenated together.
- void[]
flush
(); - Decompress and return any remaining data. The returned data should be appended to that returned by uncompress(). The UnCompress object cannot be used further.
- const @property bool
empty
(); - Returns true if all input data has been decompressed and no further data can be decompressed (inflate() returned Z_STREAM_END)Examples:
// some random data ubyte[1024] originalData = void; // append garbage data (or don't, this works in both cases) auto compressedData = cast(ubyte[]) compress(originalData) ~ cast(ubyte[]) "whatever"; auto decompressor = new UnCompress(); auto uncompressedData = decompressor.uncompress(compressedData); assert(uncompressedData[] == originalData[], "The uncompressed and the original data differ"); assert(decompressor.empty, "The UnCompressor reports not being done");
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