The Uncompress(S) command takes the given string, byte list, or integer[1] array and decompresses it back into its original expanded format.

By default the return value is an Array with datatype=integer[1].  The values in the array range from -128 to 127 as integer[1] is a signed integer format.  

When output=list is specified the return value is a list of integers in the range 0 to 256.  

When output=string is specified the return value is a character string.  This option should only be used when the original uncompressed form was a string.  Converting binary data to this format will be truncated if the data contains NULL bytes.

Both the array output format and the list output format are suitable for use with readbytes and writebytes.

The optional value n indicates that only the first n bytes should be uncompressed.  If n is unspecified, or if n <= 0 or if n exceeds the actual number of bytes, then all of S is uncompressed.

The decompression algorithm is taken from the zlib library written by Jean-loup Gailly and Mark Adler.  See http://zlib.net

All of the StringTools package commands treat strings as (null-terminated) sequences of $8$-bit (ASCII) characters.  Thus, there is no support for multibyte character encodings, such as unicode encodings.

$\mathrm{with}\left(\mathrm{StringTools}\right)\&colon;$

$r≔\mathrm{Compress}\left(''hello\; world''\right)$

$r≔\left[\begin{array}{cccccccccccccccccccc}120& \mathrm{-100}& \mathrm{-53}& 72& \mathrm{-51}& \mathrm{-55}& \mathrm{-55}& 87& 40& \mathrm{-49}& 47& \mathrm{-54}& 73& 97& 0& 0& 30& 104& 4& 93\end{array}\right]$

$\mathrm{Uncompress}\left(r\&comma;'\mathrm{output}'='\mathrm{string}'\right)$

$''hello\; world''$