- NAME
- SYNOPSIS
- DESCRIPTION
- NOTES
- RETURN VALUES
- BUGS
- SEE ALSO
- HISTORY

# NAME

     CMS_uncompress - uncompress a CMS CompressedData structure

# SYNOPSIS

     #include <openssl/cms.h>

     int CMS_uncompress(CMS_ContentInfo *cms, BIO *dcont, BIO *out, unsigned int flags);

# DESCRIPTION

`CMS_uncompress()` extracts and uncompresses the content from a CMS CompressedData structure cms. data is a BIO to write the content to and flags is an optional set of flags.

The dcont parameter is used in the rare case where the compressed content is detached. It will normally be set to NULL.

# NOTES

The only currently supported compression algorithm is zlib: if the structure indicates the use of any other algorithm an error is returned.

If zlib support is not compiled into OpenSSL then `CMS_uncompress()` will always return an error.

The following flags can be passed in the flags parameter.

If the CMS_TEXT flag is set MIME headers for type text/plain are deleted from the content. If the content is not of type text/plain then an error is returned.

# RETURN VALUES

`CMS_uncompress()` returns either 1 for success or 0 for failure. The error can be obtained from `ERR_get_error(3)`

# BUGS

The lack of single pass processing and the need to hold all data in memory as mentioned in `CMS_verify()` also applies to CMS_decompress().

# SEE ALSO

ERR_get_error, CMS_compress

# HISTORY

`CMS_uncompress()` was added to OpenSSL 0.9.8