putstate_text#

Construct or restore a Digest::SHA object from a text state string.

Accepts the text produced by getstate or dump and either:

  • As a class method (Digest::SHA->putstate($text)), returns a new object with algorithm and state taken from the string.

  • As an instance method ($sha->putstate($text)), rewrites the receiver in place, switching algorithm if the string asks for a different one.

The algorithm is read from the text, so — unlike _putstate — you do not need to preconfigure the object with the correct algorithm.

Synopsis#

my $sha = Digest::SHA->putstate($text);
$sha->putstate($text);

What you get back#

A Digest::SHA object on success, undef if the string could not be parsed.

Examples#

my $text = $other->getstate;
my $sha  = Digest::SHA->putstate($text);
$sha->add($remaining_data);

## Update an existing object from a state string:

my $sha = Digest::SHA->new(256);
$sha->putstate($text);

## Invalid input returns undef:

my $sha = Digest::SHA->putstate("garbage");
print defined $sha ? "ok" : "undef"; # undef

Edge cases#

  • Unrecognised or truncated text returns undef rather than croaking.

  • When used as an instance method, the receiver’s algorithm is overwritten by whatever the text specifies.

Differences from upstream#

Fully compatible with upstream Digest::SHA 6.04.

See also#

  • getstate — produces the strings this method consumes.

  • load — convenience wrapper that reads the text from a file.

  • _putstate — binary-state counterpart for same-machine use.