Additional X509_ALGOR documentation

Reviewed-by: NTim Hudson <tjh@openssl.org>

doc/crypto/d2i_X509_ALGOR.pod

@@ -2,7 +2,7 @@
 
 =head1 NAME
 
-d2i_X509_ALGOR, i2d_X509_ALGOR - AlgorithmIdentifier functions.
+d2i_X509_ALGOR, i2d_X509_ALGOR, X509_ALGOR_dup, X509_ALGOR_set0, X509_ALGOR_get0, X509_ALGOR_set_md, X509_ALGOR_cmp - AlgorithmIdentifier functions.
 
 =head1 SYNOPSIS
 
@@ -10,15 +10,40 @@ d2i_X509_ALGOR, i2d_X509_ALGOR - AlgorithmIdentifier functions.
 
  X509_ALGOR *d2i_X509_ALGOR(X509_ALGOR **a, unsigned char **pp, long length);
  int i2d_X509_ALGOR(X509_ALGOR *a, unsigned char **pp);
+ X509_ALGOR *X509_ALGOR_dup(X509_ALGOR *alg);
+ int X509_ALGOR_set0(X509_ALGOR *alg, ASN1_OBJECT *aobj, int ptype, void *pval);
+ void X509_ALGOR_get0(ASN1_OBJECT **paobj, int *pptype, void **ppval,
+                      X509_ALGOR *alg);
+ void X509_ALGOR_set_md(X509_ALGOR *alg, const EVP_MD *md);
+ int X509_ALGOR_cmp(const X509_ALGOR *a, const X509_ALGOR *b);
 
 =head1 DESCRIPTION
 
-These functions decode and encode an B<X509_ALGOR> structure which is
-equivalent to the B<AlgorithmIdentifier> structure.
+The functions d2i_X509() and i2d_X509() decode and encode an B<X509_ALGOR>
+structure which is equivalent to the B<AlgorithmIdentifier> structure.
 
-Otherwise these behave in a similar way to d2i_X509() and i2d_X509()
+Otherwise they behave in a similar way to d2i_X509() and i2d_X509()
 described in the L<d2i_X509(3)|d2i_X509(3)> manual page.
 
+X509_ALGOR_dup() returns a copy of B<alg>.
+
+X509_ALGOR_set0() sets the algorithm OID of B<alg> to B<aobj> and the
+associated parameter type to B<ptype> with value B<pval>. If B<ptype> is
+B<V_ASN1_UNDEF> the parameter is omitted, otherwise B<ptype> and B<pval> have
+the same meaning as the B<type> and B<value> parameters to ASN1_TYPE_set().
+All the supplied parameters are used internally so must B<NOT> be freed after
+this call.
+
+X509_ALGOR_get0() is the inverse of X509_ALGOR_set0(): it returns the
+algorithm OID in B<*paobj> and the associated parameter in B<*pptype>
+and B<*ppval> from the B<AlgorithmIdentifier> B<alg>.
+
+X509_ALGOR_set_md() sets the B<AlgorithmIdentifier> B<alg> to appropriate
+values for the message digest B<md>.
+
+X509_ALGOR_cmp() compares B<a> and B<b> and returns 0 if they have identical
+encodings and non-zero otherwise.
+
 =head1 SEE ALSO
 
 L<d2i_X509(3)|d2i_X509(3)>