+#ifndef OPENSSL_NO_SHA
+/* Compare two certificates: they must be identical for
+ * this to work. NB: Although "cmp" operations are generally
+ * prototyped to take "const" arguments (eg. for use in
+ * STACKs), the way X509 handling is - these operations may
+ * involve ensuring the hashes are up-to-date and ensuring
+ * certain cert information is cached. So this is the point
+ * where the "depth-first" constification tree has to halt
+ * with an evil cast.
+ */
+int X509_cmp(const X509 *a, const X509 *b)
+{
+ /* ensure hash is valid */
+ X509_check_purpose((X509 *)a, -1, 0);
+ X509_check_purpose((X509 *)b, -1, 0);
+
+ return memcmp(a->sha1_hash, b->sha1_hash, SHA_DIGEST_LENGTH);
+}
+#endif
+
+
+/* Case insensitive string comparision */
+static int nocase_cmp(const ASN1_STRING *a, const ASN1_STRING *b)
+{
+ int i;
+
+ if (a->length != b->length)
+ return (a->length - b->length);
+
+ for (i=0; i<a->length; i++)
+ {
+ int ca, cb;
+
+ ca = tolower(a->data[i]);
+ cb = tolower(b->data[i]);
+
+ if (ca != cb)
+ return(ca-cb);
+ }
+ return 0;
+}
+
+/* Case insensitive string comparision with space normalization
+ * Space normalization - ignore leading, trailing spaces,
+ * multiple spaces between characters are replaced by single space
+ */
+static int nocase_spacenorm_cmp(const ASN1_STRING *a, const ASN1_STRING *b)
+{
+ unsigned char *pa = NULL, *pb = NULL;
+ int la, lb;
+
+ la = a->length;
+ lb = b->length;
+ pa = a->data;
+ pb = b->data;
+
+ /* skip leading spaces */
+ while (la > 0 && isspace(*pa))
+ {
+ la--;
+ pa++;
+ }
+ while (lb > 0 && isspace(*pb))
+ {
+ lb--;
+ pb++;
+ }
+
+ /* skip trailing spaces */
+ while (la > 0 && isspace(pa[la-1]))
+ la--;
+ while (lb > 0 && isspace(pb[lb-1]))
+ lb--;
+
+ /* compare strings with space normalization */
+ while (la > 0 && lb > 0)
+ {
+ int ca, cb;
+
+ /* compare character */
+ ca = tolower(*pa);
+ cb = tolower(*pb);
+ if (ca != cb)
+ return (ca - cb);
+
+ pa++; pb++;
+ la--; lb--;
+
+ if (la <= 0 || lb <= 0)
+ break;
+
+ /* is white space next character ? */
+ if (isspace(*pa) && isspace(*pb))
+ {
+ /* skip remaining white spaces */
+ while (la > 0 && isspace(*pa))
+ {
+ la--;
+ pa++;
+ }
+ while (lb > 0 && isspace(*pb))
+ {
+ lb--;
+ pb++;
+ }
+ }
+ }
+ if (la > 0 || lb > 0)
+ return la - lb;
+
+ return 0;
+}
+
+static int asn1_string_memcmp(ASN1_STRING *a, ASN1_STRING *b)
+ {
+ int j;
+ j = a->length - b->length;
+ if (j)
+ return j;
+ return memcmp(a->data, b->data, a->length);
+ }
+
+#define STR_TYPE_CMP (B_ASN1_PRINTABLESTRING|B_ASN1_T61STRING|B_ASN1_UTF8STRING)
+
+int X509_NAME_cmp(const X509_NAME *a, const X509_NAME *b)