+ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
+{ return M_ASN1_INTEGER_dup(x);}
+
+int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
+ {
+ int neg, ret;
+ /* Compare signs */
+ neg = x->type & V_ASN1_NEG;
+ if (neg != (y->type & V_ASN1_NEG))
+ {
+ if (neg)
+ return -1;
+ else
+ return 1;
+ }
+
+ ret = ASN1_STRING_cmp(x, y);
+
+ if (neg)
+ return -ret;
+ else
+ return ret;
+ }
+
+
+/*
+ * This converts an ASN1 INTEGER into its content encoding.
+ * The internal representation is an ASN1_STRING whose data is a big endian
+ * representation of the value, ignoring the sign. The sign is determined by
+ * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
+ *
+ * Positive integers are no problem: they are almost the same as the DER
+ * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
+ *
+ * Negative integers are a bit trickier...
+ * The DER representation of negative integers is in 2s complement form.
+ * The internal form is converted by complementing each octet and finally
+ * adding one to the result. This can be done less messily with a little trick.
+ * If the internal form has trailing zeroes then they will become FF by the
+ * complement and 0 by the add one (due to carry) so just copy as many trailing
+ * zeros to the destination as there are in the source. The carry will add one
+ * to the last none zero octet: so complement this octet and add one and finally
+ * complement any left over until you get to the start of the string.
+ *
+ * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
+ * with 0xff. However if the first byte is 0x80 and one of the following bytes
+ * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
+ * followed by optional zeros isn't padded.