+#include <openssl/bn.h>
+
+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.
+ */
+
+int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
+{
+ int pad = 0, ret, i, neg;
+ unsigned char *p, *n, pb = 0;
+
+ if (a == NULL)
+ return (0);
+ neg = a->type & V_ASN1_NEG;
+ if (a->length == 0)
+ ret = 1;
+ else {
+ ret = a->length;
+ i = a->data[0];
+ if (ret == 1 && i == 0)
+ neg = 0;
+ if (!neg && (i > 127)) {
+ pad = 1;
+ pb = 0;
+ } else if (neg) {
+ if (i > 128) {
+ pad = 1;
+ pb = 0xFF;
+ } else if (i == 128) {
+ /*
+ * Special case: if any other bytes non zero we pad:
+ * otherwise we don't.
+ */
+ for (i = 1; i < a->length; i++)
+ if (a->data[i]) {
+ pad = 1;
+ pb = 0xFF;
+ break;
+ }
+ }
+ }
+ ret += pad;
+ }
+ if (pp == NULL)
+ return (ret);
+ p = *pp;
+
+ if (pad)
+ *(p++) = pb;
+ if (a->length == 0)
+ *(p++) = 0;
+ else if (!neg)
+ memcpy(p, a->data, (unsigned int)a->length);
+ else {
+ /* Begin at the end of the encoding */
+ n = a->data + a->length - 1;
+ p += a->length - 1;
+ i = a->length;
+ /* Copy zeros to destination as long as source is zero */
+ while (!*n && i > 1) {
+ *(p--) = 0;
+ n--;
+ i--;
+ }
+ /* Complement and increment next octet */
+ *(p--) = ((*(n--)) ^ 0xff) + 1;
+ i--;
+ /* Complement any octets left */
+ for (; i > 0; i--)
+ *(p--) = *(n--) ^ 0xff;
+ }
+
+ *pp += ret;
+ return (ret);
+}
+
+/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
+
+ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
+ long len)
+{
+ ASN1_INTEGER *ret = NULL;
+ const unsigned char *p, *pend;
+ unsigned char *to, *s;
+ int i;
+
+ if ((a == NULL) || ((*a) == NULL)) {
+ if ((ret = M_ASN1_INTEGER_new()) == NULL)
+ return (NULL);
+ ret->type = V_ASN1_INTEGER;
+ } else
+ ret = (*a);
+
+ p = *pp;
+ pend = p + len;