py: Support conversion of bignum to bytes.

This gets int.to_bytes working for bignum, and also struct.pack with 'q'
and 'Q' args on 32-bit machines.

Addresses issue #1155.

1 files changed, 18 insertions, 0 deletions

diff --git a/py/objint_longlong.c b/py/objint_longlong.c
index 837889704..5b2c6d3f5 100644
--- a/py/objint_longlong.c
+++ b/py/objint_longlong.c
@@ -63,6 +63,24 @@ mp_int_t mp_obj_int_hash(mp_obj_t self_in) {
     return self->val;
 }
 
+void mp_obj_int_to_bytes_impl(mp_obj_t self_in, bool big_endian, mp_uint_t len, byte *buf) {
+    assert(MP_OBJ_IS_TYPE(self_in, &mp_type_int));
+    mp_obj_int_t *self = self_in;
+    long long val = self->val;
+    if (big_endian) {
+        byte *b = buf + len;
+        while (b > buf) {
+            *--b = val;
+            val >>= 8;
+        }
+    } else {
+        for (; len > 0; --len) {
+            *buf++ = val;
+            val >>= 8;
+        }
+    }
+}
+
 bool mp_obj_int_is_positive(mp_obj_t self_in) {
     if (MP_OBJ_IS_SMALL_INT(self_in)) {
         return MP_OBJ_SMALL_INT_VALUE(self_in) >= 0;