py/objint: from_bytes(): Implement "byteorder" param and arbitrary precision.
If result guaranteedly fits in a small int, it is handled in objint.c.
Otherwise, it is delegated to mp_obj_int_from_bytes_impl(), which should
be implemented by individual objint_*.c, similar to
mp_obj_int_to_bytes_impl().
diff --git a/py/objint.c b/py/objint.c
index 5842a00..a61ed8e 100644
--- a/py/objint.c
+++ b/py/objint.c
@@ -374,26 +374,33 @@
// this is a classmethod
STATIC mp_obj_t int_from_bytes(size_t n_args, const mp_obj_t *args) {
- // TODO: Support long ints
- // TODO: Support byteorder param
// TODO: Support signed param (assumes signed=False at the moment)
(void)n_args;
- if (args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little)) {
- mp_not_implemented("");
- }
-
// get the buffer info
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_READ);
- // convert the bytes to an integer
- mp_uint_t value = 0;
- for (const byte* buf = (const byte*)bufinfo.buf + bufinfo.len - 1; buf >= (byte*)bufinfo.buf; buf--) {
- value = (value << 8) | *buf;
- }
+ #if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
+ // If result guaranteedly fits in small int, use that
+ if (!MP_SMALL_INT_FITS(1 << (bufinfo.len * 8 - 1))) {
+ return mp_obj_int_from_bytes_impl(args[2] != MP_OBJ_NEW_QSTR(MP_QSTR_little), bufinfo.len, bufinfo.buf);
+ } else
+ #endif
+ {
+ const byte* buf = (const byte*)bufinfo.buf;
+ int delta = 1;
+ if (args[2] == MP_OBJ_NEW_QSTR(MP_QSTR_little)) {
+ buf += bufinfo.len - 1;
+ delta = -1;
+ }
- return mp_obj_new_int_from_uint(value);
+ mp_uint_t value = 0;
+ for (; bufinfo.len--; buf += delta) {
+ value = (value << 8) | *buf;
+ }
+ return mp_obj_new_int_from_uint(value);
+ }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(int_from_bytes_fun_obj, 3, 4, int_from_bytes);