py: Oops, fix int.from_bytes to correctly convert bytes!

dpgeorge · dpgeorge · commit b9e7ed4ebcf8 · 2014-04-13T12:40:50.000+01:00
diff --git a/py/objint.c b/py/objint.c
@@ -277,8 +277,8 @@ STATIC mp_obj_t int_from_bytes(uint n_args, const mp_obj_t *args) {
 
     // convert the bytes to an integer
     machine_uint_t value = 0;
-    for (uint i = 0; i < bufinfo.len; i++) {
-        value += ((byte*)bufinfo.buf)[i];
+    for (const byte* buf = bufinfo.buf + bufinfo.len - 1; buf >= (byte*)bufinfo.buf; buf--) {
+        value = (value << 8) | *buf;
     }
 
     return mp_obj_new_int_from_uint(value);

Original file line number	Diff line number	Diff line change
`@@ -277,8 +277,8 @@ STATIC mp_obj_t int_from_bytes(uint n_args, const mp_obj_t *args) {`
`277`	`277`
`278`	`278`	`// convert the bytes to an integer`
`279`	`279`	`machine_uint_t value = 0;`
`280`		`- for (uint i = 0; i < bufinfo.len; i++) {`
`281`		`- value += ((byte*)bufinfo.buf)[i];`
	`280`	`+ for (const byte* buf = bufinfo.buf + bufinfo.len - 1; buf >= (byte*)bufinfo.buf; buf--) {`
	`281`	`+ value = (value << 8) \| *buf;`
`282`	`282`	`}`
`283`	`283`
`284`	`284`	`return mp_obj_new_int_from_uint(value);`