py/mpz: Normalize (remove leading zeros) xor operation result.

pfalcon · pfalcon · commit b3be4710aaa5 · 2015-11-22T22:03:18.000+02:00
diff --git a/py/mpz.c b/py/mpz.c
@@ -285,7 +285,11 @@ STATIC mp_uint_t mpn_xor(mpz_dig_t *idig, const mpz_dig_t *jdig, mp_uint_t jlen,
         *idig = *jdig;
     }
 
-    return idig - oidig;
+    // remove trailing zeros
+    for (--idig; idig >= oidig && *idig == 0; --idig) {
+    }
+
+    return idig + 1 - oidig;
 }
 
 /* computes i = i * d1 + d2

Original file line number	Diff line number	Diff line change
`@@ -285,7 +285,11 @@ STATIC mp_uint_t mpn_xor(mpz_dig_t idig, const mpz_dig_t jdig, mp_uint_t jlen,`
`285`	`285`	`idig = jdig;`
`286`	`286`	`}`
`287`	`287`
`288`		`- return idig - oidig;`
	`288`	`+ // remove trailing zeros`
	`289`	`+ for (--idig; idig >= oidig && *idig == 0; --idig) {`
	`290`	`+ }`
	`291`	`+`
	`292`	`+ return idig + 1 - oidig;`
`289`	`293`	`}`
`290`	`294`
`291`	`295`	`/* computes i = i * d1 + d2`