Do not require 4byte alignment in isValidUtf8

yongju-hong · Jan 1, 2020 · 9038988 · 9038988
1 parent 736e50b
commit 9038988
Showing 1 changed file with 30 additions and 25 deletions.
diff --git a/src/WebSocketProtocol.h b/src/WebSocketProtocol.h
@@ -105,35 +105,40 @@ T cond_byte_swap(T value) {
 static bool isValidUtf8(unsigned char *s, size_t length)
 {
     for (unsigned char *e = s + length; s != e; ) {
-        if (s + 4 <= e && ((*(uint32_t *) s) & 0x80808080) == 0) {
-            s += 4;
-        } else {
-            while (!(*s & 0x80)) {
-                if (++s == e) {
-                    return true;
-                }
+        if (s + 4 <= e) {
+            uint32_t tmp;
+            memcpy(&tmp, s, 4);
+            if ((tmp & 0x80808080) == 0) {
+                s += 4;
+                continue;
             }
+        }
 
-            if ((s[0] & 0x60) == 0x40) {
-                if (s + 1 >= e || (s[1] & 0xc0) != 0x80 || (s[0] & 0xfe) == 0xc0) {
-                    return false;
-                }
-                s += 2;
-            } else if ((s[0] & 0xf0) == 0xe0) {
-                if (s + 2 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 ||
-                        (s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) || (s[0] == 0xed && (s[1] & 0xe0) == 0xa0)) {
-                    return false;
-                }
-                s += 3;
-            } else if ((s[0] & 0xf8) == 0xf0) {
-                if (s + 3 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 || (s[3] & 0xc0) != 0x80 ||
-                        (s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) || (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4) {
-                    return false;
-                }
-                s += 4;
-            } else {
+        while (!(*s & 0x80)) {
+            if (++s == e) {
+                return true;
+            }
+        }
+
+        if ((s[0] & 0x60) == 0x40) {
+            if (s + 1 >= e || (s[1] & 0xc0) != 0x80 || (s[0] & 0xfe) == 0xc0) {
+                return false;
+            }
+            s += 2;
+        } else if ((s[0] & 0xf0) == 0xe0) {
+            if (s + 2 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 ||
+                    (s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) || (s[0] == 0xed && (s[1] & 0xe0) == 0xa0)) {
                 return false;
             }
+            s += 3;
+        } else if ((s[0] & 0xf8) == 0xf0) {
+            if (s + 3 >= e || (s[1] & 0xc0) != 0x80 || (s[2] & 0xc0) != 0x80 || (s[3] & 0xc0) != 0x80 ||
+                    (s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) || (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4) {
+                return false;
+            }
+            s += 4;
+        } else {
+            return false;
         }
     }
     return true;