run-npm-install (#44)

Reviewed-on: #44

node_modules/utf-8-validate/fallback.js

@@ -0,0 +1,62 @@
+'use strict';
+
+/**
+ * Checks if a given buffer contains only correct UTF-8.
+ * Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by
+ * Markus Kuhn.
+ *
+ * @param {Buffer} buf The buffer to check
+ * @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`
+ * @public
+ */
+function isValidUTF8(buf) {
+  const len = buf.length;
+  let i = 0;
+
+  while (i < len) {
+    if ((buf[i] & 0x80) === 0x00) {  // 0xxxxxxx
+      i++;
+    } else if ((buf[i] & 0xe0) === 0xc0) {  // 110xxxxx 10xxxxxx
+      if (
+        i + 1 === len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i] & 0xfe) === 0xc0  // overlong
+      ) {
+        return false;
+      }
+
+      i += 2;
+    } else if ((buf[i] & 0xf0) === 0xe0) {  // 1110xxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 2 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80 ||  // overlong
+        buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0  // surrogate (U+D800 - U+DFFF)
+      ) {
+        return false;
+      }
+
+      i += 3;
+    } else if ((buf[i] & 0xf8) === 0xf0) {  // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 3 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i + 3] & 0xc0) !== 0x80 ||
+        buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80 ||  // overlong
+        buf[i] === 0xf4 && buf[i + 1] > 0x8f || buf[i] > 0xf4  // > U+10FFFF
+      ) {
+        return false;
+      }
+
+      i += 4;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+module.exports = isValidUTF8;