move to4digitHex to Numbers.qll

Author: erik-krogh

shared/regex/codeql/regex/nfa/NfaUtils.qll

@@ -3,6 +3,7 @@
  */
 
 private import codeql.regex.RegexTreeView
+private import codeql.util.Numbers
 
 /**
  * Classes and predicates that create an NFA and various algorithms for working with it.
@@ -1330,18 +1331,6 @@ module Make<RegexTreeViewSig TreeImpl> {
       else result = "\\u" + to4digitHex(any(int i | i.toUnicode() = char))
     }
 
-    /**
-     * Gets a 4-digit hex representation of `i`.
-     */
-    bindingset[i]
-    string to4digitHex(int i) {
-      result =
-        "0123456789abcdef".charAt(i.bitShiftRight(12).bitAnd(15)) +
-          "0123456789abcdef".charAt(i.bitShiftRight(8).bitAnd(15)) +
-          "0123456789abcdef".charAt(i.bitShiftRight(4).bitAnd(15)) +
-          "0123456789abcdef".charAt(i.bitAnd(15))
-    }
-
     /** Holds if `char` is easily printable char, or whitespace. */
     private predicate isPrintable(string char) {
       exists(ascii(char))

shared/regex/qlpack.yml

@@ -3,4 +3,5 @@ version: 0.1.2-dev
 groups: shared
 library: true
 dependencies:
+  codeql/util: ${workspace}
 warnOnImplicitThis: true

shared/util/codeql/util/Numbers.qll

@@ -100,6 +100,18 @@ private int toHex(string hex) {
   result = 15 and hex = ["f", "F"]
 }
 
+/**
+ * Gets a 4-digit hex representation of `i`.
+ */
+bindingset[i]
+string to4digitHex(int i) {
+  result =
+    "0123456789abcdef".charAt(i.bitShiftRight(12).bitAnd(15)) +
+      "0123456789abcdef".charAt(i.bitShiftRight(8).bitAnd(15)) +
+      "0123456789abcdef".charAt(i.bitShiftRight(4).bitAnd(15)) +
+      "0123456789abcdef".charAt(i.bitAnd(15))
+}
+
 /**
  * Gets the value of 16 to the power of `n`. Holds only for `n` in the range
  * 0..7 (inclusive).