Now all modules are in core modules folder

modules/password_policy/constraints/constraint_digit_placement.inc

@@ -0,0 +1,80 @@
+<?php
+
+/**
+ * @file
+ * Restrict placement of digits in passwords.
+ *
+ * @link http://drupal.org/node/316768
+ * @author David Kent Norman (http://deekayen.net/)
+ */
+
+/****************************************************************************/
+/* Constraint API                                                           */
+/****************************************************************************/
+
+/**
+ * Description of the constraint.
+ */
+function password_policy_constraint_digit_placement_description() {
+  return array('name' => t('Digit Placement'), 'description' => t('Minimum number of digits in the password to allow a digit in the first or last position in the password (e.g. 2abcdefg and abcdefg4 are unacceptable passwords, while 2qpcxrm3 and 99qpcxrm are allowed passwords when 2 is set here).'));
+}
+
+/**
+ * Error message of the constraint.
+ */
+function password_policy_constraint_digit_placement_error($constraint) {
+  return t('Password must have a minimum of %numChars %digits in order to place any digits at the start or end of the password.',
+    array('%numChars' => $constraint,
+        '%digits' => format_plural($constraint, t('digit'), t('digits'))));
+}
+
+/**
+ * Password validation.
+ */
+function password_policy_constraint_digit_placement_validate($password, $constraint, $uid) {
+  $number_of_digits = 0;
+  for ($i=0; $i<10; $i++) {
+    // help string count by sending it a string instead of an int
+    $number_of_digits += substr_count($password, "$i");
+  }
+  if ($number_of_digits < (int)$constraint) {
+    return preg_match("/^(\d+)|(\d+)$/", $password) != 1;
+  }
+  return TRUE;
+}
+
+/**
+ * Javascript portion.
+ */
+function password_policy_constraint_digit_placement_js($constraint, $uid) {
+  return <<<JSS
+  function substr_count(haystack, needle) {
+    var pos = 0, cnt = 0;
+
+    haystack += '';
+    needle += '';
+    var offset = 0;
+    var length = 0;
+    offset--;
+
+    while ((offset = haystack.indexOf(needle, offset+1)) != -1) {
+      if (length > 0 && (offset+needle.length) > length) {
+        return false;
+      } else {
+        cnt++;
+      }
+    }
+    return cnt;
+  }
+
+  var i=0;
+  var num=0;
+  for (i=0;i<10;i++) {
+    num += substr_count(value, i);
+  }
+  if (num<$constraint && value.match(/^(\d+)|(\d+)$/) != null) {
+    strength="low";
+    msg.push(translate.constraint_digit_placement);
+  }
+JSS;
+}