From c52d9c412fa3f69ed89cf72b833329caa1c6f997 Mon Sep 17 00:00:00 2001
From: Ivan Kohler <ivan@freeside.biz>
Date: Sat, 22 Sep 2012 00:30:31 -0700
Subject: [PATCH]         - Documentation: Add link to Neil Bowers' review of
 CC check modules         - Rearrange cardtype() for performance

---
 Changes       |  1 +
 CreditCard.pm | 38 +++++++++++++++++++++++++++++++-------
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/Changes b/Changes
index 2a413fb..0d352a7 100644
--- a/Changes
+++ b/Changes
@@ -5,6 +5,7 @@ Revision history for Perl extension Business::CreditCard.
         - Add LICENSE=>perl to Makefile.PL; add license to META.yml,
           closes: cpan #27735
         - Documentation: Add link to Neil Bowers' review of CC check modules
+        - Rearrange cardtype() for performance
 
 0.31  Mon Oct 19 18:51:35 PDT 2009
         - Add LICENSE section to POD documentation
diff --git a/CreditCard.pm b/CreditCard.pm
index d657e42..d0dd3b8 100644
--- a/CreditCard.pm
+++ b/CreditCard.pm
@@ -165,6 +165,13 @@ providing credit card number verification (LUHN checking).
 
 @EXPORT = qw(cardtype validate generate_last_digit);
 
+## ref http://neilb.org/reviews/luhn.html#Comparison it looks like
+## Business::CCCheck is 2x faster than we are.  looking at their implementation
+## not entirely a fair comparison, we also do the equivalent of their CC_clean,
+## they don't recognize certain cards at all (i.e. Switch) which require
+## an expensive check before VISA, Diners doesn't exist anymore, Discover is
+## a lot more than just 6011*, they don't handle processing agreements, etc.
+
 sub cardtype {
     my ($number) = @_;
 
@@ -183,17 +190,14 @@ sub cardtype {
             && 0+$number;
     }
 
-    return "Switch"
-      if $number =~ /^49(03(0[2-9]|3[5-9])|11(0[1-2]|7[4-9]|8[1-2])|36[0-9]{2})[\dx]{10}([\dx]{2,3})?$/o
-      || $number =~ /^564182[\dx]{10}([\dx]{2,3})?$/o
-      || $number =~ /^6(3(33[0-4][0-9])|759[0-9]{2})[\dx]{10}([\dx]{2,3})?$/o;
-
-    return "VISA card" if $number =~ /^4[\dx]{12}([\dx]{3})?$/o;
+    return "VISA card" if $number =~ /^4[0-8][\dx]{11}([\dx]{3})?$/o;
 
     return "MasterCard"
       if   $number =~ /^5[1-5][\dx]{14}$/o
       ;# || ( $number =~ /^36[\dx]{12}/ && $Country =~ /^(US|CA)$/oi );
 
+    return "American Express card" if $number =~ /^3[47][\dx]{13}$/o;
+
     return "Discover card"
       if   $number =~ /^30[0-5][\dx]{11}([\dx]{2})?$/o  #diner's: 300-305
       ||   $number =~ /^3095[\dx]{10}([\dx]{2})?$/o     #diner's: 3095
@@ -204,7 +208,12 @@ sub cardtype {
       || ( $number =~ /^62[24-68][\dx]{13}$/o && uc($Country) ne 'CN' ) #CUP
       || ( $number =~ /^35(2[89]|[3-8][\dx])[\dx]{10}$/o && uc($Country) eq 'US' );
 
-    return "American Express card" if $number =~ /^3[47][\dx]{13}$/o;
+    return "Switch"
+      if $number =~ /^49(03(0[2-9]|3[5-9])|11(0[1-2]|7[4-9]|8[1-2])|36[0-9]{2})[\dx]{10}([\dx]{2,3})?$/o
+      || $number =~ /^564182[\dx]{10}([\dx]{2,3})?$/o
+      || $number =~ /^6(3(33[0-4][0-9])|759[0-9]{2})[\dx]{10}([\dx]{2,3})?$/o;
+    #redunant with above, catch 49* that's not Switch
+    return "VISA card" if $number =~ /^4[\dx]{12}([\dx]{3})?$/o;
 
     #return "Diner's Club/Carte Blanche"
     #  if $number =~ /^3(0[0-59]|[68][\dx])[\dx]{11}$/o;
@@ -248,6 +257,21 @@ sub generate_last_digit {
     return (10 - $sum % 10) % 10;
 }
 
+
+## this (GPLed) code from Business::CCCheck is apparantly 4x faster than ours
+## ref http://neilb.org/reviews/luhn.html#Comparison
+## maybe see if we can spped ours up a bit
+#  my @ccn = split('',$ccn);
+#  my $even = 0;
+#  $ccn = 0;
+#  for($i=$#ccn;$i >=0;--$i) {
+#    $ccn[$i] *= 2 if $even;
+#    $ccn -= 9 if $ccn[$i] > 9;
+#    $ccn += $ccn[$i];
+#    $even = ! $even;
+#  }
+#  $type = '' if $ccn % 10;
+#  return $type;
 sub validate {
     my ($number) = @_;
 
-- 
2.11.0