[SCM] Multi-format 1D/2D barcode image processing library branch, upstream, updated. 24d4480bc48cf9eabf7b2bd2f528248b0e458809

[luizcroc]

The following commit has been merged in the upstream branch:
commit 81ca8ccb10433c233caf894041d7c36bfcc66bca
Author: luizcroc <luizcroc at 59b500cc-1b3d-0410-9834-0bbf25fbcc57>
Date:   Mon May 31 20:58:49 2010 +0000

    Same change as Revision r1395 for C++ port: Small speedup, per issue 422
    
    git-svn-id: http://zxing.googlecode.com/svn/trunk@1404 59b500cc-1b3d-0410-9834-0bbf25fbcc57

diff --git a/cpp/core/src/zxing/common/reedsolomon/GF256.cpp b/cpp/core/src/zxing/common/reedsolomon/GF256.cpp
index 35fc692..51b621e 100644
--- a/cpp/core/src/zxing/common/reedsolomon/GF256.cpp
+++ b/cpp/core/src/zxing/common/reedsolomon/GF256.cpp
@@ -109,13 +109,10 @@ int GF256::multiply(int a, int b) {
   if (a == 0 || b == 0) {
     return 0;
   }
-  if (a == 1) {
-    return b;
-  }
-  if (b == 1) {
-    return a;
-  }
-  return exp_[(log_[a] + log_[b]) % 255];
+  int logSum = log_[a] + log_[b];
+  // index is a sped-up alternative to logSum % 255 since sum
+  // is in [0,510]. Thanks to jmsachs for the idea
+  return exp_[(logSum & 0xFF) + (logSum >> 8)];
 }
 
 GF256 GF256::QR_CODE_FIELD(0x011D); // x^8 + x^4 + x^3 + x^2 + 1

-- 
Multi-format 1D/2D barcode image processing library