X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?a=blobdiff_plain;ds=sidebyside;f=ginac%2Futils.h;h=102f09d59255d6c3db68e24ca4c50a3847648e49;hb=f9afb6aca6a971650dff63b11ca8c2ef18506690;hp=393c474f025f618785bcb3371f0f54a974571d38;hpb=1602530f716ba1d425a0667b897182b99c374823;p=ginac.git

diff --git a/ginac/utils.h b/ginac/utils.h
index 393c474f..102f09d5 100644
--- a/ginac/utils.h
+++ b/ginac/utils.h
@@ -4,7 +4,7 @@
  *  of any interest to the user of the library. */
 
 /*
- *  GiNaC Copyright (C) 1999-2009 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2011 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -128,7 +128,9 @@ int permutation_sign(It first, It last)
 				sign = -sign;
 			} else if (!(*other < *i))
 				return 0;
-			--i; --other;
+			--i;
+			if (i != first)
+				--other;
 		}
 		if (!swapped)
 			return sign;
@@ -147,7 +149,9 @@ int permutation_sign(It first, It last)
 				sign = -sign;
 			} else if (!(*i < *other))
 				return 0;
-			++i; ++other;
+			++i;
+			if (i != last)
+				++other;
 		}
 		if (!swapped)
 			return sign;
@@ -181,7 +185,9 @@ int permutation_sign(It first, It last, Cmp comp, Swap swapit)
 				sign = -sign;
 			} else if (!comp(*other, *i))
 				return 0;
-			--i; --other;
+			--i;
+			if (i != first)
+				--other;
 		}
 		if (!swapped)
 			return sign;
@@ -200,7 +206,9 @@ int permutation_sign(It first, It last, Cmp comp, Swap swapit)
 				sign = -sign;
 			} else if (!comp(*i, *other))
 				return 0;
-			++i; ++other;
+			++i; 
+			if (i != last)
+				++other;
 		}
 		if (!swapped)
 			return sign;
@@ -232,7 +240,9 @@ void shaker_sort(It first, It last, Cmp comp, Swap swapit)
 				flag = other;
 				swapped = true;
 			}
-			--i; --other;
+			--i;
+			if (i != first)
+				--other;
 		}
 		if (!swapped)
 			return;
@@ -249,7 +259,9 @@ void shaker_sort(It first, It last, Cmp comp, Swap swapit)
 				flag = other;
 				swapped = true;
 			}
-			++i; ++other;
+			++i;
+			if (i != last)
+				++other;
 		}
 		if (!swapped)
 			return;