src/lib/common.c 1.149

Index: src/lib/common.c
===================================================================
RCS file: /projects/compbio/cvsroot/kent/src/lib/common.c,v
retrieving revision 1.148
retrieving revision 1.149
diff -b -B -U 4 -r1.148 -r1.149
--- src/lib/common.c	20 Apr 2010 15:56:50 -0000	1.148
+++ src/lib/common.c	29 May 2010 20:23:41 -0000	1.149
@@ -7,8 +7,9 @@
 #include "common.h"
 #include "errabort.h"
 #include "portable.h"
 #include "linefile.h"
+#include "hash.h"
 
 static char const rcsid[] = "$Id$";
 
 void *cloneMem(void *pt, size_t size)
@@ -798,8 +799,23 @@
 slReverse(&lines);
 return lines;
 }
 
+struct slName *slNameIntersection(struct slName *a, struct slName *b)
+/* return intersection of two slName lists.  */
+{
+struct hash *hashA = newHash(0);
+struct slName *el, *retval = NULL;
+
+for (el = a; el != NULL; el = el->next)
+    hashAddInt(hashA, el->name, 1);
+for (el = b; el != NULL; el = el->next)
+    if(hashLookup(hashA, el->name) != NULL)
+        slNameAddHead(&retval, el->name);
+hashFree(&hashA);
+return retval;
+}
+
 struct slRef *refOnList(struct slRef *refList, void *val)
 /* Return ref if val is already on list, otherwise NULL. */
 {
 struct slRef *ref;