Added a library module for generic binary search.

diff --git a/lib/binsearch.h b/lib/binsearch.h
new file mode 100644 (file)
index 0000000..6741956
--- /dev/null
+++ b/lib/binsearch.h
@@ -0,0 +1,26 @@
+/*
+ *     UCW Library -- Generic Binary Search
+ *
+ *     (c) 2005 Martin Mares <mj@ucw.cz>
+ *
+ *     This software may be freely distributed and used according to the terms
+ *     of the GNU Lesser General Public License.
+ */
+
+#define BIN_SEARCH_FIRST_GE_CMP(ary,N,x,ary_lt_x)  ({          \
+  uns l = 0, r = (N);                                          \
+  while (l < r)                                                        \
+    {                                                          \
+      uns m = (l+r)/2;                                         \
+      if (ary_lt_x(ary,m,x))                                   \
+       l = m+1;                                                \
+      else                                                     \
+       r = m;                                                  \
+    }                                                          \
+  l;                                                           \
+})
+
+#define ARY_LT_NUM(ary,i,x) (ary)[i] < (x)
+
+#define BIN_SEARCH_FIRST_GE(ary,N,x) BIN_SEARCH_FIRST_GE_CMP(ary,N,x,ARY_LT_NUM)
+#define BIN_SEARCH_EQ(ary,N,x) ({ int i = BIN_SEARCH_FIRST_GE(ary,N,x); if (i >= (N) || (ary)[i] != (x)) i=-1; i; })