Main record-based I/O: documentation

[libucw.git] / ucw / binsearch.h

diff --git a/ucw/binsearch.h b/ucw/binsearch.h
index 67419563d49b30cfd65f04bd4d276bd96221f2da..f625c2ae5c71172c34ac976a3ff3430905d5ec8d 100644 (file)
--- a/ucw/binsearch.h
+++ b/ucw/binsearch.h
@@ -7,6 +7,17 @@
  *     of the GNU Lesser General Public License.
  */
 
+/***
+ * [[defs]]
+ * Definitions
+ * -----------
+ ***/
+
+/**
+ * Find the first element not lower than @x in the sorted array @ary of @N elements (non-decreasing order).
+ * Returns the index of the found element or @N if no exists. Uses `ary_lt_x(ary,i,x)` to compare the @i'th element with @x.
+ * The time complexity is `O(log(N))`.
+ **/
 #define BIN_SEARCH_FIRST_GE_CMP(ary,N,x,ary_lt_x)  ({          \
   uns l = 0, r = (N);                                          \
   while (l < r)                                                        \
@@ -20,7 +31,18 @@
   l;                                                           \
 })
 
+/**
+ * The default comparision macro for @BIN_SEARCH_FIRST_GE_CMP().
+ **/
 #define ARY_LT_NUM(ary,i,x) (ary)[i] < (x)
 
+/**
+ * Same as @BIN_SEARCH_FIRST_GE_CMP(), but uses the default `<` operator for comparisions.
+ **/
 #define BIN_SEARCH_FIRST_GE(ary,N,x) BIN_SEARCH_FIRST_GE_CMP(ary,N,x,ARY_LT_NUM)
+
+/**
+ * Search the sorted array @ary of @N elements (non-decreasing) for the first occurence of @x.
+ * Returns the index or -1 if no such element exists. Uses the `<` operator for comparisions.
+ **/
 #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; })