summaryrefslogtreecommitdiff
path: root/src/search.cc
diff options
context:
space:
mode:
Diffstat (limited to 'src/search.cc')
-rw-r--r--src/search.cc40
1 files changed, 35 insertions, 5 deletions
diff --git a/src/search.cc b/src/search.cc
index 04608c1..a1e3d70 100644
--- a/src/search.cc
+++ b/src/search.cc
@@ -31,9 +31,33 @@
#include <limits.h> /* defines INT_MIN, INT_MAX, UINT_MAX */
#include "options.h"
#include "hash-table.h"
+#include "config.h"
+
+/* ============================== Portability ============================== */
+
/* Assume ISO C++ 'for' scoping rule. */
#define for if (0) ; else for
+/* Dynamically allocated array with dynamic extent:
+
+ Example:
+ DYNAMIC_ARRAY (my_array, int, n);
+ ...
+ FREE_DYNAMIC_ARRAY (my_array);
+
+ Attention: depending on your implementation my_array is either the array
+ itself or a pointer to the array! Always use my_array only as expression!
+ */
+#if HAVE_DYNAMIC_ARRAY
+ #define DYNAMIC_ARRAY(var,eltype,size) eltype var[size]
+ #define FREE_DYNAMIC_ARRAY(var)
+#else
+ #define DYNAMIC_ARRAY(var,eltype,size) eltype *var = new eltype[size]
+ #define FREE_DYNAMIC_ARRAY(var) delete[] var
+#endif
+
+/* ================================ Theory ================================= */
+
/* The most general form of the hash function is
hash (keyword) = sum (asso_values[keyword[i] + alpha_inc[i]] : i in Pos)
@@ -589,7 +613,7 @@ Search::find_alpha_inc ()
}
}
- unsigned int indices[nindices];
+ DYNAMIC_ARRAY (indices, unsigned int, nindices);
{
unsigned int j = 0;
PositionIterator iter = _key_positions.iterator(_max_key_len);
@@ -608,8 +632,8 @@ Search::find_alpha_inc ()
/* Perform several rounds of searching for a good alpha increment.
Each round reduces the number of artificial collisions by adding
an increment in a single key position. */
- unsigned int best[_max_key_len];
- unsigned int tryal[_max_key_len];
+ DYNAMIC_ARRAY (best, unsigned int, _max_key_len);
+ DYNAMIC_ARRAY (tryal, unsigned int, _max_key_len);
do
{
/* An increment of 1 is not always enough. Try higher increments
@@ -644,6 +668,8 @@ Search::find_alpha_inc ()
}
}
while (current_duplicates_count > duplicates_goal);
+ FREE_DYNAMIC_ARRAY (tryal);
+ FREE_DYNAMIC_ARRAY (best);
if (option[DEBUG])
{
@@ -661,6 +687,7 @@ Search::find_alpha_inc ()
}
fprintf (stderr, "\n");
}
+ FREE_DYNAMIC_ARRAY (indices);
}
_alpha_inc = current;
@@ -1003,7 +1030,7 @@ Search::count_possible_collisions (EquivalenceClass *partition, unsigned int c)
Return the sum of this expression over all equivalence classes. */
unsigned int sum = 0;
unsigned int m = _max_selchars_length;
- unsigned int split_cardinalities[m+1];
+ DYNAMIC_ARRAY (split_cardinalities, unsigned int, m + 1);
for (EquivalenceClass *cls = partition; cls; cls = cls->_next)
{
for (unsigned int i = 0; i <= m; i++)
@@ -1025,6 +1052,7 @@ Search::count_possible_collisions (EquivalenceClass *partition, unsigned int c)
for (unsigned int i = 0; i <= m; i++)
sum -= split_cardinalities[i] * split_cardinalities[i];
}
+ FREE_DYNAMIC_ARRAY (split_cardinalities);
return sum;
}
@@ -1231,7 +1259,7 @@ Search::find_asso_values ()
}
unsigned int iterations = 0;
- unsigned int iter[k];
+ DYNAMIC_ARRAY (iter, unsigned int, k);
for (unsigned int i = 0; i < k; i++)
iter[i] = 0;
unsigned int ii = (_jump != 0 ? k - 1 : 0);
@@ -1384,6 +1412,8 @@ Search::find_asso_values ()
ii = 0;
}
}
+ FREE_DYNAMIC_ARRAY (iter);
+
if (option[DEBUG])
{
fprintf (stderr, "Step %u chose _asso_values[", stepno);