diff options
Diffstat (limited to 'src/search.cc')
-rw-r--r-- | src/search.cc | 40 |
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); |