Added rankLessThan

git-svn-id: svn+ssh://idea.nguyen.vg/svn/sxsi/trunk/XMLTree@237 3cdefd35-fc62-479d-8e8d-bae585ffb9ca

diff --git a/libcds/src/static_sequence/wt_node_internal.cpp b/libcds/src/static_sequence/wt_node_internal.cpp
index f5312db..50bb35f 100644 (file)
--- a/libcds/src/static_sequence/wt_node_internal.cpp
+++ b/libcds/src/static_sequence/wt_node_internal.cpp
@@ -159,6 +159,52 @@ uint wt_node_internal::rank(uint symbol, uint pos, uint l, wt_coder * c) {
        }
 }
 
+// return value is rank of symbol (less or equal to the given symbol) that has rank > 0, 
+// the parameter symbol is updated accordinly
+uint wt_node_internal::rankLessThan(uint &symbol, uint pos, uint l, wt_coder * c) 
+{
+    bool is_set = c->is_set(symbol,l);
+    using std::cout;
+    using std::endl;
+//    cout << "l = " << l << ", symbol = " << (uchar)symbol << ", rank0 = " << bitmap->rank0(pos) << ", rank1 = " << bitmap->rank1(pos) << endl;
+
+    uint result = -1;
+    if(!is_set) {
+        if(left_child==NULL) return -1;
+        uint rank = bitmap->rank0(pos);
+        if(rank != 0)
+            result = left_child->rankLessThan(symbol,rank-1,l+1,c);
+        return result;
+    }
+
+    uint rank = bitmap->rank1(pos);
+    if (rank != 0 && right_child != NULL)
+        result = right_child->rankLessThan(symbol, rank-1,l+1,c);
+
+//    cout << "recursion to leftchild at l = " << l << ", symbol = " << (uchar)symbol << ", rank0 = " << bitmap->rank0(pos) << ", rank1 = " << bitmap->rank1(pos) << endl;
+    // check left child for symbols <= givenSymbol
+    if (result != -1 || left_child == NULL)
+        return result;
+    return left_child->rankLessThan(symbol, bitmap->rank0(pos)-1);
+}
+
+uint wt_node_internal::rankLessThan(uint &symbol, uint pos) 
+{
+    uint result = -1;
+    using std::cout;
+    using std::endl;
+//    cout << "pos = " << pos << ", symbol = " << (uchar)symbol << endl;
+    
+    if (pos == -1)
+        return -1;
+    if(right_child!=NULL)
+        result = right_child->rankLessThan(symbol, bitmap->rank1(pos)-1);
+    if(result == -1 && left_child!=NULL)
+        return left_child->rankLessThan(symbol, bitmap->rank0(pos)-1);
+    return result;
+}
+
+
 uint wt_node_internal::select(uint symbol, uint pos, uint l, wt_coder * c) {
        bool is_set = c->is_set(symbol, l);
        uint ret = 0;
@@ -190,6 +236,45 @@ uint wt_node_internal::access(uint pos) {
        }
 }
 
+// Returns the value at given position and its rank
+uint wt_node_internal::access(uint pos, uint &rank) 
+{
+    // p is the internal node we are pointing our finger at each step
+    wt_node_internal *p = this;
+
+    while(1)
+    {
+        bool is_set = p->bitmap->access(pos);
+//        cout << "is_set = " << is_set << ", pos = " << pos << ", rank0 = " << bitmap->rank0(pos) << ", rank1 = " << bitmap->rank1(pos) << endl;
+        if(!is_set)
+        {
+            // recurse left
+            pos = p->bitmap->rank0(pos)-1;
+            wt_node_internal *tmp = dynamic_cast<wt_node_internal *>(p->left_child);
+            if (tmp == NULL)
+            {
+                // it's a leaf
+                rank = pos+1;
+                return p->left_child->access(0);
+            }
+            p = tmp; // new internal node
+        } 
+        else 
+        {
+            // recurse right
+            pos = p->bitmap->rank1(pos)-1;
+            wt_node_internal *tmp = dynamic_cast<wt_node_internal *>(p->right_child);
+            if (tmp == NULL)
+            {
+                // it's a leaf
+                rank = pos+1;
+                return p->right_child->access(0);
+            }
+            p = tmp; // new internal node
+        }
+    }
+}
+
 uint wt_node_internal::size() {
        uint s = bitmap->size()+sizeof(wt_node_internal);
        if(left_child!=NULL)

diff --git a/libcds/src/static_sequence/wt_node_internal.h b/libcds/src/static_sequence/wt_node_internal.h
index b39efbd..fed8e17 100644 (file)
--- a/libcds/src/static_sequence/wt_node_internal.h
+++ b/libcds/src/static_sequence/wt_node_internal.h
@@ -40,8 +40,11 @@ class wt_node_internal: public wt_node {
                wt_node_internal(uchar * seq, uint n, uint l, wt_coder * c, static_bitsequence_builder * bmb);
                virtual ~wt_node_internal();
                virtual uint rank(uint symbol, uint pos, uint level, wt_coder * c);
+               virtual uint rankLessThan(uint &symbol, uint pos, uint level, wt_coder * c);
+               virtual uint rankLessThan(uint &symbol, uint pos);
                virtual uint select(uint symbol, uint pos, uint level, wt_coder * c);
                virtual uint access(uint pos);
+                virtual uint access(uint pos, uint &rank);
                virtual uint size();
     virtual uint save(FILE *fp);
     static wt_node_internal * load(FILE *fp);