--- /dev/null
+/*
+ * Copyright (c) 2012 Google
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Gabe Black
+ */
+
+#ifndef __BASE_TRIE_HH__
+#define __BASE_TRIE_HH__
+
+#include "base/cprintf.hh"
+#include "base/misc.hh"
+#include "base/types.hh"
+
+// Key has to be an integral type.
+template <class Key, class Value>
+class Trie
+{
+ protected:
+ struct Node
+ {
+ Key key;
+ Key mask;
+
+ bool
+ matches(Key test)
+ {
+ return (test & mask) == key;
+ }
+
+ Value *value;
+
+ Node *parent;
+ Node *kids[2];
+
+ Node(Key _key, Key _mask, Value *_val) :
+ key(_key & _mask), mask(_mask), value(_val),
+ parent(NULL)
+ {
+ kids[0] = NULL;
+ kids[1] = NULL;
+ }
+
+ void
+ clear()
+ {
+ if (kids[1]) {
+ kids[1]->clear();
+ delete kids[1];
+ kids[1] = NULL;
+ }
+ if (kids[0]) {
+ kids[0]->clear();
+ delete kids[0];
+ kids[0] = NULL;
+ }
+ }
+
+ void
+ dump(int level)
+ {
+ for (int i = 1; i < level; i++) {
+ cprintf("|");
+ }
+ if (level == 0)
+ cprintf("Root ");
+ else
+ cprintf("+ ");
+ cprintf("(%p, %p, %#X, %#X, %p)\n", parent, this, key, mask, value);
+ if (kids[0])
+ kids[0]->dump(level + 1);
+ if (kids[1])
+ kids[1]->dump(level + 1);
+ }
+ };
+
+ protected:
+ Node head;
+
+ public:
+ typedef Node *Handle;
+
+ Trie() : head(0, 0, NULL)
+ {}
+
+ static const unsigned MaxBits = sizeof(Key) * 8;
+
+ private:
+ /**
+ * A utility method which checks whether the key being looked up lies
+ * beyond the Node being examined. If so, it returns true and advances the
+ * node being examined.
+ * @param parent The node we're currently "at", which can be updated.
+ * @param kid The node we may want to move to.
+ * @param key The key we're looking for.
+ * @param new_mask The mask to use when matching against the key.
+ * @return Whether the current Node was advanced.
+ */
+ bool
+ goesAfter(Node **parent, Node *kid, Key key, Key new_mask)
+ {
+ if (kid && kid->matches(key) && (kid->mask & new_mask) == kid->mask) {
+ *parent = kid;
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * A utility method which extends a mask value one more bit towards the
+ * lsb. This is almost just a signed right shift, except that the shifted
+ * in bits are technically undefined. This is also slightly complicated by
+ * the zero case.
+ * @param orig The original mask to extend.
+ * @return The extended mask.
+ */
+ Key
+ extendMask(Key orig)
+ {
+ // Just in case orig was 0.
+ const Key msb = ULL(1) << (MaxBits - 1);
+ return orig | (orig >> 1) | msb;
+ }
+
+ /**
+ * Method which looks up the Handle corresponding to a particular key. This
+ * is useful if you want to delete the Node corresponding to a key since
+ * the "remove" function takes a Node as its argument.
+ * @param key The key to look up.
+ * @return The first Node matching this key, or NULL if none was found.
+ */
+ Handle
+ lookupHandle(Key key)
+ {
+ Node *node = &head;
+ while (node) {
+ if (node->value)
+ return node;
+
+ if (node->kids[0] && node->kids[0]->matches(key))
+ node = node->kids[0];
+ else if (node->kids[1] && node->kids[1]->matches(key))
+ node = node->kids[1];
+ else
+ node = NULL;
+ }
+
+ return NULL;
+ }
+
+ public:
+ /**
+ * Method which inserts a key/value pair into the trie.
+ * @param key The key which can later be used to look up this value.
+ * @param width How many bits of the key (from msb) should be used.
+ * @param val A pointer to the value to store in the trie.
+ * @return A pointer to the Node which holds this value.
+ */
+ Handle
+ insert(Key key, unsigned width, Value *val)
+ {
+ // Build a mask which masks off all the bits we don't care about.
+ Key new_mask = ~(Key)0;
+ if (width < MaxBits)
+ new_mask <<= (MaxBits - width);
+ // Use it to tidy up the key.
+ key &= new_mask;
+
+ // Walk past all the nodes this new node will be inserted after. They
+ // can be ignored for the purposes of this function.
+ Node *node = &head;
+ while (goesAfter(&node, node->kids[0], key, new_mask) ||
+ goesAfter(&node, node->kids[1], key, new_mask))
+ {}
+ assert(node);
+
+ Key cur_mask = node->mask;
+ // If we're already where the value needs to be...
+ if (cur_mask == new_mask) {
+ assert(!node->value);
+ node->value = val;
+ return node;
+ }
+
+ for (unsigned int i = 0; i < 2; i++) {
+ Node *&kid = node->kids[i];
+ Node *new_node;
+ if (!kid) {
+ // No kid. Add a new one.
+ new_node = new Node(key, new_mask, val);
+ new_node->parent = node;
+ kid = new_node;
+ return new_node;
+ }
+
+ // Walk down the leg until something doesn't match or we run out
+ // of bits.
+ Key last_mask;
+ bool done;
+ do {
+ last_mask = cur_mask;
+ cur_mask = extendMask(cur_mask);
+ done = ((key & cur_mask) != (kid->key & cur_mask)) ||
+ last_mask == new_mask;
+ } while (!done);
+ cur_mask = last_mask;
+
+ // If this isn't the right leg to go down at all, skip it.
+ if (cur_mask == node->mask)
+ continue;
+
+ // At the point we walked to above, add a new node.
+ new_node = new Node(key, cur_mask, NULL);
+ new_node->parent = node;
+ kid->parent = new_node;
+ new_node->kids[0] = kid;
+ kid = new_node;
+
+ // If we ran out of bits, the value goes right here.
+ if (cur_mask == new_mask) {
+ new_node->value = val;
+ return new_node;
+ }
+
+ // Still more bits to deal with, so add a new node for that path.
+ new_node = new Node(key, new_mask, val);
+ new_node->parent = kid;
+ kid->kids[1] = new_node;
+ return new_node;
+ }
+
+ panic("Reached the end of the Trie insert function!\n");
+ return NULL;
+ }
+
+ /**
+ * Method which looks up the Value corresponding to a particular key.
+ * @param key The key to look up.
+ * @return The first Value matching this key, or NULL if none was found.
+ */
+ Value *
+ lookup(Key key)
+ {
+ Node *node = lookupHandle(key);
+ if (node)
+ return node->value;
+ else
+ return NULL;
+ }
+
+ /**
+ * Method to delete a value from the trie.
+ * @param node A pointer to the Node to remove.
+ * @return The Value pointer from the removed entry.
+ */
+ Value *
+ remove(Handle handle)
+ {
+ Node *node = handle;
+ Value *val = node->value;
+ if (node->kids[1]) {
+ assert(node->value);
+ node->value = NULL;
+ return val;
+ }
+ if (!node->parent)
+ panic("Trie: Can't remove root node.\n");
+
+ Node *parent = node->parent;
+
+ // If there's a kid, fix up it's parent pointer.
+ if (node->kids[0])
+ node->kids[0]->parent = parent;
+ // Figure out which kid we are, and update our parent's pointers.
+ if (parent->kids[0] == node)
+ parent->kids[0] = node->kids[0];
+ else if (parent->kids[1] == node)
+ parent->kids[1] = node->kids[0];
+ else
+ panic("Trie: Inconsistent parent/kid relationship.\n");
+ // Make sure if the parent only has one kid, it's kid[0].
+ if (parent->kids[1] && !parent->kids[0]) {
+ parent->kids[0] = parent->kids[1];
+ parent->kids[1] = NULL;
+ }
+
+ // If the parent has less than two kids and no cargo and isn't the
+ // root, delete it too.
+ if (!parent->kids[1] && !parent->value && parent->parent)
+ remove(parent);
+ delete node;
+ return val;
+ }
+
+ /**
+ * Method to lookup a value from the trie and then delete it.
+ * @param key The key to look up and then remove.
+ * @return The Value pointer from the removed entry, if any.
+ */
+ Value *
+ remove(Key key)
+ {
+ Handle handle = lookupHandle(key);
+ if (!handle)
+ return NULL;
+ return remove(handle);
+ }
+
+ /**
+ * A method which removes all key/value pairs from the trie. This is more
+ * efficient than trying to remove elements individually.
+ */
+ void
+ clear()
+ {
+ head.clear();
+ }
+
+ /**
+ * A debugging method which prints the contents of this trie.
+ * @param title An identifying title to put in the dump header.
+ */
+ void
+ dump(const char *title)
+ {
+ cprintf("**************************************************\n");
+ cprintf("*** Start of Trie: %s\n", title);
+ cprintf("*** (parent, me, key, mask, value pointer)\n");
+ cprintf("**************************************************\n");
+ head.dump(0);
+ }
+};
+
+#endif
--- /dev/null
+/*
+ * Copyright (c) 2012 Google
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Gabe Black
+ */
+
+#include <cassert>
+#include <iostream>
+
+#include "base/cprintf.hh"
+#include "base/trie.hh"
+#include "base/types.hh"
+#include "unittest/unittest.hh"
+
+using UnitTest::setCase;
+
+typedef Trie<Addr, uint32_t> TestTrie;
+
+int
+main()
+{
+ // Create an empty Ptr and verify it's data pointer is NULL.
+ setCase("An empty trie.");
+ TestTrie trie1;
+ trie1.dump("Empty");
+ cprintf("\n\n");
+
+ setCase("A single entry.");
+ trie1.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(1));
+ trie1.dump("One entry");
+ cprintf("\n\n");
+
+ setCase("Two entries, one on the way to the other.");
+ TestTrie trie2;
+ trie2.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(1));
+ trie2.insert(0x0123456789abcdef, 36, (uint32_t *)(uintptr_t)(2));
+ trie2.dump("Two entries inline v1");
+ cprintf("\n\n");
+
+ TestTrie trie3;
+ trie3.insert(0x0123456789abcdef, 36, (uint32_t *)(uintptr_t)(2));
+ trie3.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(1));
+ trie3.dump("Two entries inline v2");
+ cprintf("\n\n");
+
+ setCase("Two entries on different paths.");
+ TestTrie trie4;
+ trie4.insert(0x0123456789abcdef, 40, (uint32_t *)(uintptr_t)(2));
+ trie4.insert(0x0123456776543210, 40, (uint32_t *)(uintptr_t)(1));
+ trie4.dump("Two split entries");
+ cprintf("\n\n");
+
+ setCase("Skipping past an entry but not two.");
+ TestTrie trie5;
+ trie5.insert(0x0123456789000000, 40, (uint32_t *)(uintptr_t)(4));
+ trie5.insert(0x0123000000000000, 40, (uint32_t *)(uintptr_t)(1));
+ trie5.insert(0x0123456780000000, 40, (uint32_t *)(uintptr_t)(3));
+ trie5.insert(0x0123456700000000, 40, (uint32_t *)(uintptr_t)(2));
+ trie5.dump("Complex insertion");
+ cprintf("\n\n");
+
+ setCase("Looking things up.");
+ EXPECT_EQ((uintptr_t)trie5.lookup(0x0123000000000000), 1);
+ EXPECT_EQ((uintptr_t)trie5.lookup(0x0123456700000000), 2);
+ EXPECT_EQ((uintptr_t)trie5.lookup(0x0123456780000000), 3);
+ EXPECT_EQ((uintptr_t)trie5.lookup(0x0123456789000000), 4);
+
+ setCase("Removing entries.");
+ TestTrie trie6;
+ TestTrie::Handle node1, node2;
+ trie6.insert(0x0123456789000000, 40, (uint32_t *)(uintptr_t)(4));
+ trie6.insert(0x0123000000000000, 40, (uint32_t *)(uintptr_t)(1));
+ trie6.insert(0x0123456780000000, 40, (uint32_t *)(uintptr_t)(3));
+ node1 = trie6.insert(0x0123456700000000, 40, (uint32_t *)(uintptr_t)(2));
+ node2 = trie6.insert(0x0123456700000000, 32, (uint32_t *)(uintptr_t)(10));
+ trie6.dump("Fill before removal");
+ cprintf("\n\n");
+
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123000000000000), 1);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456700000000), 10);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456780000000), 10);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456789000000), 10);
+
+ trie6.remove(node2);
+ trie6.dump("One node removed");
+ cprintf("\n\n");
+
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123000000000000), 1);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456700000000), 2);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456780000000), 3);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456789000000), 4);
+
+ trie6.remove(node1);
+ trie6.dump("Two nodes removed");
+ cprintf("\n\n");
+
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123000000000000), 1);
+ EXPECT_EQ(trie6.lookup(0x0123456700000000), NULL);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456780000000), 3);
+ EXPECT_EQ((uintptr_t)trie6.lookup(0x0123456789000000), 4);
+
+ return UnitTest::printResults();
+}
projects / gem5.git / commitdiff