Quelle testAvlTree.cpp Sprache: C

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <set>
#include <stdio.h>

#include "ds/AvlTree.h"

#include "jsapi-tests/tests.h"

using namespace js;

////////////////////////////////////////////////////////////////////////
//                                                                    //
// AvlTree testing interface.                                         //
//                                                                    //
////////////////////////////////////////////////////////////////////////

// The "standard" AVL interface, `class AvlTree` at the end of
// js/src/ds/AvlTree.h, is too restrictive to allow proper testing of the AVL
// tree internals.  In particular it disallows insertion of duplicate values
// and removal of non-present values, and lacks various secondary functions
// such as for counting the number of nodes.
//
// So, for testing, we wrap an alternative interface `AvlTreeTestIF` around
// the core implementation.

template <class T, class C>
class AvlTreeTestIF : public AvlTreeImpl<T, C> {
  // Shorthands for names in the implementation (parent) class.
  using Impl = AvlTreeImpl<T, C>;
  using ImplTag = typename AvlTreeImpl<T, C>::Tag;
  using ImplNode = typename AvlTreeImpl<T, C>::Node;
  using ImplResult = typename AvlTreeImpl<T, C>::Result;
  using ImplNodeAndResult = typename AvlTreeImpl<T, C>::NodeAndResult;

public:
  explicit AvlTreeTestIF(LifoAlloc* alloc = nullptr) : Impl(alloc) {}

  // Insert `v` if it isn't already there, else leave the tree unchanged.
  // Returns true iff an insertion happened.
  bool testInsert(const T& v) {
    ImplNode* new_root = Impl::insert_worker(v);
    if (!new_root) {
      // OOM
      MOZ_CRASH();
    }
    if (uintptr_t(new_root) == uintptr_t(1)) {
      // Already present
      return false;
    }
    Impl::root_ = new_root;
    return true;
  }

  // Remove `v` if it is present.  Returns true iff a removal happened.
  bool testRemove(const T& v) {
    ImplNodeAndResult pair = Impl::delete_worker(Impl::root_, v);
    ImplNode* new_root = pair.first;
    ImplResult res = pair.second;
    if (res == ImplResult::Error) {
      // `v` isn't in the tree.
      return false;
    } else {
      Impl::root_ = new_root;
      return true;
    }
  }

  // Count number of elements
  size_t testSize_worker(ImplNode* n) const {
    if (n) {
      return 1 + testSize_worker(n->left) + testSize_worker(n->getRight());
    }
    return 0;
  }
  size_t testSize() const { return testSize_worker(Impl::root_); }

  size_t testDepth_worker(ImplNode* n) const {
    if (n) {
      size_t depthL = testDepth_worker(n->left);
      size_t depthR = testDepth_worker(n->getRight());
      return 1 + (depthL > depthR ? depthL : depthR);
    }
    return 0;
  }
  size_t testDepth() const { return testDepth_worker(Impl::root_); }

  bool testContains(const T& v) const {
    ImplNode* node = Impl::find_worker(v);
    return node != nullptr;
  }

  ImplNode* testGetRoot() const { return Impl::root_; }
  ImplNode* testGetFreeList() const { return Impl::freeList_; }

  bool testFreeListLooksValid(size_t maxElems) {
    size_t numElems = 0;
    ImplNode* node = Impl::freeList_;
    while (node) {
      numElems++;
      if (numElems > maxElems) {
        return false;
      }
      if (node->getTag() != ImplTag::Free || node->getRight() != nullptr) {
        return false;
      }
      node = node->left;
    }
    return true;
  }

  // For debugging only
private:
  void testShow_worker(int depth, const ImplNode* node) const {
    if (node) {
      testShow_worker(depth + 1, node->getRight());
      for (int i = 0; i < depth; i++) {
        printf(" ");
      }
      char* str = node->item.show();
      printf("%s\n", str);
      free(str);
      testShow_worker(depth + 1, node->left);
    }
  }

public:
  // For debugging only
  void testShow() const { testShow_worker(0, Impl::root_); }

  // AvlTree::Iter is also public; it's just pass-through from AvlTreeImpl.
};

////////////////////////////////////////////////////////////////////////
//                                                                    //
// AvlTree test cases.                                                //
//                                                                    //
////////////////////////////////////////////////////////////////////////

class CmpInt {
  int x_;

public:
  explicit CmpInt(int x) : x_(x) {}
  ~CmpInt() {}
  static int compare(const CmpInt& me, const CmpInt& other) {
    if (me.x_ < other.x_) return -1;
    if (me.x_ > other.x_) return 1;
    return 0;
  }
  int get() const { return x_; }
  char* show() const {
    const size_t length = 16;
    char* str = (char*)calloc(length, 1);
    snprintf(str, length, "%d", x_);
    return str;
  }
};

bool TreeIsPlausible(const AvlTreeTestIF<CmpInt, CmpInt>& tree,
                     const std::set<int>& should_be_in_tree, int UNIV_MIN,
                     int UNIV_MAX) {
  // Same cardinality
  size_t n_in_set = should_be_in_tree.size();
  size_t n_in_tree = tree.testSize();
  if (n_in_set != n_in_tree) {
    return false;
  }

  // Tree is not wildly out of balance.  Depth should not exceed 1.44 *
  // log2(size).
  size_t tree_depth = tree.testDepth();
  size_t log2_size = 0;
  {
    size_t n = n_in_tree;
    while (n > 0) {
      n = n >> 1;
      log2_size += 1;
    }
  }
  // Actually a tighter limit than stated above.  For these test cases, the
  // tree is either perfectly balanced or within one level of being so (hence
  // the +1).
  if (tree_depth > log2_size + 1) {
    return false;
  }

  // Check that everything that should be in the tree is in it, and vice
  // versa.
  for (int i = UNIV_MIN; i < UNIV_MAX; i++) {
    bool should_be_in = should_be_in_tree.find(i) != should_be_in_tree.end();

    // Look it up with a null comparator (so `contains` compares
    // directly)
    bool is_in = tree.testContains(CmpInt(i));
    if (is_in != should_be_in) {
      return false;
    }
  }

  return true;
}

template <typename T>
bool SetContains(std::set<T> s, const T& v) {
  return s.find(v) != s.end();
}

BEGIN_TEST(testAvlTree_main) {
  static const int UNIV_MIN = 5000;
  static const int UNIV_MAX = 5999;
  static const int UNIV_SIZE = UNIV_MAX - UNIV_MIN + 1;

  LifoAlloc alloc(4096, js::MallocArena);
  AvlTreeTestIF<CmpInt, CmpInt> tree(&alloc);
  std::set<int> should_be_in_tree;

  // Add numbers to the tree, checking as we go.
  for (int i = UNIV_MIN; i < UNIV_MAX; i++) {
    // Idiotic but simple
    if (i % 3 != 0) {
      continue;
    }
    bool was_added = tree.testInsert(CmpInt(i));
    should_be_in_tree.insert(i);
    CHECK(was_added);
    CHECK(TreeIsPlausible(tree, should_be_in_tree, UNIV_MIN, UNIV_MAX));
  }

  // Then remove the middle half of the tree, also checking.
  for (int i = UNIV_MIN + UNIV_SIZE / 4; i < UNIV_MIN + 3 * (UNIV_SIZE / 4);
       i++) {
    // Note that here, we're asking to delete a bunch of numbers that aren't
    // in the tree.  It should remain valid throughout.
    bool was_removed = tree.testRemove(CmpInt(i));
    bool should_have_been_removed = SetContains(should_be_in_tree, i);
    CHECK(was_removed == should_have_been_removed);
    should_be_in_tree.erase(i);
    CHECK(TreeIsPlausible(tree, should_be_in_tree, UNIV_MIN, UNIV_MAX));
  }

  // Now add some numbers which are already in the tree.
  for (int i = UNIV_MIN; i < UNIV_MIN + UNIV_SIZE / 4; i++) {
    if (i % 3 != 0) {
      continue;
    }
    bool was_added = tree.testInsert(CmpInt(i));
    bool should_have_been_added = !SetContains(should_be_in_tree, i);
    CHECK(was_added == should_have_been_added);
    should_be_in_tree.insert(i);
    CHECK(TreeIsPlausible(tree, should_be_in_tree, UNIV_MIN, UNIV_MAX));
  }

  // Then remove all numbers from the tree, in reverse order.
  for (int ir = UNIV_MIN; ir < UNIV_MAX; ir++) {
    int i = UNIV_MIN + (UNIV_MAX - ir);
    bool was_removed = tree.testRemove(CmpInt(i));
    bool should_have_been_removed = SetContains(should_be_in_tree, i);
    CHECK(was_removed == should_have_been_removed);
    should_be_in_tree.erase(i);
    CHECK(TreeIsPlausible(tree, should_be_in_tree, UNIV_MIN, UNIV_MAX));
  }

  // Now the tree should be empty.
  CHECK(should_be_in_tree.empty());
  CHECK(tree.testSize() == 0);

  // Now delete some more stuff.  Tree should still be empty :-)
  for (int i = UNIV_MIN + 10; i < UNIV_MIN + 100; i++) {
    CHECK(should_be_in_tree.empty());
    CHECK(tree.testSize() == 0);
    bool was_removed = tree.testRemove(CmpInt(i));
    CHECK(!was_removed);
    CHECK(TreeIsPlausible(tree, should_be_in_tree, UNIV_MIN, UNIV_MAX));
  }

  // The tree root should be NULL.
  CHECK(tree.testGetRoot() == nullptr);
  CHECK(tree.testGetFreeList() != nullptr);

  // Check the freelist to the extent we can: it's non-circular, and the
  // elements look plausible.  If it's not shorter than the specified length
  // then it must have a cycle, since the tests above won't have resulted in
  // more than 400 free nodes at the end.
  CHECK(tree.testFreeListLooksValid(400 /*arbitrary*/));

  // Test iteration, first in a tree with 9 nodes.  This tests the general
  // case.
  {
    CHECK(tree.testSize() == 0);
    for (int i = 10; i < 100; i += 10) {
      bool was_inserted = tree.testInsert(CmpInt(i));
      CHECK(was_inserted);
    }

    // Test iteration across the whole tree.
    AvlTreeTestIF<CmpInt, CmpInt>::Iter iter(&tree);
    // `expect` produces (independently) the next expected number.  `remaining`
    // counts the number items of items remaining.
    int expect = 10;
    int remaining = 9;
    while (iter.hasMore()) {
      CmpInt ci = iter.next();
      CHECK(ci.get() == expect);
      expect += 10;
      remaining--;
    }
    CHECK(remaining == 0);

    // Test iteration from a specified start point.
    for (int i = 10; i < 100; i += 10) {
      for (int j = i - 1; j <= i + 1; j++) {
        // Set up `expect` and `remaining`.
        remaining = (100 - i) / 10;
        switch (j % 10) {
          case 0:
            expect = j;
            break;
          case 1:
            expect = j + 9;
            remaining--;
            break;
          case 9:
            expect = j + 1;
            break;
          default:
            MOZ_CRASH();
        }
        AvlTreeTestIF<CmpInt, CmpInt>::Iter iter(&tree, CmpInt(j));
        while (iter.hasMore()) {
          CmpInt ci = iter.next();
          CHECK(ci.get() == expect);
          expect += 10;
          remaining--;
        }
        CHECK(remaining == 0);
      }
    }
  }

  // Now with a completely empty tree.
  {
    AvlTreeTestIF<CmpInt, CmpInt> emptyTree(&alloc);
    CHECK(emptyTree.testSize() == 0);
    // Full tree iteration gets us nothing.
    AvlTreeTestIF<CmpInt, CmpInt>::Iter iter1(&emptyTree);
    CHECK(!iter1.hasMore());
    // Starting iteration with any number gets us nothing.
    AvlTreeTestIF<CmpInt, CmpInt>::Iter iter2(&emptyTree, CmpInt(42));
    CHECK(!iter2.hasMore());
  }

  // Finally with a one-element tree.
  {
    AvlTreeTestIF<CmpInt, CmpInt> unitTree(&alloc);
    bool was_inserted = unitTree.testInsert(CmpInt(1337));
    CHECK(was_inserted);
    CHECK(unitTree.testSize() == 1);
    // Try full tree iteration.
    AvlTreeTestIF<CmpInt, CmpInt>::Iter iter3(&unitTree);
    CHECK(iter3.hasMore());
    CmpInt ci = iter3.next();
    CHECK(ci.get() == 1337);
    CHECK(!iter3.hasMore());
    for (int i = 1336; i <= 1338; i++) {
      int remaining = i < 1338 ? 1 : 0;
      int expect = i < 1338 ? 1337 : 99999 /*we'll never use this*/;
      AvlTreeTestIF<CmpInt, CmpInt>::Iter iter4(&unitTree, CmpInt(i));
      while (iter4.hasMore()) {
        CmpInt ci = iter4.next();
        CHECK(ci.get() == expect);
        remaining--;
        // expect doesn't change, we only expect it (or nothing)
      }
      CHECK(remaining == 0);
    }
  }

  return true;
}
END_TEST(testAvlTree_main)

quality83%

¤ Dauer der Verarbeitung: 0.16 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.