1 files changed, 220 insertions, 167 deletions

diff --git a/util/sparse_array.h b/util/sparse_array.h
index d37a10a..3b651cd 100644
--- a/util/sparse_array.h
+++ b/util/sparse_array.h
@@ -6,49 +6,49 @@
 #define UTIL_SPARSE_ARRAY_H_
 
 // DESCRIPTION
-// 
+//
 // SparseArray<T>(m) is a map from integers in [0, m) to T values.
 // It requires (sizeof(T)+sizeof(int))*m memory, but it provides
 // fast iteration through the elements in the array and fast clearing
 // of the array.  The array has a concept of certain elements being
 // uninitialized (having no value).
-// 
+//
 // Insertion and deletion are constant time operations.
-// 
-// Allocating the array is a constant time operation 
+//
+// Allocating the array is a constant time operation
 // when memory allocation is a constant time operation.
-// 
+//
 // Clearing the array is a constant time operation (unusual!).
-// 
+//
 // Iterating through the array is an O(n) operation, where n
 // is the number of items in the array (not O(m)).
 //
-// The array iterator visits entries in the order they were first 
+// The array iterator visits entries in the order they were first
 // inserted into the array.  It is safe to add items to the array while
 // using an iterator: the iterator will visit indices added to the array
 // during the iteration, but will not re-visit indices whose values
 // change after visiting.  Thus SparseArray can be a convenient
 // implementation of a work queue.
-// 
+//
 // The SparseArray implementation is NOT thread-safe.  It is up to the
 // caller to make sure only one thread is accessing the array.  (Typically
 // these arrays are temporary values and used in situations where speed is
 // important.)
-// 
+//
 // The SparseArray interface does not present all the usual STL bells and
 // whistles.
-// 
+//
 // Implemented with reference to Briggs & Torczon, An Efficient
 // Representation for Sparse Sets, ACM Letters on Programming Languages
 // and Systems, Volume 2, Issue 1-4 (March-Dec.  1993), pp.  59-69.
-// 
+//
 // Briggs & Torczon popularized this technique, but it had been known
 // long before their paper.  They point out that Aho, Hopcroft, and
 // Ullman's 1974 Design and Analysis of Computer Algorithms and Bentley's
 // 1986 Programming Pearls both hint at the technique in exercises to the
 // reader (in Aho & Hopcroft, exercise 2.12; in Bentley, column 1
 // exercise 8).
-// 
+//
 // Briggs & Torczon describe a sparse set implementation.  I have
 // trivially generalized it to create a sparse array (actually the original
 // target of the AHU and Bentley exercises).
@@ -58,7 +58,7 @@
 // SparseArray uses a vector dense_ and an array sparse_to_dense_, both of
 // size max_size_. At any point, the number of elements in the sparse array is
 // size_.
-// 
+//
 // The vector dense_ contains the size_ elements in the sparse array (with
 // their indices),
 // in the order that the elements were first inserted.  This array is dense:
@@ -67,15 +67,15 @@
 // The array sparse_to_dense_ maps from indices in [0,m) to indices in
 // [0,size_).
 // For indices present in the array, dense_[sparse_to_dense_[i]].index_ == i.
-// For indices not present in the array, sparse_to_dense_ can contain 
+// For indices not present in the array, sparse_to_dense_ can contain
 // any value at all, perhaps outside the range [0, size_) but perhaps not.
-// 
+//
 // The lax requirement on sparse_to_dense_ values makes clearing
 // the array very easy: set size_ to 0.  Lookups are slightly more
 // complicated.  An index i has a value in the array if and only if:
 //   sparse_to_dense_[i] is in [0, size_) AND
 //   dense_[sparse_to_dense_[i]].index_ == i.
-// If both these properties hold, only then it is safe to refer to 
+// If both these properties hold, only then it is safe to refer to
 //   dense_[sparse_to_dense_[i]].value_
 // as the value associated with index i.
 //
@@ -85,14 +85,24 @@
 // Deletion of specific values from the array is implemented by
 // swapping dense_[size_-1] and the dense_ being deleted and then
 // updating the appropriate sparse_to_dense_ entries.
-// 
+//
 // To make the sparse array as efficient as possible for non-primitive types,
 // elements may or may not be destroyed when they are deleted from the sparse
 // array through a call to erase(), erase_existing() or resize(). They
 // immediately become inaccessible, but they are only guaranteed to be
 // destroyed when the SparseArray destructor is called.
+//
+// A moved-from SparseArray will be empty.
+
+#include <stdint.h>
+#include <string.h>
+#include <algorithm>
+#include <memory>
+#include <utility>
+#include <vector>
 
 #include "util/util.h"
+#include "util/logging.h"
 
 namespace re2 {
 
@@ -100,23 +110,34 @@ template<typename Value>
 class SparseArray {
  public:
   SparseArray();
-  SparseArray(int max_size);
+  explicit SparseArray(int max_size);
   ~SparseArray();
 
   // IndexValue pairs: exposed in SparseArray::iterator.
   class IndexValue;
 
   typedef IndexValue value_type;
-  typedef typename vector<IndexValue>::iterator iterator;
-  typedef typename vector<IndexValue>::const_iterator const_iterator;
+  typedef typename std::vector<IndexValue>::iterator iterator;
+  typedef typename std::vector<IndexValue>::const_iterator const_iterator;
 
-  inline const IndexValue& iv(int i) const;
+  SparseArray(const SparseArray& src);
+  SparseArray(SparseArray&& src) noexcept;
+
+  SparseArray& operator=(const SparseArray& src);
+  SparseArray& operator=(SparseArray&& src) noexcept;
+
+  const IndexValue& iv(int i) const;
 
   // Return the number of entries in the array.
   int size() const {
     return size_;
   }
 
+  // Indicate whether the array is empty.
+  int empty() const {
+    return size_ == 0;
+  }
+
   // Iterate over the array.
   iterator begin() {
     return dense_.begin();
@@ -148,39 +169,68 @@ class SparseArray {
   }
 
   // Check whether index i is in the array.
-  inline bool has_index(int i) const;
+  bool has_index(int i) const;
 
   // Comparison function for sorting.
   // Can sort the sparse array so that future iterations
   // will visit indices in increasing order using
-  // sort(arr.begin(), arr.end(), arr.less);
+  // std::sort(arr.begin(), arr.end(), arr.less);
   static bool less(const IndexValue& a, const IndexValue& b);
 
  public:
   // Set the value at index i to v.
-  inline iterator set(int i, Value v);
+  iterator set(int i, const Value& v) {
+    return SetInternal(true, i, v);
+  }
+  iterator set(int i, Value&& v) {  // NOLINT
+    return SetInternal(true, i, std::move(v));
+  }
 
-  pair<iterator, bool> insert(const value_type& new_value);
+  std::pair<iterator, bool> insert(const value_type& v) {
+    return InsertInternal(v);
+  }
+  std::pair<iterator, bool> insert(value_type&& v) {  // NOLINT
+    return InsertInternal(std::move(v));
+  }
 
-  // Returns the value at index i
-  // or defaultv if index i is not initialized in the array.
-  inline Value get(int i, Value defaultv) const;
+  template <typename... Args>
+  std::pair<iterator, bool> emplace(Args&&... args) {  // NOLINT
+    return InsertInternal(value_type(std::forward<Args>(args)...));
+  }
 
-  iterator find(int i);
+  iterator find(int i) {
+    if (has_index(i))
+      return dense_.begin() + sparse_to_dense_[i];
+    return end();
+  }
 
-  const_iterator find(int i) const;
+  const_iterator find(int i) const {
+    if (has_index(i))
+      return dense_.begin() + sparse_to_dense_[i];
+    return end();
+  }
 
   // Change the value at index i to v.
   // Fast but unsafe: only use if has_index(i) is true.
-  inline iterator set_existing(int i, Value v);
+  iterator set_existing(int i, const Value& v) {
+    return SetExistingInternal(i, v);
+  }
+  iterator set_existing(int i, Value&& v) {  // NOLINT
+    return SetExistingInternal(i, std::move(v));
+  }
 
   // Set the value at the new index i to v.
   // Fast but unsafe: only use if has_index(i) is false.
-  inline iterator set_new(int i, Value v);
+  iterator set_new(int i, const Value& v) {
+    return SetInternal(false, i, v);
+  }
+  iterator set_new(int i, Value&& v) {  // NOLINT
+    return SetInternal(false, i, std::move(v));
+  }
 
   // Get the value at index i from the array..
   // Fast but unsafe: only use if has_index(i) is true.
-  inline Value get_existing(int i) const;
+  const Value& get_existing(int i) const;
 
   // Erasing items from the array during iteration is in general
   // NOT safe.  There is one special case, which is that the current
@@ -201,44 +251,122 @@ class SparseArray {
   // the iterators could walk past the end of the array.
 
   // Erases the element at index i from the array.
-  inline void erase(int i);
+  void erase(int i);
 
   // Erases the element at index i from the array.
   // Fast but unsafe: only use if has_index(i) is true.
-  inline void erase_existing(int i);
+  void erase_existing(int i);
 
  private:
+  template <typename U>
+  std::pair<iterator, bool> InsertInternal(U&& v) {
+    DebugCheckInvariants();
+    std::pair<iterator, bool> p;
+    if (has_index(v.index_)) {
+      p = {dense_.begin() + sparse_to_dense_[v.index_], false};
+    } else {
+      p = {set_new(std::forward<U>(v).index_, std::forward<U>(v).second), true};
+    }
+    DebugCheckInvariants();
+    return p;
+  }
+
+  template <typename U>
+  iterator SetInternal(bool allow_overwrite, int i, U&& v) {  // NOLINT
+    DebugCheckInvariants();
+    if (static_cast<uint32_t>(i) >= static_cast<uint32_t>(max_size_)) {
+      LOG(DFATAL) << "(jyasskin) Illegal index " << i
+                  << " passed to SparseArray(" << max_size_
+                  << ").set" << (allow_overwrite?"":"_new") << "().";
+      // Semantically, end() would be better here, but we already know
+      // the user did something stupid, so begin() insulates them from
+      // dereferencing an invalid pointer.
+      return begin();
+    }
+    if (!allow_overwrite) {
+      DCHECK(!has_index(i));
+      create_index(i);
+    } else {
+      if (!has_index(i))
+        create_index(i);
+    }
+    return set_existing(i, std::forward<U>(v));  // NOLINT
+  }
+
+  template <typename U>
+  iterator SetExistingInternal(int i, U&& v) {  // NOLINT
+    DebugCheckInvariants();
+    DCHECK(has_index(i));
+    dense_[sparse_to_dense_[i]].value() = std::forward<U>(v);
+    DebugCheckInvariants();
+    return dense_.begin() + sparse_to_dense_[i];
+  }
+
   // Add the index i to the array.
   // Only use if has_index(i) is known to be false.
   // Since it doesn't set the value associated with i,
   // this function is private, only intended as a helper
   // for other methods.
-  inline void create_index(int i);
+  void create_index(int i);
 
   // In debug mode, verify that some invariant properties of the class
   // are being maintained. This is called at the end of the constructor
   // and at the beginning and end of all public non-const member functions.
-  inline void DebugCheckInvariants() const;
+  void DebugCheckInvariants() const;
 
-  static bool InitMemory() {
-#ifdef MEMORY_SANITIZER
-    return true;
-#else
-    return RunningOnValgrind();
-#endif
-  }
+  int size_ = 0;
+  int max_size_ = 0;
+  std::unique_ptr<int[]> sparse_to_dense_;
+  std::vector<IndexValue> dense_;
+};
 
-  int size_;
-  int max_size_;
-  int* sparse_to_dense_;
-  vector<IndexValue> dense_;
+template<typename Value>
+SparseArray<Value>::SparseArray() = default;
 
-  DISALLOW_COPY_AND_ASSIGN(SparseArray);
-};
+template<typename Value>
+SparseArray<Value>::SparseArray(const SparseArray& src)
+    : size_(src.size_),
+      max_size_(src.max_size_),
+      sparse_to_dense_(new int[max_size_]),
+      dense_(src.dense_) {
+  std::copy_n(src.sparse_to_dense_.get(), max_size_, sparse_to_dense_.get());
+}
+
+template<typename Value>
+SparseArray<Value>::SparseArray(SparseArray&& src) noexcept  // NOLINT
+    : size_(src.size_),
+      max_size_(src.max_size_),
+      sparse_to_dense_(std::move(src.sparse_to_dense_)),
+      dense_(std::move(src.dense_)) {
+  src.size_ = 0;
+  src.max_size_ = 0;
+  src.dense_.clear();
+}
 
 template<typename Value>
-SparseArray<Value>::SparseArray()
-    : size_(0), max_size_(0), sparse_to_dense_(NULL), dense_() {}
+SparseArray<Value>& SparseArray<Value>::operator=(const SparseArray& src) {
+  std::unique_ptr<int[]> a(new int[src.max_size_]);
+  std::copy_n(src.sparse_to_dense_.get(), src.max_size_, a.get());
+  sparse_to_dense_ = std::move(a);
+  dense_ = src.dense_;
+  max_size_ = src.max_size_;
+  size_ = src.size_;
+  return *this;
+}
+
+template<typename Value>
+SparseArray<Value>& SparseArray<Value>::operator=(
+    SparseArray&& src) noexcept {  // NOLINT
+  size_ = src.size_;
+  max_size_ = src.max_size_;
+  sparse_to_dense_ = std::move(src.sparse_to_dense_);
+  dense_ = std::move(src.dense_);
+  // clear out the source
+  src.size_ = 0;
+  src.max_size_ = 0;
+  src.dense_.clear();
+  return *this;
+}
 
 // IndexValue pairs: exposed in SparseArray::iterator.
 template<typename Value>
@@ -249,17 +377,24 @@ class SparseArray<Value>::IndexValue {
   typedef Value second_type;
 
   IndexValue() {}
-  IndexValue(int index, const Value& value) : second(value), index_(index) {}
+  IndexValue(int i, const Value& v) : index_(i), second(v) {}
+  IndexValue(int i, Value&& v) : index_(i), second(std::move(v)) {}
 
   int index() const { return index_; }
-  Value value() const { return second; }
 
-  // Provide the data in the 'second' member so that the utilities
-  // in map-util work.
-  Value second;
+  Value& value() & { return second; }
+  const Value& value() const & { return second; }
+  Value&& value() && { return std::move(second); }  // NOLINT
 
  private:
   int index_;
+
+ public:
+  // Provide the data in the 'second' member so that the utilities
+  // in map-util work.
+  // TODO(billydonahue): 'second' is public for short-term compatibility.
+  // Users will be transitioned to using value() accessor.
+  Value second;
 };
 
 template<typename Value>
@@ -273,30 +408,25 @@ SparseArray<Value>::iv(int i) const {
 // Change the maximum size of the array.
 // Invalidates all iterators.
 template<typename Value>
-void SparseArray<Value>::resize(int new_max_size) {
+void SparseArray<Value>::resize(int max_size) {
   DebugCheckInvariants();
-  if (new_max_size > max_size_) {
-    int* a = new int[new_max_size];
+  if (max_size > max_size_) {
+    std::unique_ptr<int[]> a(new int[max_size]);
     if (sparse_to_dense_) {
-      memmove(a, sparse_to_dense_, max_size_*sizeof a[0]);
-      delete[] sparse_to_dense_;
+      std::copy_n(sparse_to_dense_.get(), max_size_, a.get());
     }
-    sparse_to_dense_ = a;
-
-    dense_.resize(new_max_size);
-
-    // These don't need to be initialized for correctness,
-    // but Valgrind will warn about use of uninitialized memory,
-    // so initialize the new memory when compiling debug binaries.
-    // Initialize it to garbage to detect bugs in the future.
-    if (InitMemory()) {
-      for (int i = max_size_; i < new_max_size; i++) {
-        sparse_to_dense_[i] = 0xababababU;
-        dense_[i].index_ = 0xababababU;
-      }
+    sparse_to_dense_ = std::move(a);
+
+    dense_.resize(max_size);
+
+#ifdef MEMORY_SANITIZER
+    for (int i = max_size_; i < max_size; i++) {
+      sparse_to_dense_[i] = 0xababababU;
+      dense_[i].index_ = 0xababababU;
     }
+#endif
   }
-  max_size_ = new_max_size;
+  max_size_ = max_size;
   if (size_ > max_size_)
     size_ = max_size_;
   DebugCheckInvariants();
@@ -307,93 +437,16 @@ template<typename Value>
 bool SparseArray<Value>::has_index(int i) const {
   DCHECK_GE(i, 0);
   DCHECK_LT(i, max_size_);
-  if (static_cast<uint>(i) >= static_cast<uint>(max_size_)) {
+  if (static_cast<uint32_t>(i) >= static_cast<uint32_t>(max_size_)) {
     return false;
   }
   // Unsigned comparison avoids checking sparse_to_dense_[i] < 0.
-  return (uint)sparse_to_dense_[i] < (uint)size_ && 
-    dense_[sparse_to_dense_[i]].index_ == i;
+  return (uint32_t)sparse_to_dense_[i] < (uint32_t)size_ &&
+         dense_[sparse_to_dense_[i]].index_ == i;
 }
 
-// Set the value at index i to v.
 template<typename Value>
-typename SparseArray<Value>::iterator SparseArray<Value>::set(int i, Value v) {
-  DebugCheckInvariants();
-  if (static_cast<uint>(i) >= static_cast<uint>(max_size_)) {
-    // Semantically, end() would be better here, but we already know
-    // the user did something stupid, so begin() insulates them from
-    // dereferencing an invalid pointer.
-    return begin();
-  }
-  if (!has_index(i))
-    create_index(i);
-  return set_existing(i, v);
-}
-
-template<typename Value>
-pair<typename SparseArray<Value>::iterator, bool> SparseArray<Value>::insert(
-    const value_type& new_value) {
-  DebugCheckInvariants();
-  pair<typename SparseArray<Value>::iterator, bool> p;
-  if (has_index(new_value.index_)) {
-    p = make_pair(dense_.begin() + sparse_to_dense_[new_value.index_], false);
-  } else {
-    p = make_pair(set_new(new_value.index_, new_value.second), true);
-  }
-  DebugCheckInvariants();
-  return p;
-}
-
-template<typename Value>
-Value SparseArray<Value>::get(int i, Value defaultv) const {
-  if (!has_index(i))
-    return defaultv;
-  return get_existing(i);
-}
-
-template<typename Value>
-typename SparseArray<Value>::iterator SparseArray<Value>::find(int i) {
-  if (has_index(i))
-    return dense_.begin() + sparse_to_dense_[i];
-  return end();
-}
-
-template<typename Value>
-typename SparseArray<Value>::const_iterator
-SparseArray<Value>::find(int i) const {
-  if (has_index(i)) {
-    return dense_.begin() + sparse_to_dense_[i];
-  }
-  return end();
-}
-
-template<typename Value>
-typename SparseArray<Value>::iterator
-SparseArray<Value>::set_existing(int i, Value v) {
-  DebugCheckInvariants();
-  DCHECK(has_index(i));
-  dense_[sparse_to_dense_[i]].second = v;
-  DebugCheckInvariants();
-  return dense_.begin() + sparse_to_dense_[i];
-}
-
-template<typename Value>
-typename SparseArray<Value>::iterator
-SparseArray<Value>::set_new(int i, Value v) {
-  DebugCheckInvariants();
-  if (static_cast<uint>(i) >= static_cast<uint>(max_size_)) {
-    // Semantically, end() would be better here, but we already know
-    // the user did something stupid, so begin() insulates them from
-    // dereferencing an invalid pointer.
-    return begin();
-  }
-  DCHECK(!has_index(i));
-  create_index(i);
-  return set_existing(i, v);
-}
-
-template<typename Value>
-Value SparseArray<Value>::get_existing(int i) const {
+const Value& SparseArray<Value>::get_existing(int i) const {
   DCHECK(has_index(i));
   return dense_[sparse_to_dense_[i]].second;
 }
@@ -412,7 +465,7 @@ void SparseArray<Value>::erase_existing(int i) {
   DCHECK(has_index(i));
   int di = sparse_to_dense_[i];
   if (di < size_ - 1) {
-    dense_[di] = dense_[size_ - 1];
+    dense_[di] = std::move(dense_[size_ - 1]);
     sparse_to_dense_[dense_[di].index_] = di;
   }
   size_--;
@@ -430,22 +483,22 @@ void SparseArray<Value>::create_index(int i) {
 
 template<typename Value> SparseArray<Value>::SparseArray(int max_size) {
   max_size_ = max_size;
-  sparse_to_dense_ = new int[max_size];
+  sparse_to_dense_ = std::unique_ptr<int[]>(new int[max_size]);
   dense_.resize(max_size);
-  // Don't need to zero the new memory, but appease Valgrind.
-  if (InitMemory()) {
-    for (int i = 0; i < max_size; i++) {
-      sparse_to_dense_[i] = 0xababababU;
-      dense_[i].index_ = 0xababababU;
-    }
-  }
   size_ = 0;
+
+#ifdef MEMORY_SANITIZER
+  for (int i = 0; i < max_size; i++) {
+    sparse_to_dense_[i] = 0xababababU;
+    dense_[i].index_ = 0xababababU;
+  }
+#endif
+
   DebugCheckInvariants();
 }
 
 template<typename Value> SparseArray<Value>::~SparseArray() {
   DebugCheckInvariants();
-  delete[] sparse_to_dense_;
 }
 
 template<typename Value> void SparseArray<Value>::DebugCheckInvariants() const {