libitm/containers.h

   1 /* Copyright (C) 2011-2021 Free Software Foundation, Inc.
   2    Contributed by Torvald Riegel <triegel@redhat.com>.
   3
   4    This file is part of the GNU Transactional Memory Library (libitm).
   5
   6    Libitm is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
  12    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  13    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14    more details.
  15
  16    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 #ifndef LIBITM_CONTAINERS_H
  26 #define LIBITM_CONTAINERS_H 1
  27
  28 #include "common.h"
  29
  30 namespace GTM HIDDEN {
  31
  32 // A simple vector-like container.
  33 // If alloc_seperate_cl is true, allocations will happen on separate cache
  34 // lines.
  35 template <typename T, bool alloc_separate_cl = true>
  36 class vector
  37 {
  38  private:
  39   size_t m_capacity;
  40   size_t m_size;
  41   T* entries;
  42
  43   // Initial capacity of the vector.
  44   static const size_t default_initial_capacity = 32;
  45   // Above that capacity, grow vector by that size for each call.
  46   static const size_t default_resize_max = 2048;
  47   // Resize vector to at least this capacity.
  48   static const size_t default_resize_min = 32;
  49
  50   // Don't try to copy this vector.
  51   vector<T, alloc_separate_cl>(const vector<T, alloc_separate_cl>& x);
  52
  53  public:
  54   typedef T datatype;
  55   typedef T* iterator;
  56
  57   iterator begin() const { return entries; }
  58   iterator end() const { return entries + m_size; }
  59   T& operator[] (size_t pos) { return entries[pos]; }
  60   const T& operator[] (size_t pos) const  { return entries[pos]; }
  61
  62   vector<T, alloc_separate_cl>(size_t initial_size = default_initial_capacity)
  63     : m_capacity(initial_size),
  64       m_size(0)
  65   {
  66     if (m_capacity > 0)
  67       entries = (T*) xmalloc(sizeof(T) * m_capacity, alloc_separate_cl);
  68     else
  69       entries = 0;
  70   }
  71   ~vector<T, alloc_separate_cl>() { if (m_capacity) free(entries); }
  72
  73   void resize(size_t additional_capacity)
  74   {
  75     size_t target = m_capacity + additional_capacity;
  76     if (target > default_resize_max)
  77       m_capacity = ((target - 1 + default_resize_max) / default_resize_max)
  78         * default_resize_max;
  79     else
  80       while (m_capacity < target)
  81         m_capacity = m_capacity * 2;
  82     if (m_capacity < default_resize_min)
  83       m_capacity = default_resize_min;
  84     entries = (T*) xrealloc(entries, sizeof(T) * m_capacity, alloc_separate_cl);
  85   }
  86   void resize_noinline() __attribute__((noinline)) { resize(1); }
  87   void resize_noinline(size_t elements) __attribute__((noinline))
  88   {
  89     resize(elements);
  90   }
  91
  92   size_t size() const { return m_size; }
  93   size_t capacity() const { return this->capacity; }
  94
  95   void set_size (size_t size) { m_size = size; }
  96   void clear() { m_size = 0; }
  97
  98   iterator push() {
  99     // We don't want inlining here since push() is often on the fast path.
 100     if (unlikely(m_size == m_capacity)) resize_noinline();
 101     return &entries[m_size++];
 102   }
 103
 104   iterator push(size_t elements)
 105   {
 106     // We don't want inlining here since push() is often on the fast path.
 107     if (unlikely(m_size + elements > m_capacity)) resize_noinline(elements);
 108     iterator it = &entries[m_size];
 109     m_size += elements;
 110     return it;
 111   }
 112
 113   iterator pop() {
 114     if (likely(m_size > 0))
 115       {
 116         m_size--;
 117         return entries + m_size;
 118       }
 119     else return 0;
 120   }
 121 };
 122
 123 } // namespace GTM
 124
 125 #endif // LIBITM_CONTAINERS_H