third_party/tcmalloc/chromium/src/linked_list.h

   1 // Copyright (c) 2008, Google Inc.
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are
   6 // met:
   7 //
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   9 // notice, this list of conditions and the following disclaimer.
  10 //     * Redistributions in binary form must reproduce the above
  11 // copyright notice, this list of conditions and the following disclaimer
  12 // in the documentation and/or other materials provided with the
  13 // distribution.
  14 //     * Neither the name of Google Inc. nor the names of its
  15 // contributors may be used to endorse or promote products derived from
  16 // this software without specific prior written permission.
  17 //
  18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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  21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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  28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29
  30 // ---
  31 // Author: Sanjay Ghemawat <opensource@google.com>
  32 //
  33 // Some very basic linked list functions for dealing with using void * as
  34 // storage.
  35
  36 #ifndef TCMALLOC_LINKED_LIST_H_
  37 #define TCMALLOC_LINKED_LIST_H_
  38
  39 #include <stddef.h>
  40
  41 namespace tcmalloc {
  42
  43 inline void *SLL_Next(void *t) {
  44   return *(reinterpret_cast<void**>(t));
  45 }
  46
  47 inline void SLL_SetNext(void *t, void *n) {
  48   *(reinterpret_cast<void**>(t)) = n;
  49 }
  50
  51 inline void SLL_Push(void **list, void *element) {
  52   SLL_SetNext(element, *list);
  53   *list = element;
  54 }
  55
  56 inline void *SLL_Pop(void **list) {
  57   void *result = *list;
  58   *list = SLL_Next(*list);
  59   return result;
  60 }
  61
  62 // Remove N elements from a linked list to which head points.  head will be
  63 // modified to point to the new head.  start and end will point to the first
  64 // and last nodes of the range.  Note that end will point to NULL after this
  65 // function is called.
  66 inline void SLL_PopRange(void **head, int N, void **start, void **end) {
  67   if (N == 0) {
  68     *start = NULL;
  69     *end = NULL;
  70     return;
  71   }
  72
  73   void *tmp = *head;
  74   for (int i = 1; i < N; ++i) {
  75     tmp = SLL_Next(tmp);
  76   }
  77
  78   *start = *head;
  79   *end = tmp;
  80   *head = SLL_Next(tmp);
  81   // Unlink range from list.
  82   SLL_SetNext(tmp, NULL);
  83 }
  84
  85 inline void SLL_PushRange(void **head, void *start, void *end) {
  86   if (!start) return;
  87   SLL_SetNext(end, *head);
  88   *head = start;
  89 }
  90
  91 inline size_t SLL_Size(void *head) {
  92   int count = 0;
  93   while (head) {
  94     count++;
  95     head = SLL_Next(head);
  96   }
  97   return count;
  98 }
  99
 100 }  // namespace tcmalloc
 101
 102 #endif  // TCMALLOC_LINKED_LIST_H_