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//
8//     * Redistributions of source code must retain the above copyright
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
20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30// ---
31// Author: Sanjay Ghemawat <opensource@google.com>
32
33#include <config.h>
34#include "span.h"
35
36#include <string.h>                     // for NULL, memset
37
38#include "internal_logging.h"  // for ASSERT
39#include "page_heap_allocator.h"  // for PageHeapAllocator
40#include "static_vars.h"       // for Static
41
42namespace tcmalloc {
43
44#ifdef SPAN_HISTORY
45void Event(Span* span, char op, int v = 0) {
46  span->history[span->nexthistory] = op;
47  span->value[span->nexthistory] = v;
48  span->nexthistory++;
49  if (span->nexthistory == sizeof(span->history)) span->nexthistory = 0;
50}
51#endif
52
53Span* NewSpan(PageID p, Length len) {
54  Span* result = Static::span_allocator()->New();
55  memset(result, 0, sizeof(*result));
56  result->start = p;
57  result->length = len;
58#ifdef SPAN_HISTORY
59  result->nexthistory = 0;
60#endif
61  return result;
62}
63
64void DeleteSpan(Span* span) {
65#ifndef NDEBUG
66  // In debug mode, trash the contents of deleted Spans
67  memset(span, 0x3f, sizeof(*span));
68#endif
69  Static::span_allocator()->Delete(span);
70}
71
72void DLL_Init(Span* list) {
73  list->next = list;
74  list->prev = list;
75}
76
77void DLL_Remove(Span* span) {
78  span->prev->next = span->next;
79  span->next->prev = span->prev;
80  span->prev = NULL;
81  span->next = NULL;
82}
83
84int DLL_Length(const Span* list) {
85  int result = 0;
86  for (Span* s = list->next; s != list; s = s->next) {
87    result++;
88  }
89  return result;
90}
91
92void DLL_Prepend(Span* list, Span* span) {
93  ASSERT(span->next == NULL);
94  ASSERT(span->prev == NULL);
95  span->next = list->next;
96  span->prev = list;
97  list->next->prev = span;
98  list->next = span;
99}
100
101}  // namespace tcmalloc
102