third_party/tcmalloc/chromium/src/span.cc

   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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  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 #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
  42 namespace tcmalloc {
  43
  44 #ifdef SPAN_HISTORY
  45 void 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
  53 Span* 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
  64 void 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
  72 void DLL_Init(Span* list) {
  73   list->next = list;
  74   list->prev = list;
  75 }
  76
  77 void 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
  84 int 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
  92 void 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