netwerk/base/SimpleBuffer.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "SimpleBuffer.h"
   8 #include <algorithm>
   9
  10 namespace mozilla {
  11 namespace net {
  12
  13 nsresult SimpleBuffer::Write(char* src, size_t len) {
  14   NS_ASSERT_OWNINGTHREAD(SimpleBuffer);
  15   if (NS_FAILED(mStatus)) {
  16     return mStatus;
  17   }
  18
  19   while (len > 0) {
  20     SimpleBufferPage* p = mBufferList.getLast();
  21     if (p && (p->mWriteOffset == SimpleBufferPage::kSimpleBufferPageSize)) {
  22       // no room.. make a new page
  23       p = nullptr;
  24     }
  25     if (!p) {
  26       p = new (fallible) SimpleBufferPage();
  27       if (!p) {
  28         mStatus = NS_ERROR_OUT_OF_MEMORY;
  29         return mStatus;
  30       }
  31       mBufferList.insertBack(p);
  32     }
  33     size_t roomOnPage =
  34         SimpleBufferPage::kSimpleBufferPageSize - p->mWriteOffset;
  35     size_t toWrite = std::min(roomOnPage, len);
  36     memcpy(p->mBuffer + p->mWriteOffset, src, toWrite);
  37     src += toWrite;
  38     len -= toWrite;
  39     p->mWriteOffset += toWrite;
  40     mAvailable += toWrite;
  41   }
  42   return NS_OK;
  43 }
  44
  45 size_t SimpleBuffer::Read(char* dest, size_t maxLen) {
  46   NS_ASSERT_OWNINGTHREAD(SimpleBuffer);
  47   if (NS_FAILED(mStatus)) {
  48     return 0;
  49   }
  50
  51   size_t rv = 0;
  52   for (SimpleBufferPage* p = mBufferList.getFirst(); p && (rv < maxLen);
  53        p = mBufferList.getFirst()) {
  54     size_t avail = p->mWriteOffset - p->mReadOffset;
  55     size_t toRead = std::min(avail, (maxLen - rv));
  56     memcpy(dest + rv, p->mBuffer + p->mReadOffset, toRead);
  57     rv += toRead;
  58     p->mReadOffset += toRead;
  59     if (p->mReadOffset == p->mWriteOffset) {
  60       p->remove();
  61       delete p;
  62     }
  63   }
  64
  65   MOZ_ASSERT(mAvailable >= rv);
  66   mAvailable -= rv;
  67   return rv;
  68 }
  69
  70 size_t SimpleBuffer::Available() {
  71   NS_ASSERT_OWNINGTHREAD(SimpleBuffer);
  72   return NS_SUCCEEDED(mStatus) ? mAvailable : 0;
  73 }
  74
  75 void SimpleBuffer::Clear() {
  76   NS_ASSERT_OWNINGTHREAD(SimpleBuffer);
  77   SimpleBufferPage* p;
  78   while ((p = mBufferList.popFirst())) {
  79     delete p;
  80   }
  81   mAvailable = 0;
  82 }
  83
  84 }  // namespace net
  85 }  // namespace mozilla