root/trunk/whisperlib/common/io/buffer/io_memory_stream.cc

// Copyright (c) 2009, Whispersoft s.r.l.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Whispersoft s.r.l. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Author: Cosmin Tudorache

#include "common/io/buffer/io_memory_stream.h"

io::IOMemoryStream::IOMemoryStream(common::ByteOrder byte_order,
                                   BlockSize block_size)
    : io::InputStream(byte_order, NULL, NULL),
      io::OutputStream(byte_order, NULL, NULL),
      ms_(new io::MemoryStream(byte_order, block_size)),
      localms_(true) {
}

io::IOMemoryStream::IOMemoryStream(io::MemoryStream* ms_to_wrap)
    : io::InputStream(ms_to_wrap->byte_order(), NULL, NULL),
      io::OutputStream(ms_to_wrap->byte_order(), NULL, NULL),
      ms_(ms_to_wrap),
      localms_(false) {
}

io::IOMemoryStream::~IOMemoryStream() {
  if ( localms_ ) {
    delete ms_;
  }
}

bool io::IOMemoryStream::operator==(const io::IOMemoryStream& in) const {
  if ( Size() != in.Size() ) {
    return false;
  }

  io::MemoryStream& a = const_cast<io::MemoryStream&>(*ms_);
  const int32 original_a_size = a.Size();
  a.MarkerSet();

  io::MemoryStream& b = const_cast<io::MemoryStream&>(*in.ms_);
  const int32 original_b_size = b.Size();
  b.MarkerSet();

  const char*  pA = NULL;
  int32        nA = 0;
  const char*  pB = NULL;
  int32        nB = 0;
  bool hasMoreDataA = false;
  bool hasMoreDataB = false;
  bool equals = false;
  while ( true ) {
    if ( nA == 0 ) {
      hasMoreDataA = a.ReadNext(&pA, &nA);
    }
    if ( nB == 0 ) {
      hasMoreDataB = b.ReadNext(&pB, &nB);
    }
    if ( !hasMoreDataA && !hasMoreDataB ) {
      CHECK_EQ(nA, 0);
      CHECK_EQ(nB, 0);
      equals = true;
      break;
    }
    if ( hasMoreDataA ^ hasMoreDataB ) {
      // we've already checked that both streams have the same size !
      CHECK(false);
      equals = false;
      break;
    }
    CHECK(hasMoreDataA);
    CHECK(hasMoreDataB);
    CHECK_GT(nA, 0);
    CHECK_GT(nB, 0);
    int32 d = min(nA, nB);
    if ( ::memcmp(pA, pB, d) ) {
      equals = false;
      break;
    }
    nA -= d;
    nB -= d;
  }
  a.MarkerRestore();
  b.MarkerRestore();

  // streams should not be modified
  CHECK_EQ(a.Size(), original_a_size);
  CHECK_EQ(b.Size(), original_b_size);
  return equals;
}

string io::IOMemoryStream::ToString() const {
#ifdef _DEBUG
  return (strutil::StringPrintf("IOMemoryStream [#%d bytes]\n",
                                static_cast<int32>(ms_->Size())) +
          ms_->DumpContent());
#else
  return (strutil::StringPrintf("IOMemoryStream [#%d bytes]\n",
                                static_cast<int32>(ms_->Size())));
#endif
}