1    :  // Copyright 2012 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  #include "syzygy/pdb/pdb_stream_reader.h"
  15    :  
  16    :  
  17    :  namespace pdb {
  18    :  
  19    :  PdbStreamReaderWithPosition::PdbStreamReaderWithPosition(PdbStream* stream)
  20  E :      : start_offset_(0), pos_(0), length_(stream->length()), stream_(stream) {
  21  E :    DCHECK_NE(static_cast<PdbStream*>(nullptr), stream_);
  22  E :  }
  23    :  
  24    :  PdbStreamReaderWithPosition::PdbStreamReaderWithPosition(size_t start_offset,
  25    :                                                           size_t len,
  26    :                                                           PdbStream* stream)
  27  E :      : start_offset_(start_offset), pos_(0), length_(len), stream_(stream) {
  28  E :    DCHECK_NE(static_cast<PdbStream*>(nullptr), stream_);
  29  E :    DCHECK_GE(stream_->length(), start_offset_ + length_);
  30  E :    DCHECK_LE(start_offset_, start_offset_ + length_);
  31  E :  }
  32    :  
  33    :  PdbStreamReaderWithPosition::PdbStreamReaderWithPosition()
  34  E :      : start_offset_(0), pos_(0), length_(0), stream_(nullptr) {
  35  E :  }
  36    :  
  37    :  void PdbStreamReaderWithPosition::SetStream(size_t start_offset,
  38    :                                              size_t len,
  39  E :                                              PdbStream* stream) {
  40  E :    DCHECK_EQ(static_cast<PdbStream*>(nullptr), stream_.get());
  41  E :    DCHECK_NE(static_cast<PdbStream*>(nullptr), stream);
  42  E :    DCHECK_GE(stream->length(), start_offset + len);
  43    :  
  44  E :    start_offset_ = start_offset;
  45  E :    length_ = len;
  46  E :    stream_ = stream;
  47  E :  }
  48    :  
  49  E :  bool PdbStreamReaderWithPosition::Read(size_t len, void* out) {
  50  E :    DCHECK(stream_);
  51  E :    if (pos_ + len > length_)
  52  E :      return false;
  53    :  
  54  E :    if (!stream_->ReadBytesAt(start_offset_ + pos_, len, out))
  55  i :      return false;
  56    :  
  57  E :    pos_ += len;
  58  E :    DCHECK_LE(pos_, length_);
  59    :  
  60  E :    return true;
  61  E :  }
  62    :  
  63  E :  size_t PdbStreamReaderWithPosition::Position() const {
  64  E :    DCHECK(stream_);
  65  E :    return pos_;
  66  E :  }
  67    :  
  68  E :  bool PdbStreamReaderWithPosition::AtEnd() const {
  69  E :    DCHECK(stream_);
  70  E :    DCHECK_LE(pos_, length_);
  71  E :    return pos_ == length_;
  72  E :  }
  73    :  
  74  E :  bool PdbStreamReaderWithPosition::Consume(size_t len) {
  75  E :    DCHECK(stream_);
  76  E :    if (pos_ + len > length_)
  77  E :      return false;
  78    :  
  79  E :    pos_ += len;
  80  E :    DCHECK_LE(pos_, length_);
  81    :  
  82  E :    return true;
  83  E :  }
  84    :  
  85    :  }  // namespace pdb