+
−/**
+
− * Orthanc - A Lightweight, RESTful DICOM Store
+
− * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+
− * Department, University Hospital of Liege, Belgium
+
− * Copyright (C) 2017-2023 Osimis S.A., Belgium
+
− * Copyright (C) 2024-2024 Orthanc Team SRL, Belgium
+
− * Copyright (C) 2021-2024 Sebastien Jodogne, ICTEAM UCLouvain, Belgium
+
− *
+
− * This program is free software: you can redistribute it and/or
+
− * modify it under the terms of the GNU Lesser General Public License
+
− * as published by the Free Software Foundation, either version 3 of
+
− * the License, or (at your option) any later version.
+
− *
+
− * This program is distributed in the hope that it will be useful, but
+
− * WITHOUT ANY WARRANTY; without even the implied warranty of
+
− * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+
− * Lesser General Public License for more details.
+
− *
+
− * You should have received a copy of the GNU Lesser General Public
+
− * License along with this program. If not, see
+
− * <http://www.gnu.org/licenses/>.
+
− **/
+
−
+
−
+
−#include "../PrecompiledHeaders.h"
+
−#include "HttpStreamTranscoder.h"
+
−
+
−#include "../OrthancException.h"
+
−#include "../Compression/ZlibCompressor.h"
+
−
+
−#include <string.h>   // For memcpy()
+
−#include <cassert>
+
−
+
−#include <stdio.h>
+
−
+
−namespace Orthanc
+
−{
+
−  void HttpStreamTranscoder::ReadSource(std::string& buffer)
+
−  {
+
−    if (source_.SetupHttpCompression(false, false) != HttpCompression_None)
+
−    {
+
−      throw OrthancException(ErrorCode_InternalError);
+
−    }
+
−    
+
−    uint64_t size = source_.GetContentLength();
+
−    if (static_cast<uint64_t>(static_cast<size_t>(size)) != size)
+
−    {
+
−      throw OrthancException(ErrorCode_NotEnoughMemory);
+
−    }
+
−
+
−    buffer.resize(static_cast<size_t>(size));
+
−    size_t offset = 0;
+
−
+
−    while (source_.ReadNextChunk())
+
−    {
+
−      size_t chunkSize = static_cast<size_t>(source_.GetChunkSize());
+
−      memcpy(&buffer[offset], source_.GetChunkContent(), chunkSize);
+
−      offset += chunkSize;
+
−    }
+
−
+
−    if (offset != size)
+
−    {
+
−      throw OrthancException(ErrorCode_InternalError);
+
−    }
+
−  }
+
−
+
−
+
−  HttpCompression HttpStreamTranscoder::SetupZlibCompression(bool deflateAllowed)
+
−  {
+
−    uint64_t size = source_.GetContentLength();
+
−
+
−    if (size == 0)
+
−    {
+
−      return HttpCompression_None;
+
−    }
+
−
+
−    if (size < sizeof(uint64_t))
+
−    {
+
−      throw OrthancException(ErrorCode_CorruptedFile);
+
−    }
+
−
+
−    if (deflateAllowed)
+
−    {
+
−      bytesToSkip_ = sizeof(uint64_t);
+
−
+
−      return HttpCompression_Deflate;
+
−    }
+
−    else
+
−    {
+
−      // TODO Use stream-based zlib decoding to reduce memory usage
+
−      std::string compressed;
+
−      ReadSource(compressed);
+
−
+
−      uncompressed_.reset(new BufferHttpSender);
+
−
+
−      ZlibCompressor compressor;
+
−      IBufferCompressor::Uncompress(uncompressed_->GetBuffer(), compressor, compressed);
+
−
+
−      return HttpCompression_None;
+
−    }
+
−  }
+
−
+
−  HttpStreamTranscoder::HttpStreamTranscoder(IHttpStreamAnswer &source, CompressionType compression) :
+
−    source_(source),
+
−    sourceCompression_(compression),
+
−    bytesToSkip_(0),
+
−    skipped_(0),
+
−    currentChunkOffset_(0),
+
−    ready_(false)
+
−  {
+
−  }
+
−
+
−
+
−  HttpCompression HttpStreamTranscoder::SetupHttpCompression(bool gzipAllowed,
+
−                                                             bool deflateAllowed)
+
−  {
+
−    if (ready_)
+
−    {
+
−      throw OrthancException(ErrorCode_BadSequenceOfCalls);
+
−    }
+
−
+
−    ready_ = true;
+
−
+
−    switch (sourceCompression_)
+
−    {
+
−      case CompressionType_None:
+
−        return HttpCompression_None;
+
−
+
−      case CompressionType_ZlibWithSize:
+
−        return SetupZlibCompression(deflateAllowed);
+
−
+
−      default:
+
−        throw OrthancException(ErrorCode_NotImplemented);
+
−    }
+
−  }
+
−
+
−  bool HttpStreamTranscoder::HasContentFilename(std::string &filename)
+
−  {
+
−    return source_.HasContentFilename(filename);
+
−  }
+
−
+
−  std::string HttpStreamTranscoder::GetContentType()
+
−  {
+
−    return source_.GetContentType();
+
−  }
+
−
+
−
+
−  uint64_t HttpStreamTranscoder::GetContentLength()
+
−  {
+
−    if (!ready_)
+
−    {
+
−      throw OrthancException(ErrorCode_BadSequenceOfCalls);
+
−    }
+
−
+
−    if (uncompressed_.get() != NULL)
+
−    {
+
−      return uncompressed_->GetContentLength();
+
−    }
+
−    else
+
−    {
+
−      uint64_t length = source_.GetContentLength();
+
−      if (length < bytesToSkip_)
+
−      {
+
−        throw OrthancException(ErrorCode_InternalError);
+
−      }
+
−
+
−      return length - bytesToSkip_;
+
−    }
+
−  }
+
−
+
−
+
−  bool HttpStreamTranscoder::ReadNextChunk()
+
−  {
+
−    if (!ready_)
+
−    {
+
−      throw OrthancException(ErrorCode_BadSequenceOfCalls);
+
−    }
+
−
+
−    if (uncompressed_.get() != NULL)
+
−    {
+
−      return uncompressed_->ReadNextChunk();
+
−    }
+
−
+
−    assert(skipped_ <= bytesToSkip_);
+
−    if (skipped_ == bytesToSkip_)
+
−    {
+
−      // We have already skipped the first bytes of the stream
+
−      currentChunkOffset_ = 0;
+
−      return source_.ReadNextChunk();
+
−    }
+
−
+
−    // This condition can only be true on the first call to "ReadNextChunk()"
+
−    for (;;)
+
−    {
+
−      assert(skipped_ < bytesToSkip_);
+
−
+
−      bool ok = source_.ReadNextChunk();
+
−      if (!ok)
+
−      {
+
−        throw OrthancException(ErrorCode_CorruptedFile);
+
−      }
+
−
+
−      size_t remaining = static_cast<size_t>(bytesToSkip_ - skipped_);
+
−      size_t s = source_.GetChunkSize();
+
−
+
−      if (s < remaining)
+
−      {
+
−        skipped_ += s;
+
−      }
+
−      else if (s == remaining)
+
−      {
+
−        // We have skipped enough bytes, but we must read a new chunk
+
−        currentChunkOffset_ = 0;            
+
−        skipped_ = bytesToSkip_;
+
−        return source_.ReadNextChunk();
+
−      }
+
−      else
+
−      {
+
−        // We have skipped enough bytes, and we have enough data in the current chunk
+
−        assert(s > remaining);
+
−        currentChunkOffset_ = remaining;
+
−        skipped_ = bytesToSkip_;
+
−        return true;
+
−      }
+
−    }
+
−  }
+
−
+
−
+
−  const char* HttpStreamTranscoder::GetChunkContent()
+
−  {
+
−    if (!ready_)
+
−    {
+
−      throw OrthancException(ErrorCode_BadSequenceOfCalls);
+
−    }
+
−
+
−    if (uncompressed_.get() != NULL)
+
−    {
+
−      return uncompressed_->GetChunkContent();
+
−    }
+
−    else
+
−    {
+
−      return source_.GetChunkContent() + currentChunkOffset_;
+
−    }
+
−  }
+
−
+
−  size_t HttpStreamTranscoder::GetChunkSize()
+
−  {
+
−    if (!ready_)
+
−    {
+
−      throw OrthancException(ErrorCode_BadSequenceOfCalls);
+
−    }
+
−
+
−    if (uncompressed_.get() != NULL)
+
−    {
+
−      return uncompressed_->GetChunkSize();
+
−    }
+
−    else
+
−    {
+
−      return static_cast<size_t>(source_.GetChunkSize() - currentChunkOffset_);
+
−    }
+
−  }
+
−}