qpdf/include/qpdf/Pl_Buffer.hh

// Copyright (c) 2005-2023 Jay Berkenbilt
//
// This file is part of qpdf.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
// or implied. See the License for the specific language governing permissions and limitations under
// the License.
//
// Versions of qpdf prior to version 7 were released under the terms of version 2.0 of the Artistic
// License. At your option, you may continue to consider qpdf to be licensed under those terms.
// Please see the manual for additional information.

#ifndef PL_BUFFER_HH
#define PL_BUFFER_HH

// This pipeline accumulates the data passed to it into a memory buffer.  Each subsequent use of
// this buffer appends to the data accumulated so far.  getBuffer() may be called only after calling
// finish() and before calling any subsequent write().  At that point, a dynamically allocated
// Buffer object is returned and the internal buffer is reset.  The caller is responsible for
// deleting the returned Buffer.
//
// For this pipeline, "next" may be null.  If a next pointer is provided, this pipeline will also
// pass the data through to it.

#include <qpdf/Buffer.hh>
#include <qpdf/Pipeline.hh>
#include <qpdf/PointerHolder.hh> // unused -- remove in qpdf 12 (see #785)

#include <memory>
#include <vector>

class QPDF_DLL_CLASS Pl_Buffer: public Pipeline
{
  public:
    QPDF_DLL
    Pl_Buffer(char const* identifier, Pipeline* next = nullptr);
    QPDF_DLL
    ~Pl_Buffer() override;
    QPDF_DLL
    void write(unsigned char const*, size_t) override;
    QPDF_DLL
    void finish() override;

    // Each call to getBuffer() resets this object -- see notes above.
    // The caller is responsible for deleting the returned Buffer object. See also
    // getBufferSharedPointer() and getMallocBuffer().
    QPDF_DLL
    Buffer* getBuffer();

    // Same as getBuffer but wraps the result in a shared pointer.
    QPDF_DLL
    std::shared_ptr<Buffer> getBufferSharedPointer();

    // getMallocBuffer behaves in the same was as getBuffer except the buffer is allocated with
    // malloc(), making it suitable for use when calling from other languages. If there is no data,
    // *buf is set to a null pointer and *len is set to 0. Otherwise, *buf is a buffer of size *len
    // allocated with malloc(). It is the caller's responsibility to call free() on the buffer.
    QPDF_DLL
    void getMallocBuffer(unsigned char** buf, size_t* len);

  private:
    class QPDF_DLL_PRIVATE Members
    {
        friend class Pl_Buffer;

      public:
        QPDF_DLL
        ~Members() = default;

      private:
        Members() = default;
        Members(Members const&) = delete;

        bool ready{true};
        std::vector<unsigned char> data;
    };

    std::shared_ptr<Members> m;
};

#endif // PL_BUFFER_HH