byte_stream_buffer.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * Byte stream buffer
 */

#pragma once

#include <stddef.h>
#include <stdint.h>
#include <type_traits>

#include <libcamera/base/class.h>
#include <libcamera/base/span.h>

namespace libcamera {

class ByteStreamBuffer
{
public:
    ByteStreamBuffer(const uint8_t *base, size_t size);
    ByteStreamBuffer(uint8_t *base, size_t size);
    ByteStreamBuffer(ByteStreamBuffer &&other);
    ByteStreamBuffer &operator=(ByteStreamBuffer &&other);

    const uint8_t *base() const { return base_; }
    uint32_t offset() const { return (write_ ? write_ : read_) - base_; }
    size_t size() const { return size_; }
    bool overflow() const { return overflow_; }

    ByteStreamBuffer carveOut(size_t size);
    int skip(size_t size);

    template<typename T>
    int read(T *t)
    {
        return read(reinterpret_cast<uint8_t *>(t), sizeof(*t));
    }

    template<typename T>
    int read(const Span<T> &data)
    {
        return read(reinterpret_cast<uint8_t *>(data.data()),
                data.size_bytes());
    }

    template<typename T>
    const std::remove_reference_t<T> *read(size_t count = 1)
    {
        using return_type = const std::remove_reference_t<T> *;
        return reinterpret_cast<return_type>(read(sizeof(T), count));
    }

    template<typename T>
    int write(const T *t)
    {
        return write(reinterpret_cast<const uint8_t *>(t), sizeof(*t));
    }

    template<typename T>
    int write(const Span<T> &data)
    {
        return write(reinterpret_cast<const uint8_t *>(data.data()),
                 data.size_bytes());
    }

private:
    LIBCAMERA_DISABLE_COPY(ByteStreamBuffer)

    void setOverflow();

    int read(uint8_t *data, size_t size);
    const uint8_t *read(size_t size, size_t count);
    int write(const uint8_t *data, size_t size);

    ByteStreamBuffer *parent_;

    const uint8_t *base_;
    size_t size_;
    bool overflow_;

    const uint8_t *read_;
    uint8_t *write_;
};

} /* namespace libcamera */