Buffer.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_BASICS_BUFFER_H_INCLUDED
#define RIPPLE_BASICS_BUFFER_H_INCLUDED
 
#include <ripple/basics/Slice.h>
#include <cassert>
#include <cstdint>
#include <cstring>
#include <memory>
#include <utility>
 
namespace ripple {
 
class Buffer
{
private:
    std::unique_ptr<std::uint8_t[]> p_;
    std::size_t size_ = 0;
 
public:
    using const_iterator = std::uint8_t const*;
 
    Buffer() = default;
 
    explicit
    Buffer (std::size_t size)
        : p_ (size ? new std::uint8_t[size] : nullptr)
        , size_ (size)
    {
    }
 
    Buffer (void const* data, std::size_t size)
        : Buffer (size)
    {
        if (size)
            std::memcpy(p_.get(), data, size);
    }
 
    Buffer (Buffer const& other)
        : Buffer (other.p_.get(), other.size_)
    {
    }
 
    Buffer& operator= (Buffer const& other)
    {
        if (this != &other)
        {
            if (auto p = alloc (other.size_))
                std::memcpy (p, other.p_.get(), size_);
        }
        return *this;
    }
 
    Buffer (Buffer&& other) noexcept
        : p_ (std::move(other.p_))
        , size_ (other.size_)
    {
        other.size_ = 0;
    }
 
    Buffer& operator= (Buffer&& other) noexcept
    {
        if (this != &other)
        {
            p_ = std::move(other.p_);
            size_ = other.size_;
            other.size_ = 0;
        }
        return *this;
    }
 
    explicit
    Buffer (Slice s)
        : Buffer (s.data(), s.size())
    {
    }
 
    Buffer& operator= (Slice s)
    {
        // Ensure the slice isn't a subset of the buffer.
        assert (s.size() == 0 || size_ == 0 ||
            s.data() < p_.get() ||
            s.data() >= p_.get() + size_);
 
        if (auto p = alloc (s.size()))
            std::memcpy (p, s.data(), s.size());
        return *this;
    }
 
    std::size_t
    size() const noexcept
    {
        return size_;
    }
 
    bool
    empty () const noexcept
    {
        return 0 == size_;
    }
 
    operator Slice() const noexcept
    {
        if (! size_)
            return Slice{};
        return Slice{ p_.get(), size_ };
    }
 
    std::uint8_t const*
    data() const noexcept
    {
        return p_.get();
    }
 
    std::uint8_t*
    data() noexcept
    {
        return p_.get();
    }
    void
    clear() noexcept
    {
        p_.reset();
        size_ = 0;
    }
 
    std::uint8_t*
    alloc (std::size_t n)
    {
        if (n != size_)
        {
            p_.reset(n ? new std::uint8_t[n] : nullptr);
            size_ = n;
        }
        return p_.get();
    }
 
    // Meet the requirements of BufferFactory
    void*
    operator()(std::size_t n)
    {
        return alloc(n);
    }
 
    const_iterator
    begin() const noexcept
    {
        return p_.get();
    }
 
    const_iterator
    cbegin() const noexcept
    {
        return p_.get();
    }
 
    const_iterator
    end() const noexcept
    {
        return p_.get() + size_;
    }
 
    const_iterator
    cend() const noexcept
    {
        return p_.get() + size_;
    }
};
 
inline bool operator==(Buffer const& lhs, Buffer const& rhs) noexcept
{
    if (lhs.size() != rhs.size())
        return false;
 
    if (lhs.size() == 0)
        return true;
 
    return std::memcmp(lhs.data(), rhs.data(), lhs.size()) == 0;
}
 
inline bool operator!=(Buffer const& lhs, Buffer const& rhs) noexcept
{
    return !(lhs == rhs);
}
 
} // ripple
 
#endif