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//
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//
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// Copyright (c) 2023 Vinnie Falco (vinnie.falco@gmail.com)
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// Copyright (c) 2023 Vinnie Falco (vinnie.falco@gmail.com)
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//
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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//
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// Official repository: https://github.com/cppalliance/capy
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// Official repository: https://github.com/cppalliance/capy
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//
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//
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#ifndef BOOST_CAPY_BUFFERS_VECTOR_DYNAMIC_BUFFER_HPP
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#ifndef BOOST_CAPY_BUFFERS_VECTOR_DYNAMIC_BUFFER_HPP
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#define BOOST_CAPY_BUFFERS_VECTOR_DYNAMIC_BUFFER_HPP
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#define BOOST_CAPY_BUFFERS_VECTOR_DYNAMIC_BUFFER_HPP
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13   
#include <boost/capy/detail/config.hpp>
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#include <boost/capy/detail/config.hpp>
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#include <boost/capy/buffers.hpp>
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#include <boost/capy/buffers.hpp>
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#include <boost/capy/detail/except.hpp>
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#include <boost/capy/detail/except.hpp>
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#include <type_traits>
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#include <type_traits>
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#include <vector>
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#include <vector>
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18  
19   
namespace boost {
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namespace boost {
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namespace capy {
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namespace capy {
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21  
22   
/** A dynamic buffer using an underlying vector.
22   
/** A dynamic buffer using an underlying vector.
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23  
24   
    This class adapts a `std::vector` of byte-sized elements
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    This class adapts a `std::vector` of byte-sized elements
25   
    to satisfy the DynamicBuffer concept. The vector provides
25   
    to satisfy the DynamicBuffer concept. The vector provides
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    automatic memory management and growth.
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    automatic memory management and growth.
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27  
28   
    @par Constraints
28   
    @par Constraints
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29  
30   
    The element type `T` must be a fundamental type with
30   
    The element type `T` must be a fundamental type with
31   
    `sizeof( T ) == 1`. This includes `char`, `unsigned char`,
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    `sizeof( T ) == 1`. This includes `char`, `unsigned char`,
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    `signed char`, and similar byte-sized fundamental types.
32   
    `signed char`, and similar byte-sized fundamental types.
33  
33  
34   
    @par Example
34   
    @par Example
35   
    @code
35   
    @code
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    std::vector<unsigned char> v;
36   
    std::vector<unsigned char> v;
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    vector_dynamic_buffer vb( &v );
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    vector_dynamic_buffer vb( &v );
38  
38  
39   
    // Write data
39   
    // Write data
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    auto mb = vb.prepare( 100 );
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    auto mb = vb.prepare( 100 );
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    std::memcpy( mb.data(), "hello", 5 );
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    std::memcpy( mb.data(), "hello", 5 );
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    vb.commit( 5 );
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    vb.commit( 5 );
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    // Read data
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    // Read data
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    auto data = vb.data();
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    auto data = vb.data();
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    // process data...
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    // process data...
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    vb.consume( 5 );
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    vb.consume( 5 );
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    @endcode
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    @endcode
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49  
50   
    @par Thread Safety
50   
    @par Thread Safety
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    Distinct objects: Safe.
51   
    Distinct objects: Safe.
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    Shared objects: Unsafe.
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    Shared objects: Unsafe.
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53  
54   
    @tparam T The element type. Must be fundamental with sizeof 1.
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    @tparam T The element type. Must be fundamental with sizeof 1.
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    @tparam Allocator The allocator type for the vector.
55   
    @tparam Allocator The allocator type for the vector.
56  
56  
57   
    @see flat_dynamic_buffer, circular_dynamic_buffer, string_dynamic_buffer
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    @see flat_dynamic_buffer, circular_dynamic_buffer, string_dynamic_buffer
58   
*/
58   
*/
59   
template<
59   
template<
60   
    class T,
60   
    class T,
61   
    class Allocator = std::allocator<T>>
61   
    class Allocator = std::allocator<T>>
62   
    requires std::is_fundamental_v<T> && (sizeof(T) == 1)
62   
    requires std::is_fundamental_v<T> && (sizeof(T) == 1)
63   
class basic_vector_dynamic_buffer
63   
class basic_vector_dynamic_buffer
64   
{
64   
{
65   
    std::vector<T, Allocator>* v_;
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    std::vector<T, Allocator>* v_;
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    std::size_t max_size_;
66   
    std::size_t max_size_;
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67  
68   
    std::size_t in_size_ = 0;
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    std::size_t in_size_ = 0;
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    std::size_t out_size_ = 0;
69   
    std::size_t out_size_ = 0;
70  
70  
71   
public:
71   
public:
72   
    /// Indicates this is a DynamicBuffer adapter over external storage.
72   
    /// Indicates this is a DynamicBuffer adapter over external storage.
73   
    using is_dynamic_buffer_adapter = void;
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    using is_dynamic_buffer_adapter = void;
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75   
    /// The underlying vector type.
75   
    /// The underlying vector type.
76   
    using vector_type = std::vector<T, Allocator>;
76   
    using vector_type = std::vector<T, Allocator>;
77  
77  
78   
    /// The ConstBufferSequence type for readable bytes.
78   
    /// The ConstBufferSequence type for readable bytes.
79   
    using const_buffers_type = const_buffer;
79   
    using const_buffers_type = const_buffer;
80  
80  
81   
    /// The MutableBufferSequence type for writable bytes.
81   
    /// The MutableBufferSequence type for writable bytes.
82   
    using mutable_buffers_type = mutable_buffer;
82   
    using mutable_buffers_type = mutable_buffer;
83 - 
    /// Destroy the buffer.
 
84  
83  
85   
    ~basic_vector_dynamic_buffer() = default;
84   
    ~basic_vector_dynamic_buffer() = default;
86  
85  
87 - 
    /** Construct by moving.
86 + 
    /** Move constructor.
88   
    */
87   
    */
89   
    basic_vector_dynamic_buffer(
88   
    basic_vector_dynamic_buffer(
90   
        basic_vector_dynamic_buffer&& other) noexcept
89   
        basic_vector_dynamic_buffer&& other) noexcept
91   
        : v_(other.v_)
90   
        : v_(other.v_)
92   
        , max_size_(other.max_size_)
91   
        , max_size_(other.max_size_)
93   
        , in_size_(other.in_size_)
92   
        , in_size_(other.in_size_)
94   
        , out_size_(other.out_size_)
93   
        , out_size_(other.out_size_)
95   
    {
94   
    {
96   
        other.v_ = nullptr;
95   
        other.v_ = nullptr;
97   
    }
96   
    }
98  
97  
99   
    /** Construct a dynamic buffer over a vector.
98   
    /** Construct a dynamic buffer over a vector.
100  
99  
101   
        @param v Pointer to the vector to use as storage.
100   
        @param v Pointer to the vector to use as storage.
102   
        @param max_size Optional maximum size limit. Defaults
101   
        @param max_size Optional maximum size limit. Defaults
103   
            to the vector's `max_size()`.
102   
            to the vector's `max_size()`.
104   
    */
103   
    */
105   
    explicit
104   
    explicit
106   
    basic_vector_dynamic_buffer(
105   
    basic_vector_dynamic_buffer(
107   
        vector_type* v,
106   
        vector_type* v,
108   
        std::size_t max_size =
107   
        std::size_t max_size =
109   
            std::size_t(-1)) noexcept
108   
            std::size_t(-1)) noexcept
110   
        : v_(v)
109   
        : v_(v)
111   
        , max_size_(
110   
        , max_size_(
112   
            max_size > v_->max_size()
111   
            max_size > v_->max_size()
113   
                ? v_->max_size()
112   
                ? v_->max_size()
114   
                : max_size)
113   
                : max_size)
115   
    {
114   
    {
116   
        if(v_->size() > max_size_)
115   
        if(v_->size() > max_size_)
117   
            v_->resize(max_size_);
116   
            v_->resize(max_size_);
118   
        in_size_ = v_->size();
117   
        in_size_ = v_->size();
119   
    }
118   
    }
120  
119  
121   
    /// Copy assignment is deleted.
120   
    /// Copy assignment is deleted.
122   
    basic_vector_dynamic_buffer& operator=(
121   
    basic_vector_dynamic_buffer& operator=(
123   
        basic_vector_dynamic_buffer const&) = delete;
122   
        basic_vector_dynamic_buffer const&) = delete;
124  
123  
125   
    /// Return the number of readable bytes.
124   
    /// Return the number of readable bytes.
126   
    std::size_t
125   
    std::size_t
127   
    size() const noexcept
126   
    size() const noexcept
128   
    {
127   
    {
129   
        return in_size_;
128   
        return in_size_;
130   
    }
129   
    }
131  
130  
132   
    /// Return the maximum number of bytes the buffer can hold.
131   
    /// Return the maximum number of bytes the buffer can hold.
133   
    std::size_t
132   
    std::size_t
134   
    max_size() const noexcept
133   
    max_size() const noexcept
135   
    {
134   
    {
136   
        return max_size_;
135   
        return max_size_;
137   
    }
136   
    }
138  
137  
139   
    /// Return the number of writable bytes without reallocation.
138   
    /// Return the number of writable bytes without reallocation.
140   
    std::size_t
139   
    std::size_t
141   
    capacity() const noexcept
140   
    capacity() const noexcept
142   
    {
141   
    {
143   
        if(v_->capacity() <= max_size_)
142   
        if(v_->capacity() <= max_size_)
144   
            return v_->capacity() - in_size_;
143   
            return v_->capacity() - in_size_;
145   
        return max_size_ - in_size_;
144   
        return max_size_ - in_size_;
146   
    }
145   
    }
147  
146  
148   
    /// Return a buffer sequence representing the readable bytes.
147   
    /// Return a buffer sequence representing the readable bytes.
149   
    const_buffers_type
148   
    const_buffers_type
150   
    data() const noexcept
149   
    data() const noexcept
151   
    {
150   
    {
152   
        return const_buffers_type(
151   
        return const_buffers_type(
153   
            v_->data(), in_size_);
152   
            v_->data(), in_size_);
154   
    }
153   
    }
155  
154  
156   
    /** Return a buffer sequence for writing.
155   
    /** Return a buffer sequence for writing.
157  
156  
158   
        Invalidates buffer sequences previously obtained
157   
        Invalidates buffer sequences previously obtained
159   
        from @ref prepare.
158   
        from @ref prepare.
160  
159  
161   
        @param n The desired number of writable bytes.
160   
        @param n The desired number of writable bytes.
162  
161  
163   
        @return A mutable buffer sequence of size @p n.
162   
        @return A mutable buffer sequence of size @p n.
164  
163  
165   
        @throws std::invalid_argument if `size() + n > max_size()`.
164   
        @throws std::invalid_argument if `size() + n > max_size()`.
166   
    */
165   
    */
167   
    mutable_buffers_type
166   
    mutable_buffers_type
168   
    prepare(std::size_t n)
167   
    prepare(std::size_t n)
169   
    {
168   
    {
170   
        if(n > max_size_ - in_size_)
169   
        if(n > max_size_ - in_size_)
171   
            detail::throw_invalid_argument();
170   
            detail::throw_invalid_argument();
172  
171  
173   
        if(v_->size() < in_size_ + n)
172   
        if(v_->size() < in_size_ + n)
174   
            v_->resize(in_size_ + n);
173   
            v_->resize(in_size_ + n);
175   
        out_size_ = n;
174   
        out_size_ = n;
176   
        return mutable_buffers_type(
175   
        return mutable_buffers_type(
177   
            v_->data() + in_size_, out_size_);
176   
            v_->data() + in_size_, out_size_);
178   
    }
177   
    }
179  
178  
180   
    /** Move bytes from the output to the input sequence.
179   
    /** Move bytes from the output to the input sequence.
181  
180  
182   
        Invalidates buffer sequences previously obtained
181   
        Invalidates buffer sequences previously obtained
183   
        from @ref prepare. Buffer sequences from @ref data
182   
        from @ref prepare. Buffer sequences from @ref data
184   
        remain valid.
183   
        remain valid.
185  
184  
186   
        @param n The number of bytes to commit. If greater
185   
        @param n The number of bytes to commit. If greater
187   
            than the prepared size, all prepared bytes
186   
            than the prepared size, all prepared bytes
188   
            are committed.
187   
            are committed.
189   
    */
188   
    */
190   
    void
189   
    void
191   
    commit(std::size_t n) noexcept
190   
    commit(std::size_t n) noexcept
192   
    {
191   
    {
193   
        if(n < out_size_)
192   
        if(n < out_size_)
194   
            in_size_ += n;
193   
            in_size_ += n;
195   
        else
194   
        else
196   
            in_size_ += out_size_;
195   
            in_size_ += out_size_;
197   
        out_size_ = 0;
196   
        out_size_ = 0;
198   
        v_->resize(in_size_);
197   
        v_->resize(in_size_);
199   
    }
198   
    }
200  
199  
201   
    /** Remove bytes from the beginning of the input sequence.
200   
    /** Remove bytes from the beginning of the input sequence.
202  
201  
203   
        Invalidates buffer sequences previously obtained
202   
        Invalidates buffer sequences previously obtained
204   
        from @ref data. Buffer sequences from @ref prepare
203   
        from @ref data. Buffer sequences from @ref prepare
205   
        remain valid.
204   
        remain valid.
206  
205  
207   
        @param n The number of bytes to consume. If greater
206   
        @param n The number of bytes to consume. If greater
208   
            than @ref size(), all readable bytes are consumed.
207   
            than @ref size(), all readable bytes are consumed.
209   
    */
208   
    */
210   
    void
209   
    void
211   
    consume(std::size_t n) noexcept
210   
    consume(std::size_t n) noexcept
212   
    {
211   
    {
213   
        if(n < in_size_)
212   
        if(n < in_size_)
214   
        {
213   
        {
215   
            v_->erase(v_->begin(), v_->begin() + n);
214   
            v_->erase(v_->begin(), v_->begin() + n);
216   
            in_size_ -= n;
215   
            in_size_ -= n;
217   
        }
216   
        }
218   
        else
217   
        else
219   
        {
218   
        {
220   
            v_->clear();
219   
            v_->clear();
221   
            in_size_ = 0;
220   
            in_size_ = 0;
222   
        }
221   
        }
223   
        out_size_ = 0;
222   
        out_size_ = 0;
224   
    }
223   
    }
225   
};
224   
};
226  
225  
227   
/// A dynamic buffer using `std::vector<unsigned char>`.
226   
/// A dynamic buffer using `std::vector<unsigned char>`.
228   
using vector_dynamic_buffer =
227   
using vector_dynamic_buffer =
229   
    basic_vector_dynamic_buffer<unsigned char>;
228   
    basic_vector_dynamic_buffer<unsigned char>;
230  
229  
231   
/** Create a dynamic buffer from a vector.
230   
/** Create a dynamic buffer from a vector.
232  
231  
233   
    @param v The vector to wrap. Element type must be
232   
    @param v The vector to wrap. Element type must be
234   
        a fundamental type with sizeof 1.
233   
        a fundamental type with sizeof 1.
235   
    @param max_size Optional maximum size limit.
234   
    @param max_size Optional maximum size limit.
236   
    @return A vector_dynamic_buffer wrapping the vector.
235   
    @return A vector_dynamic_buffer wrapping the vector.
237   
*/
236   
*/
238   
template<class T, class Allocator>
237   
template<class T, class Allocator>
239   
    requires std::is_fundamental_v<T> && (sizeof(T) == 1)
238   
    requires std::is_fundamental_v<T> && (sizeof(T) == 1)
240   
basic_vector_dynamic_buffer<T, Allocator>
239   
basic_vector_dynamic_buffer<T, Allocator>
241   
dynamic_buffer(
240   
dynamic_buffer(
242   
    std::vector<T, Allocator>& v,
241   
    std::vector<T, Allocator>& v,
243   
    std::size_t max_size = std::size_t(-1))
242   
    std::size_t max_size = std::size_t(-1))
244   
{
243   
{
245   
    return basic_vector_dynamic_buffer<T, Allocator>(&v, max_size);
244   
    return basic_vector_dynamic_buffer<T, Allocator>(&v, max_size);
246   
}
245   
}
247  
246  
248   
} // capy
247   
} // capy
249   
} // boost
248   
} // boost
250  
249  
251   
#endif
250   
#endif