libs/capy/include/boost/capy/buffers/string_dynamic_buffer.hpp

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1			//
2			// Copyright (c) 2023 Vinnie Falco (vinnie.falco@gmail.com)
3			//
4			// Distributed under the Boost Software License, Version 1.0. (See accompanying
5			// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6			//
7			// Official repository: https://github.com/cppalliance/capy
8			//
9
10			#ifndef BOOST_CAPY_BUFFERS_STRING_DYNAMIC_BUFFER_HPP
11			#define BOOST_CAPY_BUFFERS_STRING_DYNAMIC_BUFFER_HPP
12
13			#include <boost/capy/detail/config.hpp>
14			#include <boost/capy/buffers.hpp>
15			#include <boost/capy/detail/except.hpp>
16			#include <string>
17
18			namespace boost {
19			namespace capy {
20
21			/** A dynamic buffer using an underlying string
22			*/
23			template<
24			class CharT,
25			class Traits = std::char_traits<CharT>,
26			class Allocator = std::allocator<CharT>>
27			class basic_string_dynamic_buffer
28			{
29			std::basic_string<
30			CharT, Traits, Allocator>* s_;
31			std::size_t max_size_;
32
33			std::size_t in_size_ = 0;
34			std::size_t out_size_ = 0;
35
36			public:
37			using is_dynamic_buffer_adapter = void;
38			using string_type = std::basic_string<
39			CharT, Traits, Allocator>;
40			using const_buffers_type = const_buffer;
41			using mutable_buffers_type = mutable_buffer;
42
43			~basic_string_dynamic_buffer() = default;
44
45			/** Constructor.
46			*/
47		266	basic_string_dynamic_buffer(
48			basic_string_dynamic_buffer&& other) noexcept
49		266	: s_(other.s_)
50		266	, max_size_(other.max_size_)
51		266	, in_size_(other.in_size_)
52		266	, out_size_(other.out_size_)
53			{
54		266	other.s_ = nullptr;
55		266	}
56
57			/** Constructor.
58			*/
59			explicit
60		433	basic_string_dynamic_buffer(
61			string_type* s,
62			std::size_t max_size =
63			std::size_t(-1)) noexcept
64		433	: s_(s)
65		433	, max_size_(
66		433	max_size > s_->max_size()
67	2/2 ✓ Branch 0 taken 418 times. ✓ Branch 1 taken 15 times.	433	? s_->max_size()
68		433	: max_size)
69			{
70	2/2 ✓ Branch 1 taken 1 time. ✓ Branch 2 taken 432 times.	433	if(s_->size() > max_size_)
71		1	s_->resize(max_size_);
72		433	in_size_ = s_->size();
73		433	}
74
75			/** Assignment.
76			*/
77			basic_string_dynamic_buffer& operator=(
78			basic_string_dynamic_buffer const&) = delete;
79
80			std::size_t
81		1280	size() const noexcept
82			{
83		1280	return in_size_;
84			}
85
86			std::size_t
87		410	max_size() const noexcept
88			{
89		410	return max_size_;
90			}
91
92			std::size_t
93		2	capacity() const noexcept
94			{
95	2/2 ✓ Branch 1 taken 1 time. ✓ Branch 2 taken 1 time.	2	if(s_->capacity() <= max_size_)
96		1	return s_->capacity() - in_size_;
97		1	return max_size_ - in_size_;
98			}
99
100			const_buffers_type
101		387	data() const noexcept
102			{
103		387	return const_buffers_type(
104		774	s_->data(), in_size_);
105			}
106
107			mutable_buffers_type
108		557	prepare(std::size_t n)
109			{
110			// n exceeds available space
111	2/2 ✓ Branch 0 taken 1 time. ✓ Branch 1 taken 556 times.	557	if(n > max_size_ - in_size_)
112		1	detail::throw_invalid_argument();
113
114	2/2 ✓ Branch 1 taken 555 times. ✓ Branch 2 taken 1 time.	556	if( s_->size() < in_size_ + n)
115		555	s_->resize(in_size_ + n);
116		556	out_size_ = n;
117		556	return mutable_buffers_type(
118	1/1 ✓ Branch 1 taken 186 times.	1112	&(*s_)[in_size_], out_size_);
119			}
120
121		455	void commit(std::size_t n) noexcept
122			{
123	2/2 ✓ Branch 0 taken 257 times. ✓ Branch 1 taken 198 times.	455	if(n < out_size_)
124		257	in_size_ += n;
125			else
126		198	in_size_ += out_size_;
127		455	out_size_ = 0;
128		455	s_->resize(in_size_);
129		455	}
130
131		168	void consume(std::size_t n) noexcept
132			{
133	2/2 ✓ Branch 0 taken 3 times. ✓ Branch 1 taken 165 times.	168	if(n < in_size_)
134			{
135		3	s_->erase(0, n);
136		3	in_size_ -= n;
137			}
138			else
139			{
140		165	s_->clear();
141		165	in_size_ = 0;
142			}
143		168	out_size_ = 0;
144		168	}
145			};
146
147			using string_dynamic_buffer = basic_string_dynamic_buffer<char>;
148
149			/** Create a dynamic buffer from a string.
150
151			@param s The string to wrap.
152			@param max_size Optional maximum size limit.
153			@return A string_dynamic_buffer wrapping the string.
154			*/
155			template<class CharT, class Traits, class Allocator>
156			basic_string_dynamic_buffer<CharT, Traits, Allocator>
157		132	dynamic_buffer(
158			std::basic_string<CharT, Traits, Allocator>& s,
159			std::size_t max_size = std::size_t(-1))
160			{
161		132	return basic_string_dynamic_buffer<CharT, Traits, Allocator>(&s, max_size);
162			}
163
164			} // capy
165			} // boost
166
167			#endif
168