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diff --git a/src/lib/util/vecstream.h b/src/lib/util/vecstream.h
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+// license:BSD-3-Clause
+// copyright-holders:Vas Crabb
+/***************************************************************************
+
+ vecstream.h
+
+ streams with vector storage
+
+ These types are useful if you want a persistent buffer for formatted
+ text and you need to use it like a character array or character
+ pointer, as you get read-only access to it without copying. The
+ storage is always guaranteed to be contiguous. Writing to the
+ stream may invalidate pointers to storage.
+
+***************************************************************************/
+
+#ifndef __MAME_UTIL_VECSTREAM_H__
+#define __MAME_UTIL_VECSTREAM_H__
+
+#include <cassert>
+#include <ostream>
+#include <streambuf>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+namespace util {
+template <typename CharT, typename Traits = std::char_traits<CharT>, typename Allocator = std::allocator<CharT> >
+class basic_vectorbuf : public std::basic_streambuf<CharT, Traits>
+{
+public:
+ typedef typename std::basic_streambuf<CharT, Traits>::char_type char_type;
+ typedef typename std::basic_streambuf<CharT, Traits>::int_type int_type;
+ typedef typename std::basic_streambuf<CharT, Traits>::pos_type pos_type;
+ typedef typename std::basic_streambuf<CharT, Traits>::off_type off_type;
+ typedef Allocator allocator_type;
+ typedef std::vector<char_type, Allocator> vector_type;
+
+ basic_vectorbuf(std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) : std::basic_streambuf<CharT, Traits>(), m_mode(mode), m_storage(), m_threshold(nullptr)
+ {
+ setup();
+ }
+
+ basic_vectorbuf(vector_type const &content, std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) : std::basic_streambuf<CharT, Traits>(), m_mode(mode), m_storage(content), m_threshold(nullptr)
+ {
+ setup();
+ }
+
+ basic_vectorbuf(vector_type &&content, std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) : std::basic_streambuf<CharT, Traits>(), m_mode(mode), m_storage(std::move(content)), m_threshold(nullptr)
+ {
+ setup();
+ }
+
+ basic_vectorbuf(basic_vectorbuf const &that) : std::basic_streambuf<CharT, Traits>(that), m_mode(that.m_mode), m_storage(that.m_storage), m_threshold(nullptr)
+ {
+ adjust();
+ }
+
+ basic_vectorbuf(basic_vectorbuf &&that) : std::basic_streambuf<CharT, Traits>(that), m_mode(that.m_mode), m_storage(std::move(that.m_storage)), m_threshold(that.m_threshold)
+ {
+ that.clear();
+ }
+
+ vector_type const &vec() const
+ {
+ if (m_mode & std::ios_base::out)
+ {
+ if (this->pptr() > m_threshold) m_threshold = this->pptr();
+ auto const base(this->pbase());
+ auto const end(m_threshold - base);
+ if (m_storage.size() > std::make_unsigned_t<decltype(end)>(end))
+ {
+ m_storage.resize(std::make_unsigned_t<decltype(end)>(end));
+ assert(&m_storage[0] == base);
+ auto const put_offset(this->pptr() - base);
+ const_cast<basic_vectorbuf *>(this)->setp(base, base + put_offset);
+ const_cast<basic_vectorbuf *>(this)->pbump(put_offset);
+ }
+ }
+ return m_storage;
+ }
+
+ void vec(const vector_type &content)
+ {
+ m_storage = content;
+ setup();
+ }
+
+ void vec(vector_type &&content)
+ {
+ m_storage = std::move(content);
+ setup();
+ }
+
+ void clear()
+ {
+ m_storage.clear();
+ setup();
+ }
+
+ void reserve(typename vector_type::size_type size)
+ {
+ if ((m_mode & std::ios_base::out) && (m_storage.size() < size))
+ {
+ m_storage.reserve(size);
+ adjust();
+ }
+ }
+
+ basic_vectorbuf &operator=(basic_vectorbuf const &that)
+ {
+ std::basic_streambuf<CharT, Traits>::operator=(that);
+ m_mode = that.m_mode;
+ m_storage = that.m_storage;
+ m_threshold = that.m_threshold;
+ adjust();
+ return *this;
+ }
+
+ basic_vectorbuf &operator=(basic_vectorbuf &&that)
+ {
+ std::basic_streambuf<CharT, Traits>::operator=(that);
+ m_mode = that.m_mode;
+ m_storage = std::move(that.m_storage);
+ m_threshold = that.m_threshold;
+ that.clear();
+ return *this;
+ }
+
+protected:
+ pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode which = std::ios_base::in | std::ios_base::out) override
+ {
+ bool const in(which & std::ios_base::in);
+ bool const out(which & std::ios_base::out);
+ if ((!in && !out) ||
+ (in && out && (std::ios_base::cur == dir)) ||
+ (in && (!(m_mode & std::ios_base::in) || !this->gptr())) ||
+ (out && (!(m_mode & std::ios_base::out) || !this->pptr())))
+ {
+ return pos_type(off_type(-1));
+ }
+ maximise_egptr();
+ off_type const end((m_mode & std::ios_base::out) ? off_type(m_threshold - this->pbase()) : off_type(m_storage.size()));
+ switch (dir)
+ {
+ case std::ios_base::beg:
+ break;
+ case std::ios_base::end:
+ off += end;
+ break;
+ case std::ios_base::cur:
+ off += off_type(in ? (this->gptr() - this->eback()) : (this->pptr() - this->pbase()));
+ break;
+ default:
+ return pos_type(off_type(-1));
+ }
+ if ((off_type(0) > off) || (end < off) || ((m_mode & std::ios_base::app) && out && (end != off)))
+ return pos_type(off_type(-1));
+ if (in) this->setg(this->eback(), this->eback() + off, this->egptr());
+ if (out)
+ {
+ this->setp(this->pbase(), this->epptr());
+ this->pbump(off);
+ }
+ return pos_type(off);
+ }
+
+ virtual pos_type seekpos(pos_type pos, std::ios_base::openmode which = std::ios_base::in |std:: ios_base::out) override
+ {
+ return seekoff(off_type(pos), std::ios_base::beg, which);
+ }
+
+ virtual int_type underflow() override
+ {
+ if (!this->gptr()) return Traits::eof();
+ maximise_egptr();
+ return (this->gptr() < this->egptr()) ? Traits::to_int_type(*this->gptr()) : Traits::eof();
+ }
+
+ virtual int_type overflow(int_type ch = Traits::eof()) override
+ {
+ if (!(m_mode & std::ios_base::out)) return Traits::eof();
+ if (Traits::eq_int_type(ch, Traits::eof())) return Traits::not_eof(ch);
+ auto const put_offset(this->pptr() - this->pbase() + 1);
+ auto const threshold_offset((std::max)(m_threshold - this->pbase(), put_offset));
+ m_storage.push_back(Traits::to_char_type(ch));
+ m_storage.resize(m_storage.capacity());
+ auto const base(&m_storage[0]);
+ this->setp(base, base + m_storage.size());
+ m_threshold = base + threshold_offset;
+ if (m_mode & std::ios_base::in) this->setg(base, base + (this->gptr() - this->eback()), m_threshold);
+ this->pbump(int(put_offset));
+ return ch;
+ }
+
+ virtual int_type pbackfail(int_type ch = Traits::eof()) override
+ {
+ if (this->gptr() != this->eback())
+ {
+ if (Traits::eq_int_type(ch, Traits::eof()))
+ {
+ this->gbump(-1);
+ return Traits::not_eof(ch);
+ }
+ else if (Traits::eq(Traits::to_char_type(ch), this->gptr()[-1]))
+ {
+ this->gbump(-1);
+ return ch;
+ }
+ else if (m_mode & std::ios_base::out)
+ {
+ this->gbump(-1);
+ *this->gptr() = Traits::to_char_type(ch);
+ return ch;
+ }
+ }
+ return Traits::eof();
+ }
+
+private:
+ void setup()
+ {
+ if (m_mode & std::ios_base::out)
+ {
+ auto const end(m_storage.size());
+ m_storage.resize(m_storage.capacity());
+ if (m_storage.empty())
+ {
+ m_threshold = nullptr;
+ this->setg(nullptr, nullptr, nullptr);
+ this->setp(nullptr, nullptr);
+ }
+ else
+ {
+ auto const base(&m_storage[0]);
+ m_threshold = base + end;
+ this->setp(base, base + m_storage.size());
+ if (m_mode & std::ios_base::in) this->setg(base, base, m_threshold);
+ }
+ if (m_mode & (std::ios_base::app | std::ios_base::ate)) this->pbump(int(unsigned(end)));
+ }
+ else if (m_storage.empty())
+ {
+ this->setg(nullptr, nullptr, nullptr);
+ }
+ else if (m_mode & std::ios_base::in)
+ {
+ auto const base(&m_storage[0]);
+ this->setg(base, base, base + m_storage.size());
+ }
+ }
+
+ void adjust()
+ {
+ auto const put_offset(this->pptr() - this->pbase());
+ auto const get_offset(this->gptr() - this->eback());
+ setup();
+ if (m_mode & std::ios_base::out)
+ {
+ this->pbump(int(put_offset));
+ m_threshold = this->pptr();
+ if (m_mode & std::ios_base::in)
+ {
+ auto const base(&m_storage[0]);
+ this->setg(base, base + get_offset, m_threshold);
+ }
+ }
+ else if (m_mode & std::ios_base::in)
+ {
+ this->gbump(int(get_offset));
+ }
+ }
+
+ void maximise_egptr()
+ {
+ if (m_mode & std::ios_base::out)
+ {
+ if (m_threshold < this->pptr()) m_threshold = this->pptr();
+ if ((m_mode & std::ios_base::in) && (this->egptr() < m_threshold)) this->setg(this->eback(), this->gptr(), m_threshold);
+ }
+ }
+
+ std::ios_base::openmode m_mode;
+ mutable vector_type m_storage;
+ mutable CharT *m_threshold;
+};
+
+template <typename CharT, typename Traits = std::char_traits<CharT>, typename Allocator = std::allocator<CharT> >
+class basic_ivectorstream : public std::basic_istream<CharT, Traits>
+{
+public:
+ typedef typename basic_vectorbuf<CharT, Traits, Allocator>::vector_type vector_type;
+
+ basic_ivectorstream(std::ios_base::openmode mode = std::ios_base::in) : std::basic_istream<CharT, Traits>(&m_rdbuf), m_rdbuf(mode) { }
+ basic_ivectorstream(vector_type const &content, std::ios_base::openmode mode = std::ios_base::in) : std::basic_istream<CharT, Traits>(&m_rdbuf), m_rdbuf(content, mode) { }
+ basic_ivectorstream(vector_type &&content, std::ios_base::openmode mode = std::ios_base::in) : std::basic_istream<CharT, Traits>(&m_rdbuf), m_rdbuf(std::move(content), mode) { }
+
+ basic_vectorbuf<CharT, Traits, Allocator> *rdbuf() const { return reinterpret_cast<basic_vectorbuf<CharT, Traits, Allocator> *>(std::basic_istream<CharT, Traits>::rdbuf()); }
+ vector_type const &vec() const { return rdbuf()->vec(); }
+ void vec(const vector_type &content) { rdbuf()->vec(content); }
+ void vec(vector_type &&content) { rdbuf()->vec(std::move(content)); }
+ void clear() { rdbuf()->clear(); }
+
+private:
+ basic_vectorbuf<CharT, Traits, Allocator> m_rdbuf;
+};
+
+template <typename CharT, typename Traits = std::char_traits<CharT>, typename Allocator = std::allocator<CharT> >
+class basic_ovectorstream : public std::basic_ostream<CharT, Traits>
+{
+public:
+ typedef typename basic_vectorbuf<CharT, Traits, Allocator>::vector_type vector_type;
+
+ basic_ovectorstream(std::ios_base::openmode mode = std::ios_base::out) : std::basic_ostream<CharT, Traits>(&m_rdbuf), m_rdbuf(mode) { }
+ basic_ovectorstream(vector_type const &content, std::ios_base::openmode mode = std::ios_base::out) : std::basic_ostream<CharT, Traits>(&m_rdbuf), m_rdbuf(content, mode) { }
+ basic_ovectorstream(vector_type &&content, std::ios_base::openmode mode = std::ios_base::out) : std::basic_ostream<CharT, Traits>(&m_rdbuf), m_rdbuf(std::move(content), mode) { }
+
+ basic_vectorbuf<CharT, Traits, Allocator> *rdbuf() const { return reinterpret_cast<basic_vectorbuf<CharT, Traits, Allocator> *>(std::basic_ostream<CharT, Traits>::rdbuf()); }
+
+ vector_type const &vec() const { return rdbuf()->vec(); }
+ void vec(const vector_type &content) { rdbuf()->vec(content); }
+ void vec(vector_type &&content) { rdbuf()->vec(std::move(content)); }
+ void clear() { rdbuf()->clear(); }
+ void reserve(typename vector_type::size_type size) { rdbuf->reserve(size); }
+
+private:
+ basic_vectorbuf<CharT, Traits, Allocator> m_rdbuf;
+};
+
+template <typename CharT, typename Traits = std::char_traits<CharT>, typename Allocator = std::allocator<CharT> >
+class basic_vectorstream : public std::basic_iostream<CharT, Traits>
+{
+public:
+ typedef typename basic_vectorbuf<CharT, Traits, Allocator>::vector_type vector_type;
+
+ basic_vectorstream(std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) : std::basic_iostream<CharT, Traits>(&m_rdbuf), m_rdbuf(mode) { }
+ basic_vectorstream(vector_type const &content, std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) : std::basic_iostream<CharT, Traits>(&m_rdbuf), m_rdbuf(content, mode) { }
+ basic_vectorstream(vector_type &&content, std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) : std::basic_iostream<CharT, Traits>(&m_rdbuf), m_rdbuf(std::move(content), mode) { }
+
+ basic_vectorbuf<CharT, Traits, Allocator> *rdbuf() const { return reinterpret_cast<basic_vectorbuf<CharT, Traits, Allocator> *>(std::basic_iostream<CharT, Traits>::rdbuf()); }
+
+ vector_type const &vec() const { return rdbuf()->vec(); }
+ void vec(const vector_type &content) { rdbuf()->vec(content); }
+ void vec(vector_type &&content) { rdbuf()->vec(std::move(content)); }
+ void clear() { rdbuf()->clear(); }
+ void reserve(typename vector_type::size_type size) { rdbuf->reserve(size); }
+
+private:
+ basic_vectorbuf<CharT, Traits, Allocator> m_rdbuf;
+};
+
+typedef basic_ivectorstream<char> ivectorstream;
+typedef basic_ivectorstream<wchar_t> wivectorstream;
+typedef basic_ovectorstream<char> ovectorstream;
+typedef basic_ovectorstream<wchar_t> wovectorstream;
+typedef basic_vectorstream<char> vectorstream;
+typedef basic_vectorstream<wchar_t> wvectorstream;
+
+} // namespace util
+
+#endif // __MAME_UTIL_VECSTREAM_H__