71 lines
1.7 KiB
C++
71 lines
1.7 KiB
C++
/*
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* \brief Implementation of the output interface that buffers characters
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* \author Norman Feske
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* \date 2016-05-03
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*/
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/*
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* Copyright (C) 2016-2019 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _INCLUDE__BASE__BUFFERED_OUTPUT_H_
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#define _INCLUDE__BASE__BUFFERED_OUTPUT_H_
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#include <base/output.h>
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namespace Genode { template <size_t, typename> class Buffered_output; }
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/**
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* Implementation of the output interface that buffers characters
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*
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* \param BUF_SIZE maximum number of characters to buffer before writing
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* \param WRITE_FN functor called to writing the buffered characters to a
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* backend.
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*
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* The 'WRITE_FN' functor is called with a null-terminated 'char const *'
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* as argument.
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*/
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template <Genode::size_t BUF_SIZE, typename BACKEND_WRITE_FN>
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class Genode::Buffered_output : public Output
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{
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private:
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BACKEND_WRITE_FN _write_fn;
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char _buf[BUF_SIZE];
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unsigned _num_chars = 0;
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void _flush()
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{
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/* null-terminate string */
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_buf[_num_chars] = 0;
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_write_fn(_buf);
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/* restart with empty buffer */
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_num_chars = 0;
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}
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public:
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Buffered_output(BACKEND_WRITE_FN const &write_fn) : _write_fn(write_fn) { }
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~Buffered_output() { _flush(); }
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void out_char(char c) override
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{
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/* ensure enough buffer space for complete escape sequence */
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if ((c == 27) && (_num_chars + 8 > BUF_SIZE)) _flush();
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_buf[_num_chars++] = c;
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/* flush immediately on line break */
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if (c == '\n' || _num_chars >= sizeof(_buf) - 1)
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_flush();
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}
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};
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#endif /* _INCLUDE__BASE__BUFFERED_OUTPUT_H_ */
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