50 lines
1.3 KiB
C++
50 lines
1.3 KiB
C++
/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#pragma once
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#include <iostream>
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#include <fstream>
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namespace lean {
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/**
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\brief Wrapper for std::ostream.
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The idea is to be able to have an output stream that can be
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"reassigned".
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std::unique_ptr<output_channel> out;
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out = new stdout_channel();
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(*out) << "writting to standard output";
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out = new stderr_channel();
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(*out) << "writting to standard input";
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out = new file_output_channel("file.txt");
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(*out) << "writting to file";
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*/
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class output_channel {
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public:
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virtual ~output_channel() {}
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virtual std::ostream & get_stream() = 0;
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};
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class stdout_channel : public output_channel {
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public:
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virtual std::ostream & get_stream() { return std::cout; }
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};
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class stderr_channel : public output_channel {
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public:
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virtual std::ostream & get_stream() { return std::cerr; }
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};
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class file_output_channel : public output_channel {
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std::ofstream m_out;
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public:
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file_output_channel(char const * fname):m_out(fname) {}
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virtual ~file_output_channel() {}
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virtual std::ostream & get_stream() { return m_out; }
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};
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template<typename T>
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output_channel & operator<<(output_channel & out, T const & v) {
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out.get_stream() << v;
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return out;
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}
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}
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