143 lines
3.4 KiB
C++
143 lines
3.4 KiB
C++
/*
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* Copyright 2014-2021 Max Kellermann <max.kellermann@gmail.com>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef BUFFERED_OUTPUT_STREAM_HXX
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#define BUFFERED_OUTPUT_STREAM_HXX
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#include "util/Compiler.h"
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#include "util/DynamicFifoBuffer.hxx"
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#include <cstddef>
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#ifdef _UNICODE
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#include <wchar.h>
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#endif
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class OutputStream;
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/**
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* An #OutputStream wrapper that buffers its output to reduce the
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* number of OutputStream::Write() calls.
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*
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* All wchar_t based strings are converted to UTF-8.
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*
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* To make sure everything is written to the underlying #OutputStream,
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* call Flush() before destructing this object.
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*/
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class BufferedOutputStream {
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OutputStream &os;
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DynamicFifoBuffer<char> buffer;
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public:
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explicit BufferedOutputStream(OutputStream &_os,
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size_t buffer_size=32768) noexcept
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:os(_os), buffer(buffer_size) {}
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/**
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* Write the contents of a buffer.
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*/
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void Write(const void *data, std::size_t size);
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/**
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* Write the given object. Note that this is only safe with
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* POD types. Types with padding can expose sensitive data.
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*/
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template<typename T>
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void WriteT(const T &value) {
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Write(&value, sizeof(value));
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}
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/**
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* Write one narrow character.
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*/
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void Write(const char &ch) {
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WriteT(ch);
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}
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/**
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* Write a null-terminated string.
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*/
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void Write(const char *p);
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/**
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* Write a printf-style formatted string.
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*/
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gcc_printf(2,3)
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void Format(const char *fmt, ...);
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#ifdef _UNICODE
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/**
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* Write one narrow character.
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*/
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void Write(const wchar_t &ch) {
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WriteWideToUTF8(&ch, 1);
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}
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/**
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* Write a null-terminated wide string.
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*/
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void Write(const wchar_t *p);
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#endif
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/**
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* Write buffer contents to the #OutputStream.
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*/
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void Flush();
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/**
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* Discard buffer contents.
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*/
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void Discard() noexcept {
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buffer.Clear();
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}
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private:
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bool AppendToBuffer(const void *data, std::size_t size) noexcept;
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#ifdef _UNICODE
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void WriteWideToUTF8(const wchar_t *p, std::size_t length);
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#endif
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};
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/**
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* Helper function which constructs a #BufferedOutputStream, calls the
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* given function and flushes the #BufferedOutputStream.
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*/
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template<typename F>
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void
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WithBufferedOutputStream(OutputStream &os, F &&f)
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{
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BufferedOutputStream bos(os);
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f(bos);
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bos.Flush();
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}
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#endif
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