Added a class for handling terminal linebuffering.

sortix/Makefile

@@ -78,6 +78,7 @@ sound.o \
 pci.o \
 uart.o \
 terminal.o \
+linebuffer.o \
 vgaterminal.o \
 serialterminal.o \
 descriptors.o \

sortix/linebuffer.cpp

@@ -0,0 +1,124 @@
+/******************************************************************************
+
+	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2012.
+
+	This file is part of Sortix.
+
+	Sortix is free software: you can redistribute it and/or modify it under the
+	terms of the GNU General Public License as published by the Free Software
+	Foundation, either version 3 of the License, or (at your option) any later
+	version.
+
+	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+	details.
+
+	You should have received a copy of the GNU General Public License along
+	with Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	linebuffer.cpp
+	Provides a simple queue-like line buffering for terminals.
+
+******************************************************************************/
+
+#include "platform.h"
+#include <libmaxsi/memory.h>
+#include "linebuffer.h"
+
+using namespace Maxsi;
+
+namespace Sortix
+{
+	static size_t OffsetIndex(size_t offset, size_t index, size_t length)
+	{
+		// TODO: Possible overflow here.
+		return (offset + index) % length;
+	}
+
+	LineBuffer::LineBuffer()
+	{
+		buffer = NULL;
+		bufferlength = 0;
+		bufferoffset = 0;
+		buffercommitted = 0;
+		bufferfrozen = 0;
+		bufferused = 0;
+	}
+
+	LineBuffer::~LineBuffer()
+	{
+		delete[] buffer;
+	}
+
+	bool LineBuffer::Push(uint32_t unicode)
+	{
+		// Check if we need to allocate or resize the circular queue.
+		if ( bufferused == bufferlength )
+		{
+			size_t newbufferlength = (bufferlength) ? bufferlength * 2 : 32UL;
+			uint32_t* newbuffer = new uint32_t[newbufferlength];
+			if ( !newbuffer ) { return false; }
+			size_t elemsize = sizeof(*buffer);
+			size_t leadingavai = bufferlength-bufferoffset;
+			size_t leading = (leadingavai < bufferused) ? leadingavai : bufferused;
+			size_t trailing = bufferused - leading;
+			Memory::Copy(newbuffer, buffer + bufferoffset, leading * elemsize);
+			Memory::Copy(newbuffer + leading, buffer, trailing * elemsize);
+			delete[] buffer;
+			buffer = newbuffer;
+			bufferlength = newbufferlength;
+			bufferoffset = 0;
+		}
+
+		size_t index = OffsetIndex(bufferoffset, bufferused++, bufferlength);
+		buffer[index] = unicode;
+		return true;
+	}
+
+	uint32_t LineBuffer::Pop()
+	{
+		if ( !CanPop() ) { return 0; }
+		uint32_t result = Peek();
+		bufferoffset = (bufferoffset+1) % bufferlength;
+		buffercommitted--;
+		bufferfrozen--;
+		bufferused--;
+		return result;
+	}
+
+	uint32_t LineBuffer::Peek() const
+	{
+		if ( !CanPop() ) { return 0; }
+		size_t index = OffsetIndex(bufferoffset, 0, bufferlength);
+		return buffer[index];
+	}
+
+	uint32_t LineBuffer::Backspace()
+	{
+		if ( !CanBackspace() ) { return 0; }
+		size_t index = OffsetIndex(bufferoffset, --bufferused, bufferlength);
+		return buffer[index];
+	}
+
+	void LineBuffer::Commit()
+	{
+		buffercommitted = bufferfrozen = bufferused;
+	}
+
+	void LineBuffer::Freeze()
+	{
+		bufferfrozen = bufferused;
+	}
+
+	bool LineBuffer::CanPop() const
+	{
+		return buffercommitted;
+	}
+
+	bool LineBuffer::CanBackspace() const
+	{
+		return bufferused - bufferfrozen;
+	}
+}
+

sortix/linebuffer.h

@@ -0,0 +1,58 @@
+/******************************************************************************
+
+	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2012.
+
+	This file is part of Sortix.
+
+	Sortix is free software: you can redistribute it and/or modify it under the
+	terms of the GNU General Public License as published by the Free Software
+	Foundation, either version 3 of the License, or (at your option) any later
+	version.
+
+	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
+	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+	details.
+
+	You should have received a copy of the GNU General Public License along
+	with Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	linebuffer.h
+	Provides a simple queue-like line buffering for terminals.
+
+******************************************************************************/
+
+#ifndef SORTIX_LINEBUFFER_H
+#define SORTIX_LINEBUFFER_H
+
+namespace Sortix
+{
+	class LineBuffer
+	{
+	public:
+		LineBuffer();
+		~LineBuffer();
+
+	public:
+		bool Push(uint32_t unicode);
+		uint32_t Pop();
+		uint32_t Peek() const;
+		uint32_t Backspace();
+		void Commit();
+		void Freeze();
+		bool CanPop() const;
+		bool CanBackspace() const;
+
+	private:
+		uint32_t* buffer;
+		size_t bufferlength;
+		size_t bufferoffset;
+		size_t buffercommitted;
+		size_t bufferfrozen;
+		size_t bufferused;
+
+	};
+}
+
+#endif
+