1 files changed, 216 insertions, 0 deletions
diff --git a/src/core/BufferedCharReader.cpp b/src/core/BufferedCharReader.cpp
new file mode 100644
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--- /dev/null
+++ b/src/core/BufferedCharReader.cpp
@@ -0,0 +1,216 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program 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.
+
+    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "BufferedCharReader.hpp"
+
+namespace ousia {
+namespace utils {
+
+// Constants used within the linebreak statemachine.
+static const uint8_t LB_STATE_NONE = 0x00;
+static const uint8_t LB_STATE_ONE = 0x01;
+static const uint8_t LB_STATE_LF = 0x10;
+static const uint8_t LB_STATE_CR = 0x20;
+static const uint8_t LB_STATE_MASK_CNT = 0x0F;
+static const uint8_t LB_STATE_MASK_TYPE = 0xF0;
+
+/*******************************************************************************
+ * Struct BufferedCharReader::ReadCursor
+ ******************************************************************************/
+
+BufferedCharReader::ReadCursor::ReadCursor(const bool destructive) :
+		destructive(destructive)
+{
+	reset();
+}
+
+void BufferedCharReader::ReadCursor::assign(const ReadCursor &cursor)
+{
+	this->line = cursor.line;
+	this->column = cursor.column;
+	this->bufferElem = cursor.bufferElem;
+	this->bufferPos = cursor.bufferPos;
+	this->lbState = cursor.lbState;
+}
+
+void BufferedCharReader::ReadCursor::reset()
+{
+	this->line = 1;
+	this->column = 1;
+	this->bufferElem = 0;
+	this->bufferPos = 0;
+	this->lbState = LB_STATE_NONE;
+}
+
+/*******************************************************************************
+ * Class BufferedCharReader
+ ******************************************************************************/
+
+BufferedCharReader::BufferedCharReader() :
+	readCursor(true), peekCursor(false)
+{
+	reset();
+}
+
+void BufferedCharReader::reset()
+{
+	readCursor.reset();
+	peekCursor.reset();
+	buffer.clear();
+	closed = false;
+}
+
+bool BufferedCharReader::feed(const std::string &data)
+{
+	// Abort if the BufferedCharReader was closed
+	if (closed) {
+		return false;
+	}
+
+	// Append the data onto the queue
+	buffer.push_back(data);
+	return true;
+}
+
+void BufferedCharReader::close()
+{
+	closed = true;
+}
+
+bool BufferedCharReader::substituteLinebreaks(ReadCursor *cursor, char *c)
+{
+	// Handle line breaks, inserts breakes after the following character
+	// combinations: \n, \r, \n\r, \r\n TODO: Change behaviour to \n, \n\r, \r\n
+	if ((*c == '\n') || (*c == '\r')) {
+		// Determine the type of the current linebreak character
+		const uint8_t type = (*c == '\n') ? LB_STATE_LF : LB_STATE_CR;
+
+		// Read the last count and the last type from the state
+		const uint8_t lastCount = cursor->lbState & LB_STATE_MASK_CNT;
+		const uint8_t lastType = cursor->lbState & LB_STATE_MASK_TYPE;
+
+		// Set the current linebreak type and counter in the state
+		cursor->lbState = ((lastCount + 1) & 1) | type;
+
+		// If either this is the first instance of this character or the same
+		// return character is repeated
+		if (!lastCount || (lastType == type)) {
+			*c = '\n';
+			return true;
+		}
+		return false;
+	}
+
+	// Find the state
+	cursor->lbState = LB_STATE_NONE;
+	return true;
+}
+
+bool BufferedCharReader::readCharacterAtCursor(ReadCursor *cursor,
+		char *c)
+{
+	bool hasChar = false;
+	while (!hasChar) {
+		// Abort if the current buffer element does not point to a valid entry
+		// in the buffer -- we must wait until another data block has been fed
+		// into the buffer
+		if (cursor->bufferElem >= buffer.size()) {
+			return false;
+		}
+
+		// Fetch the current element the peek pointer points to
+		const std::string &data = buffer[cursor->bufferElem];
+
+		// Handle the "no data" case -- either in a destructive or
+		// non-destructive manner.
+		if (cursor->bufferPos >= data.length()) {
+			if (cursor->destructive) {
+				buffer.pop_front();
+			} else {
+				cursor->bufferElem++;
+			}
+			cursor->bufferPos = 0;
+			continue;
+		}
+
+		// Read the character, advance the buffer position
+		*c = *(data.data() + cursor->bufferPos);
+		cursor->bufferPos++;
+
+		// Substitute linebreaks with a single LF (0x0A)
+		hasChar = substituteLinebreaks(cursor, c);
+	}
+
+	// Update the position counter
+	if (*c == '\n') {
+		cursor->line++;
+		cursor->column = 1;
+	} else {
+		// Ignore UTF-8 continuation bytes
+		if (!((*c & 0x80) && !(*c & 0x40))) {
+			cursor->column++;
+		}
+	}
+
+	return true;
+}
+
+bool BufferedCharReader::peek(char *c)
+{
+	return readCharacterAtCursor(&peekCursor, c);
+}
+
+bool BufferedCharReader::read(char *c)
+{
+	resetPeek();
+	return readCharacterAtCursor(&readCursor, c);
+}
+
+void BufferedCharReader::consumePeek()
+{
+	// Remove all no longer needed buffer elements
+	for (unsigned int i = 0; i < peekCursor.bufferElem; i++) {
+		buffer.pop_front();
+	}
+	peekCursor.bufferElem = 0;
+
+	// Copy the peek cursor to the read cursor
+	readCursor.assign(peekCursor);
+}
+
+void BufferedCharReader::resetPeek()
+{
+	// Reset the peek cursor to the read cursor
+	peekCursor.assign(readCursor);
+}
+
+bool BufferedCharReader::atEnd()
+{
+	if (closed) {
+		if (buffer.size() <= 0) {
+			return true;
+		} else if (buffer.size() == 1) {
+			return buffer[0].size() == readCursor.bufferPos;
+		}
+	}
+	return false;
+}
+
+}
+}
+