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+/*
+ * libpinyin
+ * Library to deal with pinyin.
+ *
+ * Copyright (C) 2011 Peng Wu <alexepico@gmail.com>
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef PHRASE_LOGGER_H
+#define PHRASE_LOGGER_H
+
+#include <assert.h>
+#include "novel_types.h"
+#include "memory_chunk.h"
+
+/**
+ * File Format
+ * Logger Record type: add/remove/modify
+ *
+ * Modify Header: header/null token/len/old data chunk/new data chunk
+ *
+ * Add Record: add/token/len/data chunk
+ * Remove Record: remove/token/len/data chunk
+ * Modify Record: modify/token/old len/new len/old data chunk/new data chunk
+ *
+ */
+
+namespace pinyin{
+
+enum LOG_TYPE{
+ LOG_ADD_RECORD = 1,
+ LOG_REMOVE_RECORD,
+ LOG_MODIFY_RECORD,
+ LOG_MODIFY_HEADER
+};
+
+
+/**
+ * PhraseIndexLogger:
+ *
+ * The logger of phrase index changes.
+ *
+ */
+class PhraseIndexLogger{
+protected:
+ MemoryChunk * m_chunk;
+ size_t m_offset;
+ bool m_error;
+
+ void reset(){
+ if ( m_chunk ){
+ delete m_chunk;
+ m_chunk = NULL;
+ }
+ m_offset = 0;
+ m_error = false;
+ }
+public:
+ /**
+ * PhraseIndexLogger::PhraseIndexLogger:
+ *
+ * The constructor of the PhraseIndexLogger.
+ *
+ */
+ PhraseIndexLogger():m_offset(0), m_error(false){
+ m_chunk = new MemoryChunk;
+ }
+
+ /**
+ * PhraseIndexLogger::~PhraseIndexLogger:
+ *
+ * The destructor of the PhraseIndexLogger.
+ *
+ */
+ ~PhraseIndexLogger(){
+ reset();
+ }
+
+ /**
+ * PhraseIndexLogger::load:
+ * @chunk: the memory chunk of the logs.
+ * @returns: whether the load operation is successful.
+ *
+ * Load the logs from the memory chunk.
+ *
+ */
+ bool load(MemoryChunk * chunk) {
+ reset();
+ m_chunk = chunk;
+ return true;
+ }
+
+ /**
+ * PhraseIndexLogger::store:
+ * @new_chunk: the new memory chunk to store the logs.
+ * @returns: whether the store operation is successful.
+ *
+ * Store the logs to the new memory chunk.
+ *
+ */
+ bool store(MemoryChunk * new_chunk){
+ new_chunk->set_content(0, m_chunk->begin(), m_chunk->size());
+ return true;
+ }
+
+ /**
+ * PhraseIndexLogger::has_next_record:
+ * @returns: whether this logger has next record.
+ *
+ * Whether this logger has next record.
+ *
+ */
+ bool has_next_record(){
+ if (m_error)
+ return false;
+
+ return m_offset < m_chunk->size();
+ }
+
+ /**
+ * PhraseIndexLogger::rewind:
+ * @returns: whether the rewind operation is successful.
+ *
+ * Rewind this logger to the begin of logs.
+ *
+ */
+ bool rewind(){
+ m_offset = 0;
+ return true;
+ }
+
+ /**
+ * PhraseIndexLogger::next_record:
+ * @log_type: the type of this log record.
+ * @token: the token of this log record.
+ * @oldone: the original content of the phrase item.
+ * @newone: the new content of the phrase item.
+ *
+ * Read the next log record.
+ *
+ * Prolog: has_next_record() returned true.
+ *
+ */
+ bool next_record(LOG_TYPE & log_type, phrase_token_t & token,
+ MemoryChunk * oldone, MemoryChunk * newone){
+ size_t offset = m_offset;
+ m_chunk->get_content(offset, &log_type, sizeof(LOG_TYPE));
+ offset += sizeof(LOG_TYPE);
+ m_chunk->get_content(offset, &token, sizeof(phrase_token_t));
+ offset += sizeof(phrase_token_t);
+
+ oldone->set_size(0); newone->set_size(0);
+
+ switch(log_type){
+ case LOG_ADD_RECORD:{
+ guint16 len = 0;
+ m_chunk->get_content(offset, &len, sizeof(guint16));
+ offset += sizeof(guint16);
+ newone->set_content(0, ((char *)m_chunk->begin()) + offset, len);
+ offset += len;
+ break;
+ }
+ case LOG_REMOVE_RECORD:{
+ guint16 len = 0;
+ m_chunk->get_content(offset, &len, sizeof(guint16));
+ offset += sizeof(guint16);
+ oldone->set_content(0, ((char *)m_chunk->begin()) + offset, len);
+ offset += len;
+ break;
+ }
+ case LOG_MODIFY_RECORD:{
+ guint16 oldlen = 0, newlen = 0;
+ m_chunk->get_content(offset, &oldlen, sizeof(guint16));
+ offset += sizeof(guint16);
+ m_chunk->get_content(offset, &newlen, sizeof(guint16));
+ offset += sizeof(guint16);
+ oldone->set_content(0, ((char *)m_chunk->begin()) + offset,
+ oldlen);
+ offset += oldlen;
+ newone->set_content(0, ((char *)m_chunk->begin()) + offset, newlen);
+ offset += newlen;
+ break;
+ }
+ case LOG_MODIFY_HEADER:{
+ assert(token == null_token);
+ guint16 len = 0;
+ m_chunk->get_content(offset, &len, sizeof(guint16));
+ offset += sizeof(guint16);
+ oldone->set_content(0, ((char *)m_chunk->begin()) + offset,
+ len);
+ offset += len;
+ newone->set_content(0, ((char *)m_chunk->begin()) + offset,
+ len);
+ offset += len;
+ break;
+ }
+ default:
+ m_error = true;
+ return false;
+ }
+
+ m_offset = offset;
+ return true;
+ }
+
+ /**
+ * PhraseIndexLogger::append_record:
+ * @log_type: the type of this log record.
+ * @token: the token of this log record.
+ * @oldone: the original content of the phrase item.
+ * @newone: the new content of the phrase item.
+ *
+ * Append one log record to the logger.
+ *
+ */
+ bool append_record(LOG_TYPE log_type, phrase_token_t token,
+ MemoryChunk * oldone, MemoryChunk * newone){
+
+ MemoryChunk chunk;
+ size_t offset = 0;
+ chunk.set_content(offset, &log_type, sizeof(LOG_TYPE));
+ offset += sizeof(LOG_TYPE);
+ chunk.set_content(offset, &token, sizeof(phrase_token_t));
+ offset += sizeof(phrase_token_t);
+
+ switch(log_type){
+ case LOG_ADD_RECORD:{
+ assert( NULL == oldone );
+ assert( NULL != newone );
+ /* use newone chunk */
+ guint16 len = newone->size();
+ chunk.set_content(offset, &len, sizeof(guint16));
+ offset += sizeof(guint16);
+ chunk.set_content(offset, newone->begin(), newone->size());
+ offset += newone->size();
+ break;
+ }
+ case LOG_REMOVE_RECORD:{
+ assert(NULL != oldone);
+ assert(NULL == newone);
+ /* use oldone chunk */
+ guint16 len = oldone->size();
+ chunk.set_content(offset, &len, sizeof(guint16));
+ offset += sizeof(guint16);
+ chunk.set_content(offset, oldone->begin(), oldone->size());
+ offset += oldone->size();
+ break;
+ }
+ case LOG_MODIFY_RECORD:{
+ assert(NULL != oldone);
+ assert(NULL != newone);
+ guint16 oldlen = oldone->size();
+ guint16 newlen = newone->size();
+ chunk.set_content(offset, &oldlen, sizeof(guint16));
+ offset += sizeof(guint16);
+ chunk.set_content(offset, &newlen, sizeof(guint16));
+ offset += sizeof(guint16);
+ chunk.set_content(offset, oldone->begin(), oldone->size());
+ offset += oldlen;
+ chunk.set_content(offset, newone->begin(), newone->size());
+ offset += newlen;
+ break;
+ }
+ case LOG_MODIFY_HEADER:{
+ assert(NULL != oldone);
+ assert(NULL != newone);
+ assert(null_token == token);
+ guint16 oldlen = oldone->size();
+ guint16 newlen = newone->size();
+ assert(oldlen == newlen);
+ chunk.set_content(offset, &oldlen, sizeof(guint16));
+ offset += sizeof(guint16);
+ chunk.set_content(offset, oldone->begin(), oldone->size());
+ offset += oldlen;
+ chunk.set_content(offset, newone->begin(), newone->size());
+ offset += newlen;
+ break;
+ }
+ default:
+ assert(false);
+ }
+
+ /* store log record. */
+ m_chunk->set_content(m_chunk->size(), chunk.begin(), chunk.size());
+ return true;
+ }
+};
+
+};
+
+#endif
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