simplefsa_impl.hpp
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/*
* File: simplefsa_impl.hpp
* Author: mlenart
*
* Created on November 4, 2013, 1:05 PM
*/
#ifndef SIMPLEFSA_IMPL_HPP
#define SIMPLEFSA_IMPL_HPP
#include <iostream>
#include "fsa.hpp"
//#pragma pack(push, 1) /* push current alignment to stack */
struct StateData {
unsigned char transitionsNum;
bool accepting;
};
//#pragma pack(pop) /* restore original alignment from stack */
template <class T>
SimpleFSA<T>::SimpleFSA(const unsigned char* ptr, const Deserializer<T>& deserializer, bool isTransducer)
: FSA<T>(ptr, deserializer), isTransducer(isTransducer) {
}
template <class T>
SimpleFSA<T>::~SimpleFSA() {
}
static inline unsigned int decodeOffset(const unsigned char* ptr) {
unsigned int res = 0;
res = ptr[0] << 16 | ptr[1] << 8 | ptr[2];
return res;
}
static inline StateData decodeStateData(const unsigned char* ptr) {
static const unsigned char acceptingFlag = 128;
static const unsigned char transitionsNumMask = 127;
StateData res;
res.transitionsNum = (*ptr) & transitionsNumMask;
res.accepting = (*ptr) & acceptingFlag;
return res;
}
template <class T>
void SimpleFSA<T>::proceedToNext(const char c, State<T>& state) const {
const unsigned char* fromPointer = this->initialStatePtr + state.getOffset();
long transitionsTableOffset = 1;
if (state.isAccepting()) {
transitionsTableOffset += state.getValueSize();
}
StateData stateData = decodeStateData(fromPointer);
const unsigned char* foundTransition = fromPointer + transitionsTableOffset;
bool found = false;
unsigned int increment = this->isTransducer ? 5 : 4;
for (unsigned int i = 0; i < stateData.transitionsNum; i++, foundTransition += increment) {
if ((char) *foundTransition == c) {
found = true;
break;
}
}
if (!found) {
state.setNextAsSink();
}
else {
unsigned int offset = decodeOffset(foundTransition + 1);
const unsigned char* nextStatePointer = this->initialStatePtr + offset;
StateData nextStateData = decodeStateData(nextStatePointer);
if (nextStateData.accepting) {
T object;
long size = this->deserializer.deserialize(nextStatePointer + 1, object);
state.setNext(offset, object, size);
}
else {
state.setNext(offset);
}
}
}
#endif /* SIMPLEFSA_IMPL_HPP */