oop-benchmarks/c++/turing/sp-with-structs.cpp
2024-01-18 00:00:50 +01:00

155 lines
5 KiB
C++

#include <cmath>
#include "common.h"
using namespace std;
typedef struct transition {
int state;
Direction direction;
Symbol write;
} transition_t;
transition_t transitionTable(int state, Symbol symbolRead) {
switch (state) {
case 0: // init; look for first symbol
switch (symbolRead) {
case UNDEFINED: return {200, RIGHT, UNDEFINED};
case TRUE: return {10, RIGHT, UNDEFINED};
case FALSE: return {20, RIGHT, UNDEFINED};
}
case 10: // look for right hand side - we need TRUE
switch (symbolRead) {
case UNDEFINED: return {11, LEFT, UNDEFINED};
case TRUE: return {10, RIGHT, TRUE};
case FALSE: return {10, RIGHT, FALSE};
}
case 11: // right hand side - this should be TRUE
switch (symbolRead) {
case UNDEFINED: return {200, LEFT, UNDEFINED};
case TRUE: return {12, LEFT, UNDEFINED};
case FALSE: return {100, LEFT, UNDEFINED};
}
case 12: // right hand side - new decision
switch (symbolRead) {
case UNDEFINED: return {200, RIGHT, UNDEFINED};
case TRUE: return {13, LEFT, UNDEFINED};
case FALSE: return {23, LEFT, UNDEFINED};
}
case 13: // look for left hand side - we need TRUE
switch (symbolRead) {
case UNDEFINED: return {14, RIGHT, UNDEFINED};
case TRUE: return {13, LEFT, TRUE};
case FALSE: return {13, LEFT, FALSE};
}
case 14: // left hand side - should be TRUE
switch (symbolRead) {
case UNDEFINED: return {200, RIGHT, UNDEFINED};
case TRUE: return {0, RIGHT, UNDEFINED};
case FALSE: return {100, RIGHT, UNDEFINED};
}
case 20: // look for right hand side - we need FALSE
switch (symbolRead) {
case UNDEFINED: return {21, LEFT, UNDEFINED};
case TRUE: return {20, RIGHT, TRUE};
case FALSE: return {20, RIGHT, FALSE};
}
case 21: // right hand side - this should be FALSE
switch (symbolRead) {
case UNDEFINED: return {200, LEFT, UNDEFINED};
case TRUE: return {100, LEFT, UNDEFINED};
case FALSE: return {22, LEFT, UNDEFINED};
}
case 22: // right hand side - new decision
switch (symbolRead) {
case UNDEFINED: return {200, RIGHT, UNDEFINED};
case TRUE: return {13, LEFT, UNDEFINED};
case FALSE: return {23, LEFT, UNDEFINED};
}
case 23: // look for left hand side - we need FALSE
switch (symbolRead) {
case UNDEFINED: return {24, RIGHT, UNDEFINED};
case TRUE: return {23, LEFT, TRUE};
case FALSE: return {23, LEFT, FALSE};
}
case 24: // left hand side - should be FALSE
switch (symbolRead) {
case UNDEFINED: return {200, RIGHT, UNDEFINED};
case TRUE: return {100, RIGHT, UNDEFINED};
case FALSE: return {0, RIGHT, UNDEFINED};
}
default:
return {100, RIGHT, UNDEFINED};
}
}
bool reject(int state) {
return state == 100;
}
bool accept(int state) {
return state == 200;
}
int getNextPosition(int position, Direction direction) {
if (direction == LEFT) {
return position - 1;
} else {
return position + 1;
}
}
void initBand(Symbol band[MAX_BAND_SIZE], int input) {
int numberOfDigits = input == 0 ? 1 : static_cast<int>(floor(log2(input)) + 1);
int i = 0;
for (; i < numberOfDigits; i++) {
band[i] = (input & (1 << (numberOfDigits - i - 1))) ? TRUE : FALSE;
}
for (; i < MAX_BAND_SIZE; i++) {
band[i] = UNDEFINED;
}
}
Symbol getFromBand(Symbol band[MAX_BAND_SIZE], int position) {
if (position < 0 || position >= MAX_BAND_SIZE) {
return UNDEFINED;
} else {
return band[position];
}
}
void setOnBand(Symbol band[MAX_BAND_SIZE], int position, Symbol symbol) {
if (!(position < 0 || position >= MAX_BAND_SIZE)) {
band[position] = symbol;
}
}
bool abort(int state) {
return reject(state) || accept(state);
}
bool runMachine(Symbol band[MAX_BAND_SIZE]) {
int state = 0;
int position = 0;
while(!abort(state)) {
Symbol read = getFromBand(band, position);
auto transition = transitionTable(state, read);
state = transition.state;
setOnBand(band, position, transition.write);
position = getNextPosition(position, transition.direction);
}
return accept(state);
}
bool test(int input) {
Symbol band[MAX_BAND_SIZE];
initBand(band, input);
return runMachine(band);
}