79 lines
2.5 KiB
C++
79 lines
2.5 KiB
C++
#include <iostream>
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#include <cmath>
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#include <cassert>
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#include "Spigot.hpp"
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Spigot::Spigot(int requestedNumDigits) {
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/* create list for number of digits times 10 / 3 */
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this->spigotListLength = (requestedNumDigits * 10) / 3;
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this->spigotList.resize(this->spigotListLength, 2); // list is initialized with all 2
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this->carry = 0;
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return;
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}
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void Spigot::pump(void) {
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int tempPreDigit = 0;
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int j = this->spigotListLength - 1;
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int i = j;
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/*
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* This could be handled using boost::compute
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* with a BOOST_COMPUTE_FUNCTION that just
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* multiplies every item by 10.
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*/
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while(i >= 0) {
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this->spigotList[i] *= 10;
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i--;
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}
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this->carry = 0;
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i = j;
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// note this does *not* handle the i=0 case
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/*
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* This might also be able to be sped up
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* with OpenCL/boost::compute by creating
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* another custom function, but because
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* the carry has to be passed along this might
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* not work well
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*/
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while(i > 0) {
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this->spigotList[i] += this->carry;
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this->carry = (this->spigotList[i] / (i * 2 + 1)) * i;
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this->spigotList[i] = this->spigotList[i] % (i * 2 + 1);
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i--;
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}
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// special case of i = 0
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this->spigotList[0] += this->carry;
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tempPreDigit = this->spigotList[0] / 10;
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this->spigotList[0] -= (tempPreDigit * 10);
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try {
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// handle the cases depending on the tempPreDigit
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if(tempPreDigit >= 0 && tempPreDigit <= 8) {
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// output all predigits
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long unsigned pdLen = this->preDigits.size();
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for(long unsigned int j = 0; j < pdLen; j++) {
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std::cout << this->preDigits.back();
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this->preDigits.pop_back();
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}
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this->preDigits.insert(this->preDigits.begin(), tempPreDigit);
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} else if(tempPreDigit == 9) {
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this->preDigits.insert(this->preDigits.begin(), tempPreDigit);
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} else if(tempPreDigit == 10) {
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tempPreDigit = 0;
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long unsigned pdLen = this->preDigits.size();
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for(long unsigned int j = 0; j < pdLen; j++) {
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std::cout << (this->preDigits.back() + 1) % 10;
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this->preDigits.pop_back();
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}
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this->preDigits.insert(this->preDigits.begin(), tempPreDigit);
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} else {
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std::cout << "We should never have gotten here -- shit has hit the fan!" << std::endl;
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}
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} catch (int e) {
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std::cout << "An exception " << e << " occurred." << std::endl;
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}
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std::cout << std::flush;
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return;
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}
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