4jcraft/Minecraft.World/Util/WeighedRandom.cpp

#include "../Platform/stdafx.h"
#include "WeighedRandom.h"

int WeighedRandom::getTotalWeight(std::vector<WeighedRandomItem*>* items) {
    int totalWeight = 0;
    for (auto it = items->begin(); it != items->end(); it++) {
        totalWeight += (*it)->randomWeight;
    }
    return totalWeight;
}

WeighedRandomItem* WeighedRandom::getRandomItem(
    Random* random, std::vector<WeighedRandomItem*>* items, int totalWeight) {
    if (totalWeight <= 0) {
        __debugbreak();
    }

    int selection = random->nextInt(totalWeight);

    for (auto it = items->begin(); it != items->end(); it++) {
        selection -= (*it)->randomWeight;
        if (selection < 0) {
            return *it;
        }
    }
    return nullptr;
}

WeighedRandomItem* WeighedRandom::getRandomItem(
    Random* random, std::vector<WeighedRandomItem*>* items) {
    return getRandomItem(random, items, getTotalWeight(items));
}

int WeighedRandom::getTotalWeight(WeighedRandomItemArray items) {
    int totalWeight = 0;
    for (unsigned int i = 0; i < items.length; i++) {
        totalWeight += items[i]->randomWeight;
    }
    return totalWeight;
}

WeighedRandomItem* WeighedRandom::getRandomItem(Random* random,
                                                WeighedRandomItemArray items,
                                                int totalWeight) {
    if (totalWeight <= 0) {
        __debugbreak();
    }

    int selection = random->nextInt(totalWeight);
    for (unsigned int i = 0; i < items.length; i++) {
        selection -= items[i]->randomWeight;
        if (selection < 0) {
            return items[i];
        }
    }
    return nullptr;
}

WeighedRandomItem* WeighedRandom::getRandomItem(Random* random,
                                                WeighedRandomItemArray items) {
    return getRandomItem(random, items, getTotalWeight(items));
}