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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
/*
0000 0000 0000 0000 0000 0000 0000 0000
rc topscore botflag. botscore.
topflag x x
0000 0000 0000 0000 0000 0000 0000 0000
xd4. d3.d 2.d1 .d0. prng state.... ....
*/
typedef struct {
uint8_t topflag_w_roll;
uint8_t topscore;
uint8_t botflag;
uint8_t botscore;
uint16_t dice;
uint16_t seed;
} yhtz_state;
enum Category {
ACE = 0,
TWO = 1,
THREE = 2,
FOUR = 3,
FIVE = 4,
SIX = 5,
THREE_OF_A_KIND = 10,
FOUR_OF_A_KIND = 11,
FULL_HOUSE = 12,
SMALL_STRAIGHT = 13,
LARGE_STRAIGHT = 14,
YAHTZEE = 15,
CHANCE = 16
};
static enum Category CATEGORIES[] = {
ACE,
TWO,
THREE,
FOUR,
FIVE,
SIX,
THREE_OF_A_KIND,
FOUR_OF_A_KIND,
FULL_HOUSE,
SMALL_STRAIGHT,
LARGE_STRAIGHT,
YAHTZEE,
CHANCE
};
static int NUMBER_OF_CATEGORIES = 13;
/* Note: all macros take in a yhtz_state* as input 's' */
/* ROLLS */
#define GET_ROLL(s) ((uint8_t)((s->topflag_w_roll & 0xC0) >> 6)) /* top 2 bits */
#define SET_ROLL(s, x) (s->topflag_w_roll = (s->topflag_w_roll & 0x3F | ((uint8_t)x << 6)))
/* FLAGS -- x is an offset based on Category */
#define GET_TOPFLAG(s, x) ((uint8_t)((s->topflag_w_roll & (1 << x)) >> x))
#define SET_TOPFLAG(s, x) (s->topflag_w_roll = (s->topflag_w_roll | (1 << x)))
#define GET_BOTFLAG(s, x) ((uint8_t)((s->botflag & (1 << x)) >> x))
#define SET_BOTFLAG(s, x) (s->botflag = (s->botflag | (1 << x)))
#define GET_FLAG(s, x) (x < 10 ? GET_TOPFLAG(s, x) : GET_BOTFLAG(s, x - 10))
/* DICE -- x is die number (0-4), y is value (1-6) */
#define GET_DIE(s, x) ((uint8_t)((s->dice & (0x07 << (3 * x))) >> (3 * x)))
#define SET_DIE(s, x, y) (s->dice = (s->dice & (0xFFFF ^ (0x0007 << (3 * x))) | (y << (3 * x))))
/* 16-bit prng, with thanks/apologies to Dr. Lemire (https://lemire.me/blog/2019/07/03/a-fast-16-bit-random-number-generator/) */
uint32_t hash16(uint32_t input, uint32_t key) {
uint32_t hash = input * key;
return ((hash >> 16) ^ hash) & 0xFFFF;
}
uint16_t wyhash16(uint16_t* seed) {
*seed += 0xfc15;
return hash16(*seed, 0x2ab);
}
uint16_t roll_die(uint16_t* seed) {
const uint16_t s = 6; /* generating in the range of [0,6) */
uint16_t x = wyhash16(seed);
uint32_t m = (uint32_t)x * (uint32_t)s;
uint32_t l = (uint16_t)m;
if (l < s) {
uint16_t t = -s % s;
while (l < t) {
x = wyhash16(seed);
m = (uint32_t)x * (uint32_t)s;
l = (uint16_t)m;
}
}
return (m >> 16) + 1; /* we ultimately want [1,7) */
}
void print_dice(yhtz_state* state) {
char* label = " %d ";
char* top = ",---,";
char* mid = "| %d | ";
char* bot = "'---'";
printf("\n%s %s %s %s %s\n", top, top, top, top, top);
for (int i = 0; i < 5; i++)
printf(mid, GET_DIE(state, i));
printf("\n%s %s %s %s %s\n", bot, bot, bot, bot, bot);
for (int i = 0; i < 5; i++)
printf(label, i);
printf("\n\n");
}
void ask_for_rerolls(yhtz_state* state) {
char buf[10];
printf("which dice should be re-rolled? ");
fgets(buf, sizeof(buf), stdin);
int dice[6] = { -1, -1, -1, -1, -1, -1 }; /* we only ever look for 5 dice, so should always hit -1 at some point */
sscanf(buf, "%d %d %d %d %d", &dice[0], &dice[1], &dice[2], &dice[3], &dice[4]);
for (int i = 0; i < 5; i++) {
if (dice[i] == -1)
break;
SET_DIE(state, dice[i], 0);
}
}
void do_roll(yhtz_state* state) {
int roll = GET_ROLL(state);
bool reset = false;
// if we're out of rolls, reset
if (roll == 3) {
reset = true;
roll = 0;
}
for (int i = 0; i < 5; i++) {
if (reset || (GET_DIE(state, i) == 0)) {
SET_DIE(state, i, roll_die(&(state->seed)));
}
}
SET_ROLL(state, ++roll);
}
void ask_for_category(yhtz_state* state) {
char buf[2];
printf("what category should this be scored in? ");
fgets(buf, sizeof(buf), stdin);
}
void do_turn(yhtz_state* state) {
for (int i = 0; i < 3; i++) {
do_roll(state);
print_dice(state);
if (i < 2)
ask_for_rerolls(state);
}
ask_for_category(state);
}
int turn_count(yhtz_state* state) {
int ret = 1;
for (int i = 0; i < NUMBER_OF_CATEGORIES; i++)
ret += GET_FLAG(state, CATEGORIES[i]);
return ret;
}
void init_yhtz_state(yhtz_state* state) {
state->topflag_w_roll = 0;
state->topscore = 0;
state->botflag = 0;
state->botscore = 0;
state->dice = 0;
state->seed = 13; /* TODO this isn't random */
}
void main() {
yhtz_state y;
init_yhtz_state(&y);
/*
* until the win condition is met
* - roll all dice
* - up to 2 times, ask user which dice to reroll
* - ask user which category to mark it in
* - validate and update state
*
*
*/
int tc;
while (true) {
tc = turn_count(&y);
printf("~*~ turn %d ~*~\n", tc);
do_turn(&y);
}
}
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