rotagen/rotagen.c

150 lines
3.5 KiB
C

/*
* Copyright (c) Rhizome <rhizome@wip.sh>
* SPDX-License-Identifier: AGPL-3.0-only
*/
#include "rotagen.h"
#include <math.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/time.h>
#define POOL_SIZE 0x1000
#define MAX_PEOPLE 32
static struct config conf;
static uint8_t pool[POOL_SIZE];
static uint8_t *free_ptr;
static void *pool_alloc(int size)
{
if (free_ptr + size > pool + POOL_SIZE)
return NULL;
void *ptr = free_ptr;
free_ptr += size;
return ptr;
}
int main(int argc, char **argv)
{
free_ptr = &pool[0];
unsigned seed;
struct timeval now;
if (gettimeofday(&now, NULL) == 0) {
seed = now.tv_usec;
} else {
fprintf(stderr,
"Warning: failed to get time of day to seed random number "
"generation; falling back to hard-coded seed.\n");
seed = 0xdeadbeef;
}
srand(seed);
const char *config_path = argc > 1 ? argv[1] : "rotagen.conf";
memset(&conf, 0, sizeof(conf));
read_config(config_path, &conf);
struct slot_result *rota
= pool_alloc(conf.num_slots * sizeof(struct slot_result));
if (rota == NULL) {
fprintf(stderr,
"Fatal error: memory pool exhausted in %s().\n",
__func__);
exit(1);
}
generate_rota(rota);
print_rota(rota);
return 0;
}
void generate_rota(struct slot_result *rota_out)
{
int prev[MAX_JOBS];
for (int job = 0; job < conf.num_jobs; ++job)
prev[job] = conf.num_people;
for (int slot = 0; slot < conf.num_slots; ++slot) {
do {
for (int job = 0; job < conf.num_jobs; ++job) {
struct assignment *assignment
= &rota_out[slot].assignments[job];
do {
assignment->slot = slot;
assignment->job = job;
assignment->person = rand() % conf.num_people;
} while (!satisfies_assignment_constraints(assignment)
|| previously_allocated(prev, assignment->person));
}
} while (!satisfies_slot_constraints(&rota_out[slot]));
for (int job = 0; job < conf.num_jobs; ++job)
prev[job] = rota_out[slot].assignments[job].person;
}
}
bool satisfies_assignment_constraints(const struct assignment *assignment)
{
for (int i = 0; i < conf.num_constraints; ++i) {
if (assignment->person != conf.constraints[i].person)
continue;
switch (conf.constraints[i].type) {
case JOB_EXEMPTION_CONSTRAINT:
if (assignment->job == conf.constraints[i].object.job)
return false;
break;
case SLOT_EXEMPTION_CONSTRAINT:
if (assignment->slot == conf.constraints[i].object.slot)
return false;
break;
default:
fprintf(stderr,
"Warning: unhandled constraint type %d in %s()",
conf.constraints[i].type,
__func__);
break;
}
}
return true;
}
bool previously_allocated(int prev[MAX_JOBS], int person)
{
for (int job = 0; job < conf.num_jobs; ++job) {
if (prev[job] == person)
return true;
}
return false;
}
bool satisfies_slot_constraints(const struct slot_result *result)
{
for (int i = 0; i < conf.num_jobs; ++i) {
for (int j = i + 1; j < conf.num_jobs; ++j) {
if (result->assignments[i].person == result->assignments[j].person)
return false;
}
}
return true;
}
void print_rota(const struct slot_result *rota)
{
for (int slot = 0; slot < conf.num_slots; ++slot) {
printf("----------------------------------------\n");
for (int job = 0; job < conf.num_jobs; ++job) {
printf("%s\t%s\t\t%s\n",
job == 0 ? conf.slots[slot] : " ",
conf.jobs[job],
conf.people[rota[slot].assignments[job].person]);
}
}
printf("----------------------------------------\n");
}