cirbuf.c

#include "all.h"
#include <stdlib.h>

void
udx__cirbuf_init (udx_cirbuf_t *c, uint32_t initial_size) {
    // OBS: initial_size MUST be 2^n
    c->size = initial_size;
    c->mask = initial_size - 1;
    c->values = calloc(initial_size, sizeof(udx_packet_t *));
}

void
udx__cirbuf_destroy (udx_cirbuf_t *c) {
    if (c->values != NULL) free(c->values);
    c->size = c->mask = 0;
    c->values = NULL;
}

void
udx__cirbuf_set (udx_cirbuf_t *c, udx_packet_t *val) {
    udx_packet_t **values = c->values + (val->seq & c->mask);
    udx_packet_t *v = *values;

    if (v == NULL || v->seq == val->seq) {
        *values = val;
        return;
    }

    uint32_t old_size = c->size;
    udx_packet_t **old_values = c->values;

    while ((v->seq & c->mask) == (val->seq & c->mask)) {
        c->size *= 2;
        c->mask = c->size - 1;
    }

    c->values = calloc(c->size, sizeof(udx_packet_t *));
    c->values[val->seq & c->mask] = val;
    for (uint32_t i = 0; i < old_size; i++) {
        udx_packet_t *v = old_values[i];
        if (v != NULL) c->values[v->seq & c->mask] = v;
    }

    free(old_values);
}

udx_packet_t *
udx__cirbuf_get (udx_cirbuf_t *c, uint32_t seq) {
    udx_packet_t *v = c->values[seq & c->mask];
    return (v == NULL || v->seq != seq) ? NULL : v;
}

udx_packet_t *
udx__cirbuf_remove (udx_cirbuf_t *c, uint32_t seq) {
    udx_packet_t **values = c->values + (seq & c->mask);
    udx_packet_t *v = *values;

    if (v == NULL || v->seq != seq) return NULL;

    *values = NULL;
    return v;
}