nine_helpers.c

/*
 * Copyright 2013 Christoph Bumiller
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE. */

#include "nine_helpers.h"

static struct nine_range *
nine_range_pool_more(struct nine_range_pool *pool)
{
    struct nine_range *r = MALLOC(64 * sizeof(struct nine_range));
    int i;
    assert(!pool->free);

    if (pool->num_slabs == pool->num_slabs_max) {
        unsigned p = pool->num_slabs_max;
        unsigned n = pool->num_slabs_max * 2;
        if (!n)
            n = 4;
        pool->slabs = REALLOC(pool->slabs,
                              p * sizeof(struct nine_range *),
                              n * sizeof(struct nine_range *));
        pool->num_slabs_max = n;
    }
    pool->free = pool->slabs[pool->num_slabs++] = r;

    for (i = 0; i < 63; ++i, r = r->next)
        r->next = (struct nine_range *)
            ((uint8_t *)r + sizeof(struct nine_range));
    r->next = NULL;

    return pool->free;
}

static inline struct nine_range *
nine_range_pool_get(struct nine_range_pool *pool, int16_t bgn, int16_t end)
{
    struct nine_range *r = pool->free;
    if (!r)
        r = nine_range_pool_more(pool);
    assert(r);
    pool->free = r->next;
    r->bgn = bgn;
    r->end = end;
    return r;
}

static inline void
nine_ranges_coalesce(struct nine_range *r, struct nine_range_pool *pool)
{
    struct nine_range *n;

    while (r->next && r->end >= r->next->bgn) {
        n = r->next->next;
        r->end = (r->end >= r->next->end) ? r->end : r->next->end;
        nine_range_pool_put(pool, r->next);
        r->next = n;
    }
}

void
nine_ranges_insert(struct nine_range **head, int16_t bgn, int16_t end,
                   struct nine_range_pool *pool)
{
    struct nine_range *r, **pn = head;

    for (r = *head; r && bgn > r->end; pn = &r->next, r = r->next);

    if (!r || end < r->bgn) {
        *pn = nine_range_pool_get(pool, bgn, end);
        (*pn)->next = r;
    } else
    if (bgn < r->bgn) {
        r->bgn = bgn;
        if (end > r->end)
            r->end = end;
        nine_ranges_coalesce(r, pool);
    } else
    if (end > r->end) {
        r->end = end;
        nine_ranges_coalesce(r, pool);
    }
}