intrusivelist.qh

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#pragma once

#include "iter.qh"

const int IL_MAX = 128;

ERASEABLE
void IL_INIT(entity this);
ERASEABLE
void IL_DTOR(entity this);
ERASEABLE
void IL_ENDFRAME();

CLASS(IntrusiveList, Object)
    ATTRIB(IntrusiveList, il_head, entity);
    ATTRIB(IntrusiveList, il_tail, entity);
    ATTRIB(IntrusiveList, il_nextfld, .entity, nil);
    ATTRIB(IntrusiveList, il_prevfld, .entity, nil);
    INIT(IntrusiveList) { IL_INIT(this); }
    DESTRUCTOR(IntrusiveList) { IL_DTOR(this); }
ENDCLASS(IntrusiveList)

// bitflags
.vector il_lists;
// bitflags
.vector il_listmask;

#define IL_NEW() NEW(IntrusiveList)

#define IL_EMPTY(this) (this.il_head == NULL)

#define IL_FIRST(this) (this.il_head)
#define IL_LAST(this) (this.il_tail)
#define IL_PEEK(this) (this.il_tail)

ERASEABLE
bool IL_CONTAINS(IntrusiveList this, entity it)
{
    assert(this, return false);
    return it.(this.il_nextfld) || this.il_head == it || this.il_tail == it;
}

ERASEABLE
entity IL_PUSH(IntrusiveList this, entity it)
{
    assert(this, return NULL);
    assert(it, return NULL);
    .entity il_next = this.il_nextfld;
    .entity il_prev = this.il_prevfld;
    assert(!IL_CONTAINS(this, it), return NULL);

    entity tail = it.(il_prev) = this.il_tail;
    tail ? (tail.(il_next) = it) : this.il_head = it;
    this.il_tail = it;
    it.il_lists |= this.il_listmask;
    return it;
}

ERASEABLE
entity IL_UNSHIFT(IntrusiveList this, entity it)
{
    assert(this, return NULL);
    assert(it, return NULL);
    .entity il_next = this.il_nextfld;
    .entity il_prev = this.il_prevfld;
    assert(!IL_CONTAINS(this, it), return NULL);

    entity head = it.(il_next) = this.il_head;
    head ? (head.(il_prev) = it) : this.il_tail = it;
    this.il_head = it;
    it.il_lists |= this.il_listmask;
    return it;
}

ERASEABLE
entity IL_POP(IntrusiveList this)
{
    assert(this, return NULL);
    .entity il_next = this.il_nextfld;
    .entity il_prev = this.il_prevfld;

    if (!this.il_tail) return NULL;
    entity it = this.il_tail;
    entity prev = it.(il_prev);
    if (prev) (this.il_tail = prev).(il_next) = NULL;
    else this.il_head = this.il_tail = NULL;
    return it;
}

ERASEABLE
entity IL_SHIFT(IntrusiveList this)
{
    assert(this, return NULL);
    .entity il_next = this.il_nextfld;
    .entity il_prev = this.il_prevfld;

    if (!this.il_head) return NULL;
    entity it = this.il_head;
    entity next = it.(il_next);
    if (next) (this.il_head = next).(il_prev) = NULL;
    else this.il_head = this.il_tail = NULL;
    return it;
}

ERASEABLE
void IL_REMOVE(IntrusiveList this, entity it)
{
    assert(this, return);
    .entity il_next = this.il_nextfld;
    .entity il_prev = this.il_prevfld;
    //assert(!IL_CONTAINS(this, it), return);
    entity next = it.(il_next);
    entity prev = it.(il_prev);
    entity ohead = this.il_head;
    entity otail = this.il_tail;
    next ? next.(il_prev) = prev : this.il_tail = prev;
    prev ? prev.(il_next) = next : this.il_head = next;
    LOG_DEBUGF("remove %i (%i :: %i), head: %i -> %i, tail: %i -> %i", it, it.(il_prev), it.(il_next), ohead, this.il_head, otail, this.il_tail);
    it.(il_next) = it.(il_prev) = NULL;
}

#define IL_CLEAR(this) \
    MACRO_BEGIN \
        IntrusiveList __il = this; \
        assert(__il); \
        .entity il_prev = __il.il_prevfld; \
        IL_EACH(__il, true, it.(il_next) = it.(il_prev) = NULL); \
        __il.il_head = __il.il_tail = NULL; \
    MACRO_END

#define IL_DELETE(this) \
    MACRO_BEGIN \
        delete(this); \
        this = NULL; \
    MACRO_END

#define IL_EACH(this, cond, body) \
    MACRO_BEGIN \
        IntrusiveList _il = this; \
        assert(_il); \
        .entity il_next = _il.il_nextfld; \
        noref int i = 0; \
        for (entity _next, _it = _il.il_head; _it; (_it = _next, ++i)) \
        { \
            const noref entity it = _it; \
            _next = it.(il_next); \
            if (cond) { LAMBDA(body) } \
        } \
    MACRO_END

.int il_id;
IntrusiveList il_links[IL_MAX];
.entity il_links_flds[IL_MAX * 2];
int il_links_ptr;

#define IL_FLOOR(n) ((n) | 0)
#define IL_CEIL(n)  IL_FLOOR((n) + 0.5)

#define IL_LISTS_PER_BIT IL_CEIL(IL_MAX / (3 * 24))

ERASEABLE
void IL_INIT(IntrusiveList this)
{
    .entity nextfld, prevfld;
    for (int i = il_links_ptr; i < il_links_ptr + IL_MAX; ++i) {
        int idx = i;
        if (idx >= IL_MAX) idx -= IL_MAX;
        int id = idx;
        idx *= 2;
        if (!il_links[idx]) {
            il_links[idx] = this;
            nextfld = il_links_flds[idx + 0];
            prevfld = il_links_flds[idx + 1];
            this.il_id = id;
            int bit = IL_FLOOR(id / IL_LISTS_PER_BIT);
            if (bit < (1 * 24)) this.il_listmask = '1 0 0' * (1 << (bit - (0 * 24)));
            else if (bit < (2 * 24)) this.il_listmask = '0 1 0' * (1 << (bit - (1 * 24)));
            else if (bit < (3 * 24)) this.il_listmask = '0 0 1' * (1 << (bit - (2 * 24)));
            else assert(false);
            il_links_ptr = id + 1;
            if (il_links_ptr >= IL_MAX) il_links_ptr -= IL_MAX;
            this.il_nextfld = nextfld;
            this.il_prevfld = prevfld;
            return;
        }
    }
    LOG_WARN("IntrusiveList overflow");
}

ERASEABLE
void IL_DTOR(IntrusiveList this)
{
    IL_CLEAR(this);
    il_links[this.il_id] = NULL;
}

ERASEABLE
void IL_ENDFRAME()
{
#if 0
    // incompatible with CSQC, remove() clears entities
    for (int i = 0; i < IL_MAX; ++i) {
        IntrusiveList list = il_links[i];
        if (list) {
            .entity nextfld = list.il_nextfld;
            for (entity next, it = list.il_head; it; it = next) {
                next = it.(nextfld);
                if (wasfreed(it)) {
                    IL_REMOVE(list, it);
                }
            }
        }
    }
#endif
}

// called when an entity is deleted with delete() / remove()
// or when a player disconnects
void ONREMOVE(entity this)
{
    // remove 'this' from any intrusive lists it is on
    vector lists = this.il_lists;
    if (lists) {
        for (int i = 0; i < IL_MAX; ++i) {
            IntrusiveList list = il_links[i];
            if ((lists & list.il_listmask) && IL_CONTAINS(list, this)) {
                IL_REMOVE(list, this);
            }
        }
    }
}