| /* |
| Copyright (c) 2013 Martin Sustrik All rights reserved. |
| Copyright (c) 2013 GoPivotal, Inc. All rights reserved. |
| |
| 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 |
| the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| 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 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 NONINFRINGEMENT. IN NO EVENT SHALL |
| THE AUTHORS OR COPYRIGHT HOLDERS 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 "priolist.h" |
| |
| #include "../../utils/cont.h" |
| #include "../../utils/fast.h" |
| #include "../../utils/err.h" |
| #include "../../utils/attr.h" |
| |
| #include <stddef.h> |
| |
| void nn_priolist_init (struct nn_priolist *self) |
| { |
| int i; |
| |
| for (i = 0; i != NN_PRIOLIST_SLOTS; ++i) { |
| nn_list_init (&self->slots [i].pipes); |
| self->slots [i].current = NULL; |
| } |
| self->current = -1; |
| } |
| |
| void nn_priolist_term (struct nn_priolist *self) |
| { |
| int i; |
| |
| for (i = 0; i != NN_PRIOLIST_SLOTS; ++i) |
| nn_list_term (&self->slots [i].pipes); |
| } |
| |
| void nn_priolist_add (NN_UNUSED struct nn_priolist *self, |
| struct nn_priolist_data *data, struct nn_pipe *pipe, int priority) |
| { |
| data->pipe = pipe; |
| data->priority = priority; |
| nn_list_item_init (&data->item); |
| } |
| |
| void nn_priolist_rm (struct nn_priolist *self, struct nn_priolist_data *data) |
| { |
| struct nn_priolist_slot *slot; |
| struct nn_list_item *it; |
| |
| /* Non-active pipes don't need any special processing. */ |
| if (!nn_list_item_isinlist (&data->item)) { |
| nn_list_item_term (&data->item); |
| return; |
| } |
| |
| /* If the pipe being removed is not current, we can simply erase it |
| from the list. */ |
| slot = &self->slots [data->priority - 1]; |
| if (slot->current != data) { |
| nn_list_erase (&slot->pipes, &data->item); |
| nn_list_item_term (&data->item); |
| return; |
| } |
| |
| /* Advance the current pointer (with wrap-over). */ |
| it = nn_list_erase (&slot->pipes, &data->item); |
| slot->current = nn_cont (it, struct nn_priolist_data, item); |
| nn_list_item_term (&data->item); |
| if (!slot->current) { |
| it = nn_list_begin (&slot->pipes); |
| slot->current = nn_cont (it, struct nn_priolist_data, item); |
| } |
| |
| /* If we are not messing with the current slot, we are done. */ |
| if (self->current != data->priority) |
| return; |
| |
| /* Otherwise, the current slot may have become empty and we have switch |
| to lower priority slots. */ |
| while (nn_list_empty (&self->slots [self->current - 1].pipes)) { |
| ++self->current; |
| if (self->current > NN_PRIOLIST_SLOTS) { |
| self->current = -1; |
| return; |
| } |
| } |
| } |
| |
| void nn_priolist_activate (struct nn_priolist *self, |
| struct nn_priolist_data *data) |
| { |
| struct nn_priolist_slot *slot; |
| |
| slot = &self->slots [data->priority - 1]; |
| |
| /* If there are already some elements in this slot, current pipe is not |
| going to change. */ |
| if (!nn_list_empty (&slot->pipes)) { |
| nn_list_insert (&slot->pipes, &data->item, nn_list_end (&slot->pipes)); |
| return; |
| } |
| |
| /* Add first pipe into the slot. If there are no pipes in priolist at all |
| this slot becomes current. */ |
| nn_list_insert (&slot->pipes, &data->item, nn_list_end (&slot->pipes)); |
| slot->current = data; |
| if (self->current == -1) { |
| self->current = data->priority; |
| return; |
| } |
| |
| /* If the current priority is lower than the one of the newly activated |
| pipe, this slot becomes current. */ |
| if (self->current > data->priority) { |
| self->current = data->priority; |
| return; |
| } |
| |
| /* Current doesn't change otherwise. */ |
| } |
| |
| int nn_priolist_is_active (struct nn_priolist *self) |
| { |
| return self->current == -1 ? 0 : 1; |
| } |
| |
| struct nn_pipe *nn_priolist_getpipe (struct nn_priolist *self) |
| { |
| if (nn_slow (self->current == -1)) |
| return NULL; |
| return self->slots [self->current - 1].current->pipe; |
| } |
| |
| void nn_priolist_advance (struct nn_priolist *self, int release) |
| { |
| struct nn_priolist_slot *slot; |
| struct nn_list_item *it; |
| |
| nn_assert (self->current > 0); |
| slot = &self->slots [self->current - 1]; |
| |
| /* Move slot's current pointer to the next pipe. */ |
| if (release) |
| it = nn_list_erase (&slot->pipes, &slot->current->item); |
| else |
| it = nn_list_next (&slot->pipes, &slot->current->item); |
| if (!it) |
| it = nn_list_begin (&slot->pipes); |
| slot->current = nn_cont (it, struct nn_priolist_data, item); |
| |
| /* If there are no more pipes in this slot, find a non-empty slot with |
| lower priority. */ |
| while (nn_list_empty (&slot->pipes)) { |
| ++self->current; |
| if (self->current > NN_PRIOLIST_SLOTS) { |
| self->current = -1; |
| return; |
| } |
| slot = &self->slots [self->current - 1]; |
| } |
| } |
| |
| int nn_priolist_get_priority (struct nn_priolist *self) { |
| return self->current; |
| } |