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436 lines
10 KiB
436 lines
10 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* ALSA sequencer Priority Queue |
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* Copyright (c) 1998-1999 by Frank van de Pol <[email protected]> |
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*/ |
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#include <linux/time.h> |
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#include <linux/slab.h> |
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#include <sound/core.h> |
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#include "seq_timer.h" |
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#include "seq_prioq.h" |
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/* Implementation is a simple linked list for now... |
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This priority queue orders the events on timestamp. For events with an |
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equeal timestamp the queue behaves as a FIFO. |
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* |
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* +-------+ |
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* Head --> | first | |
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* +-------+ |
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* |next |
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* +-----v-+ |
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* | | |
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* +-------+ |
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* | |
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* +-----v-+ |
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* | | |
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* +-------+ |
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* | |
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* +-----v-+ |
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* Tail --> | last | |
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* +-------+ |
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* |
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*/ |
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/* create new prioq (constructor) */ |
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struct snd_seq_prioq *snd_seq_prioq_new(void) |
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{ |
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struct snd_seq_prioq *f; |
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f = kzalloc(sizeof(*f), GFP_KERNEL); |
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if (!f) |
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return NULL; |
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spin_lock_init(&f->lock); |
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f->head = NULL; |
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f->tail = NULL; |
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f->cells = 0; |
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return f; |
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} |
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/* delete prioq (destructor) */ |
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void snd_seq_prioq_delete(struct snd_seq_prioq **fifo) |
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{ |
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struct snd_seq_prioq *f = *fifo; |
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*fifo = NULL; |
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if (f == NULL) { |
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pr_debug("ALSA: seq: snd_seq_prioq_delete() called with NULL prioq\n"); |
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return; |
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} |
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/* release resources...*/ |
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/*....................*/ |
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if (f->cells > 0) { |
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/* drain prioQ */ |
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while (f->cells > 0) |
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snd_seq_cell_free(snd_seq_prioq_cell_out(f, NULL)); |
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} |
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kfree(f); |
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} |
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/* compare timestamp between events */ |
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/* return 1 if a >= b; 0 */ |
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static inline int compare_timestamp(struct snd_seq_event *a, |
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struct snd_seq_event *b) |
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{ |
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if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) { |
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/* compare ticks */ |
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return (snd_seq_compare_tick_time(&a->time.tick, &b->time.tick)); |
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} else { |
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/* compare real time */ |
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return (snd_seq_compare_real_time(&a->time.time, &b->time.time)); |
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} |
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} |
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/* compare timestamp between events */ |
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/* return negative if a < b; |
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* zero if a = b; |
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* positive if a > b; |
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*/ |
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static inline int compare_timestamp_rel(struct snd_seq_event *a, |
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struct snd_seq_event *b) |
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{ |
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if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) { |
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/* compare ticks */ |
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if (a->time.tick > b->time.tick) |
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return 1; |
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else if (a->time.tick == b->time.tick) |
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return 0; |
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else |
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return -1; |
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} else { |
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/* compare real time */ |
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if (a->time.time.tv_sec > b->time.time.tv_sec) |
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return 1; |
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else if (a->time.time.tv_sec == b->time.time.tv_sec) { |
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if (a->time.time.tv_nsec > b->time.time.tv_nsec) |
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return 1; |
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else if (a->time.time.tv_nsec == b->time.time.tv_nsec) |
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return 0; |
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else |
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return -1; |
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} else |
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return -1; |
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} |
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} |
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/* enqueue cell to prioq */ |
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int snd_seq_prioq_cell_in(struct snd_seq_prioq * f, |
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struct snd_seq_event_cell * cell) |
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{ |
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struct snd_seq_event_cell *cur, *prev; |
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unsigned long flags; |
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int count; |
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int prior; |
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if (snd_BUG_ON(!f || !cell)) |
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return -EINVAL; |
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/* check flags */ |
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prior = (cell->event.flags & SNDRV_SEQ_PRIORITY_MASK); |
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spin_lock_irqsave(&f->lock, flags); |
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/* check if this element needs to inserted at the end (ie. ordered |
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data is inserted) This will be very likeley if a sequencer |
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application or midi file player is feeding us (sequential) data */ |
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if (f->tail && !prior) { |
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if (compare_timestamp(&cell->event, &f->tail->event)) { |
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/* add new cell to tail of the fifo */ |
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f->tail->next = cell; |
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f->tail = cell; |
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cell->next = NULL; |
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f->cells++; |
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spin_unlock_irqrestore(&f->lock, flags); |
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return 0; |
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} |
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} |
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/* traverse list of elements to find the place where the new cell is |
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to be inserted... Note that this is a order n process ! */ |
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prev = NULL; /* previous cell */ |
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cur = f->head; /* cursor */ |
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count = 10000; /* FIXME: enough big, isn't it? */ |
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while (cur != NULL) { |
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/* compare timestamps */ |
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int rel = compare_timestamp_rel(&cell->event, &cur->event); |
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if (rel < 0) |
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/* new cell has earlier schedule time, */ |
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break; |
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else if (rel == 0 && prior) |
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/* equal schedule time and prior to others */ |
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break; |
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/* new cell has equal or larger schedule time, */ |
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/* move cursor to next cell */ |
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prev = cur; |
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cur = cur->next; |
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if (! --count) { |
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spin_unlock_irqrestore(&f->lock, flags); |
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pr_err("ALSA: seq: cannot find a pointer.. infinite loop?\n"); |
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return -EINVAL; |
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} |
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} |
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/* insert it before cursor */ |
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if (prev != NULL) |
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prev->next = cell; |
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cell->next = cur; |
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if (f->head == cur) /* this is the first cell, set head to it */ |
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f->head = cell; |
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if (cur == NULL) /* reached end of the list */ |
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f->tail = cell; |
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f->cells++; |
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spin_unlock_irqrestore(&f->lock, flags); |
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return 0; |
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} |
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/* return 1 if the current time >= event timestamp */ |
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static int event_is_ready(struct snd_seq_event *ev, void *current_time) |
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{ |
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if ((ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) |
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return snd_seq_compare_tick_time(current_time, &ev->time.tick); |
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else |
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return snd_seq_compare_real_time(current_time, &ev->time.time); |
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} |
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/* dequeue cell from prioq */ |
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struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f, |
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void *current_time) |
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{ |
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struct snd_seq_event_cell *cell; |
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unsigned long flags; |
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if (f == NULL) { |
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pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n"); |
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return NULL; |
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} |
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spin_lock_irqsave(&f->lock, flags); |
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cell = f->head; |
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if (cell && current_time && !event_is_ready(&cell->event, current_time)) |
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cell = NULL; |
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if (cell) { |
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f->head = cell->next; |
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/* reset tail if this was the last element */ |
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if (f->tail == cell) |
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f->tail = NULL; |
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cell->next = NULL; |
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f->cells--; |
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} |
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spin_unlock_irqrestore(&f->lock, flags); |
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return cell; |
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} |
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/* return number of events available in prioq */ |
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int snd_seq_prioq_avail(struct snd_seq_prioq * f) |
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{ |
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if (f == NULL) { |
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pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n"); |
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return 0; |
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} |
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return f->cells; |
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} |
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static inline int prioq_match(struct snd_seq_event_cell *cell, |
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int client, int timestamp) |
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{ |
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if (cell->event.source.client == client || |
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cell->event.dest.client == client) |
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return 1; |
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if (!timestamp) |
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return 0; |
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switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) { |
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case SNDRV_SEQ_TIME_STAMP_TICK: |
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if (cell->event.time.tick) |
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return 1; |
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break; |
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case SNDRV_SEQ_TIME_STAMP_REAL: |
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if (cell->event.time.time.tv_sec || |
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cell->event.time.time.tv_nsec) |
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return 1; |
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break; |
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} |
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return 0; |
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} |
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/* remove cells for left client */ |
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void snd_seq_prioq_leave(struct snd_seq_prioq * f, int client, int timestamp) |
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{ |
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register struct snd_seq_event_cell *cell, *next; |
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unsigned long flags; |
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struct snd_seq_event_cell *prev = NULL; |
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struct snd_seq_event_cell *freefirst = NULL, *freeprev = NULL, *freenext; |
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/* collect all removed cells */ |
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spin_lock_irqsave(&f->lock, flags); |
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cell = f->head; |
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while (cell) { |
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next = cell->next; |
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if (prioq_match(cell, client, timestamp)) { |
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/* remove cell from prioq */ |
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if (cell == f->head) { |
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f->head = cell->next; |
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} else { |
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prev->next = cell->next; |
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} |
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if (cell == f->tail) |
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f->tail = cell->next; |
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f->cells--; |
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/* add cell to free list */ |
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cell->next = NULL; |
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if (freefirst == NULL) { |
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freefirst = cell; |
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} else { |
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freeprev->next = cell; |
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} |
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freeprev = cell; |
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} else { |
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#if 0 |
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pr_debug("ALSA: seq: type = %i, source = %i, dest = %i, " |
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"client = %i\n", |
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cell->event.type, |
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cell->event.source.client, |
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cell->event.dest.client, |
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client); |
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#endif |
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prev = cell; |
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} |
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cell = next; |
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} |
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spin_unlock_irqrestore(&f->lock, flags); |
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/* remove selected cells */ |
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while (freefirst) { |
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freenext = freefirst->next; |
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snd_seq_cell_free(freefirst); |
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freefirst = freenext; |
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} |
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} |
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static int prioq_remove_match(struct snd_seq_remove_events *info, |
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struct snd_seq_event *ev) |
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{ |
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int res; |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) { |
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if (ev->dest.client != info->dest.client || |
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ev->dest.port != info->dest.port) |
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return 0; |
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} |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST_CHANNEL) { |
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if (! snd_seq_ev_is_channel_type(ev)) |
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return 0; |
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/* data.note.channel and data.control.channel are identical */ |
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if (ev->data.note.channel != info->channel) |
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return 0; |
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} |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_AFTER) { |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK) |
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res = snd_seq_compare_tick_time(&ev->time.tick, &info->time.tick); |
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else |
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res = snd_seq_compare_real_time(&ev->time.time, &info->time.time); |
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if (!res) |
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return 0; |
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} |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_BEFORE) { |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK) |
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res = snd_seq_compare_tick_time(&ev->time.tick, &info->time.tick); |
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else |
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res = snd_seq_compare_real_time(&ev->time.time, &info->time.time); |
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if (res) |
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return 0; |
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} |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_EVENT_TYPE) { |
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if (ev->type != info->type) |
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return 0; |
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} |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_IGNORE_OFF) { |
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/* Do not remove off events */ |
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switch (ev->type) { |
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case SNDRV_SEQ_EVENT_NOTEOFF: |
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/* case SNDRV_SEQ_EVENT_SAMPLE_STOP: */ |
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return 0; |
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default: |
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break; |
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} |
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} |
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if (info->remove_mode & SNDRV_SEQ_REMOVE_TAG_MATCH) { |
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if (info->tag != ev->tag) |
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return 0; |
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} |
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return 1; |
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} |
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/* remove cells matching remove criteria */ |
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void snd_seq_prioq_remove_events(struct snd_seq_prioq * f, int client, |
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struct snd_seq_remove_events *info) |
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{ |
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struct snd_seq_event_cell *cell, *next; |
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unsigned long flags; |
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struct snd_seq_event_cell *prev = NULL; |
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struct snd_seq_event_cell *freefirst = NULL, *freeprev = NULL, *freenext; |
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/* collect all removed cells */ |
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spin_lock_irqsave(&f->lock, flags); |
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cell = f->head; |
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while (cell) { |
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next = cell->next; |
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if (cell->event.source.client == client && |
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prioq_remove_match(info, &cell->event)) { |
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/* remove cell from prioq */ |
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if (cell == f->head) { |
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f->head = cell->next; |
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} else { |
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prev->next = cell->next; |
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} |
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if (cell == f->tail) |
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f->tail = cell->next; |
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f->cells--; |
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/* add cell to free list */ |
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cell->next = NULL; |
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if (freefirst == NULL) { |
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freefirst = cell; |
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} else { |
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freeprev->next = cell; |
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} |
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freeprev = cell; |
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} else { |
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prev = cell; |
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} |
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cell = next; |
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} |
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spin_unlock_irqrestore(&f->lock, flags); |
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/* remove selected cells */ |
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while (freefirst) { |
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freenext = freefirst->next; |
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snd_seq_cell_free(freefirst); |
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freefirst = freenext; |
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} |
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} |
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