2010-12-03 05:34:57 +01:00
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/* go-chan-cap.c -- the cap function applied to a channel.
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Copyright 2009 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include <stddef.h>
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#include "go-assert.h"
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#include "channel.h"
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/* Return the cap function applied to a channel--the size of the
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buffer. This could be done inline but I'm doing it as a function
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for now to make it easy to change the channel structure. */
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2011-04-13 23:00:59 +02:00
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int
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2010-12-03 05:34:57 +01:00
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__go_chan_cap (struct __go_channel *channel)
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{
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int i;
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2011-04-13 23:00:59 +02:00
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int ret;
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2010-12-03 05:34:57 +01:00
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if (channel == NULL)
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return 0;
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i = pthread_mutex_lock (&channel->lock);
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__go_assert (i == 0);
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if (channel->num_entries == 0)
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ret = 0;
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else
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{
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/* One slot is always unused. We added 1 when we created the
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channel. */
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ret = channel->num_entries - 1;
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}
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i = pthread_mutex_unlock (&channel->lock);
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__go_assert (i == 0);
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return ret;
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}
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