71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/* go-new-channel.c -- allocate a new 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 <stdint.h>
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#include "go-alloc.h"
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#include "go-assert.h"
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#include "go-panic.h"
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#include "channel.h"
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struct __go_channel*
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__go_new_channel (const struct __go_type_descriptor *channel_type,
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uintptr_t entries)
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{
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const struct __go_channel_type *ctd;
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const struct __go_type_descriptor *element_type;
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uintptr_t element_size;
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int ientries;
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struct __go_channel* ret;
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size_t alloc_size;
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int i;
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__go_assert (channel_type->__code == GO_CHAN);
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ctd = (const struct __go_channel_type *) channel_type;
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element_type = ctd->__element_type;
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element_size = element_type->__size;
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ientries = (int) entries;
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if (ientries < 0
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|| (uintptr_t) ientries != entries
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|| entries > (uintptr_t) -1 / element_size)
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__go_panic_msg ("chan size out of range");
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alloc_size = (element_size + sizeof (uint64_t) - 1) / sizeof (uint64_t);
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/* We use a circular buffer which means that when next_fetch ==
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next_store we don't know whether the buffer is empty or full. So
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we allocate an extra space, and always leave a space open.
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FIXME. */
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if (entries != 0)
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++entries;
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ret = (struct __go_channel*) __go_alloc (sizeof (struct __go_channel)
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+ ((entries == 0 ? 1 : entries)
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* alloc_size
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* sizeof (uint64_t)));
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i = pthread_mutex_init (&ret->lock, NULL);
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__go_assert (i == 0);
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i = pthread_cond_init (&ret->cond, NULL);
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__go_assert (i == 0);
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ret->element_type = element_type;
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ret->waiting_to_send = 0;
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ret->waiting_to_receive = 0;
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ret->selected_for_send = 0;
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ret->selected_for_receive = 0;
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ret->is_closed = 0;
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ret->select_send_queue = NULL;
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ret->select_receive_queue = NULL;
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ret->select_mutex = NULL;
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ret->select_cond = NULL;
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ret->num_entries = entries;
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ret->next_store = 0;
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ret->next_fetch = 0;
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return ret;
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}
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