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/* go-new-channel.c -- allocate a new channel.
Copyright 2009 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file. */
#include <stddef.h>
#include <stdint.h>
#include "go-alloc.h"
#include "go-assert.h"
#include "go-panic.h"
#include "channel.h"
struct __go_channel*
__go_new_channel (const struct __go_type_descriptor *channel_type,
uintptr_t entries)
{
const struct __go_channel_type *ctd;
const struct __go_type_descriptor *element_type;
uintptr_t element_size;
int ientries;
struct __go_channel* ret;
size_t alloc_size;
int i;
__go_assert (channel_type->__code == GO_CHAN);
ctd = (const struct __go_channel_type *) channel_type;
element_type = ctd->__element_type;
element_size = element_type->__size;
ientries = (int) entries;
if (ientries < 0
|| (uintptr_t) ientries != entries
|| entries > (uintptr_t) -1 / element_size)
__go_panic_msg ("chan size out of range");
alloc_size = (element_size + sizeof (uint64_t) - 1) / sizeof (uint64_t);
/* We use a circular buffer which means that when next_fetch ==
next_store we don't know whether the buffer is empty or full. So
we allocate an extra space, and always leave a space open.
FIXME. */
if (entries != 0)
++entries;
ret = (struct __go_channel*) __go_alloc (sizeof (struct __go_channel)
+ ((entries == 0 ? 1 : entries)
* alloc_size
* sizeof (uint64_t)));
i = pthread_mutex_init (&ret->lock, NULL);
__go_assert (i == 0);
i = pthread_cond_init (&ret->cond, NULL);
__go_assert (i == 0);
ret->element_type = element_type;
ret->waiting_to_send = 0;
ret->waiting_to_receive = 0;
ret->selected_for_send = 0;
ret->selected_for_receive = 0;
ret->is_closed = 0;
ret->select_send_queue = NULL;
ret->select_receive_queue = NULL;
ret->select_mutex = NULL;
ret->select_cond = NULL;
ret->num_entries = entries;
ret->next_store = 0;
ret->next_fetch = 0;
return ret;
}
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