libgo/runtime/go-rec-nb-big.c

   1 /* go-rec-nb-big.c -- nonblocking receive of something big on a channel.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include <stdint.h>
   8
   9 #include "channel.h"
  10
  11 _Bool
  12 __go_receive_nonblocking_big (struct __go_channel* channel, void *val)
  13 {
  14   size_t alloc_size;
  15   size_t offset;
  16
  17   alloc_size = ((channel->element_size + sizeof (uint64_t) - 1)
  18                 / sizeof (uint64_t));
  19
  20   int data = __go_receive_nonblocking_acquire (channel);
  21   if (data != RECEIVE_NONBLOCKING_ACQUIRE_DATA)
  22     {
  23       __builtin_memset (val, 0, channel->element_size);
  24       if (data == RECEIVE_NONBLOCKING_ACQUIRE_NODATA)
  25         return 0;
  26       else
  27         {
  28           /* Channel is closed.  */
  29           return 1;
  30         }
  31     }
  32
  33   offset = channel->next_fetch * alloc_size;
  34   __builtin_memcpy (val, &channel->data[offset], channel->element_size);
  35
  36   __go_receive_release (channel);
  37
  38   return 1;
  39 }