libgo/runtime/chan.goc

// Copyright 2010 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.

package runtime
#include "config.h"
#include "channel.h"

typedef _Bool bool;
typedef unsigned char byte;
typedef struct __go_channel chan;

/* Do a nonblocking channel receive.  */

func chanrecv2(c *chan, val *byte) (pres bool) {
	if (c->element_size > 8) {
		return __go_receive_nonblocking_big(c, val);
	} else {
		struct __go_receive_nonblocking_small rs;
		union {
			char b[8];
			uint64_t v;
		} u;

		rs = __go_receive_nonblocking_small (c);
		if (!rs.__success) {
			__builtin_memset(val, 0, c->element_size);
			return 0;
		}
		u.v = rs.__val;
#ifndef WORDS_BIGENDIAN
		__builtin_memcpy(val, u.b, c->element_size);
#else
		__builtin_memcpy(val, u.b + 8 - c->element_size,
				 c->element_size);
#endif
		return 1;
	}
}