libcoro/coro.h

/*
 * Copyright (c) 2001 Marc Alexander Lehmann <pcg@goof.com>
 * 
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 * 
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 * 
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 * 
 *   3.  The name of the author may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This library is modelled strictly after Ralf S. Engelschalls article at
 * http://www.gnu.org/software/pth/rse-pmt.ps.  So most of the credit must
 * go to Ralf S. Engelschall <rse@engelschall.com>.
 *
 * This coroutine library is very much stripped down. You should either
 * build your own process avstraction using it or - better - just use GNU
 * Portable Threads, http://www.gnu.org/software/pth/.
 */

#ifndef CORO_H
#define CORO_H

/*
 * This library consists of only three files
 * coro.h, coro.c and LICENSE
 *
 * It implements what is known as coroutines, in a hopefully
 * portable way. At the moment you have to define which kind
 * of implementation flavour you want:
 *
 * -DCORO_UCONTEXT
 *
 *    This flavour uses SUSv2's get/set/swap/makecontext functions that
 *    unfortunately only newer unices support.
 *    Use this for GNU/Linux + glibc-2.2.3.
 *
 * -DCORO_SJLJ
 *
 *    This flavour uses SUSv'2 setjmp/longjmp and sigaltstack functions to
 *    do it's job. Coroutine creation is much slower than UCONTEXT, but
 *    context switching is often a bit cheaper. It should work on almost
 *    all unices. Use this for GNU/Linux + glibc-2.2. glibc-2.1 and below
 *    do not work with any model (neither sigaltstack nor context functions
 *    are implemented)
 *
 * -DCORO_LOOSE
 *
 *    Microsoft's highly proprietary platform doesn't support sigaltstack, and
 *    this automatically selects a suitable workaround for this platform.
 *    (untested)
 *
 * If you define neither of these symbols, coro.h will try to autodetect
 * the model.  This currently works for CORO_LOOSE only. For the other
 * alternatives you should check (e.g. using autoconf) and define the
 * following symbols: HAVE_UCONTEXT_H / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
 */

/*
 * This is the type for the top function of a new coroutine.
 */
typedef void (*coro_func)(void *);


/*
 * A coroutine state is saved in the following structure. Treat it as a
 * opaque type. errno and sigmask might be saved, but don't rely on it,
 * implement your own switching primitive.
 */
typedef struct coro_context coro_context;

/*
 * This function creates a new coroutine. Apart from a pointer to an
 * uninitialized coro_context, it expects a pointer to the entry function
 * and the single pointer value that is given to it as argument.
 *
 * Allocating/deallocating the stack is your own responsibility, so there is
 * no coro_destroy function.
 */
void coro_create(coro_context *ctx,
                 coro_func coro, void *arg,
                 void *sptr, long ssize);

/*
 * The following prototype defines the coroutine switching function. It is
 * usually implemented as a macro, so watch out.
 *
void coro_transfer(coro_context *prev, coro_context *next);
 */

/*
 * That was it. No other user-visible functions are implemented here.
 */

#if !defined(CORO_LOOSE) && !defined(CORO_UCONTEXT) && !defined(CORO_SJLJ)
# if defined(WINDOWS)
#  define CORO_LOOSE 1 /* you don't win with windoze */
# elif defined(HAVE_UCONTEXT_H)
#  define CORO_UCONTEXT 1
# elif defined(HAVE_SETJMP_H) && defined(HAVE_SIGALTSTACK)
#  define CORO_SJLJ 1
# else
error unknown or unsupported architecture
# endif
#endif

#if CORO_UCONTEXT

#include <ucontext.h>

struct coro_context {
  ucontext_t uc;
};

#define coro_transfer(p,n) swapcontext(&((p)->uc), &((n)->uc))

#elif CORO_SJLJ || CORO_LOOSE

#include <setjmp.h>

struct coro_context {
  jmp_buf env;
};

#define coro_transfer(p,n) if (!setjmp ((p)->env)) longjmp ((n)->env, 1)

#endif

#endif

Revision:	1.2
Committed:	Mon Jul 23 18:04:59 2001 UTC (22 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.1:	+82 -15 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* Copyright (c) 2001 Marc Alexander Lehmann <pcg@goof.com>
3	*
4	* Redistribution and use in source and binary forms, with or without modifica-
5	* tion, are permitted provided that the following conditions are met:
6	*
7	* 1. Redistributions of source code must retain the above copyright notice,
8	* this list of conditions and the following disclaimer.
9	*
10	* 2. Redistributions in binary form must reproduce the above copyright
11	* notice, this list of conditions and the following disclaimer in the
12	* documentation and/or other materials provided with the distribution.
13	*
14	* 3. The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.
16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21	* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25	* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26	* OF THE POSSIBILITY OF SUCH DAMAGE.
27	*
28	* This library is modelled strictly after Ralf S. Engelschalls article at
29	* http://www.gnu.org/software/pth/rse-pmt.ps. So most of the credit must
30	* go to Ralf S. Engelschall <rse@engelschall.com>.
31	*
32	* This coroutine library is very much stripped down. You should either
33	* build your own process avstraction using it or - better - just use GNU
34	* Portable Threads, http://www.gnu.org/software/pth/.
35	*/
36
37	#ifndef CORO_H
38	#define CORO_H
39
40	/*
41	* This library consists of only three files
42	* coro.h, coro.c and LICENSE
43	*
44	* It implements what is known as coroutines, in a hopefully
45	* portable way. At the moment you have to define which kind
46	* of implementation flavour you want:
47	*
48	* -DCORO_UCONTEXT
49	*
50	* This flavour uses SUSv2's get/set/swap/makecontext functions that
51	* unfortunately only newer unices support.
52	* Use this for GNU/Linux + glibc-2.2.3.
53	*
54	* -DCORO_SJLJ
55	*
56	* This flavour uses SUSv'2 setjmp/longjmp and sigaltstack functions to
57	* do it's job. Coroutine creation is much slower than UCONTEXT, but
58	* context switching is often a bit cheaper. It should work on almost
59	* all unices. Use this for GNU/Linux + glibc-2.2. glibc-2.1 and below
60	* do not work with any model (neither sigaltstack nor context functions
61	* are implemented)
62	*
63	* -DCORO_LOOSE
64	*
65	* Microsoft's highly proprietary platform doesn't support sigaltstack, and
66	* this automatically selects a suitable workaround for this platform.
67	* (untested)
68	*
69	* If you define neither of these symbols, coro.h will try to autodetect
70	* the model. This currently works for CORO_LOOSE only. For the other
71	* alternatives you should check (e.g. using autoconf) and define the
72	* following symbols: HAVE_UCONTEXT_H / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
73	*/
74
75	/*
76	* This is the type for the top function of a new coroutine.
77	*/
78	typedef void (coro_func)(void );
79
80
81	/*
82	* A coroutine state is saved in the following structure. Treat it as a
83	* opaque type. errno and sigmask might be saved, but don't rely on it,
84	* implement your own switching primitive.
85	*/
86	typedef struct coro_context coro_context;
87
88	/*
89	* This function creates a new coroutine. Apart from a pointer to an
90	* uninitialized coro_context, it expects a pointer to the entry function
91	* and the single pointer value that is given to it as argument.
92	*
93	* Allocating/deallocating the stack is your own responsibility, so there is
94	* no coro_destroy function.
95	*/
96	void coro_create(coro_context *ctx,
97	coro_func coro, void *arg,
98	void *sptr, long ssize);
99
100	/*
101	* The following prototype defines the coroutine switching function. It is
102	* usually implemented as a macro, so watch out.
103	*
104	void coro_transfer(coro_context prev, coro_context next);
105	*/
106
107	/*
108	* That was it. No other user-visible functions are implemented here.
109	*/
110
111	#if !defined(CORO_LOOSE) && !defined(CORO_UCONTEXT) && !defined(CORO_SJLJ)
112	# if defined(WINDOWS)
113	# define CORO_LOOSE 1 /* you don't win with windoze */
114	# elif defined(HAVE_UCONTEXT_H)
115	# define CORO_UCONTEXT 1
116	# elif defined(HAVE_SETJMP_H) && defined(HAVE_SIGALTSTACK)
117	# define CORO_SJLJ 1
118	# else
119	error unknown or unsupported architecture
120	# endif
121	#endif
122
123	#if CORO_UCONTEXT
124
125	#include <ucontext.h>
126
127	struct coro_context {
128	ucontext_t uc;
129	};
130
131	#define coro_transfer(p,n) swapcontext(&((p)->uc), &((n)->uc))
132
133	#elif CORO_SJLJ \|\| CORO_LOOSE
134
135	#include <setjmp.h>
136
137	struct coro_context {
138	jmp_buf env;
139	};
140
141	#define coro_transfer(p,n) if (!setjmp ((p)->env)) longjmp ((n)->env, 1)
142
143	#endif
144
145	#endif
146