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 sane model (neither sigaltstack nor context
 *    functions are implemented)
 *
 * -DCORO_LINUX
 *
 *    Old GNU/Linux systems (<= glibc-2.1) work with this implementation
 *    (very fast).
 *
 * -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) && !defined(CORO_LINUX)
# if defined(WINDOWS)
#  define CORO_LOOSE 1 /* you don't win with windoze */
# elif defined(__linux) && defined(__x86)
# 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 || CORO_LINUX

#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:	1.3
Committed:	Tue Jul 24 19:52:55 2001 UTC (22 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+11 -4 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 sane model (neither sigaltstack nor context
61	* functions are implemented)
62	*
63	* -DCORO_LINUX
64	*
65	* Old GNU/Linux systems (<= glibc-2.1) work with this implementation
66	* (very fast).
67	*
68	* -DCORO_LOOSE
69	*
70	* Microsoft's highly proprietary platform doesn't support sigaltstack, and
71	* this automatically selects a suitable workaround for this platform.
72	* (untested)
73	*
74	* If you define neither of these symbols, coro.h will try to autodetect
75	* the model. This currently works for CORO_LOOSE only. For the other
76	* alternatives you should check (e.g. using autoconf) and define the
77	* following symbols: HAVE_UCONTEXT_H / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
78	*/
79
80	/*
81	* This is the type for the top function of a new coroutine.
82	*/
83	typedef void (coro_func)(void );
84
85
86	/*
87	* A coroutine state is saved in the following structure. Treat it as a
88	* opaque type. errno and sigmask might be saved, but don't rely on it,
89	* implement your own switching primitive.
90	*/
91	typedef struct coro_context coro_context;
92
93	/*
94	* This function creates a new coroutine. Apart from a pointer to an
95	* uninitialized coro_context, it expects a pointer to the entry function
96	* and the single pointer value that is given to it as argument.
97	*
98	* Allocating/deallocating the stack is your own responsibility, so there is
99	* no coro_destroy function.
100	*/
101	void coro_create(coro_context *ctx,
102	coro_func coro, void *arg,
103	void *sptr, long ssize);
104
105	/*
106	* The following prototype defines the coroutine switching function. It is
107	* usually implemented as a macro, so watch out.
108	*
109	void coro_transfer(coro_context prev, coro_context next);
110	*/
111
112	/*
113	* That was it. No other user-visible functions are implemented here.
114	*/
115
116	#if !defined(CORO_LOOSE) && !defined(CORO_UCONTEXT) \
117	&& !defined(CORO_SJLJ) && !defined(CORO_LINUX)
118	# if defined(WINDOWS)
119	# define CORO_LOOSE 1 /* you don't win with windoze */
120	# elif defined(__linux) && defined(__x86)
121	# elif defined(HAVE_UCONTEXT_H)
122	# define CORO_UCONTEXT 1
123	# elif defined(HAVE_SETJMP_H) && defined(HAVE_SIGALTSTACK)
124	# define CORO_SJLJ 1
125	# else
126	error unknown or unsupported architecture
127	# endif
128	#endif
129
130	#if CORO_UCONTEXT
131
132	#include <ucontext.h>
133
134	struct coro_context {
135	ucontext_t uc;
136	};
137
138	#define coro_transfer(p,n) swapcontext(&((p)->uc), &((n)->uc))
139
140	#elif CORO_SJLJ \|\| CORO_LOOSE \|\| CORO_LINUX
141
142	#include <setjmp.h>
143
144	struct coro_context {
145	jmp_buf env;
146	};
147
148	#define coro_transfer(p,n) if (!setjmp ((p)->env)) longjmp ((n)->env, 1)
149
150	#endif
151
152	#endif
153