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/.
 *
 * VERSION: 0.1
 */

#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)
 *
 * -DCORO_IRIX
 *
 *    SGI's version of Microsoft's NT ;)
 *
 * 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) \
    && !defined(CORO_IRIX)
# 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 || CORO_IRIX

#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:	1.5
Committed:	Mon Sep 3 02:50:18 2001 UTC (25 years ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.4:	+11 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
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	root	1.4	*
36			* VERSION: 0.1
37	root	1.1	*/
38
39			#ifndef CORO_H
40			#define CORO_H
41
42	root	1.2	/*
43			* This library consists of only three files
44			* coro.h, coro.c and LICENSE
45			*
46			* It implements what is known as coroutines, in a hopefully
47			* portable way. At the moment you have to define which kind
48			* of implementation flavour you want:
49			*
50			* -DCORO_UCONTEXT
51			*
52			* This flavour uses SUSv2's get/set/swap/makecontext functions that
53			* unfortunately only newer unices support.
54			* Use this for GNU/Linux + glibc-2.2.3.
55			*
56			* -DCORO_SJLJ
57			*
58			* This flavour uses SUSv'2 setjmp/longjmp and sigaltstack functions to
59			* do it's job. Coroutine creation is much slower than UCONTEXT, but
60			* context switching is often a bit cheaper. It should work on almost
61			* all unices. Use this for GNU/Linux + glibc-2.2. glibc-2.1 and below
62	root	1.3	* do not work with any sane model (neither sigaltstack nor context
63			* functions are implemented)
64			*
65			* -DCORO_LINUX
66			*
67			* Old GNU/Linux systems (<= glibc-2.1) work with this implementation
68			* (very fast).
69	root	1.2	*
70			* -DCORO_LOOSE
71			*
72			* Microsoft's highly proprietary platform doesn't support sigaltstack, and
73			* this automatically selects a suitable workaround for this platform.
74			* (untested)
75			*
76	root	1.5	* -DCORO_IRIX
77			*
78			* SGI's version of Microsoft's NT ;)
79			*
80	root	1.2	* If you define neither of these symbols, coro.h will try to autodetect
81			* the model. This currently works for CORO_LOOSE only. For the other
82			* alternatives you should check (e.g. using autoconf) and define the
83			* following symbols: HAVE_UCONTEXT_H / HAVE_SETJMP_H / HAVE_SIGALTSTACK.
84			*/
85
86			/*
87			* This is the type for the top function of a new coroutine.
88			*/
89	root	1.1	typedef void (coro_func)(void );
90
91	root	1.2
92			/*
93			* A coroutine state is saved in the following structure. Treat it as a
94			* opaque type. errno and sigmask might be saved, but don't rely on it,
95			* implement your own switching primitive.
96			*/
97			typedef struct coro_context coro_context;
98
99			/*
100			* This function creates a new coroutine. Apart from a pointer to an
101			* uninitialized coro_context, it expects a pointer to the entry function
102			* and the single pointer value that is given to it as argument.
103			*
104			* Allocating/deallocating the stack is your own responsibility, so there is
105			* no coro_destroy function.
106			*/
107			void coro_create(coro_context *ctx,
108			coro_func coro, void *arg,
109			void *sptr, long ssize);
110
111			/*
112			* The following prototype defines the coroutine switching function. It is
113			* usually implemented as a macro, so watch out.
114			*
115			void coro_transfer(coro_context prev, coro_context next);
116			*/
117
118			/*
119			* That was it. No other user-visible functions are implemented here.
120			*/
121
122	root	1.5	/*****************************************************************************/
123
124	root	1.3	#if !defined(CORO_LOOSE) && !defined(CORO_UCONTEXT) \
125	root	1.5	&& !defined(CORO_SJLJ) && !defined(CORO_LINUX) \
126			&& !defined(CORO_IRIX)
127	root	1.2	# if defined(WINDOWS)
128			# define CORO_LOOSE 1 /* you don't win with windoze */
129	root	1.3	# elif defined(__linux) && defined(__x86)
130	root	1.2	# elif defined(HAVE_UCONTEXT_H)
131			# define CORO_UCONTEXT 1
132			# elif defined(HAVE_SETJMP_H) && defined(HAVE_SIGALTSTACK)
133			# define CORO_SJLJ 1
134			# else
135	root	1.1	error unknown or unsupported architecture
136	root	1.2	# endif
137	root	1.1	#endif
138
139	root	1.5	/*****************************************************************************/
140
141	root	1.1	#if CORO_UCONTEXT
142
143			#include <ucontext.h>
144
145	root	1.2	struct coro_context {
146	root	1.1	ucontext_t uc;
147	root	1.2	};
148	root	1.1
149			#define coro_transfer(p,n) swapcontext(&((p)->uc), &((n)->uc))
150
151	root	1.5	#elif CORO_SJLJ \|\| CORO_LOOSE \|\| CORO_LINUX \|\| CORO_IRIX
152	root	1.1
153			#include <setjmp.h>
154
155	root	1.2	struct coro_context {
156	root	1.1	jmp_buf env;
157	root	1.2	};
158	root	1.1
159			#define coro_transfer(p,n) if (!setjmp ((p)->env)) longjmp ((n)->env, 1)
160
161			#endif
162
163			#endif
164