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 |
|