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authorPaul Gilbert2012-05-11 23:08:27 +1000
committerPaul Gilbert2012-05-11 23:08:27 +1000
commit50153aba8832d8707031df2219512515797d93ce (patch)
tree9ed5074c635ba5106894e7590b267a28dc4a4caf /engines/tinsel
parent724deb6b84b8a5f5a3aa96adc2a512c962f7081a (diff)
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COMMON: Merged the Tinsel & Tony Coroutine schedulers into Common
Diffstat (limited to 'engines/tinsel')
-rw-r--r--engines/tinsel/coroutine.h282
1 files changed, 0 insertions, 282 deletions
diff --git a/engines/tinsel/coroutine.h b/engines/tinsel/coroutine.h
deleted file mode 100644
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--- a/engines/tinsel/coroutine.h
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-/* ScummVM - Graphic Adventure Engine
- *
- * ScummVM is the legal property of its developers, whose names
- * are too numerous to list here. Please refer to the COPYRIGHT
- * file distributed with this source distribution.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
-
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
-
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- *
- */
-
-#ifndef TINSEL_COROUTINE_H
-#define TINSEL_COROUTINE_H
-
-#include "common/scummsys.h"
-#include "common/util.h" // for SCUMMVM_CURRENT_FUNCTION
-
-namespace Tinsel {
-
-/**
- * @defgroup TinselCoroutines Coroutine support for Tinsel
- *
- * The following is loosely based on an article by Simon Tatham:
- * <http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html>.
- * However, many improvements and tweaks have been made, in particular
- * by taking advantage of C++ features not available in C.
- *
- * Why is this code here? Well, the Tinsel engine apparently used
- * setjmp/longjmp based coroutines as a core tool from the start, and
- * so they are deeply ingrained into the whole code base. When we
- * started to get Tinsel ready for ScummVM, we had to deal with that.
- * It soon got clear that we could not simply rewrite the code to work
- * without some form of coroutines. While possible in principle, it
- * would have meant a major restructuring of the entire code base, a
- * rather daunting task. Also, it would have very likely introduced
- * tons of regressons.
- *
- * So instead of getting rid of the coroutines, we chose to implement
- * them in an alternate way, using Simon Tatham's trick as described
- * above. While the trick is dirty, the result seems to be clear enough,
- * we hope; plus, it allowed us to stay relatively close to the
- * original structure of the code, which made it easier to avoid
- * regressions, and will be helpful in the future when comparing things
- * against the original code base.
- */
-//@{
-
-
-// Enable this macro to enable some debugging support in the coroutine code.
-//#define COROUTINE_DEBUG 1
-
-/**
- * The core of any coroutine context which captures the 'state' of a coroutine.
- * Private use only.
- */
-struct CoroBaseContext {
- int _line;
- int _sleep;
- CoroBaseContext *_subctx;
-#if COROUTINE_DEBUG
- const char *_funcName;
-#endif
- CoroBaseContext(const char *func);
- ~CoroBaseContext();
-};
-
-typedef CoroBaseContext *CoroContext;
-
-
-// FIXME: Document this!
-extern CoroContext nullContext;
-
-/**
- * Wrapper class which holds a pointer to a pointer to a CoroBaseContext.
- * The interesting part is the destructor, which kills the context being held,
- * but ONLY if the _sleep val of that context is zero. This way, a coroutine
- * can just 'return' w/o having to worry about freeing the allocated context
- * (in Simon Tatham's original code, one had to use a special macro to
- * return from a coroutine).
- */
-class CoroContextHolder {
- CoroContext &_ctx;
-public:
- CoroContextHolder(CoroContext &ctx) : _ctx(ctx) {
- assert(ctx);
- assert(ctx->_sleep >= 0);
- ctx->_sleep = 0;
- }
- ~CoroContextHolder() {
- if (_ctx && _ctx->_sleep == 0) {
- delete _ctx;
- _ctx = 0;
- }
- }
-};
-
-
-#define CORO_PARAM CoroContext &coroParam
-
-
-/**
- * Begin the declaration of a coroutine context.
- * This allows declaring variables which are 'persistent' during the
- * lifetime of the coroutine. An example use would be:
- *
- * CORO_BEGIN_CONTEXT;
- * int var;
- * char *foo;
- * CORO_END_CONTEXT(_ctx);
- *
- * It is not possible to initialize variables here, due to the way this
- * macro is implemented. Furthermore, to use the variables declared in
- * the coroutine context, you have to access them via the context variable
- * name that was specified as parameter to CORO_END_CONTEXT, e.g.
- * _ctx->var = 0;
- *
- * @see CORO_END_CONTEXT
- *
- * @note We declare a variable 'DUMMY' to allow the user to specify an 'empty'
- * context, and so compilers won't complain about ";" following the macro.
- */
-#define CORO_BEGIN_CONTEXT \
- struct CoroContextTag : CoroBaseContext { \
- CoroContextTag() : CoroBaseContext(SCUMMVM_CURRENT_FUNCTION) {} \
- int DUMMY
-
-/**
- * End the declaration of a coroutine context.
- * @param x name of the coroutine context
- * @see CORO_BEGIN_CONTEXT
- */
-#define CORO_END_CONTEXT(x) } *x = (CoroContextTag *)coroParam
-
-/**
- * Begin the code section of a coroutine.
- * @param x name of the coroutine context
- * @see CORO_BEGIN_CODE
- */
-#define CORO_BEGIN_CODE(x) \
- if (&coroParam == &nullContext) assert(!nullContext);\
- if (!x) {coroParam = x = new CoroContextTag();}\
- CoroContextHolder tmpHolder(coroParam);\
- switch (coroParam->_line) { case 0:;
-
-/**
- * End the code section of a coroutine.
- * @see CORO_END_CODE
- */
-#define CORO_END_CODE \
- if (&coroParam == &nullContext) { \
- delete nullContext; \
- nullContext = NULL; \
- } \
- }
-
-/**
- * Sleep for the specified number of scheduler cycles.
- */
-#define CORO_SLEEP(delay) do {\
- coroParam->_line = __LINE__;\
- coroParam->_sleep = delay;\
- assert(&coroParam != &nullContext);\
- return; case __LINE__:;\
- } while (0)
-
-#define CORO_GIVE_WAY do { g_scheduler->giveWay(); CORO_SLEEP(1); } while (0)
-#define CORO_RESCHEDULE do { g_scheduler->reschedule(); CORO_SLEEP(1); } while (0)
-
-/**
- * Stop the currently running coroutine and all calling coroutines.
- *
- * This sets _sleep to -1 rather than 0 so that the context doesn't get
- * deleted by CoroContextHolder, since we want CORO_INVOKE_ARGS to
- * propogate the _sleep value and return immediately (the scheduler will
- * then delete the entire coroutine's state, including all subcontexts).
- */
-#define CORO_KILL_SELF() \
- do { if (&coroParam != &nullContext) { coroParam->_sleep = -1; } return; } while (0)
-
-
-/**
- * This macro is to be used in conjunction with CORO_INVOKE_ARGS and
- * similar macros for calling coroutines-enabled subroutines.
- */
-#define CORO_SUBCTX coroParam->_subctx
-
-/**
- * Invoke another coroutine.
- *
- * If the subcontext still exists after the coroutine is invoked, it has
- * either yielded/slept or killed itself, and so we copy the _sleep value
- * to our own context and return (execution will continue at the case
- * statement below, where we loop and call the coroutine again).
- * If the subcontext is null, the coroutine ended normally, and we can
- * simply break out of the loop and continue execution.
- *
- * @param subCoro name of the coroutine-enabled function to invoke
- * @param ARGS list of arguments to pass to subCoro
- *
- * @note ARGS must be surrounded by parentheses, and the first argument
- * in this list must always be CORO_SUBCTX. For example, the
- * regular function call
- * myFunc(a, b);
- * becomes the following:
- * CORO_INVOKE_ARGS(myFunc, (CORO_SUBCTX, a, b));
- */
-#define CORO_INVOKE_ARGS(subCoro, ARGS) \
- do {\
- coroParam->_line = __LINE__;\
- coroParam->_subctx = 0;\
- do {\
- subCoro ARGS;\
- if (!coroParam->_subctx) break;\
- coroParam->_sleep = coroParam->_subctx->_sleep;\
- assert(&coroParam != &nullContext);\
- return; case __LINE__:;\
- } while (1);\
- } while (0)
-
-/**
- * Invoke another coroutine. Similar to CORO_INVOKE_ARGS,
- * but allows specifying a return value which is returned
- * if invoked coroutine yields (thus causing the current
- * coroutine to yield, too).
- */
-#define CORO_INVOKE_ARGS_V(subCoro, RESULT, ARGS) \
- do {\
- coroParam->_line = __LINE__;\
- coroParam->_subctx = 0;\
- do {\
- subCoro ARGS;\
- if (!coroParam->_subctx) break;\
- coroParam->_sleep = coroParam->_subctx->_sleep;\
- assert(&coroParam != &nullContext);\
- return RESULT; case __LINE__:;\
- } while (1);\
- } while (0)
-
-/**
- * Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
- * with no parameters.
- */
-#define CORO_INVOKE_0(subCoroutine) \
- CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX))
-
-/**
- * Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
- * with one parameter.
- */
-#define CORO_INVOKE_1(subCoroutine, a0) \
- CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0))
-
-/**
- * Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
- * with two parameters.
- */
-#define CORO_INVOKE_2(subCoroutine, a0,a1) \
- CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0,a1))
-
-/**
- * Convenience wrapper for CORO_INVOKE_ARGS for invoking a coroutine
- * with three parameters.
- */
-#define CORO_INVOKE_3(subCoroutine, a0,a1,a2) \
- CORO_INVOKE_ARGS(subCoroutine,(CORO_SUBCTX,a0,a1,a2))
-
-//@}
-
-} // End of namespace Tinsel
-
-#endif // TINSEL_COROUTINE_H