104 lines
3.4 KiB
C
104 lines
3.4 KiB
C
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/**
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* @file backtrack.c
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @section DESCRIPTION
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*
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* Synopsis:
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* backtrack_point()
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* backtrack_point::go()
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*
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* Description:
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* The backtrack_point() statement creates a backtrack point, going up immedietely.
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* The go() method triggers backtracking to the backtrack point, i.e. makes the
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* backtrack_point() statement go down and back up at atomically. The go() method
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* itself goes up immedietely, but side effects of triggering backtracking have
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* priority.
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*/
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#include <stddef.h>
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#include <ncd/NCDModule.h>
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#include <generated/blog_channel_ncd_backtrack.h>
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#define ModuleLog(i, ...) NCDModuleInst_Backend_Log((i), BLOG_CURRENT_CHANNEL, __VA_ARGS__)
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static void func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
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{
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// check arguments
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if (!NCDVal_ListRead(params->args, 0)) {
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ModuleLog(i, BLOG_ERROR, "wrong arity");
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goto fail0;
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}
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// go up
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NCDModuleInst_Backend_Up(i);
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return;
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fail0:
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NCDModuleInst_Backend_DeadError(i);
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}
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static void go_func_new (void *unused, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
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{
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// check arguments
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if (!NCDVal_ListRead(params->args, 0)) {
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ModuleLog(i, BLOG_ERROR, "wrong arity");
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goto fail0;
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}
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// get backtrack point
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NCDModuleInst *backtrack_point_inst = params->method_user;
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// go up (after toggling)
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NCDModuleInst_Backend_Up(i);
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// toggle backtrack point
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NCDModuleInst_Backend_DownUp(backtrack_point_inst);
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return;
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fail0:
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NCDModuleInst_Backend_DeadError(i);
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}
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static struct NCDModule modules[] = {
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{
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.type = "backtrack_point",
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.func_new2 = func_new
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}, {
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.type = "backtrack_point::go",
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.func_new2 = go_func_new
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}, {
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.type = NULL
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}
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};
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const struct NCDModuleGroup ncdmodule_backtrack = {
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.modules = modules
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};
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