ai_info_dummy.cpp

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00001 /* $Id: ai_info_dummy.cpp 18862 2010-01-18 15:41:38Z rubidium $ */
00002 
00003 /*
00004  * This file is part of OpenTTD.
00005  * OpenTTD 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, version 2.
00006  * OpenTTD 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.
00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
00008  */
00009 
00012 #include <squirrel.h>
00013 #include "../stdafx.h"
00014 
00015 #include "../string_func.h"
00016 #include "../strings_func.h"
00017 #include "table/strings.h"
00018 
00019 /* The reason this exists in C++, is that a user can trash his ai/ dir,
00020  *  leaving no AIs available. The complexity to solve this is insane, and
00021  *  therefor the alternative is used, and make sure there is always an AI
00022  *  available, no matter what the situation is. By defining it in C++, there
00023  *  is simply now way a user can delete it, and therefor safe to use. It has
00024  *  to be noted that this AI is complete invisible for the user, and impossible
00025  *  to select manual. It is a fail-over in case no AIs are available.
00026  */
00027 
00028 const SQChar _dummy_script_info[] = _SC("                                                       \n\
00029 class DummyAI extends AIInfo {                                                                  \n\
00030   function GetAuthor()      { return \"OpenTTD NoAI Developers Team\"; }                        \n\
00031   function GetName()        { return \"DummyAI\"; }                                             \n\
00032   function GetShortName()   { return \"DUMM\"; }                                                \n\
00033   function GetDescription() { return \"A Dummy AI that is loaded when your ai/ dir is empty\"; }\n\
00034   function GetVersion()     { return 1; }                                                       \n\
00035   function GetDate()        { return \"2008-07-26\"; }                                          \n\
00036   function CreateInstance() { return \"DummyAI\"; }                                             \n\
00037 }                                                                                               \n\
00038                                                                                                 \n\
00039 RegisterDummyAI(DummyAI());                                                                     \n\
00040 ");
00041 
00042 void AI_CreateAIInfoDummy(HSQUIRRELVM vm)
00043 {
00044   sq_pushroottable(vm);
00045 
00046   /* Load and run the script */
00047   if (SQ_SUCCEEDED(sq_compilebuffer(vm, _dummy_script_info, scstrlen(_dummy_script_info), _SC("dummy"), SQTrue))) {
00048     sq_push(vm, -2);
00049     if (SQ_SUCCEEDED(sq_call(vm, 1, SQFalse, SQTrue))) {
00050       sq_pop(vm, 1);
00051       return;
00052     }
00053   }
00054   NOT_REACHED();
00055 }
00056 
00057 void AI_CreateAIDummy(HSQUIRRELVM vm)
00058 {
00059   /* We want to translate the error message.
00060    * We do this in three steps:
00061    * 1) We get the error message
00062    */
00063   char error_message[1024];
00064   GetString(error_message, STR_ERROR_AI_NO_AI_FOUND, lastof(error_message));
00065 
00066   /* Make escapes for all quotes and slashes. */
00067   char safe_error_message[1024];
00068   char *q = safe_error_message;
00069   for (const char *p = error_message; *p != '\0' && q < lastof(safe_error_message) - 2; p++, q++) {
00070     if (*p == '"' || *p == '\\') *q++ = '\\';
00071     *q = *p;
00072   }
00073   *q = '\0';
00074 
00075   /* 2) We construct the AI's code. This is done by merging a header, body and footer */
00076   char dummy_script[4096];
00077   char *dp = dummy_script;
00078   dp = strecpy(dp, "class DummyAI extends AIController {\n  function Start()\n  {\n", lastof(dummy_script));
00079 
00080   /* As special trick we need to split the error message on newlines and
00081    * emit each newline as a separate error printing string. */
00082   char *newline;
00083   char *p = safe_error_message;
00084   do {
00085     newline = strchr(p, '\n');
00086     if (newline != NULL) *newline = '\0';
00087 
00088     dp += seprintf(dp, lastof(dummy_script), "    AILog.Error(\"%s\");\n", p);
00089     p = newline + 1;
00090   } while (newline != NULL);
00091 
00092   dp = strecpy(dp, "  }\n}\n", lastof(dummy_script));
00093 
00094   /* 3) We translate the error message in the character format that Squirrel wants.
00095    *    We can use the fact that the wchar string printing also uses %s to print
00096    *    old style char strings, which is what was generated during the script generation. */
00097   const SQChar *sq_dummy_script = OTTD2SQ(dummy_script);
00098 
00099   /* And finally we load and run the script */
00100   sq_pushroottable(vm);
00101   if (SQ_SUCCEEDED(sq_compilebuffer(vm, sq_dummy_script, scstrlen(sq_dummy_script), _SC("dummy"), SQTrue))) {
00102     sq_push(vm, -2);
00103     if (SQ_SUCCEEDED(sq_call(vm, 1, SQFalse, SQTrue))) {
00104       sq_pop(vm, 1);
00105       return;
00106     }
00107   }
00108   NOT_REACHED();
00109 }

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