add parameter parsing

src/main.cpp

@@ -13,6 +13,94 @@
 
 DivEngine e;
 
+std::vector<TAParam> params;
+
+bool pHelp(String) {
+  printf("usage: furnace [params] [filename]\n"
+         "you may specify the following parameters:\n");
+  for (auto& i: params) {
+    if (i.value) {
+      printf("  -%s %s: %s\n",i.name.c_str(),i.valName.c_str(),i.desc.c_str());
+    } else {
+      printf("  -%s: %s\n",i.name.c_str(),i.desc.c_str());
+    }
+  }
+  return false;
+}
+
+bool pAudio(String val) {
+  if (val=="jack") {
+    e.setAudio(DIV_AUDIO_JACK);
+  } else if (val=="sdl") {
+    e.setAudio(DIV_AUDIO_SDL);
+  } else {
+    logE("invalid value for audio engine! valid values are: jack, sdl.\n");
+    return false;
+  }
+  return true;
+}
+
+bool pView(String val) {
+  if (val=="pattern") {
+    e.setView(DIV_STATUS_PATTERN);
+  } else if (val=="commands") {
+    e.setView(DIV_STATUS_COMMANDS);
+  } else if (val=="nothing") {
+    e.setView(DIV_STATUS_NOTHING);
+  } else {
+    logE("invalid value for view type! valid values are: pattern, commands, nothing.\n");
+    return false;
+  }
+  return true;
+}
+
+bool pVersion(String) {
+  printf("Furnace version " DIV_VERSION ".\n\n");
+  printf("developed by tildearrow. copyright (C) 2021.\n");
+  printf("licensed under the GNU General Public License version 2\n");
+  printf("<https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>.\n\n");
+  printf("this is free software with ABSOLUTELY NO WARRANTY.\n");
+  printf("pass the -warranty parameter for more information.\n\n");
+  printf("DISCLAIMER: this program is not affiliated with Delek in any form.\n");
+  return false;
+}
+
+bool pWarranty(String) {
+  printf("This program is free software; you can redistribute it and/or\n"
+         "modify it under the terms of the GNU General Public License\n"
+         "as published by the Free Software Foundation; either version 2\n"
+         "of the License, or (at your option) any later version.\n\n"
+
+         "This program is distributed in the hope that it will be useful,\n"
+         "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
+         "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
+         "GNU General Public License for more details.\n\n"
+
+         "You should have received a copy of the GNU General Public License\n"
+         "along with this program; if not, write to the Free Software\n"
+         "Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.\n");
+  return false;
+}
+
+bool needsValue(String param) {
+  for (size_t i=0; i<params.size(); i++) {
+    if (params[i].name==param) {
+      return params[i].value;
+    }
+  }
+  return false;
+}
+
+void initParams() {
+  params.push_back(TAParam("h","help",false,pHelp,"","display this help"));
+
+  params.push_back(TAParam("a","audio",true,pAudio,"jack|sdl","set audio engine (SDL by default)"));
+  params.push_back(TAParam("v","view",true,pView,"pattern|commands|nothing","set visualization (pattern by default)"));
+
+  params.push_back(TAParam("V","version",false,pVersion,"","view information about Furnace."));
+  params.push_back(TAParam("W","warranty",false,pWarranty,"","view warranty disclaimer."));
+}
+
 int main(int argc, char** argv) {
 #ifdef _WIN32
   HANDLE winin=GetStdHandle(STD_INPUT_HANDLE);
@@ -26,13 +114,55 @@ int main(int argc, char** argv) {
   SetConsoleMode(winout,termprop);
   SetConsoleMode(winin,termpropi);
 #endif
-  if (argc<2) {
+
+  initParams();
+
+  // parse arguments
+  String arg, val, fileName;
+  size_t eqSplit, argStart;
+  for (int i=1; i<argc; i++) {
+    arg=""; val="";
+    if (argv[i][0]=='-') {
+      if (argv[i][1]=='-') {
+        argStart=2;
+      } else {
+        argStart=1;
+      }
+      arg=&argv[i][argStart];
+      eqSplit=arg.find_first_of('=');
+      if (eqSplit==String::npos) {
+        if (needsValue(arg)) {
+          if ((i+1)<argc) {
+            val=argv[i+1];
+            i++;
+          } else {
+            logE("incomplete param %s.\n",arg.c_str());
+            return 1;
+          }
+        }
+      } else {
+        val=arg.substr(eqSplit+1);
+        arg=arg.substr(0,eqSplit);
+      }
+      for (size_t j=0; j<params.size(); j++) {
+        if (params[j].name==arg || params[j].shortName==arg) {
+          if (!params[j].func(val)) return 1;
+          break;
+        }
+      }
+    } else {
+      fileName=argv[i];
+      printf("fn: %s\n",fileName.c_str());
+    }
+  }
+
+  if (fileName.empty()) {
     logI("usage: %s file\n",argv[0]);
     return 1;
   }
   logI("Furnace version " DIV_VERSION ".\n");
   logI("loading module...\n");
-  FILE* f=fopen(argv[1],"rb");
+  FILE* f=fopen(fileName.c_str(),"rb");
   if (f==NULL) {
     perror("error");
     return 1;