Index: TODO
==================================================================
--- TODO
+++ TODO
@@ -30,12 +30,9 @@
 * Bugs
   * Figure out why the $SeekerCloser class doesn't seem to work properly
   * Level 232 of SUPERHRO puzzle set (the Lava shouldn't expand? why?)
 * Display solution comments/timestamp
 * VCR mode
-* Portable mode, not needing installing files in home directory
-  * Maybe not needed? You can override the HOME environment variable
-  * An alternative is to check argv[0]; if it contains / then don't use HOME
 * Command-line switch for batch import/export levels
 * SQL
   * Implement the GROUP column in the CLASSES table
   * Allow multiple SQL statements in one binding

Index: commandline.doc
==================================================================
--- commandline.doc
+++ commandline.doc
@@ -38,10 +38,14 @@
   Start in the editor instead of game.
 
 -f
   Only flush the user cache and then terminate.
 
+-h
+  Disable portable mode; always use the HOME environment variable to find
+  the configuration and database files.
+
 -n
   Create a new puzzle set. The .xclass and .class files should already
   exist; the .level and .solution files should not already exist, and will
   be created with minimal data.
 
@@ -87,5 +91,24 @@
   Disable loading SQLite extensions.
 
 .x1
   Enable loading SQLite extensions.
 
+
+=== Portable mode ===
+
+Free Hero Mesh may run either in "home mode" or in "portable mode". The
+following rules are used to determine which mode to use:
+
+1. If the -h switch is present, use home mode.
+
+2. If the HEROMESH_PREFIX environment variable is present, use portable
+mode; its value is the file name prefix (the ".heromeshsession" and
+".heromeshrc" names are appended directly to this value, so if it does
+not end with a slash, it will be a prefix to the file name too).
+
+3. If argv[0] contains a forward slash, use portable mode; it will use
+files "current.heromeshrc" and "current.heromeshsession" in the directory
+where the executable file is allegedly found.
+
+4. Otherwise, home mode is used.
+

Index: main.c
==================================================================
--- main.c
+++ main.c
@@ -65,10 +65,11 @@
 static SDL_Cursor*cursor[77];
 static FILE*levelfp;
 static FILE*solutionfp;
 static sqlite3_int64 leveluc,solutionuc;
 static sqlite3_stmt*readusercachest;
+static char*hpath;
 
 static sqlite3_int64 reset_usercache(FILE*fp,const char*nam,struct stat*stats,const char*suffix) {
   sqlite3_stmt*st;
   sqlite3_int64 t,id;
   char buf[128];
@@ -543,19 +544,12 @@
   v=xrm_get_resource(resourcedb,optionquery,optionquery,2)?:"";
   sqlite3_config(SQLITE_CONFIG_COVERING_INDEX_SCAN,(int)boolxrm(v,1));
   if(sqlite3_initialize()) fatal("Failure to initialize SQLite.\n");
   optionquery[1]=Q_sqlFile;
   v=xrm_get_resource(resourcedb,optionquery,optionquery,2);
-  if(v && *v) {
-    s=sqlite3_mprintf("%s",v);
-  } else {
-    v=getenv("HOME")?:".";
-    s=sqlite3_mprintf("%s%s.heromeshsession",v,v[strlen(v)-1]=='/'?"":"/");
-  }
-  if(!s) fatal("Allocation failed\n");
-  if(z=sqlite3_open(s,&userdb)) fatal("Failed to open user database %s (%s)\n",s,userdb?sqlite3_errmsg(userdb):sqlite3_errstr(z));
-  sqlite3_free(s);
+  if(!v || !*v) strcpy(hpath+strlen(hpath)-2,"session"),v=hpath;
+  if(z=sqlite3_open(v,&userdb)) fatal("Failed to open user database %s (%s)\n",v,userdb?sqlite3_errmsg(userdb):sqlite3_errstr(z));
   optionquery[1]=Q_sqlExtensions;
   v=xrm_get_resource(resourcedb,optionquery,optionquery,2)?:"";
   sqlite3_db_config(userdb,SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION,*v?1:0,&z);
   if(*v) {
     p=s=strdup(v);
@@ -588,19 +582,37 @@
 void set_cursor(int id) {
   id>>=1;
   if(!cursor[id]) cursor[id]=SDL_CreateCursor((void*)cursorimg+(id<<6),(void*)cursorimg+(id<<6)+32,16,16,cursorhot[id]>>4,cursorhot[id]&15);
   SDL_SetCursor(cursor[id]);
 }
+
+static void set_path(const char*arg) {
+  const char*s;
+  if(main_options['h']) goto home;
+  if((s=getenv("HEROMESH_PREFIX")) && *s) {
+    hpath=malloc(strlen(s)+32);
+    if(!hpath) fatal("Allocation failed\n");
+    sprintf(hpath,"%s.heromeshrc",s);
+    return;
+  }
+  if(s=strrchr(arg,'/')) {
+    hpath=malloc(s+64-arg);
+    if(!hpath) fatal("Allocation failed\n");
+    sprintf(hpath,"%.*s/current.heromeshrc",(int)(s-arg),arg);
+    return;
+  }
+  home:
+  s=getenv("HOME")?:".";
+  hpath=malloc(strlen(s)+32);
+  if(!hpath) fatal("Allocation failed\n");
+  sprintf(hpath,"%s%s.heromeshrc",s,s[strlen(s)-1]=='/'?"":"/");
+}
 
 static void load_options(void) {
-  const char*home=getenv("HOME")?:".";
-  char*nam=malloc(strlen(home)+16);
   FILE*fp;
-  sprintf(nam,"%s%s.heromeshrc",home,home[strlen(home)-1]=='/'?"":"/");
-  fp=fopen(nam,"r");
-  if(!fp) fatal("Failed to open %s (%m)\n",nam);
-  free(nam);
+  fp=fopen(hpath,"r");
+  if(!fp) fatal("Failed to open %s (%m)\n",hpath);
   if(xrm_load(resourcedb,fp,1)) fatal("Error while loading .heromeshrc\n");
   fclose(fp);
 }
 
 static void read_options(int argc,char**argv) {
@@ -889,11 +901,14 @@
     main_options['x']=1;
   }
   if(main_options['a']) main_options['r']=main_options['x']=1;
   if(main_options['p']) main_options['r']=1;
   if(main_options['f']) main_options['x']=1;
-  if(!main_options['c']) load_options();
+  if(!main_options['c']) {
+    set_path(argv[0]);
+    load_options();
+  }
   if(argc>optind) read_options(argc-optind,argv+optind);
   *optionquery=xrm_make_quark(globalclassname,0)?:xrm_anyq;
 #ifdef __GNUC__
   stack_protect_mark=__builtin_frame_address(0);
   set_stack_protection();
@@ -909,10 +924,11 @@
     run_picture_editor();
     return 0;
   }
   load_pictures();
   if(main_options['T']) {
+    printf("argv[0] = %s\n",argv[0]);
     test_mode();
     return 0;
   }
   init_usercache();
   if(main_options['n']) return 0;

Index: man6/heromesh.6
==================================================================
--- man6/heromesh.6
+++ man6/heromesh.6
@@ -29,10 +29,13 @@
 You can also use it with some other options to display details.
 .IP -e
 Start the level editor.
 .IP -f
 Only flush the user cache and then terminate.
+.IP -h
+Disable portable mode;
+always use the HOME environment variable to find the files.
 .IP -n
 Create a new puzzle set.
 The class definition file and image set must already exist.
 .IP -p
 Start the picture editor.
@@ -54,11 +57,30 @@
 .I ~/.heromeshsession
 A SQLite database containing user cache data.
 .TP
 .I \*[Document_Dir]/*.doc
 Documentation.
+.PP
+The files it expects to find in the home directory may be looked for elsewhere if portable mode is used.
 .SH ENVIRONMENT
 .TP
+.B HEROMESH_PREFIX
+If defined, force portable mode.
+This value is used as the prefix to find the files.
+(It may include a file name prefix as well as a directory path.)
+.TP
 .B HOME
 The home directory; used to find .heromeshrc and .heromeshsession files.
 .PP
 Any of the SDL environment variables can also be used.
+.SH "PORTABLE MODE"
+There is a "portable mode" available.
+The following rules are used to determine if portable mode should be used:
+.PP
+1. If the -h switch is specified, use home mode.
+.PP
+2. If the HEROMESH_PREFIX environment variable is nonempty, use portable mode.
+.PP
+3. If argv[0] contains a forward slash, use portable mode.
+In this case, the files are named "current.heromeshrc" and "current.heromeshsession" in the directory where the executable file is found.
+.PP
+4. Otherwise, use home mode.