git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@11701 f3b2605a-c512-4ea7-a41b-209d697bcdaa

src/force.cpp

@@ -780,6 +780,77 @@ bigint Force::bnumeric(const char *file, int line, char *str)
   return ATOLL(str);
 }
 
+/* ----------------------------------------------------------------------
+   open a potential file as specified by name; failing that,
+   search in dir specified by env variable LAMMPS_POTENTIALS
+------------------------------------------------------------------------- */
+
+FILE *Force::open_potential(const char *name)
+{
+  FILE *fp;
+
+  if (name == NULL) return NULL;
+
+  // attempt to open file directly
+  // if successful, return ptr
+
+  fp = fopen(name,"r");
+  if (fp) return fp;
+
+  // try the environment variable directory
+
+  const char *path = getenv("LAMMPS_POTENTIALS");
+  if (path == NULL) return NULL;
+
+  const char *pot = potname(name);
+  if (pot == NULL) return NULL;
+
+  size_t len1 = strlen(path);
+  size_t len2 = strlen(pot);
+  char *newpath = new char[len1+len2+2];
+
+  strcpy(newpath,path);
+#if defined(_WIN32)
+  newpath[len1] = '\\';
+  newpath[len1+1] = 0;
+#else
+  newpath[len1] = '/';
+  newpath[len1+1] = 0;
+#endif
+  strcat(newpath,pot);
+
+  fp = fopen(newpath,"r");
+  delete[] newpath;
+  return fp;
+}
+
+/* ----------------------------------------------------------------------
+   strip off leading part of path, return just the filename
+------------------------------------------------------------------------- */
+
+const char *Force::potname(const char *path)
+{
+  const char *pot;
+
+  if (path == NULL) return NULL;
+
+#if defined(_WIN32)
+  // skip over the disk drive part of windows pathnames
+  if (isalpha(path[0]) && path[1] == ':') 
+    path += 2;
+#endif
+
+  for (pot = path; *path != '\0'; ++path) {
+#if defined(_WIN32)
+    if ((*path == '\\') || (*path == '/')) pot = path + 1;
+#else
+    if (*path == '/') pot = path + 1;
+#endif
+  }
+
+  return pot;
+}
+
 /* ----------------------------------------------------------------------
    memory usage of force classes
 ------------------------------------------------------------------------- */