+/// ParseCStringVector - Break INPUT up wherever one or more
+/// whitespace characters are found, and store the resulting tokens in
+/// OUTPUT. The tokens stored in OUTPUT are dynamically allocated
+/// using strdup (), so it is the caller's responsibility to free ()
+/// them later.
+///
+static void ParseCStringVector(std::vector<char *> &output,
+ const char *input) {
+ // Characters which will be treated as token separators:
+ static const char *delims = " \v\f\t\r\n";
+
+ std::string work (input);
+ // Skip past any delims at head of input string.
+ size_t pos = work.find_first_not_of (delims);
+ // If the string consists entirely of delims, then exit early.
+ if (pos == std::string::npos) return;
+ // Otherwise, jump forward to beginning of first word.
+ work = work.substr (pos);
+ // Find position of first delimiter.
+ pos = work.find_first_of (delims);
+
+ while (!work.empty() && pos != std::string::npos) {
+ // Everything from 0 to POS is the next word to copy.
+ output.push_back (strdup (work.substr (0,pos).c_str ()));
+ // Is there another word in the string?
+ size_t nextpos = work.find_first_not_of (delims, pos + 1);
+ if (nextpos != std::string::npos) {
+ // Yes? Then remove delims from beginning ...
+ work = work.substr (work.find_first_not_of (delims, pos + 1));
+ // and find the end of the word.
+ pos = work.find_first_of (delims);
+ } else {
+ // No? (Remainder of string is delims.) End the loop.
+ work = "";
+ pos = std::string::npos;
+ }
+ }
+
+ // If `input' ended with non-delim char, then we'll get here with
+ // the last word of `input' in `work'; copy it now.
+ if (!work.empty ()) {
+ output.push_back (strdup (work.c_str ()));
+ }
+}
+
+/// ParseEnvironmentOptions - An alternative entry point to the
+/// CommandLine library, which allows you to read the program's name
+/// from the caller (as PROGNAME) and its command-line arguments from
+/// an environment variable (whose name is given in ENVVAR).
+///
+void cl::ParseEnvironmentOptions(const char *progName, const char *envVar,
+ const char *Overview) {
+ // Check args.
+ assert(progName && "Program name not specified");
+ assert(envVar && "Environment variable name missing");
+
+ // Get the environment variable they want us to parse options out of.
+ const char *envValue = getenv(envVar);
+ if (!envValue)
+ return;
+
+ // Get program's "name", which we wouldn't know without the caller
+ // telling us.
+ std::vector<char*> newArgv;
+ newArgv.push_back(strdup(progName));
+
+ // Parse the value of the environment variable into a "command line"
+ // and hand it off to ParseCommandLineOptions().
+ ParseCStringVector(newArgv, envValue);
+ int newArgc = newArgv.size();
+ ParseCommandLineOptions(newArgc, &newArgv[0], Overview);
+
+ // Free all the strdup()ed strings.
+ for (std::vector<char*>::iterator i = newArgv.begin(), e = newArgv.end();
+ i != e; ++i)
+ free (*i);
+}
+
+void cl::ParseCommandLineOptions(int argc, char **argv,