source: trunk/source/geometry/solids/test/SBT/src/G4UIcmdPargList.cc @ 1316

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//
//
// G4UIcmdPargList.cc
//
// Implementation of a (generic) list argument for G4UIcmdWithPargs
//

#include "G4UIcmdPargList.hh"

#include <sstream>
#include <iomanip>

//
// Constructor
//
G4UIcmdPargList::G4UIcmdPargList( const  G4String &theName, G4int theMaxItem ) 
                : G4UIcmdParg( theName )
{
        nItem = 0;
        maxItem = theMaxItem;
}


//
// Fetch argument value from input stream
//
std::istream &G4UIcmdPargList::FetchValue( std::istream &istr )
{
        //
        // Because of limitations of G4UIcommand, we must avoid
        // requiring any spaces.
        //
        // Require '(' to be the leading character, and read in
        // character strings until ',' or ')' are found. If the
        // latter is found, input is terminated.
        //
        // In actual usage, we expect leading blanks to be removed
        // before this method is invoked,
        // but there is no need to assume that.
        //
        // Notice that blank items are allowed. It is up to decendent
        // classes to decide what to do in this case. To allow an
        // empty list (i.e. no items, nItem==0), the special symbol
        // "-" is reserved.
        //
        char buffer[256];       // Buffer for each item
        char a;                 // Single character input
        
        //
        // Remove leading blanks
        //
        do {
                istr.get(a);
                if (istr.fail()) return istr;
        } while( a == ' ' );
        
        //
        // Check for empty list ( '-', followed by EOF or blank)
        //
        if (a == '-') {
                istr.get(a);
                if (istr.fail() || a == ' ') {
                        nItem = 0;
                        return istr;
                }
        }
                
        
        //
        // Otherwise: Insist argument begin with a '('
        //
        if (a != '(') {
                G4cerr << "Listed argument must begin with '(' or consist of only '-'" << G4endl;
                istr.clear(std::ios::failbit|istr.rdstate());   // Is there a better way to do this???
                return istr;
        }

        //
        // Loop over items in argument
        //
        G4int nItemFetched = 0;
        do {
                //
                // Next item
                //
                char *b = buffer;
                for(;;) {
                        //
                        // Next character
                        //
                        istr.get(*b);
                        if (istr.fail()) return istr;
                        
                        //
                        // Check for delimiter
                        //
                        if (*b == ',' || *b == ')') {
                                a = *b;         // Remember 
                                *b = '\0';
                                break;
                        }
                        
                        //
                        // Go to next character
                        //
                        if (++b > buffer+255) {
                                G4cerr << "Listed argument item must be less than 255 characters" << G4endl;
                                istr.clear(std::ios::failbit|istr.rdstate());
                                return istr;
                        }
                } 
                
                //
                // Interpret
                //
                if (nItemFetched >= maxItem) {
                        G4cerr << "Maximum of " << maxItem << " items exceeded in listed argument" << G4endl;
                        istr.clear(std::ios::failbit|istr.rdstate());
                        return istr;
                }
                
                if (!FetchItem( buffer, nItemFetched++ )) {
                        istr.clear(std::ios::failbit|istr.rdstate());
                        return istr;
                }
        } while( a == ',' );
        
        //
        // Set nItem only on success
        //
        nItem = nItemFetched;
        
        return istr;
}


//
// ConvertToString
//
G4String G4UIcmdPargList::ConvertToString()
{
        //
        // Empty case
        //
        if (nItem == 0) return "-";
        
        //
        // Allocate a buffer, big enough to hold all items plus
        // a command and '()'. Each item is allowed to take 255 
        // characters.
        //
        // buffSize = 255*nItem+4;
        
        std::ostringstream os;
        
        //
        // Write out everything in turn
        //
        os << '(';
        
        G4int item;
        for( item=0; item<nItem; item++) {
                if (item) os << ',';
                if (!WriteItem(os,item)) return "(error)";
        }
        
        os << ')';
        
        //
        // Convert to G4String
        //
        G4String answer = os.str();
                
        //
        // Return G4String
        //
        return answer;
}