Method CalculateChecksum

neo/game/script/Script_Program.cpp:2060–2124

================ idProgram::CalculateChecksum ================ */

================
*/
int idProgram::CalculateChecksum( bool forOldSavegame ) const {
	int i, result;

	typedef struct {
		unsigned short	op;
		int				a;
		int				b;
		int				c;
		unsigned short	linenumber;
		unsigned short	file;
	} statementBlock_t;

	statementBlock_t	*statementList = new statementBlock_t[ statements.Num() ];

	memset( statementList, 0, ( sizeof(statementBlock_t) * statements.Num() ) );

	// DG hack: get the vardef for the argSize == 0 constant for savegame-compat
	int constantZeroNum = -1;
	if ( forOldSavegame ) {
		for( idVarDef* def = GetDefList( "<IMMEDIATE>" ); def != NULL; def = def->Next() ) {
			if ( def->Type() == ev_argsize && def->value.argSize == 0 ) {
				constantZeroNum = def->num;
				break;
			}
		}
	}

	// Copy info into new list, using the variable numbers instead of a pointer to the variable
	for( i = 0; i < statements.Num(); i++ ) {
		statementList[i].op = statements[i].op;

		if ( statements[i].a ) {
			statementList[i].a = statements[i].a->num;
		} else {
			statementList[i].a = -1;
		}
		if ( statements[i].b ) {
			statementList[i].b = statements[i].b->num;
		} else {
			statementList[i].b = -1;
		}
		if ( statements[i].c ) {
			// DG: old savegames wrongly assumed argSize 0 for some statements.
			//     So for the checksums to match we need to use the corresponding vardef num here
			//     See idCompiler::EmitFunctionParms() and ParseFunctionDef() for more details.
			if ( forOldSavegame && statements[i].op == OP_OBJECTCALL
			     && statements[i].flags == statement_t::FLAG_OBJECTCALL_IMPL_NOT_PARSED_YET ) {
				statementList[i].c = constantZeroNum;
			} else {
				statementList[i].c = statements[i].c->num;
			}
		} else {
			statementList[i].c = -1;
		}

		statementList[i].linenumber = statements[i].linenumber;
		statementList[i].file = statements[i].file;
	}