Function readHeader

factstore/simplecolumn.go:371–412

(scanner *bufio.Scanner)

}

func readHeader(scanner *bufio.Scanner) ([]ast.PredicateSym, []int, error) {
	if ok := scanner.Scan(); !ok {
		return nil, nil, ErrCouldNotRead
	}
	numPreds, err := strconv.Atoi(scanner.Text())
	if err != nil {
		return nil, nil, ErrCouldNotRead
	}
	if numPreds < 0 {
		return nil, nil, fmt.Errorf("invalid number of predicates %d: %w", numPreds, ErrWrongArgument)
	}
	if numPreds > maxNumPreds {
		return nil, nil, ErrTooManyPreds
	}
	preds := make([]ast.PredicateSym, numPreds)
	predNumFacts := make([]int, numPreds)
	for i := 0; i < numPreds; i++ {
		if ok := scanner.Scan(); !ok {
			return nil, nil, ErrCouldNotRead
		}
		var (
			name     string
			arity    int
			numFacts int
		)
		if _, err = fmt.Sscanf(scanner.Text(), "%s %d %d", &name, &arity, &numFacts); err != nil {
			return nil, nil, ErrCouldNotRead
		}
		if _, err := parse.PredicateName(name); err != nil {
			return nil, nil, fmt.Errorf("invalid name %q predicate %d: %w", name, i, ErrWrongArgument)
		}
		if arity < 0 || arity > maxArity {
			return nil, nil, fmt.Errorf("for predicate %v: %w", name, ErrUnsupportedArity)
		}
		if numFacts > maxFactsPerPredicate {
			return nil, nil, fmt.Errorf("for predicate %v: %w", name, ErrTooManyFacts)
		}
		preds[i] = ast.PredicateSym{name, arity}
		predNumFacts[i] = numFacts
	}
	return preds, predNumFacts, nil
}

// ReadInto reads contents in simplecolumn format into a fact store.
func (sc SimpleColumn) ReadInto(r io.Reader, store FactStore) error {