Extract scanning ASCII files into a util package

internal/util/asciiscan/asciiscan.go

@@ -0,0 +1,90 @@
+// package asciiscan is used to parse plaintext files into structured data
+package asciiscan
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"os"
+	"strconv"
+)
+
+var hashComment = []byte("#")
+
+type Scanner struct {
+	bufio  *bufio.Scanner
+	closer io.Closer
+}
+
+func New(filename string) (*Scanner, error) {
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Scanner{
+		bufio:  bufio.NewScanner(f),
+		closer: f,
+	}, nil
+}
+
+func (s *Scanner) Bufio() *bufio.Scanner {
+	return s.bufio
+}
+
+func (s *Scanner) Close() error {
+	return s.closer.Close()
+}
+
+func (s *Scanner) ConsumeString() (string, error) {
+	for s.bufio.Scan() {
+		line := s.bufio.Bytes()
+
+		if len(line) == 0 || line[0] == hashComment[0] { // Most .dat files use # for comments
+			continue
+		}
+
+		comment := bytes.Index(line, hashComment)
+		if comment > 0 {
+			line = line[0:comment]
+		}
+
+		return string(bytes.TrimRight(line, "\r\n\t ")), nil
+	}
+
+	err := s.bufio.Err()
+	if err == nil {
+		return "", io.EOF
+	}
+
+	return "", err
+}
+
+func (s *Scanner) ConsumeInt() (int, error) {
+	str, err := s.ConsumeString()
+	if err != nil {
+		return 0, err
+	}
+
+	return strconv.Atoi(str)
+}
+
+func (s *Scanner) ConsumeIntPtr(to *int) error {
+	val, err := s.ConsumeInt()
+	if err != nil {
+		return err
+	}
+
+	*to = val
+	return nil
+}
+
+func (s *Scanner) ConsumeIntPtrs(ptrs ...*int) error {
+	for _, ptr := range ptrs {
+		if err := s.ConsumeIntPtr(ptr); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}