1 files changed, 161 insertions, 0 deletions
diff --git a/tvloader/reader/reader.go b/tvloader/reader/reader.go
new file mode 100644
index 0000000..786f7ea
--- /dev/null
+++ b/tvloader/reader/reader.go
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+
+package reader
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strings"
+	"unicode"
+)
+
+// TagValuePair is a convenience struct for a (tag, value) string pair.
+type TagValuePair struct {
+	Tag   string
+	Value string
+}
+
+// ReadTagValues takes an io.Reader, scans it line by line and returns
+// a slice of {string, string} structs in the form {tag, value}.
+func ReadTagValues(content io.Reader) ([]TagValuePair, error) {
+	r := &tvReader{}
+
+	scanner := bufio.NewScanner(content)
+	for scanner.Scan() {
+		// read each line, one by one
+		err := r.readNextLine(scanner.Text())
+		if err != nil {
+			return nil, err
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	// finalize and make sure all is well
+	tvList, err := r.finalize()
+	if err != nil {
+		return nil, err
+	}
+
+	// convert internal format to exported TagValueList
+	var exportedTVList []TagValuePair
+	for _, tv := range tvList {
+		tvPair := TagValuePair{Tag: tv.tag, Value: tv.value}
+		exportedTVList = append(exportedTVList, tvPair)
+	}
+
+	return exportedTVList, nil
+}
+
+type tagvalue struct {
+	tag   string
+	value string
+}
+
+type tvReader struct {
+	midtext      bool
+	tvList       []tagvalue
+	currentLine  int
+	currentTag   string
+	currentValue string
+}
+
+func (reader *tvReader) finalize() ([]tagvalue, error) {
+	if reader.midtext {
+		return nil, fmt.Errorf("finalize called while still midtext parsing a text tag")
+	}
+	return reader.tvList, nil
+}
+
+func (reader *tvReader) readNextLine(line string) error {
+	reader.currentLine++
+
+	if reader.midtext {
+		return reader.readNextLineFromMidtext(line)
+	}
+
+	return reader.readNextLineFromReady(line)
+}
+
+func (reader *tvReader) readNextLineFromReady(line string) error {
+	// strip whitespace from beginning of line
+	line2 := strings.TrimLeftFunc(line, func(r rune) bool {
+		return unicode.IsSpace(r)
+	})
+
+	// ignore empty lines
+	if line2 == "" {
+		return nil
+	}
+
+	// ignore comment lines
+	if strings.HasPrefix(line2, "#") {
+		return nil
+	}
+
+	// split at colon
+	substrings := strings.SplitN(line2, ":", 2)
+	if len(substrings) == 1 {
+		// error if a colon isn't found
+		return fmt.Errorf("no colon found in '%s'", line)
+	}
+
+	// the first substring is the tag
+	reader.currentTag = strings.TrimSpace(substrings[0])
+
+	// determine whether the value contains (or starts) a <text> line
+	substrings = strings.SplitN(substrings[1], "<text>", 2)
+	if len(substrings) == 1 {
+		// no <text> tag found means this is a single-line value
+		// strip whitespace and use as a single line
+		reader.currentValue = strings.TrimSpace(substrings[0])
+	} else {
+		// there was a <text> tag; now decide whether it's multi-line
+		substrings = strings.SplitN(substrings[1], "</text>", 2)
+		if len(substrings) > 1 {
+			// there is also a </text> tag; take the middle part and
+			// set as value
+			reader.currentValue = substrings[0]
+		} else {
+			// there is no </text> tag on this line; switch to midtext
+			reader.currentValue = substrings[0] + "\n"
+			reader.midtext = true
+			return nil
+		}
+	}
+
+	// if we got here, the value was on a single line
+	// so go ahead and add it to the tag-value list
+	tv := tagvalue{reader.currentTag, reader.currentValue}
+	reader.tvList = append(reader.tvList, tv)
+
+	// and reset
+	reader.currentTag = ""
+	reader.currentValue = ""
+
+	return nil
+}
+
+func (reader *tvReader) readNextLineFromMidtext(line string) error {
+	// look for whether the line closes here
+	substrings := strings.SplitN(line, "</text>", 2)
+	if len(substrings) == 1 {
+		// doesn't contain </text>, so keep building the current value
+		reader.currentValue += line + "\n"
+		return nil
+	}
+
+	// contains </text>, so end and record this pair
+	reader.currentValue += substrings[0]
+	tv := tagvalue{reader.currentTag, reader.currentValue}
+	reader.tvList = append(reader.tvList, tv)
+
+	// and reset
+	reader.midtext = false
+	reader.currentTag = ""
+	reader.currentValue = ""
+
+	return nil
+}