add render unicode in gemspec parser

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/cataloger/bundler/parse_gemspec.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"regexp"
+	"strconv"
 	"strings"
 
 	"github.com/mitchellh/mapstructure"
@@ -62,18 +63,15 @@ func parseGemSpecEntries(_ string, reader io.Reader) ([]pkg.Package, error) {
 	for scanner.Scan() {
 		line := scanner.Text()
 
-		// TODO: sanitize unicode? (see engine code)
 		sanitizedLine := strings.TrimSpace(line)
 		sanitizedLine = strings.ReplaceAll(sanitizedLine, ".freeze", "")
+		sanitizedLine = renderUtf8(sanitizedLine)
 
 		if sanitizedLine == "" {
 			continue
 		}
 
 		for field, pattern := range patterns {
-			if strings.Contains(sanitizedLine, "licenses") {
-				println("Found it.")
-			}
 			matchMap := matchCaptureGroups(pattern, sanitizedLine)
 			if value := matchMap[field]; value != "" {
 				if postProcessor := postProcessors[field]; postProcessor != nil {
@@ -106,6 +104,49 @@ func parseGemSpecEntries(_ string, reader io.Reader) ([]pkg.Package, error) {
 	return pkgs, nil
 }
 
+// renderUtf8 takes any string escaped string sub-sections from the ruby string and replaces those sections with the UTF8 runes.
+func renderUtf8(s string) string {
+	pattern := regexp.MustCompile(`\\u(?P<unicode>[0-9A-F]{4,8})`)
+	fullReplacement := replaceAllStringSubmatchFunc(pattern, s, func(unicodeSection []string) string {
+		replacement := ""
+		if len(unicodeSection) == 1 {
+			return unicodeSection[0]
+		}
+		for idx, m := range unicodeSection {
+			if idx == 0 {
+				continue
+			}
+			value, err := strconv.ParseInt(m, 16, 64)
+			if err != nil {
+				// TODO: log?
+				panic(err)
+				//return unicodeSection[0]
+			}
+			replacement = strings.ReplaceAll(unicodeSection[0], "\\u"+m, string(rune(value)))
+		}
+		return replacement
+	})
+	return fullReplacement
+}
+
+// replaceAllStringSubmatchFunc finds and replaces the given capture groups from the
+func replaceAllStringSubmatchFunc(re *regexp.Regexp, str string, repl func([]string) string) string {
+	result := ""
+	lastIndex := 0
+
+	for _, v := range re.FindAllSubmatchIndex([]byte(str), -1) {
+		var groups []string
+		for i := 0; i < len(v); i += 2 {
+			groups = append(groups, str[v[i]:v[i+1]])
+		}
+
+		result += str[lastIndex:v[0]] + repl(groups)
+		lastIndex = v[1]
+	}
+
+	return result + str[lastIndex:]
+}
+
 // matchCaptureGroups takes a regular expression and string and returns all of the named capture group results in a map.
 func matchCaptureGroups(regEx *regexp.Regexp, str string) map[string]string {
 	match := regEx.FindStringSubmatch(str)