Initial commit

pkg/scan/scan.go

@@ -0,0 +1,58 @@
+package scan
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+
+	"google.golang.org/protobuf/encoding/protowire"
+)
+
+func ScanFile(path string) ([][]byte, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("Couldn't open file: %w", err)
+	}
+	return Scan(data), nil
+}
+
+func consumeBytes(data []byte, position int) int {
+	start := position
+	for {
+		_, _, len := protowire.ConsumeField(data[position:])
+		if len < 0 {
+			_ = protowire.ParseError(len)
+			return position - start
+
+		}
+		position += len
+	}
+}
+
+func Scan(data []byte) [][]byte {
+	results := make([][]byte, 0)
+
+	for {
+		index := bytes.Index(data, []byte(".proto"))
+		if index == -1 {
+			break
+		}
+
+		// Look for a 0xa byte: 0 0001 010
+		//                      ^ no more bytes for varint
+		//                           ^ field 1 (file name)
+		//                             ^ type 2 (LEN)
+		start := bytes.LastIndexByte(data[:index], 0xa)
+		if start == -1 {
+			// fmt.Printf("Warn: couldn't find start to proto definition at offset:0x%s\n", strconv.FormatInt(int64(index), 16))
+			data = data[index+1:]
+			continue
+		}
+
+		length := consumeBytes(data, start)
+		results = append(results, data[start:start+length])
+		data = data[start+length:]
+	}
+
+	return results
+}

pkg/scan/scan_test.go

@@ -0,0 +1 @@
+package scan