first commit

parse/const.go

@@ -0,0 +1,3 @@
+package parse
+
+const SIGNATURE = "PBDEMS2\x00"

parse/parse.go

@@ -0,0 +1,98 @@
+package parse
+
+import (
+	"bufio"
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/golang/snappy"
+	"github.com/olemorud/replay-parser/demo"
+	"google.golang.org/protobuf/proto"
+)
+
+type Frame struct {
+	Kind    uint64              `json:"kind"`    // see demo.proto
+	Tick    uint64              `json:"tick"`    // time elapsed in replay time
+	Size    uint64              `json:"size"`    // size of message in bytes
+	Message *demo.CDemoFileInfo `json:"message"` // protobuf encoded message (may be compressed with snappy)
+}
+
+// If kind has a certain bit set, the frame message is compressed
+// returns true if frame is compressed
+func isCompressed(frame *Frame) bool {
+	return (frame.Kind&uint64(demo.EDemoCommands_DEM_IsCompressed) != 0)
+}
+
+// Checks if file header is correct and returns number the address of the last frame
+func First(r *bufio.Reader) (uint64, error) {
+	// Check if first 8 bytes of file matches the source 2 replay file header
+	header := make([]byte, 8)
+	if _, err := io.ReadFull(r, header); err != nil {
+		return 0, fmt.Errorf("error when reading file: %v", err)
+	}
+	if string(header) != SIGNATURE {
+		return 0, fmt.Errorf("wrong file signature: %v, should be ", SIGNATURE)
+	}
+
+	// Read last frame
+	var offset uint32
+	err := binary.Read(r, binary.LittleEndian, &offset)
+	if err != nil {
+		return 0, fmt.Errorf("error reading number of frames in replay: %v", err)
+	}
+
+	/// remove later
+	println("size of demo is", offset, "frames")
+
+	return uint64(offset), nil
+}
+
+// Parses the next frame on the reader
+func DecodeNextFrame(r *bufio.Reader) (*Frame, error) {
+	// Read kind, tick, size and message
+	frame := new(Frame)
+	var err error
+
+	if frame.Kind, err = binary.ReadUvarint(r); err != nil {
+		return nil, fmt.Errorf("error reading frame kind for frame: %v", err)
+	}
+
+	if frame.Tick, err = binary.ReadUvarint(r); err != nil {
+		return nil, fmt.Errorf("error reading frame tick for frame: %v", err)
+	}
+
+	if frame.Size, err = binary.ReadUvarint(r); err != nil {
+		return nil, fmt.Errorf("error reading frame size for frame: %v", err)
+	}
+
+	message := make([]byte, frame.Size)
+	io.ReadFull(r, message)
+
+	frame.Message = new(demo.CDemoFileInfo)
+
+	if isCompressed(frame) {
+		decoded, err := snappy.Decode(nil, message)
+		if err != nil {
+			return nil, fmt.Errorf("error decoding message: %v", err)
+		}
+		fmt.Println("I got decompressed :O")
+		proto.Unmarshal(decoded, frame.Message)
+	} else {
+		proto.Unmarshal(message, frame.Message)
+	}
+
+	return frame, nil
+}
+
+// Reads every single frame (probably not very efficient)
+func DecodeAllFrames(r *bufio.Reader, frameCount uint64) ([]*Frame, error) {
+	replay := make([]*Frame, frameCount)
+
+	// Decode all frames and add them to *Frame slice
+	for i := 0; i < int(frameCount); i++ {
+		replay[i], _ = DecodeNextFrame(r)
+	}
+
+	return replay, nil
+}