From b9b1310346c8fe1d696d979c2dbc979030c8c128 Mon Sep 17 00:00:00 2001
From: Alex Yatskov <alex@foosoft.net>
Date: Sun, 16 Dec 2018 18:07:24 -0800
Subject: [PATCH] work in progress on getting dc6 files read in

---
 formats/dc6/dc6.go | 97 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

diff --git a/formats/dc6/dc6.go b/formats/dc6/dc6.go
index c751858..49c1fb6 100644
--- a/formats/dc6/dc6.go
+++ b/formats/dc6/dc6.go
@@ -1 +1,98 @@
 package dc6
+
+import (
+	"encoding/binary"
+	"io"
+)
+
+const (
+	FlagIsSerialized = 1 << iota
+	FlagIsLoadedInHw
+	FlagIs24Bits
+)
+
+type FileHeader struct {
+	Version      uint32
+	Flags        uint32
+	Format       uint32
+	SkipColor    uint32
+	DirCount     uint32
+	FramesPerDir uint32
+}
+
+type FrameHeader struct {
+	Flip      uint32
+	Width     uint32
+	Height    uint32
+	OffsetX   uint32
+	OffsetY   uint32
+	AllocSize uint32
+	NextBlock uint32
+	Block     uint32
+}
+
+type Frame struct {
+	Width   int
+	Height  int
+	OffsetX int
+	OffsetY int
+	Data    []byte
+}
+
+type Dc6 struct {
+	Frames []Frame
+}
+
+func New(reader io.ReadSeeker) (*Dc6, error) {
+	sprite := new(Dc6)
+
+	var fileHeader FileHeader
+	if err := binary.Read(reader, binary.LittleEndian, &fileHeader); err != nil {
+		return nil, err
+	}
+
+	var frameOffsets []uint32
+	for i := 0; i < int(fileHeader.DirCount*fileHeader.FramesPerDir); i++ {
+		var frameOffset uint32
+		if err := binary.Read(reader, binary.LittleEndian, &frameOffset); err != nil {
+			return nil, err
+		}
+
+		frameOffsets = append(frameOffsets, frameOffset)
+	}
+
+	for _, frameOffset := range frameOffsets {
+		var frameHeader FrameHeader
+		if _, err := reader.Seek(int64(frameOffset), io.SeekStart); err != nil {
+			return nil, err
+		}
+
+		if err := binary.Read(reader, binary.LittleEndian, &frameHeader); err != nil {
+			return nil, err
+		}
+
+		frame := Frame{
+			int(frameHeader.Width),
+			int(frameHeader.Height),
+			int(frameHeader.OffsetX),
+			int(frameHeader.OffsetY),
+			make([]byte, frameHeader.Width*frameHeader.Height),
+		}
+
+		if _, err := io.ReadFull(reader, frame.Data); err != nil {
+			return nil, err
+		}
+
+		if err := extractFrame(reader, frameHeader); err != nil {
+			return nil, err
+		}
+
+		sprite.Frames = append(sprite.Frames, frame)
+	}
+
+	return sprite, nil
+}
+
+func extractFrame(reader io.ReadSeeker, header FrameHeader) error {
+	return nil
+}