From c2a6fc7fa37b52065f458921b633a46563377214 Mon Sep 17 00:00:00 2001
From: Zorchenhimer <zorchenhimer@gmail.com>
Date: Fri, 12 Dec 2025 23:37:13 -0500
Subject: [PATCH] Add the 0x05 block type; Remove --extract from fdslist

- Block type 0x05 is some weird test pattern thing???
- Removed --extract from the fdslist utility
---
 blocks.go      | 19 +++++++++++++++++++
 cmd/fdslist.go | 46 +++++++++++++++++++++-------------------------
 reader.go      | 28 +++++++++++++++++++++++++++-
 3 files changed, 67 insertions(+), 26 deletions(-)

diff --git a/blocks.go b/blocks.go
index 0a79104..379399e 100644
--- a/blocks.go
+++ b/blocks.go
@@ -2,6 +2,7 @@ package fds
 
 import (
 	"fmt"
+	"strings"
 )
 
 type BlockType byte
@@ -11,6 +12,7 @@ const (
 	BtFileAmount BlockType = 0x02
 	BtFileHeader BlockType = 0x03
 	BtFileData   BlockType = 0x04
+	BtTest       BlockType = 0x05
 )
 
 func (bt BlockType) String() string {
@@ -192,3 +194,20 @@ func (b *BlockFileData) Type() BlockType {
 func (b *BlockFileData) String() string {
 	return "BlockFileData"
 }
+
+type BlockTest struct {
+	Raw []byte
+}
+
+func (b *BlockTest) Type() BlockType {
+	return BtTest
+}
+
+func (b *BlockTest) String() string {
+	bytes := []string{}
+	for _, byt := range b.Raw {
+		bytes = append(bytes, fmt.Sprintf("$%02X", byt))
+	}
+	return fmt.Sprintf("BlockTest Raw:[%s]", strings.Join(bytes, " "))
+}
+
diff --git a/cmd/fdslist.go b/cmd/fdslist.go
index 7e25e1d..a208c5d 100644
--- a/cmd/fdslist.go
+++ b/cmd/fdslist.go
@@ -3,10 +3,6 @@ package main
 import (
 	"fmt"
 	"os"
-	//"encoding/binary"
-	//"bufio"
-	//"bytes"
-	//"io"
 	"path/filepath"
 
 	"github.com/alexflint/go-arg"
@@ -16,7 +12,8 @@ import (
 
 type Arguments struct {
 	Input string `arg:"positional,required"`
-	Extract string `arg:"--extract" help:"Extract files to the given directory"`
+
+	Blocks bool `arg:"--blocks"`
 }
 
 
@@ -32,6 +29,25 @@ func main() {
 }
 
 func run(args *Arguments) error {
+	if args.Blocks {
+		file, err := os.Open(args.Input)
+		if err != nil {
+			return err
+		}
+		defer file.Close()
+
+		blocks, err := fds.ReadRomBlocks(file, filepath.Ext(args.Input) == ".fds")
+		if err != nil {
+			return err
+		}
+
+		for _, block := range blocks {
+			fmt.Println(block.String())
+		}
+
+		return nil
+	}
+
 	rom, err := fds.ReadRomFile(args.Input)
 	if err != nil {
 		return err
@@ -39,26 +55,6 @@ func run(args *Arguments) error {
 
 	fmt.Println(rom.Info())
 
-	if args.Extract != "" {
-		err = os.MkdirAll(args.Extract, 0775)
-		if err != nil {
-			return err
-		}
-
-		num := 0
-		for _, side := range rom.Sides {
-			sideName := fmt.Sprintf("Side%d", side.Header.PhysicalSide)
-			for _, file := range side.Files {
-				fileName := filepath.Join(args.Extract, fmt.Sprintf("%03d_%s_%02d_%02X", num, sideName, file.Number, file.Id))
-				err := os.WriteFile(fileName, file.Data, 0664)
-				if err != nil {
-					return err
-				}
-				num++
-			}
-		}
-	}
-
 	return nil
 }
 
diff --git a/reader.go b/reader.go
index a03186a..55e6e3b 100644
--- a/reader.go
+++ b/reader.go
@@ -52,6 +52,7 @@ func ReadBlocks(r io.Reader, IsFds bool) ([]DiskBlock, error) {
 
 	reader := bufio.NewReader(r)
 
+	outerLoop:
 	for {
 		raw, err := reader.Peek(1)
 		if err != nil {
@@ -79,6 +80,31 @@ func ReadBlocks(r io.Reader, IsFds bool) ([]DiskBlock, error) {
 			// variable length
 			readLen = dataSize+3
 
+		case 0x05: // some weird test block??
+			reader.Discard(1)
+			bt := &BlockTest{}
+			for {
+				b, err := reader.ReadByte()
+				if err != nil {
+					if err == io.EOF {
+						blocks = append(blocks, bt)
+						break outerLoop
+					}
+					return blocks, fmt.Errorf("error reading 0x05 block type: %w", err)
+				}
+
+				switch b {
+				case 0x6D, 0xB6, 0xDB:
+					bt.Raw = append(bt.Raw, b)
+					continue
+				case 0x00:
+					blocks = append(blocks, bt)
+					continue outerLoop
+				}
+
+				return blocks, fmt.Errorf("Read unknown byte in 0x05 block: 0x%02X", b)
+			}
+
 		case 0x00:
 			reader.Discard(1)
 			continue
@@ -144,9 +170,9 @@ func ReadBlocks(r io.Reader, IsFds bool) ([]DiskBlock, error) {
 			db.Data = buf[1:readLen]
 			//fmt.Println("len(db.Data)", len(db.Data))
 			block = db
-			//fmt.Printf("Block:%#v\n", block)
 		}
 
+		//fmt.Printf("Block:%s\n", block.String())
 		blocks = append(blocks, block)
 	}