src/components/DiskInfo.vue

@@ -13,10 +13,6 @@ const floppyDisk = computed(() => {
   <section v-if="floppyDisk.bootSectorInfo">
     <h3>Boot Sector</h3>
     <pre>{{ floppyDisk.bootSectorInfo }}</pre>
-    <h3>Root Dir</h3>
-    <pre>{{ floppyDisk.rootDirEntries }}</pre>
-    <h3>Data</h3>
-    <pre>Offset: {{ floppyDisk.dataOffset }}</pre>
   </section>
 </template>
 

src/floppy/disk.ts

@@ -30,38 +30,6 @@ export interface IBiosParameterBlock {
   totalSectorsLarge: number
 }
 
-export interface IAttributes {
-  readOnly: boolean
-  hidden: boolean
-  system: boolean
-  volumeId: boolean
-  directory: boolean
-  archive: boolean
-}
-
-export interface IStandardDirEntry {
-  type: 'standard-entry'
-  name: string
-  extension: string
-  attributes: IAttributes
-  size: number
-  firstCluster: number
-}
-
-export interface ILongFileNameDirEntry {
-  type: 'long-filename-entry'
-}
-
-export interface IFinalDirEntry {
-  type: 'final-entry'
-}
-
-export interface IUnusedDirEntry {
-  type: 'unused-entry'
-}
-
-export type DirEntry = IStandardDirEntry | ILongFileNameDirEntry | IFinalDirEntry | IUnusedDirEntry
-
 export class FloppyDisk {
   private readonly _buffer = new ArrayBuffer(0)
   private _bootSector: IBootSectorInfo | null = null
@@ -70,87 +38,18 @@ export class FloppyDisk {
     this._buffer = buffer
   }
 
-  private _rootDirEntries: DirEntry[] | null = null
-
-  get rootDirEntries() {
-    if (this._rootDirEntries === null) {
-      const offset = this.rootDirOffset
-      const size = this.rootDirSize
-
-      const end = offset + size
-
-      if (this._buffer.byteLength >= end) {
-        this._rootDirEntries = decodeDirectoryEntries(
-          new DataView(this._buffer, this.rootDirOffset, this.rootDirSize),
-        )
-      }
-    }
-    return this._rootDirEntries
-  }
-
   get bootSectorInfo() {
-    if (this._buffer.byteLength < 512) {
+    return (this._bootSector = this._bootSector ?? decodeBootSector(this._buffer))
-      return null
-    }
-    return (this._bootSector =
-      this._bootSector ?? decodeBootSector(new DataView(this._buffer, 0, 512)))
-  }
-
-  get tableSize() {
-    return this.bootSectorInfo?.biosParameterBlock?.sectorsPerTableSmall ?? 0
-  }
-
-  get rootEntryCount() {
-    return this.bootSectorInfo?.biosParameterBlock?.rootEntryCount ?? 0
-  }
-
-  get tableCount() {
-    return this.bootSectorInfo?.biosParameterBlock?.tableCount ?? 0
-  }
-
-  get reservedSectorCount() {
-    return this.bootSectorInfo?.biosParameterBlock?.reservedSectorCount ?? 0
-  }
-
-  get bytesPerSector() {
-    return this.bootSectorInfo?.biosParameterBlock?.bytesPerSector ?? 0
-  }
-
-  get rootDirSectors() {
-    if (this.bytesPerSector === 0) {
-      return 0
-    } else {
-      return Math.ceil((this.rootEntryCount * 32) / this.bytesPerSector)
   }
 }
 
-  get firstDataSector() {
+function decodeBootSector(buffer: ArrayBuffer): IBootSectorInfo | null {
-    return this.reservedSectorCount + this.tableCount * this.tableSize + this.rootDirSectors
+  if (buffer.byteLength < 512) {
-  }
-
-  get dataOffset() {
-    return this.firstDataSector * this.bytesPerSector
-  }
-
-  get firstRootDirSector() {
-    return this.firstDataSector - this.rootDirSectors
-  }
-
-  get rootDirOffset() {
-    return this.firstRootDirSector * this.bytesPerSector
-  }
-
-  get rootDirSize() {
-    return this.rootDirSectors * this.bytesPerSector
-  }
-}
-
-function decodeBootSector(data: DataView): IBootSectorInfo | null {
-  if (data.byteLength < 512) {
     return null
   }
 
   const asciiDecoder = new TextDecoder('ascii')
+  const data = new DataView(buffer)
 
   const jumpInstruction: [number, number, number] = [
     data.getUint8(0),
@@ -158,7 +57,7 @@ function decodeBootSector(data: DataView): IBootSectorInfo | null {
     data.getUint8(2),
   ]
 
-  const oemName = asciiDecoder.decode(data.buffer.slice(3, 11))
+  const oemName = asciiDecoder.decode(buffer.slice(3, 11))
   const bytesPerSector = data.getUint16(11, true)
   const sectorsPerCluster = data.getUint8(13)
   const reservedSectorCount = data.getUint16(14, true)
@@ -182,12 +81,12 @@ function decodeBootSector(data: DataView): IBootSectorInfo | null {
 
   let volumeLabel
   if (bootSignature === 0x29) {
-    volumeLabel = asciiDecoder.decode(data.buffer.slice(43, 54))
+    volumeLabel = asciiDecoder.decode(buffer.slice(43, 54))
   }
 
   let fileSystemType
   if (bootSignature === 0x29) {
-    fileSystemType = asciiDecoder.decode(data.buffer.slice(54, 62))
+    fileSystemType = asciiDecoder.decode(buffer.slice(54, 62))
   }
 
   const bootPartitionSignature = data.getUint16(510, true)
@@ -220,72 +119,3 @@ function decodeBootSector(data: DataView): IBootSectorInfo | null {
     },
   }
 }
-
-function decodeDirectoryEntry(data: DataView): DirEntry | null {
-  if (data.byteLength < 32) {
-    return null
-  }
-
-  const firstByte = data.getUint8(0)
-  const attributeByte = data.getUint8(11)
-
-  if (firstByte === 0) {
-    return { type: 'final-entry' }
-  } else if (firstByte === 0xe5) {
-    return { type: 'unused-entry' }
-  } else if (attributeByte === 0x0f) {
-    return { type: 'long-filename-entry' }
-  } else {
-    const asciiDecoder = new TextDecoder('ascii')
-    const name = asciiDecoder.decode(data.buffer.slice(data.byteOffset, data.byteOffset + 8))
-    const extension = asciiDecoder.decode(
-      data.buffer.slice(data.byteOffset + 8, data.byteOffset + 11),
-    )
-
-    const attributeByte = data.getUint8(11)
-
-    const attributes: IAttributes = {
-      readOnly: (attributeByte & 0x01) !== 0,
-      hidden: (attributeByte & 0x02) !== 0,
-      system: (attributeByte & 0x04) !== 0,
-      volumeId: (attributeByte & 0x08) !== 0,
-      directory: (attributeByte & 0x10) !== 0,
-      archive: (attributeByte & 0x20) !== 0,
-    }
-
-    const firstCluster = (data.getUint16(20, true) << 16) | data.getUint16(26, true)
-    const size = data.getUint32(28, true)
-
-    return {
-      type: 'standard-entry',
-      name,
-      extension,
-      attributes,
-      firstCluster,
-      size,
-    }
-  }
-}
-
-function decodeDirectoryEntries(data: DataView): DirEntry[] {
-  const entries: DirEntry[] = []
-
-  let offset = 0
-  while (data.byteLength - offset >= 32) {
-    const dirData = new DataView(data.buffer, data.byteOffset + offset, 32)
-    offset += 32
-
-    const entry = decodeDirectoryEntry(dirData)
-    if (entry === null) {
-      break
-    }
-
-    entries.push(entry)
-
-    if (entry.type === 'final-entry') {
-      break
-    }
-  }
-
-  return entries
-}