複合二進制文件
複合二進制文件（CFBF），簡稱複合文件，[1]英文全名 Composite Document File V2 Document[2]，是微軟開發、用於實現COM結構化儲存的檔案格式，用於把多個物件內容存放在同一個硬碟檔案。[3][4][5]
Microsoft已經開放了這個檔案格式。廣泛用於Microsoft Word與Microsoft Access。也是Advanced Authoring Format的基礎。[6]
檔案結構 編輯
CFBF檔案頭部是512位元組，隨後跟着是儲存數據的磁區。磁區的長度在檔案頭部指定，通常是512位元組或4096位元組。
CFBF的磁區類型:
- FAT磁區
- MiniFAT磁區：用於Mini-Stream
- Double-Indirect FAT （DIFAT）磁區 - 包含FAT磁區索引的鏈結串列數據
- Directory磁區
- Stream磁區 - 包含數據內容
- Range Lock磁區 - 包含大檔案的上鎖的位元組範圍
CFBF檔案頭 編輯
CFBF頭是該檔案的最前的512位元組。對應於C語言數據結構為：
typedef unsigned long ULONG; // 4 Bytes
typedef unsigned short USHORT; // 2 Bytes
typedef short OFFSET; // 2 Bytes
typedef ULONG SECT; // 4 Bytes
typedef ULONG FSINDEX; // 4 Bytes
typedef USHORT FSOFFSET; // 2 Bytes
typedef USHORT WCHAR; // 2 Bytes
typedef ULONG DFSIGNATURE; // 4 Bytes
typedef unsigned char BYTE; // 1 Byte
typedef unsigned short WORD; // 2 Bytes
typedef unsigned long DWORD; // 4 Bytes
typedef ULONG SID; // 4 Bytes
typedef GUID CLSID; // 16 Bytes
struct StructuredStorageHeader { // [offset from start (bytes), length (bytes)]
BYTE _abSig[8]; // [00H,08] {0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1,
// 0x1a, 0xe1} for current version
CLSID _clsid; // [08H,16] reserved must be zero (WriteClassStg/
// GetClassFile uses root directory class id)
USHORT _uMinorVersion; // [18H,02] minor version of the format: 33 is
// written by reference implementation
USHORT _uDllVersion; // [1AH,02] major version of the dll/format: 3 for
// 512-byte sectors, 4 for 4 KB sectors
USHORT _uByteOrder; // [1CH,02] 0xFFFE: indicates Intel byte-ordering
USHORT _uSectorShift; // [1EH,02] size of sectors in power-of-two;
// typically 9 indicating 512-byte sectors
USHORT _uMiniSectorShift; // [20H,02] size of mini-sectors in power-of-two;
// typically 6 indicating 64-byte mini-sectors
USHORT _usReserved; // [22H,02] reserved, must be zero
ULONG _ulReserved1; // [24H,04] reserved, must be zero
FSINDEX _csectDir; // [28H,04] must be zero for 512-byte sectors,
// number of SECTs in directory chain for 4 KB
// sectors
FSINDEX _csectFat; // [2CH,04] number of SECTs in the FAT chain
SECT _sectDirStart; // [30H,04] first SECT in the directory chain
DFSIGNATURE _signature; // [34H,04] signature used for transactions; must
// be zero. The reference implementation
// does not support transactions
ULONG _ulMiniSectorCutoff; // [38H,04] maximum size for a mini stream;
// typically 4096 bytes
SECT _sectMiniFatStart; // [3CH,04] first SECT in the MiniFAT chain
FSINDEX _csectMiniFat; // [40H,04] number of SECTs in the MiniFAT chain
SECT _sectDifStart; // [44H,04] first SECT in the DIFAT chain
FSINDEX _csectDif; // [48H,04] number of SECTs in the DIFAT chain
SECT _sectFat[109]; // [4CH,436] the SECTs of first 109 FAT sectors
};
FAT磁區 編輯
每個FAT條目長度4位元組，包含下個FAT鏈結串列條目的磁區號，或下述特定值：
- FREESECT (0xFFFFFFFF) - 未用磁區
- ENDOFCHAIN (0xFFFFFFFE) - FAT鏈結串列最後一個磁區
- FATSECT (0xFFFFFFFD) - 用於FAT數據儲存
- DIFSECT (0xFFFFFFFC) - 用於DIFAT數據儲存
詞彙表 編輯
- FAT - 檔案分配表，也稱 SAT - 磁區分配表
- DIFAT - Double-Indirect File Allocation Table
- FAT Chain - 一群FAT條目指出分配給一個流的那些磁區
- Stream - 一個數據物件的內容
- Sector - 磁區，佔據512或4096個位元組
參見 編輯
參考文獻 編輯
- ^ Apache POI - POIFS. POI Project. [10 May 2011]. （原始內容存檔於2011-04-26）.
- ^ How to convert documents between LibreOffice and Microsoft Office file formats on Linux. [25 Nov 2016]. （原始內容存檔於2019-09-21）.
- ^ Compound Files (Windows). Microsoft Developers Network (MSDN) library – COM SDK. Microsoft Corporation. 20 November 2008 [23 September 2009]. （原始內容存檔於2016-03-07）.
- ^ Containers: Compound Files. Microsoft Developers Network (MSDN) library – Visual Studio 2008 documentation. Microsoft Corporation. [23 September 2009]. （原始內容存檔於2012-10-18）.
- ^ Understand Compound Files. Microsoft Developers Network (MSDN) library – ActiveDirectory Rights Management. 25 June 2009 [23 September 2009]. （原始內容存檔於2016-03-09）.
- ^ AMW Association (formerly AAF Association) 互聯網檔案館的存檔，存檔日期15 August 2000.
外部連結 編輯
- Microsoft Compound Document File Format (PDF). OpenOffice.org CFBF description. [2006-05-22]. （原始內容存檔 (PDF)於2011-10-12）.
- Advanced Authoring Format Low-Level Container Specification (PDF). Microsoft Structured Storage version 3 specification (PDF). [2006-05-22]. （原始內容 (PDF)存檔於2011-08-09）.