复合二进制文档
复合二进制文档(CFBF),簡称复合文档,[1]英文全名 Composite Document File V2 Document[2],是微软开发、用於实现COM结构化存储的文件格式,用于把多个对象内容存放在同一个硬盘文件。[3][4][5]
Microsoft已经开放了这个文件格式。广泛用于Microsoft Word与Microsoft Access。也是Advanced Authoring Format的基础。[6]
文件结构
CFBF文件头部是512字节,随后跟着是保存数据的扇区。扇区的长度在文件头部指定,通常是512字节或4096字节。
CFBF的扇区类型:
- FAT扇区
- MiniFAT扇区:用于Mini-Stream
- Double-Indirect FAT (DIFAT)扇区 - 包含FAT扇区索引的链表数据
- Directory扇区
- Stream扇区 - 包含数据内容
- Range Lock扇区 - 包含大文件的上锁的字节范围
CFBF文件头
CFBF头是该文件的最前的512字节。对应于C语言数据结构为:
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扇区
每个FAT条目长度4字节,包含下个FAT链表条目的扇区号,或下述特定值:
- FREESECT (0xFFFFFFFF) - 未用扇区
- ENDOFCHAIN (0xFFFFFFFE) - FAT链表最后一个扇区
- FATSECT (0xFFFFFFFD) - 用于FAT数据存储
- DIFSECT (0xFFFFFFFC) - 用于DIFAT数据存储
词汇表
- FAT - 文件分配表,也称 SAT - 扇区分配表
- DIFAT - Double-Indirect File Allocation Table
- FAT Chain - 一群FAT条目指出分配给一个流的那些扇区
- Stream - 一个数据对象的内容
- Sector - 扇区,占据512或4096个字节
参见
参考文献
- ^ Apache POI - POIFS. POI Project. [10 May 2011]. (原始内容存档于2011-04-26).
- ^ How to convert documents between LibreOffice and Microsoft Office file formats on Linux. [25 Nov 2016]. (原始内容存档于2019-09-21).
- ^ Compound Files (Windows). Microsoft Developers Network (MSDN) library – COM SDK. Microsoft Corporation. 20 November 2008 [23 September 2009]. (原始内容存档于2016-03-07).
- ^ Containers: Compound Files. Microsoft Developers Network (MSDN) library – Visual Studio 2008 documentation. Microsoft Corporation. [23 September 2009]. (原始内容存档于2012-10-18).
- ^ Understand Compound Files. Microsoft Developers Network (MSDN) library – ActiveDirectory Rights Management. 25 June 2009 [23 September 2009]. (原始内容存档于2016-03-09).
- ^ AMW Association (formerly AAF Association) 互联网档案馆的存檔,存档日期15 August 2000.
外部链接
- Microsoft Compound Document File Format (PDF). OpenOffice.org CFBF description. [2006-05-22]. (原始内容存档 (PDF)于2011-10-12).
- Advanced Authoring Format Low-Level Container Specification (PDF). Microsoft Structured Storage version 3 specification (PDF). [2006-05-22]. (原始内容 (PDF)存档于2011-08-09).