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（英語：Advanced Authoring Format）的基礎。^[6]

檔案結構

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

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

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

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

COM結構化儲存

參考文獻

^ 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

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）.

[1] Apache POI - POIFS. POI Project. [10 May 2011]. （原始內容存檔於2011-04-26）.

[2] 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）.

[3] 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）.

[4] 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）.

[5] 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）.

[6] AMW Association (formerly AAF Association) 互聯網檔案館的存檔，存檔日期15 August 2000.

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