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2.2.2.7.1 PAGETRAILER

Office

A PAGETRAILER structure contains information about the page in which it is contained. PAGETRAILER structure is present at the very end of each page in a PST file.

Unicode:


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ptype

ptypeRepeat

wSig

dwCRC

bid

...

ANSI:


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ptype

ptypeRepeat

wSig

bid

dwCRC

ptype (1 byte): This value indicates the type of data contained within the page. This field MUST contain one of the following values.

Value

Friendly name

Meaning

wSig value

0x80

ptypeBBT

Block BTree page.

Block or page signature (section 5.5).

0x81

ptypeNBT

Node BTree page.

Block or page signature (section 5.5).

0x82

ptypeFMap

Free Map page.

0x0000

0x83

ptypePMap

Allocation Page Map page.

0x0000

0x84

ptypeAMap

Allocation Map page.

0x0000

0x85

ptypeFPMap

Free Page Map page.

0x0000

0x86

ptypeDL

Density List page.

Block or page signature (section 5.5).

ptypeRepeat (1 byte): MUST be set to the same value as ptype.

wSig (2 bytes): Page signature. This value depends on the value of the ptype field. This value is zero (0x0000) for AMap, PMap, FMap, and FPMap pages. For BBT, NBT, and DList pages, a page / block signature is computed (see section 5.5).

dwCRC (4 bytes): 32-bit CRC of the page data, excluding the page trailer. See section 5.3 for the CRC algorithm. Note the locations of the dwCRC and bid are differs between the Unicode and ANSI version of this structure.

bid (Unicode: 8 bytes; ANSI 4 bytes): The BID of the page's block. AMap, PMap, FMap, and FPMap pages have a special convention where their BID is assigned the same value as their IB (that is, the absolute file offset of the page). The bidIndex for other page types are allocated from the special bidNextP counter in the HEADER structure.

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