file structure can be divided into four areas:
1, first. Using a text editor to open when you will see:% PDF-1.4 such a word, the last of which is a PDF file format version number, software version number than the total file format version number of the high-1, for example, Read 5 content is able to open 4.
2, document body. There are a number of obj to form, OBJ this form:
30979 0 obj
<<
/ Linearized 1
/ O 30982
/ H [15061 25084]
/ L 9379963
/ E 166967
/ N 978
/ T 8760262
>>
Endobj
The first number is the sequence number of the OBJ, xref in order to facilitate the search, the latter in order to distinguish between different 0 of OBJ, the back is the keyword obj. Below the line is the attribute / value form of keywords.
3. Index Table.
Obj index used in the document all the starting position, its form is:
Xref
0 211
0000000000 65535 f
0000000009 00000 n
... ...
0000087999 00000 n
4, paper tail.
Trailer
<<
/ Size 211
/ Root 2 0 R
/ Info 1 0 R
/ ID [ ]
>>
Startxref
88019
%% EOF
0211 on behalf of one of the xref of the initiation and termination of obj serial number. Where 0 is estimated that this process is to add a good deal so that (the level of individuals not in English, some places do not understand), can not join this. Below the line on behalf of all obj files in the start position, the first string of characters (10) on behalf of the initial position, the middle of the five characters is also used to distinguish between, we have the whole of 0, followed by the letters f on behalf of the deletion of two of the, n to be used on behalf of. Behind the trailer is a summary of the entire xref shows how many there are OBJ, Reading OBJ from which to start analysis, information such as node, ID is to enable a number of document search tools can only distinguish between documents.