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Detailed Description

This macro displays the physical ROOT file structure.

pict1_file.py.png
1 
2 from ROOT import TCanvas, TPaveLabel, TPave, TLine, TArrow, TText, TPaveText
3 from ROOT import gROOT
4 
5 c1 = TCanvas( 'c1', 'ROOT File description', 200, 10, 700, 550 )
6 
7 c1.Range( 0, -0.25, 21, 14 )
8 title = TPaveLabel( 5, 12, 15, 13.7, c1.GetTitle() )
9 title.SetFillColor( 16 )
10 title.Draw()
11 
12 # horizonthal file layout
13 file = TPave( 1, 8.5, 20, 11 )
14 file.SetFillColor( 11 )
15 file.Draw()
16 fileh = TPave( 1, 8.5, 2.5, 11 )
17 fileh.SetFillColor( 44 )
18 fileh.Draw()
19 lrh = TPave( 2.5, 8.5, 3.3, 11, 1 )
20 lrh.SetFillColor( 33 )
21 lrh.Draw()
22 lrh.DrawPave( 6.9, 8.5, 7.7, 11, 1 )
23 lrh.DrawPave( 10.5, 8.5, 11.3, 11, 1 )
24 lrh.DrawPave( 14.5, 8.5, 15.3, 11, 1 )
25 ldot = TLine( 1, 8.5, 0.5, 6.5 )
26 ldot.SetLineStyle( 2 )
27 ldot.Draw()
28 ldot.DrawLine( 2.5, 8.5, 9.4, 6.5 )
29 ldot.DrawLine( 10.5, 8.5, 10, 6.5 )
30 ldot.DrawLine( 11.3, 8.5, 19.5, 6.5 )
31 line = TLine( 2.6, 11, 2.6, 11.5 )
32 line.Draw()
33 line.DrawLine( 2.6, 11.5, 7, 11.5 )
34 arrow = TArrow( 7, 11.5, 7, 11.1, 0.01, '|>' )
35 arrow.SetFillStyle( 1001 )
36 arrow.Draw()
37 line.DrawLine( 7, 8.5, 7, 8.0 )
38 line.DrawLine( 7, 8.0, 10.6, 8 )
39 arrow.DrawArrow( 10.6,8, 10.6, 8.4, 0.01, '|>' )
40 line.DrawLine( 10.6, 11, 10.6, 11.5 )
41 line.DrawLine( 10.6, 11.5, 14.6, 11.5 )
42 arrow.DrawArrow( 14.6, 11.5, 14.6, 11.1, 0.01, '|>' )
43 line.DrawLine( 14.6, 8.5, 14.6, 8.0 )
44 line.DrawLine( 14.6, 8.0, 16, 8 )
45 ldot.DrawLine( 16, 8, 19, 8 )
46 vert = TText( 1.5, 9.75, 'File' )
47 vert.SetTextAlign( 21 )
48 vert.SetTextAngle( 90 )
49 vert.SetTextSize( 0.025 )
50 vert.Draw()
51 vert.DrawText( 2.0, 9.75, 'Header' )
52 vert.DrawText( 2.9, 9.75, 'Logical Record' )
53 vert.DrawText( 3.2, 9.75, 'Header' )
54 vert.DrawText( 7.3, 9.75, 'Logical Record' )
55 vert.DrawText( 7.6, 9.75, 'Header' )
56 vert.DrawText( 10.9, 9.75, 'Logical Record' )
57 vert.DrawText( 11.2, 9.75, 'Header' )
58 vert.DrawText( 14.9, 9.75, 'Logical Record' )
59 vert.DrawText( 15.2, 9.75, 'Header' )
60 hori = TText( 4.75, 10, 'Object' )
61 hori.SetTextAlign( 22 )
62 hori.SetTextSize( 0.035 )
63 hori.Draw()
64 hori.DrawText( 4.75, 9.5, 'Data' )
65 hori.DrawText( 9.2, 10, 'Deleted' )
66 hori.DrawText( 9.2, 9.5, 'Object' )
67 line.DrawLine( 6.9, 8.5, 10.5, 11 )
68 line.DrawLine( 6.9, 11, 10.5, 8.5 )
69 tbig = TText( 17, 9.75, '............' )
70 tbig.SetTextAlign( 22 )
71 tbig.SetTextSize( 0.03 )
72 tbig.Draw()
73 tbig.DrawText( 2.6, 7, 'fBEGIN' )
74 tbig.DrawText( 20., 7, 'fEND' )
75 arrow.DrawArrow( 2.6, 7, 2.6, 8.4, 0.01, '|>' )
76 arrow.DrawArrow( 20, 7, 20, 8.4, 0.01, '|>' )
77 
78 #file header
79 header = TPaveText( 0.5, .2, 9.4, 6.5 )
80 header.SetFillColor( 44 )
81 header.Draw()
82 fh = header.AddText( 'File Header' )
83 fh.SetTextAlign( 22 )
84 fh.SetTextSize( 0.04 )
85 header.SetTextSize( 0.027 )
86 header.SetTextAlign( 12 )
87 header.AddText( ' ' )
88 header.AddLine( 0, 0, 0, 0 )
89 header.AddText( '"root": Root File Identifier' )
90 header.AddText( 'fVersion: File version identifier' )
91 header.AddText( 'fBEGIN: Pointer to first data record' )
92 header.AddText( 'fEND: Pointer to first free word at EOF' )
93 header.AddText( 'fSeekFree: Pointer to FREE data record' )
94 header.AddText( 'fNbytesFree: Number of bytes in FREE' )
95 header.AddText( 'fNfree: Number of free data records' )
96 header.AddText( 'fNbytesName: Number of bytes in name/title' )
97 header.AddText( 'fUnits: Number of bytes for pointers' )
98 header.AddText( 'fCompress: Compression level' )
99 
100 #logical record header
101 lrecord = TPaveText( 10, 0.2, 19.5, 6.5 )
102 lrecord.SetFillColor( 33 )
103 lrecord.Draw()
104 tlrh = lrecord.AddText( 'Logical Record Header (TKEY)' )
105 tlrh.SetTextAlign( 22 )
106 tlrh.SetTextSize( 0.04 )
107 lrecord.SetTextSize( 0.027 )
108 lrecord.SetTextAlign( 12 )
109 lrecord.AddText( ' ' )
110 lrecord.AddLine( 0, 0, 0, 0 )
111 lrecord.AddText( 'fNbytes: Length of compressed object' )
112 lrecord.AddText( 'fVersion: Key version identifier' )
113 lrecord.AddText( 'fObjLen: Length of uncompressed object' )
114 lrecord.AddText( 'fDatime: Date/Time when written to store' )
115 lrecord.AddText( 'fKeylen: Number of bytes for the key' )
116 lrecord.AddText( 'fCycle : Cycle number' )
117 lrecord.AddText( 'fSeekKey: Pointer to object on file' )
118 lrecord.AddText( 'fSeekPdir: Pointer to directory on file' )
119 lrecord.AddText( 'fClassName: class name of the object' )
120 lrecord.AddText( 'fName: name of the object' )
121 lrecord.AddText( 'fTitle: title of the object' )
122 
123 c1.Update()
Author
Wim Lavrijsen

Definition in file file.py.