Subj : NodeDiff creation
To   : Jasen Betts
From : Dan Egli
Date : Wed Aug 13 2003 06:09 pm

> Hi Dan.

> 10-Aug-03 21:57:16, Dan Egli wrote to All


> diff programs are fun :-%

Tell me about it!
>> I cannot figure out how to check out the reason for
>> the delete and insert the propper delete reason in the diff

> reason?

Reason? For what? For having trouble figuring the delete setup? Here's two 
exaples of deletes:

1) Nodes 1:311/5, 6, 12, and 18 (all four next to each other in the nodelist) 
have dropped out. That's easy. Delete those 4 lines (D4). Figure it out by 
scanning the new file and seeing line N+1 (where N is the number of the last 
matching line) is the same as line N+5 in the old list. (N+5)-(N+1)=4, so D4. 
That's an easy example.

This one is harder:

Nodes 1:3005/3, and 4 (two nodes, one bbs) go temp down (Sysop warned he's on 
vacation and will fix things in a couple of weeks. Meanwhile his system has 
stopped responding. Rings and rings, no answer). Delete those two lines, but 
replace them with Down entries. I.e, assume the old entries looked like:

,3,My_Old_bbs,NOWhwere_US,Joe_Sysop,801-555-1212,CM,XA,v32b,v42b
,4,My_Old_bbs,NoWjhere_US,Joe_Sysop,000-000-000-000,CM,XX,INA:some.internet.dom
ain.tld,IBN,IFC,ITN,IFT

Now replace then with:

Down,3,My_Old_bbs,NOWhwere_US,Joe_Sysop,801-555-1212,CM,XA,v32b,v42b
Down,4,My_Old_bbs,NoWjhere_US,Joe_Sysop,000-000-000-000,CM,XX,INA:some.internet
..domain.tld,IBN,IFC,ITN,IFT

Problem: the previous formula does't work. Here' N+3 in the old file is the 
same as N+3 in the new file. So, assuming P1 is the number of lines between old 
match and new match in the old file, and P2 is the number of lines between old 
match and new match in the new file, We'd get: (N+P1)-(N+P2)=0. So if we used 
that formula, the result would be along these lines in the new list:

,3,My_Old_bbs,NOWhwere_US,Joe_Sysop,801-555-1212,CM,XA,v32b,v42b
,4,My_Old_bbs,NoWjhere_US,Joe_Sysop,000-000-000-000,CM,XX,INA:some.internet.dom
ain.tld,IBN,IFC,ITN,IFT
Down,3,My_Old_bbs,NOWhwere_US,Joe_Sysop,801-555-1212,CM,XA,v32b,v42b
Down,4,My_Old_bbs,NoWjhere_US,Joe_Sysop,000-000-000-000,CM,XX,INA:some.internet
..domain.tld,IBN,IFC,ITN,IFT


The diff would show:
C3
A2
Down,3,My_Old_bbs,NOWhwere_US,Joe_Sysop,801-555-1212,CM,XA,v32b,v42b
Down,4,My_Old_bbs,NoWjhere_US,Joe_Sysop,000-000-000-000,CM,XX,INA:some.internet
..domain.tld,IBN,IFC,ITN,IFT
; continuing on

That won't work. So I need some kind of algorythum for determining how many 
lines have CHANGED. Then I can generate this:

C1
D2
A2
Down,3,My_Old_bbs,NOWhwere_US,Joe_Sysop,801-555-1212,CM,XA,v32b,v42b
Down,4,My_Old_bbs,NoWjhere_US,Joe_Sysop,000-000-000-000,CM,XX,INA:some.internet
..domain.tld,IBN,IFC,ITN,IFT
; continuing on.

Make sense?

--- BBBS/LiI v4.01 Flag-5
 * Origin: (1:3005/3)

.