1. Pattern matching
- Posted by thomasj866 at yahoo.com
Apr 15, 2004
Hi,
I need to find IP in a string.
Using wildcard_match() in wildcard.e
i.e wildcard_match("*.*.*.*", string) only return true or false.
I want it to return position and if possible test if it is legal.
thanks
Tj
2. Re: Pattern matching
> I need to find IP in a string.
> Using wildcard_match() in wildcard.e
> i.e wildcard_match("*.*.*.*", string) only return true or false.
> I want it to return position and if possible test if it is legal.
You could try tokenizing the string on '.' and checking the number of fields.
You could use Kat's strtok.e for this:
http://www.tiggrbox.info/program/strtok-v2-1.html
There are also some regular expression libraries in the archives that could
probably be used. Something like: /^(\d+\.){3}\d+$/ should work (assuming
Perl-compatible regexp).
Matt Lewis
3. Re: Pattern matching
On 15 Apr 2004, at 4:12, Guest wrote:
>
>
> posted by: matthewwalkerlewis at yahoo.com
>
>
> > I need to find IP in a string.
> > Using wildcard_match() in wildcard.e
> > i.e wildcard_match("*.*.*.*", string) only return true or false.
> > I want it to return position and if possible test if it is legal.
>
> You could try tokenizing the string on '.' and checking the number of fields.
> You could use Kat's strtok.e for this:
>
> http://www.tiggrbox.info/program/strtok-v2-1.html
Assuming the string is a sentence or database, with "words" separated by
spaces or commas or such, using wildtok() will do nicely to get the matching
token. You can specify getting all the "*.*.*.*" matches, or the first one, 2nd
one, etc. If you are parsing a sentence, specify all separators likely to be
seen around the ip#, but not '.' , of course. The last example in the html
shows using multiple * in a pattern match on a string. If you want only the
location of the token, use wildntok().
If the possible matches are complicated, then use Mathew's suggestion on
field counting, use toknum(), parsing on '.' in the return from wildtok(), as
you
know, there should be 4 on a legal match. You won't match the ip# in "This
is 127.0.0.1.", because of the period at the end of that sentence, so change
that period (delete it).
I wasn't trying to implement regexp in wildtok(), but that's an interesting
thought!
Kat
4. Re: Pattern matching
wrote:
> I want it to return position and if possible test if it is legal.
>
> thanks
> Tj
>
5. Re: Pattern matching
wrote:
> I want it to return position and if possible test if it is legal.
>
> thanks
> Tj
>
A little late but I have a routine that I did to check if an IP address was a
valid format. It checks for no more than 3 '.'s in the string, also checks it is
only numeric, also checks for no greater than 255 in any field and finally
strips
off any leading zeros. I'm sure it could be written better than this but this
was the very first program I did with EU...
global function IP_Address_Valid(sequence is_it_valid)
atom ip_length, number
sequence valid_digits, store, addr_to_strip, stripped_addr
trace(1)
store={}
valid_digits = ".1234567890"
ip_length = length(is_it_valid)
-- Check if it a valid IP address (as much as possible!)
if ip_length < 7 then return 0 -- it is definitly not an ip address, too short
elsif ip_length > 15 then return 0 -- or too long
elsif not wildcard_match("*?.*?.*?.*?", is_it_valid) then return 0 -- invalid
characters
else
for x = 1 to ip_length do -- check for valid characters
if not find(is_it_valid[x], valid_digits) then
return 0
exit
elsif is_it_valid[x] = '.' then -- count the "." - is there more than 3?
store= append(store,x)
if length(store) > 3 then
return 0
exit
end if
end if
end for
end if
--check no number greater than 255
number= value(is_it_valid[1..(store[1]-1)])
if number[2] > 255 then return 0 end if
number = value(is_it_valid[store[1]+1..store[2]-1])
if number[2] > 255 then return 0 end if
number = value(is_it_valid[store[2]+1..store[3]-1])
if number[2] > 255 then return 0 end if
number = value(is_it_valid[store[3]+1..length(is_it_valid)])
if number[2] > 255 then return 0 end if
if length(store) != 3 then return 0 end if
--break address into sequence of number sections (prior to finding leading
zeros)
stripped_addr = {}
addr_to_strip = {}
addr_to_strip = append(addr_to_strip,is_it_valid[1..(store[1]-1)])
addr_to_strip = append(addr_to_strip,is_it_valid[store[1]+1..store[2]-1])
addr_to_strip = append(addr_to_strip,is_it_valid[store[2]+1..store[3]-1])
addr_to_strip =
append(addr_to_strip,is_it_valid[store[3]+1..length(is_it_valid)])
for i = 1 to 4 do
if length(addr_to_strip[i]) > 3 then return 0
elsif length(addr_to_strip[i]) > 1 and match("0",addr_to_strip[i]) = 1 then
if length(addr_to_strip[i]) > 1 and equal('0',addr_to_strip[i][2]) then
if length(addr_to_strip[i]) = 2 then
stripped_addr = stripped_addr & addr_to_strip[i][2]
end if
if length(addr_to_strip[i]) = 3 then
stripped_addr = stripped_addr & addr_to_strip[i][3]
end if
if i != 4 then stripped_addr = stripped_addr & "." end if
else stripped_addr = stripped_addr &
addr_to_strip[i][2..length(addr_to_strip[i])]
if i != 4 then stripped_addr = stripped_addr & "." end if
end if
else stripped_addr = stripped_addr & addr_to_strip[i]
if i != 4 then stripped_addr = stripped_addr & "." end if
end if
end for
return stripped_addr
end function
Pete.
6. Re: Pattern matching
Pete wrote:
>
>
> wrote:
> > I want it to return position and if possible test if it is legal.
> >
> > thanks
> > Tj
> >
> A little late but I have a routine that I did to check if an IP address was
> a
> valid format. It checks for no more than 3 '.'s in the string, also checks it
> is
>
> only numeric, also checks for no greater than 255 in any field and finally
> strips
>
> off any leading zeros. I'm sure it could be written better than this but this
> was the very first program I did with EU...
Thanks for all thelp it gave me incentive to do my own code.
-- parse_ip.e
--
include wildcard.e
sequence string
string = "<html><head><title>Current IP Check</title></head><body>Current IP
Address: 127.0.0.1</body></html>"
function match_ip(sequence string)
integer pos
object void
pos = 0
for n=1 to length(string) do
if wildcard_match("*.*.*.*", string[n..length(string)]) = 0 then
void = string[n..length(string)]
pos = n
exit
end if
end for
void = string[pos-4..length(string)]
while find(void[length(void)], ".0123456789") = 0 do
void = void[1..length(void)-1]
end while
while find(void[1], ".0123456789") = 0 do
void = void[2..length(void)]
end while
return void
end function
?match_ip(string)
puts(1, match_ip(string))
--
TJ
