1. reading strings
just wanted to share a small routine for reading strings. I use it to load large
strings (no longer than 256 bytes) into euphoria.
nb. probably not very fast for smaller type strings.
you could change the 'TERMINMATOR' and 'MAXLENGTH' constants to suit your
application
--==============================================--
constant
--
TERMINATOR = 0, -- the string terminator
MAXLENGTH = 256 -- maximum string length
--------------------------------------------------
-- returns sequence as a string from memory/device
global function string(atom lp)
sequence chunk
integer loc
chunk = peek({lp, MAXLENGTH})
loc = find(TERMINATOR, chunk)
if loc then
chunk = chunk[1..(loc-1)]
end if
return chunk
end function
2. Re: reading strings
Hayden McKay wrote:
>
>
> just wanted to share a small routine for reading strings. I use it to load
> large
> strings (no longer than 256 bytes) into euphoria.
>
> nb. probably not very fast for smaller type strings.
>
> you could change the 'TERMINMATOR' and 'MAXLENGTH' constants to suit your
> application
>
> }}}
<eucode>
> --==============================================--
> constant
> --
> TERMINATOR = 0, -- the string terminator
> MAXLENGTH = 256 -- maximum string length
>
> --------------------------------------------------
> -- returns sequence as a string from memory/device
>
> global function string(atom lp)
>
> sequence chunk
> integer loc
>
> chunk = peek({lp, MAXLENGTH})
>
> loc = find(TERMINATOR, chunk)
> if loc then
> chunk = chunk[1..(loc-1)]
> end if
>
> return chunk
>
> end function
> </eucode>
{{{
Hayden:
Couldn't you do it this way ?
constant
--
TERMINATOR = 0, -- the string terminator
MAXLENGTH = 256 -- maximum string length
--
global function string(atom lp)
return find(TERMINATOR, peek({lp, MAXLENGTH}))
end function
Bernie
My files in archive:
WMOTOR, XMOTOR, W32ENGIN, MIXEDLIB, EU_ENGIN, WIN32ERU, WIN32API
Can be downloaded here:
http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan
3. Re: reading strings
Bernie Ryan wrote:
>
> Hayden McKay wrote:
> >
> >
> > just wanted to share a small routine for reading strings. I use it to load
> > large
> > strings (no longer than 256 bytes) into euphoria.
> >
> > nb. probably not very fast for smaller type strings.
> >
> > you could change the 'TERMINMATOR' and 'MAXLENGTH' constants to suit your
> > application
> >
> > }}}
<eucode>
> > --==============================================--
> > constant
> > --
> > TERMINATOR = 0, -- the string terminator
> > MAXLENGTH = 256 -- maximum string length
> >
> > --------------------------------------------------
> > -- returns sequence as a string from memory/device
> >
> > global function string(atom lp)
> >
> > sequence chunk
> > integer loc
> >
> > chunk = peek({lp, MAXLENGTH})
> >
> > loc = find(TERMINATOR, chunk)
> > if loc then
> > chunk = chunk[1..(loc-1)]
> > end if
> >
> > return chunk
> >
> > end function
> > </eucode>
{{{
>
> Hayden:
> Couldn't you do it this way ?
>
> }}}
<eucode>
> constant
> --
> TERMINATOR = 0, -- the string terminator
> MAXLENGTH = 256 -- maximum string length
> --
> global function string(atom lp)
> return find(TERMINATOR, peek({lp, MAXLENGTH}))
> end function
> </eucode>
{{{
>
> Bernie
>
> My files in archive:
> WMOTOR, XMOTOR, W32ENGIN, MIXEDLIB, EU_ENGIN, WIN32ERU, WIN32API
>
> Can be downloaded here:
> <a
> href="http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan">http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan</a>
The result returned by your function is an 'integer' (the position of the zero
terminator) either 1..256 or 0 if none was found. where my function returns an
actual sequence.
nb. After reading your post and doing some testing I found that my routine will
crash if 'atom lp' points to a 0. I have'nt had to read empty strings before so
an application crash was never a problem for me, but I should change routine to
accomodate as follows.
--==============================================--
constant
--
TERMINATOR = 0, -- the string terminator
MAXLENGTH = 256 -- maximum string length
--------------------------------------------------
-- changes...
-- function now returns "{}" if the string
-- is empty or the terminator is not found
global function string(atom lp)
sequence chunk
integer loc
chunk = peek({lp, MAXLENGTH})
loc = find(TERMINATOR, chunk)
-- if loc then
if loc >= 1 then
chunk = chunk[1..(loc-1)]
else
chunk = {} -- return empty string.
end if
return chunk
end function
4. Re: reading strings
On Tue, 05 Sep 2006 19:45:02 -0700, Hayden McKay
<guest at RapidEuphoria.com> wrote:
>nb. After reading your post and doing some testing I found that my routine will
>crash if 'atom lp' points to a 0.
<snip>
>but I should change routine to accomodate as follows.
>}}}
<eucode>
>-- if loc then
> if loc >= 1 then
> chunk = chunk[1..(loc-1)]
> else
> chunk = {} -- return empty string.
> end if
></eucode>
{{{
This rang a few alarm bells. First question is what error message did
you get, exactly, that this is supposed to fix? I expect it was an
error in the peek, if lp was zero or pointed to a zero in memory which
was not followed by 255 bytes of readable memory. The change might
solve an error "slice end is xxx ", but I doubt you got that. What you
might have done is by adding those 4 lines of code made sure that a
zero was now followed by at least 255 bytes of readable memory (code).
Note that chunk = chunk[1..0] is a valid Eu statement.
If anything, I'd say that as it stands if you peek a 256-character
string, with no terminator in it anywhere, it will return {}, or would
have crashed before.
Regards,
Pete
5. Re: reading strings
Hayden McKay wrote:
> }}}
<eucode>
> --==============================================--
> constant
> --
> TERMINATOR = 0, -- the string terminator
> MAXLENGTH = 256 -- maximum string length
>
> --------------------------------------------------
> -- changes...
> -- function now returns "{}" if the string
> -- is empty or the terminator is not found
>
> global function string(atom lp)
>
> sequence chunk
> integer loc
>
> chunk = peek({lp, MAXLENGTH})
>
> loc = find(TERMINATOR, chunk)
>
> -- if loc then
> if loc >= 1 then
> chunk = chunk[1..(loc-1)]
> else
> chunk = {} -- return empty string.
> end if
>
> return chunk
>
> end function
> </eucode>
{{{
Hayden:
Try this one.
constant
TERMINATOR = 0, -- the string terminator
MAXLENGTH = 256 -- maximum string length
--
global function string(object lp)
if atom(lp) then
return string(peek({lp, MAXLENGTH}))
else
return lp[1..find(TERMINATOR,lp)-1]
end if
end function
Bernie
My files in archive:
WMOTOR, XMOTOR, W32ENGIN, MIXEDLIB, EU_ENGIN, WIN32ERU, WIN32API
Can be downloaded here:
http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan
