1. Changing data types Concluded
Derek wrote:
<<Yes, it was a rather salient point as we all assumed you were using standard
Euphoria code to read and search the file. Using the API and raw ram buffers
instead changes things a lot, as we are no longer talking about atoms and
sequences.
Derek >>
Sorry about the confusion. I am a math teacher, not a programmer, and I learn
the lingo by having programmers kick me when I make a mistake.
Back to my original question.
I am reading a 200MB text file into a preallocated buffer via an API method
suggested by Euman. The file consists of 2^24 fixed length fields, each 12 bytes
long. I would like to take advantage of EU's features to the greatest extent
possible in searching the file. I am currently doing this by successively peeking
at the first 4 characters of each field and telling EU that they represent an
unsigned integer (actually an atom).
The search of the 16,777,216 fields is done in 6.6 seconds if "not equal()" is
used, and in 5.8 seconds if != is used. The latter is possible because the
4-character sub-field is treated as an integer.
Questions:
1. Does anyone see a way to improve on this time?
2. Could I also arrange to use an 8-byte sub-field?
3. Is there some way to persuade EU "position()" to allow the display line to be
greater than 24 (using vanilla DOS)?
Allen
2. Re: Changing data types Concluded
On Wednesday 24 March 2004 01:01 am, Derek Parnell wrote:
> -- Find first text record that begins with 'abcd'.
> FindStr = allocate_string("abcd")
> len = 4
> offset = 0
> while offset < FileSize do
> result = c_func(CompareString,{0, 0, RAMADDR+offset, len, FindStr,
> len}) if result = CSTR_ERROR or result = CSTR_EQUAL then
> exit
> end if
> offset += recsize
> end while
> -- Copy the whole record into a sequence
> TheRecord = peek({RAMADDR+offset, recsize})
Allen,
Make sure you free that allocated string.
Euman
