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There are at least 2 ways.
Using INSTR or a for loop.
check for $CRLF or chr$(13)+chr$(10)
possibly using parse$ also.
Code:
strng$="test"+$crlf
strng$=strng$+"xxx"+$CRLF+"zxcv"+$CRLF
l&=88
DO
l&=INSTR(l&+1,strng$,$CRLF)
if l& then count&=count&+1
IF l&=0 OR l&=LEN(strng$)-1 THEN EXIT DO
LOOP
count&=0
FOR k&=1 TO LEN(strng$)
IF MID$(strng$,k&,2)=$CRLF THEN count&=count&+1:k&=k&+1
NEXT
------------------
[This message has been edited by Fred Buffington (edited May 03, 2001).]
TALLY is 'slightly' less work than PARSECOUNT since you don't need to subtract one.
Using INSTR in a loop is even less efficient, since you can do it with TALLY or PARSECOUNT with one line of code.
Borje's code is probably the most efficient way to enumerate the actual positions. If you just want to extract the text between the %CRLF pairs, then PARSE$ is the perfect solution.
heh! To be clear, PARSE$ functions perfectly with any size string, from zero bytes through to two gigibytes.
The point is that PARSE$ provides a way to extract the text without writing masses of code. It is "perfect" in the sense that you can be more efficient in writing your own code.
What this thread clearly demonstrates is that there are any number of ways to skin a cat... PowerBASIC provide the tools to write application code, and it provides functionality that you can exploit if you want super performance (pointers, inline assembly, etc).
How you use these tools and my advice is completely up to you. To use one of Bob's expressions: You can attach any value you like to my comments.
Ouch, please don't - I tend to attach wrong values all the time..
But seriously - I agree, almost unlimited flexibility is probably *the*
best feature in all PowerBasic compilers. A far more efficient way to
find positions is to use pointers. I love pointers - can't live without
them, because they provide such a clean and fast way to manipulate text.
Following little sample does the same job as DO/LOOP above but is much
faster, even a MB string is processed in a fraction of a second:
Code:
LOCAL I AS LONG, Letter AS BYTE PTR
Letter = STRPTR(MyString) 'point Letter to start address of string
FOR I = 1 TO LEN(MyString) 'loop through entire text
IF @Letter = 13 THEN 'Letter's value is 13 = Carriage Return = $CR
'I is position in string - do what you like with it..
END IF
INCR Letter 'set pointer to to next character
NEXT
However, if goal is to parse out a certain line in a text, PARSE$
definitely is the one to use.
What this thread clearly demonstrates is that there are any number of ways to skin a cat...How you use these tools and my advice is completely up to you..
You mean, "It's not the paintbrush, it's the artist?"
You said that "any size string, from zero bytes through to two gigibytes"? this tells me that PB uses LONGS internally for string length. Why on earth would they use LONG instead of DWORD. I don't think you can have strings of negitive length Does this have anything to do with how windows deals with OEM strings?
Thanks for your answers. I find these different methods very revealing. A few times befor I have seen a new way to approach my writing from the simplist question
This is how i used it:
IF Confirm AND AttachStr+ResourceStr+ConsoleStr+CompressStr+CRCStr <> "" THEN
ResourceStr = LEFT$(ResourceStr, LEN(ResourceStr)-2) ' trim off last $CRLFs
IF ResourceStr <> "" THEN DisplayStr = DisplayStr + $CRLF + $CRLF + ResourceStr
IF AttachStr <> "" THEN DisplayStr = DisplayStr + $CRLF + $CRLF + AttachStr
IF ConsoleStr <> "" THEN DisplayStr = DisplayStr + $CRLF + $CRLF + ConsoleStr
IF CompressStr <> "" THEN DisplayStr = DisplayStr + $CRLF + $CRLF + CompressStr
IF CRCStr <> "" THEN DisplayStr = DisplayStr + $CRLF + $CRLF + CRCStr
DisplayStr = RIGHT$(DisplayStr, LEN(DisplayStr)-4) ' trim off leading $CRLFs and space
Ht = (TALLY(DisplayStr, $CRLF)+1)*9 + 24 ' 24 for OK button
DIALOG NEW 0 ,"Compile Information", , , 110, Ht, %WS_POPUP OR %WS_DLGFRAME TO hDlg
CONTROL ADD LABEL, hDlg, 110, DisplayStr, 4, 4, 105, Ht-5,
CONTROL ADD BUTTON, hDlg, 102, "OK", 35, Ht-18, 40, 16, 1 CALL OKProc
DIALOG SHOW MODAL hDlg ' Show confirmation window
END IF
This makes a window just the right height for any combination of the componant strings.
Originally posted by mark smit:
You said that "any size string, from zero bytes through to two gigibytes"? this tells me that PB uses LONGS internally for string length. Why on earth would they use LONG instead of DWORD. I don't think you can have strings of negitive length Does this have anything to do with how windows deals with OEM strings?
2Gb for a single string is a 32-bit Windows limit - most Win32 versions only provide a maximum of 2Gb of application address space.
In this sense, comparing LONG and DWORD is irrelevant.
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