Mega Code Archive
Blockread
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The following code shows how to use a untyped input file to blockread a text file, scan the input
buffer for any character, and replace it with a carriage return and line feed. Since it is using 16k
input and output buffers the speed is quite reasonable.
NOTE: If when you are through, if the line length of the output file exceeds 255 characters and
you want to read it using ReadLn just use more than one string in the ReadLn statement to as
follows:
ReadLn(infile,string1,string2);
This will read up to a 510 char line with the 1st 255 char in string1 and the remainder in string2;
program fixfile;{ Compile from the DOS prompt: DCC FIXFILE.PAS }
uses { execute from File Manager }
sysutils,dialogs,forms;
type
bufptr = obufr;
iobufr = array[0..16384] of char;
var
infile : file;
oufile : textfile;
inbufr,
oubufr : bufptr;
idx: integer;
bytesread: integer;
bytes2read: integer;
totalbytesread: longint;
actualfilesize: longint;
OpenDialog1: TOpenDialog;
infilename,oufilename: string;
begin
infilename := '';
OpenDialog1 := TOpenDialog.Create(Application);
OpenDialog1.Options := [];
OpenDialog1.Filter := 'All files|*.*';
OpenDialog1.FilterIndex := 1;
OpenDialog1.Title := 'Enter Source file name to be converted';
if OpenDialog1.execute then
infilename := OpenDialog1.filename;
if infilename='' then
begin
OpenDialog1.free;
halt;
end;
OpenDialog1.Title := 'Enter Destination file name to be created';
if OpenDialog1.execute then
oufilename := OpenDialog1.filename;
OpenDialog1.free;
if oufilename='' then
halt;
if infilename=oufilename then
halt;
new(inbufr);
new(oubufr);
assignfile(infile,infilename);
reset(infile,1);
actualfilesize := filesize(infile);
assignfile(oufile,oufilename);
system.settextbuf(oufile,oubufr^);
rewrite(oufile);
totalbytesread := 0;
bytesread := 0;
bytes2read := 0;
while (totalbytesread < actualfilesize)
and (bytes2read=bytesread) and (IOresult=0) do
begin
if (actualfilesize-totalbytesread)>sizeof(inbufr^) then
bytes2read := sizeof(inbufr^)
else
bytes2read := actualfilesize-totalbytesread;
blockread(infile,inbufr^,bytes2read,bytesread);
totalbytesread := totalbytesread + bytesread;
for idx := 0 to bytesread do
if inbufr^ [idx]='''' then { <= character to be converted }
writeln(oufile)
else
write(oufile,inbufr^ [idx]);
end;
closefile(infile);
closefile(oufile);
dispose(inbufr);
dispose(oubufr);
end.
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