X-Git-Url: http://www.lcore.org/git/lcore.git/blobdiff_plain/68a9dbf11abd9f30877e7ceda480a795fdebe1c8..a1858883733a454b6ffb73aa263ef5badc2a1d07:/readtxt2.pas?ds=inline

diff --git a/readtxt2.pas b/readtxt2.pas
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+{ Copyright (C) 2009 Bas Steendijk and Peter Green
+  For conditions of distribution and use, see copyright notice in zlib_license.txt
+  which is included in the package
+  ----------------------------------------------------------------------------- }
+
+unit readtxt2;
+
+interface
+
+{
+readtxt, version 2
+by beware
+
+this can be used to read a text file exposed as a tstream line by line.
+automatic handling of CR, LF, and CRLF line endings, and readout of detected line ending type.
+fast: 1.5-2 times faster than textfile readln in tests.
+}
+
+uses
+  classes,sysutils;
+
+const
+  bufsize=4096;
+  eoltype_none=0;
+  eoltype_cr=1;
+  eoltype_lf=2;
+  eoltype_crlf=3;
+
+type
+  treadtxt=class(tobject)
+  public
+    sourcestream:tstream;
+    destroysourcestream:boolean;
+    constructor create(asourcestream: tstream; adestroysourcestream:boolean);
+    constructor createf(filename : string);
+
+    function readline:string;
+    function eof:boolean;
+    destructor destroy; override;
+  private
+    buf:array[0..bufsize-1] of byte;
+    numread:integer;
+    bufpointer:integer;
+    currenteol,preveol:integer;
+    fileeof,reachedeof:boolean;
+    eoltype:integer;
+  end;
+
+implementation
+
+constructor treadtxt.create(asourcestream: tstream; adestroysourcestream:boolean);
+begin
+  inherited create;
+  sourcestream := asourcestream;
+  destroysourcestream := adestroysourcestream;
+
+  if sourcestream.Position >= sourcestream.size then fileeof := true;
+  bufpointer := bufsize;
+  destroysourcestream := false;
+end;
+
+constructor treadtxt.createf(filename : string);
+begin
+  create(tfilestream.create(filename,fmOpenRead),true);
+end;
+
+
+function treadtxt.readline;
+var
+  a,b,c,d:integer;
+begin
+
+  result := '';
+  repeat
+    if bufpointer >= bufsize then begin
+      numread := sourcestream.read(buf,bufsize);
+      bufpointer := 0;
+      if sourcestream.Position >= sourcestream.size then fileeof := true;
+    end;
+    b := numread-1;
+
+    {core search loop begin}
+    d := -1;
+    for a := bufpointer to b do begin
+      c := buf[a];
+      if (c = 10) or (c = 13) then begin
+         d := a;
+         break;
+      end;
+    end;
+    {core search loop end}
+    
+    c := length(result);
+    if (d = -1) then begin
+      {ran out of buffer before end of line}
+      b := numread-bufpointer;
+      setlength(result,c+b);
+      move(buf[bufpointer],result[c+1],b);
+      bufpointer := numread;
+      if numread < bufsize then begin
+        reachedeof := true;
+        exit;
+      end;
+    end else begin
+
+      preveol := currenteol;
+      currenteol := buf[d];
+
+      {end of line before end of buffer}
+      if (currenteol = 10) and (preveol = 13) then begin
+        {it's the second EOL char of a DOS line ending, don't cause a line}
+        bufpointer := d+1;
+        eoltype := eoltype_crlf;
+      end else begin
+        if eoltype = eoltype_none then begin
+          if (currenteol = 10) then eoltype := eoltype_lf else eoltype := eoltype_cr;
+        end;  
+        b := d-bufpointer;
+        setlength(result,c+b);
+        move(buf[bufpointer],result[c+1],b);
+        bufpointer := d+1;
+
+        {EOF check}
+        if fileeof then begin
+          if (bufpointer >= numread) then reachedeof := true;
+          if (currenteol = 13) and (bufpointer = numread-1) then if (buf[bufpointer] = 10) then reachedeof := true;
+        end;  
+
+        exit;
+      end;
+    end;
+  until false;
+end;
+
+function treadtxt.eof:boolean;
+begin
+
+  result := ((bufpointer >= bufsize) and fileeof) or reachedeof;
+end;
+
+destructor treadtxt.destroy;
+begin
+  if destroysourcestream then if assigned(sourcestream) then sourcestream.destroy;
+  inherited destroy;
+end;
+
+end.