In fpcsrc, many places can use StartsStr/StartsText

[AlexTP]

I did the search using regex (regex is visible in the report on 1st line). All these places can use StartsStr. the only minus is that StartsStr is in the StrUtils unit...

I don't post this trivial issue to the bugtracker.

Code: [Select]

+Search "copy\(.+?\s*,\s*1\s*,\s*\d+\s*\)\s*=\s*'". Report with [styles].
<compiler\aggas.pas>: #1
< 349>:         if (atype=sec_fpc) and (Copy(aname,1,3)='res') then
<compiler\cmsgs.pas>: #1
< 247>:         else if (Length(s)>11) and (Copy(s,1,11)='# CodePage ') then
<compiler\dirparse.pas>: #3
< 122>:           if Copy(tok,1,2)='NO' then
< 168>:           if Copy(tok,1,2)='NO' then
< 221>:           if Copy(tok,1,2)='NO' then
<compiler\globals.pas>: #1
<1324>:         if Copy(S,1,2)='NO' then
<compiler\link.pas>: #1
<1173>:         if copy(ExtractFileName(para),1,6)='libimp' then
<compiler\ogbase.pas>: #3
<2493>:                           if Copy(hs,1,5)='VTREF' then
<2499>:                           else if Copy(hs,1,7)='VTENTRY' then
<2501>:                           else if Copy(hs,1,9)='VTINHERIT' then
<compiler\ogelf.pas>: #1
< 573>:             if (atype=sec_fpc) and (Copy(aname,1,3)='res') then
<compiler\ognlm.pas>: #1
< 357>:     if (s = '.data') or (copy(s,1,4)='.bss') then result := Section_data else
<compiler\pkgutil.pas>: #1
< 410>:                    if copy(s,1,3)='lib' then
<compiler\arm\raarmgas.pas>: #1
<1400>:                 if copy(hs,1,2) = '.W' then
<compiler\avr\raavrgas.pas>: #1
< 641>:         if ((copy(hs,1,2)='BR') and (length(hs)=4)) then
<compiler\systems\t_emx.pas>: #1
< 297>:     if profile_flag and not (copy(func,1,4)='_16_') then
<compiler\systems\t_nwm.pas>: #2
< 677>:             if copy(option,1,1)='@' then
< 728>:             if copy(option,1,1)='@' then
<compiler\systems\t_os2.pas>: #2
< 298>:     if profile_flag and not (copy(func,1,4)='_16_') then
< 300>:     if profile_flag and not (copy(tmp2,1,4)='_16_') then
<compiler\utils\msg2inc.pp>: #1
< 156>:         else if (Length(s)>11) and (Copy(s,1,11)='# CodePage ') then
<compiler\utils\ppumove.pp>: #2
< 401>:                if copy(s,1,3)='lib' then
< 405>:                if copy(s,1,3)='lib' then
<compiler\utils\ppuutils\ppudump.pp>: #1
<4980>:   while copy(paramstr(startpara),1,1)='-' do
<installer\install.pas>: #2
<1440>:                   if copy(package[i].zip,1,3)='ide' then
<1442>:                   if copy(package[i].zip,1,7)='doc-htm' then
<packages\cdrom\src\fpcddb.pp>: #3
< 471>:             else if (Copy(L,1,6)='TTITLE') then
< 480>:             else if (Copy(L,1,6)='EXTT') then
< 487>:             else if (Copy(L,1,9)='PLAYORDER') then
<packages\fcl-base\src\gettext.pp>: #3
< 302>:     if (Copy(Buffer,1,3)='CHS') or (Copy(Buffer,1,3)='CHT') then FallbackLang:='zh';
< 311>:     if (Copy(Buffer,1,3)='CHN') then Country:='CN'; 
<packages\fcl-db\examples\sqlshell.pas>: #1
< 196>:       if Copy(S,1,1)='\' then
<packages\fcl-db\src\sqldb\interbase\ibconnection.pp>: #1
< 298>:   Result:=(Copy(LS,1,7)='version') and (Length(LS)=8);
<packages\fcl-js\tests\tcscanner.pp>: #1
< 813>:     If (Copy(V,1,2)='0x') then
<packages\fcl-passrc\src\pscanner.pp>: #2
<4811>:         if Copy(CurTokenString,1,1)='$' then
<5131>:       if (Copy(CurTokenString,1,1)='$') then
<packages\fcl-pdf\src\fppdfobjects.pp>: #1
<2965>:   If not (Copy(Value,1,2)='D:') then
<packages\fcl-report\src\fplazreport.pp>: #2
< 286>:     if copy(tmp,1,1)='P' then
< 306>:       if copy(tmp,1,1)='P' then
<packages\fcl-res\src\coffreader.pp>: #1
<  72>:     Result:=copy(s,1,6)='.rsrc$';
<packages\fcl-res\src\rcparserfn.inc>: #3
< 128>:   if Copy(s, 1, 2) = '0x' then
< 130>:   if Copy(s, 1, 2) = '0o' then
< 132>:   if Copy(s, 1, 1) = '0' then
<packages\fcl-web\src\base\custfcgi.pp>: #1
< 348>:       if (V=hvPathInfo) and (Copy(Value,1,2)='//') then //mod_proxy_fcgi gives double slashes at the beginning for some reason
<packages\fcl-web\src\restbridge\sqldbrestdata.pp>: #1
< 529>:   if Copy(CT,1,5)='mysql' then
<packages\fpgtk\src\def\objectdef.pp>: #4
<1058>:       else if copy(PascalType,1,4) = 'pgtk' then
<1077>:     else if copy(PascalType,1,4)='pgtk' then
<1096>:       if (copy(variable,1,4)='gtk.') and
<1104>:       if (copy(variable,1,4)='gtk.') and
<packages\fppkg\src\pkgoptions.pp>: #1
< 843>:         if (Copy(s, 1, 1) = '[') and (Copy(s, length(s), 1) = ']') then
<packages\fv\src\stddlg.pas>: #1
<1309>:         if (S<>'') and (Copy(Dir,1,3)='..'+DirSeparator) then
<packages\gdbint\src\gdbcon.pp>: #1
< 385>:   if copy(RegValueStr,1,2)='0x' then
<packages\ide\fpswitch.pas>: #1
<1048>:       if (Copy(s,1,7)='#IFDEF ') then
<packages\ide\fpsymbol.pas>: #1
< 433>:         if (copy(S,1,1)='_') and (Pos('$$',S)>0) then
<packages\ide\fptools.pas>: #1
<1320>:         if copy(WordS,1,1)='$' then
<packages\ide\fpusrscr.pas>: #3
< 765>:       if ((Copy(ThisTTY, 1, 8) = '/dev/tty') and (ThisTTY[9]<>'p')) or (Copy(ThisTTY,1,8)='/dev/vc/') Then
< 787>:      If Copy(GetEnv('TERM'),1,6)='cons25' Then
<packages\ide\fpviews.pas>: #2
<2840>:       if copy(line,1,3)='=> ' then
<2850>:           if copy(curaddress,1,2)='0x' then
<packages\ide\wchmhwrap.pas>: #2
<  63>:   while (length(relpath)>0) and (copy(relpath,1,3)='../') do
< 292>:   if copy(href,1,7)='ms-its:' then
<packages\ide\whtml.pas>: #2
< 404>:   if copy(Name,1,1)='#' then
< 561>:   if copy(Tag,1,1)='<' then Delete(Tag,1,1);
<packages\ide\whtmlhlp.pas>: #2
<1349>:  if copy(relative,1,6)='http:/' then // external links don't need to be fixed since we can't load them.
<1368>:   if copy(href,1,7)='ms-its:' then
<packages\ide\wini.pas>: #1
< 449>:       if copy(TS,1,1)='[' then
<packages\pastojs\src\pas2jscompiler.pp>: #1
<3530>:     Result:=copy(aValue,1,3)='cmd';
<packages\ptc\src\dos\vga\vgaconsolei.inc>: #1
< 108>:   if (System.Copy(_option, 1, 8) = 'FAKEMODE') and (Length(_option) = 10) and
<packages\ptc\src\win32\directx\win32directxconsolei.inc>: #4
< 167>:   if System.Copy(AOption, 1, 13) = 'default width' then
< 180>:   if System.Copy(AOption, 1, 14) = 'default height' then
< 193>:   if System.Copy(AOption, 1, 12) = 'default bits' then
< 309>:   if System.Copy(AOption, 1, 9) = 'frequency' then
<packages\rtl-console\src\unix\keyboard.pp>: #3
<1209>:   if copy(fpgetenv('TERM'),1,4)='cons' then
<1471>:       if copy(fpgetenv('TERM'),1,5)='xterm' then
<1493>:   if copy(fpgetenv('TERM'),1,5)='xterm' then
<packages\rtl-console\src\unix\video.pp>: #1
<1106>:      if copy(ThisTTY, 1, 9) = '/dev/ttyv' then  {FreeBSD has these}
<packages\users\examples\testpass.pp>: #1
<  66>:   If Copy(EncPass,1,3) = '$1$' then
<packages\vcl-compat\src\system.ioutils.pp>: #1
< 614>:   if (Length(aPath)>=3) and (Copy(aPath,1,2)='//') then
<packages\winunits-base\src\typelib.pas>: #3
< 326>:     if (copy(typename,1,3)='tag') then
< 328>:     else if (copy(typename,1,4)='_tag') then
< 330>:     else if (copy(typename,1,5)='__tag') then
<rtl\go32v2\system.pp>: #1
< 393>:         if Copy(proxy_s,1,7)=' !proxy' then
<rtl\watcom\system.pp>: #1
< 339>:         if Copy(proxy_s,1,7)=' !proxy' then
<tests\utils\dbconfig.pp>: #1
< 360>:         if (copy(O,1,2)='--') then
<tests\utils\dbdigest.pp>: #3
< 357>:         if (copy(O,1,2)='--') then
< 508>:   if not FileExists(FN) and (Copy(FN,1,3)='../') then
< 529>:   if not FileExists(FN) and (Copy(FN,1,3)='../') then
<tests\utils\avx\cmpoptions.pas>: #3
<  75>:     if copy(ParamStr(i), 1, 1) = '-' then
<  86>:                 if copy(FSourceMask, 1, 2) = '\\' then FSourceMask := ExpandUNCFileName(FSourceMask)
<  98>:                 if copy(FDestPath, 1, 2) = '\\' then FDestPath := ExpandUNCFileName(FDestPath)
<tests\utils\avx\options.pas>: #1
<  76>:     if copy(ParamStr(i), 1, 1) = '-' then
<tests\utils\dosbox\dosbox_wrapper.pas>: #1
< 618>:       if (paramcount>1) and (copy(paramstr(2),1,2)='-S') then
<utils\ppdep.pp>: #5
< 420>:                     if (Copy(hs^,1,4)='USES') and ((length(hs^)=4) or (hs^[5] in [' ',#9])) then
< 430>:                         if (Copy(hs^,1,7)='PROGRAM') then
< 436>:                          if InImplementation and ((copy(hs^,1,5)='CONST') or
< 437>:                             (copy(hs^,1,3)='VAR') or (copy(hs^,1,5)='BEGIN')) then
<utils\fpcres\paramparser.pas>: #2
< 368>:   if copy(s,1,1)='-' then Result:=true;
< 423>:         if copy(tmp,1,1)='@' then
<utils\fpcreslipo\paramparser.pp>: #1
< 120>:   if copy(s,1,1)='-' then Result:=true;
<utils\fpdoc\dwriter.pp>: #1
< 364>:     (Copy(AMember.Name, 1, 2) = 'On');
<utils\fpdoc\dw_chm.pp>: #1
< 799>:     if copy(ALinkPrefix,1,2)='..' then // workaround for project files.
<utils\fpdoc\fpclasschart.pp>: #1
< 667>:     if Copy(FileName, 1, 1) = '@' then
<utils\fpdoc\fpdoc.pp>: #3
< 211>:     Result:=(Copy(s,1,3)='-p=') or (Copy(s,1,Length(SOptProject))=SOptProject) or (Copy(s,1,Length(SOptMacro))=SOptMacro);
< 217>:     Result:=((Copy(s,1,3)='-a=') or (Copy(s,1,Length(SOptPackage))=SOptPackage));
< 296>:     if Copy(FileName, 1, 1) = '@' then
<utils\fpdoc\makeskel.pp>: #1
< 509>:     if Copy(FileName, 1, 1) = '@' then
<utils\h2pas\scan.pas>: #1
< 646>:                            if copy(yytext,1,2)='0x' then
<utils\instantfpc\instantfpc.pas>: #2
< 119>:   else if copy(p,1,11)='--compiler=' then
< 124>:   else if copy(p,1,12)='--set-cache=' then
<utils\instantfpc\instantfptools.pas>: #2
< 363>:     if (Copy(p,1,1)='-') and (copy(p,1,2)<>'--') then
< 373>:   While (I<=ParamCount) and (Copy(ParamStr(i),1,1)='-') do
<utils\pas2jni\pas2jni.pas>: #2
<  54>:   if Copy(p, 1, 1) = '@' then begin
<  85>:     if Copy(s, 1, 1) = '-' then begin
<utils\pas2jni\ppuparser.pas>: #1
< 407>:         if Copy(d.Name, 1, 1) = '$' then
<utils\pas2jni\writer.pas>: #1
<1352>:     if Copy(d.Value, 1, 1) = '"' then
<utils\pas2js\webidl2pas.pp>: #1
< 142>:   if (Copy(A,1,1)='@') then
<utils\tply\plex.pas>: #1
< 630>:     if copy(paramStr(i), 1, 1)='-' then
<utils\tply\pyacc.pas>: #1
<2406>:     if copy(paramStr(i), 1, 1)='-' then

[marcov]

And strutils is in packages/rtl-objpas and not yet compiled when the compiler compiles itself.

[AlexTP]

Ok, you cannot use StrUtils, but you can make a tiny unit with StartsStr and use it in the compiler?

[marcov]

I assume it could be added to cutils. I'm not a compiler dev, please file a bug.

[PascalDragon]

Even if StrUtils would be usable in the compiler this function would not be usable, because the compiler uses predominantly ShortString and not AnsiString and thus calling the AnsiString-based StartsStr would lead to unnecessary conversions from/to ShortString (this is something that a simple search can not discover).

[AlexTP]

Ok, then some replacements for StartsStr must be defined, eg in the 'cutils', for the ShortString.

[avk]

Even if StrUtils would be usable in the compiler this function would not be usable, because the compiler uses predominantly ShortString and not AnsiString and thus calling the AnsiString-based StartsStr would lead to unnecessary conversions from/to ShortString (this is something that a simple search can not discover).

What about such function

Code: Pascal  [Select][+][-]

1. function SameChars(const L, R: array of AnsiChar): Boolean;
2. begin
3.   if Length(L) <> Length(R) then exit(False);
4.   if Length(L) = 0 then exit(True);
5.   Result := CompareByte(L[0], R[0], Length(L)) = 0;
6. end;
7.  

[PascalDragon]

• ShortString can not be passed to array of AnsiChar
• Your function still means that Copy needs to be used, so you're essentially replacing the =-operator with a function call

[avk]

I meant

Code: Pascal  [Select][+][-]

1. program char_arr_test;
2. {$mode objfpc}
3.  
4. function SameChars(const L, R: array of AnsiChar): Boolean;
5. begin
6.   if Length(L) <> Length(R) then exit(False);
7.   if Length(L) = 0 then exit(True);
8.   Result := CompareByte(L[0], R[0], Length(L)) = 0;
9. end;
10.  
11. var
12.   s: string;
13. begin
14.   s := 'abcdefgh';
15.   WriteLn(SameChars(s[3..8], 'cdefgh'));
16. end.
17.  

code that FPC generated to call the function

Code: ASM  [Select][+][-]

1. # [16] WriteLn(SameChars(s[3..8], 'cdefgh'));
2.         call    fpc_get_output
3.         movq    %rax,%rbx
4.         leaq    U_$P$CHAR_ARR_TEST_$$_S+3(%rip),%rcx
5.         leaq    .Ld2(%rip),%r8
6.         movl    $5,%r9d
7.         movl    $5,%edx
8.         call    P$CHAR_ARR_TEST_$$_SAMECHARS$array_of_ANSICHAR$array_of_ANSICHAR$$BOOLEAN
9.         movb    %al,%r8b
10.         movq    %rbx,%rdx
11.         xorl    %ecx,%ecx
12.         call    fpc_write_text_boolean
13.         call    fpc_iocheck
14.         movq    %rbx,%rcx
15.         call    fpc_writeln_end
16.         call    fpc_iocheck
17.  

There doesn't seem to be any copying.

[Khrys]

Why though? To improve readability?

I do think that  StartsStr(hs,'VTREF')  is more readable than  Copy(hs,1,5)='VTREF',  but ultimately it's up to the compiler devs.

[cdbc]

Hi
My 2 cents worth:
"Why would you want to add an abstraction-layer in a place, where speed counts the most"?!?
...I wouldn't!
In the compiler it's just "Get up and go"  ...no need for syntactic sugar!!!
Regards Benny

[Khrys]

Hi
My 2 cents worth:
"Why would you want to add an abstraction-layer in a place, where speed counts the most"?!?
...I wouldn't!
In the compiler it's just "Get up and go"  ...no need for syntactic sugar!!!
Regards Benny

But  Copy()  creates, well, a copy of the relevant string part and only then does a comparison, while  StartsStr  skips the copying part and does just the comparison - this isn't just syntactic sugar.

[Thaddy]

Doesn't what avk shows contradict this? Btw, his code is repeatable.

[BrunoK]

• ShortString can not be passed to array of AnsiChar
• Your function still means that Copy needs to be used, so you're essentially replacing the =-operator with a function call

So what about :

Code: Pascal  [Select][+][-]

1. program char_arr_test;
2.   {$mode objfpc}
3.  
4.   function SameChars(const L, R: array of ansichar): boolean;
5.   begin
6.     if Length(L) <> Length(R) then exit(False);
7.     if Length(L) = 0 then exit(True);
8.     Result := CompareByte(L[0], R[0], Length(L)) = 0;
9.   end;
10.  
11. var
12.   s, s1: string;
13.   ss, ss1: shortstring;
14.   lAreSame: boolean;
15. begin
16.   s := 'abcdefgh';
17.   s1 := 'cdefg';
18.   s := s + 'i';
19.   s1 := s1 + 'h';
20.   asm      NOP end;
21.   lAreSame := SameChars(s[3..8], s1[1..6]);
22.   // lea r8,[rip+$00010A46]    # $0000000100012111
23.   // lea rcx,[rip+$00010941]    # $0000000100012013
24.   // mov r9d,$00000005
25.   // mov edx,$00000005
26.   // call -$00000112    # $00000001000015D0 SameChars project1.lpr:5
27.   // mov [rip+$00010D28],al
28.   asm      NOP end;
29.   WriteLn(lAreSame);
30.  
31.   ss := s;    // shortstring
32.   ss1 := s1;  // shortstring
33.   asm      NOP end;
34.   lAreSame := SameChars(ss[3..8], ss1[1..6]);
35.   // lea r8,[rip+$00010BC5]    # $0000000100012311
36.   // lea rcx,[rip+$00010AC0]    # $0000000100012213
37.   // mov r9d,$00000005
38.   // mov edx,$00000005
39.   // call -$00000193    # $00000001000015D0 SameChars project1.lpr:5
40.   // mov [rip+$00010CA7],al
41.   asm      NOP end;
42.   WriteLn(lAreSame);
43.  
44.   ReadLn;
45. end.

It compiles and give correct result without any copy generated in the assembler code.

[AlexTP]

Instead of
  lAreSame := SameChars(s[3..8], s1[1..6]);

can we avoid indexes over vars? To keep code more readable.
this is ugly:
  lAreSame := SameChars(prefix[1..Length(prefix)], s1[1..Length(prefix)]);