{
    This file is part of the Free Pascal run time library.
    Copyright (c) 2013 by Yury Sidorov,
    member of the Free Pascal development team.

    Wide string support for Android

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 **********************************************************************}

{$mode objfpc}
{$inline on}
{$implicitexceptions off}

unit cwstring;

interface

procedure SetCWidestringManager;

implementation

uses dynlibs;

type
  UErrorCode = SizeInt;
  int32_t = longint;
  uint32_t = longword;
  PUConverter = pointer;
  PUCollator = pointer;
  UBool = LongBool;

var
  hlibICU: TLibHandle;
  hlibICUi18n: TLibHandle;
  ucnv_open: function (converterName: PAnsiChar; var pErrorCode: UErrorCode): PUConverter; cdecl;
  ucnv_close: procedure (converter: PUConverter); cdecl;
  ucnv_setSubstChars: procedure (converter: PUConverter; subChars: PAnsiChar; len: byte; var pErrorCode: UErrorCode); cdecl;
  ucnv_setFallback: procedure (cnv: PUConverter; usesFallback: UBool); cdecl;
  ucnv_fromUChars: function (cnv: PUConverter; dest: PAnsiChar; destCapacity: int32_t; src: PUnicodeChar; srcLength: int32_t; var pErrorCode: UErrorCode): int32_t; cdecl;
  ucnv_toUChars: function (cnv: PUConverter; dest: PUnicodeChar; destCapacity: int32_t; src: PAnsiChar; srcLength: int32_t; var pErrorCode: UErrorCode): int32_t; cdecl;
  u_strToUpper: function (dest: PUnicodeChar; destCapacity: int32_t; src: PUnicodeChar; srcLength: int32_t; locale: PAnsiChar; var pErrorCode: UErrorCode): int32_t; cdecl;
  u_strToLower: function (dest: PUnicodeChar; destCapacity: int32_t; src: PUnicodeChar; srcLength: int32_t; locale: PAnsiChar; var pErrorCode: UErrorCode): int32_t; cdecl;
  u_strCompare: function (s1: PUnicodeChar; length1: int32_t; s2: PUnicodeChar; length2: int32_t; codePointOrder: UBool): int32_t; cdecl;
  u_strCaseCompare: function (s1: PUnicodeChar; length1: int32_t; s2: PUnicodeChar; length2: int32_t; options: uint32_t; var pErrorCode: UErrorCode): int32_t; cdecl;

  ucol_open: function(loc: PAnsiChar; var status: UErrorCode): PUCollator; cdecl;
  ucol_close: procedure (coll: PUCollator); cdecl;
  ucol_strcoll: function (coll: PUCollator; source: PUnicodeChar; sourceLength: int32_t; target: PUnicodeChar; targetLength: int32_t): int32_t; cdecl;
	ucol_setStrength: procedure (coll: PUCollator; strength: int32_t); cdecl;
  u_errorName: function (code: UErrorCode): PAnsiChar; cdecl;

  DefConv, LastConv: PUConverter;
  LastCP: TSystemCodePage;
  DefColl: PUCollator;

function OpenConverter(const name: ansistring): PUConverter;
var
  err: UErrorCode;
begin
  err:=0;
  Result:=ucnv_open(PAnsiChar(name), err);
  if Result <> nil then begin
    ucnv_setSubstChars(Result, '?', 1, err);
    ucnv_setFallback(Result, True);
  end;
end;

function GetConverter(cp: TSystemCodePage): PUConverter;
var
  s: ansistring;
begin
  if hlibICU = 0 then begin
    Result:=nil;
    exit;
  end;
  if (cp = DefaultSystemCodePage) or (cp = CP_ACP) then
    Result:=DefConv
  else begin
    if cp <> LastCP then begin
      Str(cp, s);
      LastConv:=OpenConverter('cp' + s);
      LastCP:=cp;
    end;
    Result:=LastConv;
  end;
end;

procedure Unicode2AnsiMove(source: PUnicodeChar; var dest: RawByteString; cp: TSystemCodePage; len: SizeInt);
var
  len2: SizeInt;
  conv: PUConverter;
  err: UErrorCode;
begin
  if len = 0 then begin
    dest:='';
    exit;
  end;
  conv:=GetConverter(cp);
  if conv = nil then begin
    DefaultUnicode2AnsiMove(source,dest,DefaultSystemCodePage,len);
    exit;
  end;

  len2:=len*3;
  SetLength(dest, len2);
  err:=0;
  len2:=ucnv_fromUChars(conv, PAnsiChar(dest), len2, source, len, err);
  if len2 > Length(dest) then begin
    SetLength(dest, len2);
    err:=0;
    len2:=ucnv_fromUChars(conv, PAnsiChar(dest), len2, source, len, err);
  end;
  SetLength(dest, len2);
  SetCodePage(dest, cp, False);
end;

procedure Ansi2UnicodeMove(source:pchar;cp : TSystemCodePage;var dest:unicodestring;len:SizeInt);
var
  len2: SizeInt;
  conv: PUConverter;
  err: UErrorCode;
begin
  if len = 0 then begin
    dest:='';
    exit;
  end;
  conv:=GetConverter(cp);
  if conv = nil then begin
    DefaultAnsi2UnicodeMove(source,DefaultSystemCodePage,dest,len);
    exit;
  end;

  len2:=len;
  SetLength(dest, len2);
  err:=0;
  len2:=ucnv_toUChars(conv, PUnicodeChar(dest), len2, source, len, err);
  if len2 > Length(dest) then begin
    SetLength(dest, len2);
    err:=0;
    len2:=ucnv_toUChars(conv, PUnicodeChar(dest), len2, source, len, err);
  end;
  SetLength(dest, len2);
end;

function UpperUnicodeString(const s : UnicodeString) : UnicodeString;
var
  len, len2: SizeInt;
  err: UErrorCode;
begin
  if hlibICU = 0 then begin
    // fallback implementation
    Result:=UnicodeString(UpCase(AnsiString(s)));
    exit;
  end;
  len:=Length(s);
  SetLength(Result, len);
  if len = 0 then
    exit;
  err:=0;
  len2:=u_strToUpper(PUnicodeChar(Result), len, PUnicodeChar(s), len, nil, err);
  if len2 > len then begin
    SetLength(Result, len2);
    err:=0;
    len2:=u_strToUpper(PUnicodeChar(Result), len2, PUnicodeChar(s), len, nil, err);
  end;
  SetLength(Result, len2);
end;

function LowerUnicodeString(const s : UnicodeString) : UnicodeString;
var
  len, len2: SizeInt;
  err: UErrorCode;
begin
  if hlibICU = 0 then begin
    // fallback implementation
    Result:=UnicodeString(LowerCase(AnsiString(s)));
    exit;
  end;
  len:=Length(s);
  SetLength(Result, len);
  if len = 0 then
    exit;
  err:=0;
  len2:=u_strToLower(PUnicodeChar(Result), len, PUnicodeChar(s), len, nil, err);
  if len2 > len then begin
    SetLength(Result, len2);
    err:=0;
    len2:=u_strToLower(PUnicodeChar(Result), len2, PUnicodeChar(s), len, nil, err);
  end;
  SetLength(Result, len2);
end;

function _CompareStr(const S1, S2: UnicodeString): PtrInt;
var
  count, count1, count2: SizeInt;
begin
  result := 0;
  Count1 := Length(S1);
  Count2 := Length(S2);
  if Count1>Count2 then
    Count:=Count2
  else
    Count:=Count1;
  result := CompareByte(PUnicodeChar(S1)^, PUnicodeChar(S2)^, Count*SizeOf(UnicodeChar));
  if result=0 then
    result:=Count1 - Count2;
end;

function CompareUnicodeString(const s1, s2 : UnicodeString) : PtrInt;
begin
  if hlibICU = 0 then begin
    // fallback implementation
    Result:=_CompareStr(s1, s2);
    exit;
  end;
  if DefColl <> nil then
    Result:=ucol_strcoll(DefColl, PUnicodeChar(s1), Length(s1), PUnicodeChar(s2), Length(s2))
  else
    Result:=u_strCompare(PUnicodeChar(s1), Length(s1), PUnicodeChar(s2), Length(s2), True);
end;

function CompareTextUnicodeString(const s1, s2 : UnicodeString): PtrInt;
const
  U_COMPARE_CODE_POINT_ORDER = $8000;
var
  err: UErrorCode;
begin
  if hlibICU = 0 then begin
    // fallback implementation
    Result:=_CompareStr(UpperUnicodeString(s1), UpperUnicodeString(s2));
    exit;
  end;
  err:=0;
  Result:=u_strCaseCompare(PUnicodeChar(s1), Length(s1), PUnicodeChar(s2), Length(s2), U_COMPARE_CODE_POINT_ORDER, err);
end;

function UpperAnsiString(const s : AnsiString) : AnsiString;
begin
  Result:=AnsiString(UpperUnicodeString(UnicodeString(s)));
end;

function LowerAnsiString(const s : AnsiString) : AnsiString;
begin
  Result:=AnsiString(LowerUnicodeString(UnicodeString(s)));
end;

function CompareStrAnsiString(const s1, s2: ansistring): PtrInt;
begin
  Result:=CompareUnicodeString(UnicodeString(s1), UnicodeString(s2));
end;

function StrCompAnsi(s1,s2 : PChar): PtrInt;
begin
  Result:=CompareUnicodeString(UnicodeString(s1), UnicodeString(s2));
end;

function AnsiCompareText(const S1, S2: ansistring): PtrInt;
begin
  Result:=CompareTextUnicodeString(UnicodeString(s1), UnicodeString(s2));
end;

function AnsiStrIComp(S1, S2: PChar): PtrInt;
begin
  Result:=CompareTextUnicodeString(UnicodeString(s1), UnicodeString(s2));
end;

function AnsiStrLComp(S1, S2: PChar; MaxLen: PtrUInt): PtrInt;
begin
  Result:=CompareUnicodeString(UnicodeString(Copy(s1, 1, MaxLen)), UnicodeString(Copy(s2, 1, MaxLen)));
end;

function AnsiStrLIComp(S1, S2: PChar; MaxLen: PtrUInt): PtrInt;
begin
  Result:=CompareTextUnicodeString(UnicodeString(Copy(s1, 1, MaxLen)), UnicodeString(Copy(s2, 1, MaxLen)));
end;

function AnsiStrLower(Str: PChar): PChar;
var
  s, res: ansistring;
begin
  s:=Str;
  res:=LowerAnsiString(s);
  if Length(res) > Length(s) then
    SetLength(res, Length(s));
  Move(PAnsiChar(res)^, Str, Length(res) + 1);
  Result:=Str;
end;

function AnsiStrUpper(Str: PChar): PChar;
var
  s, res: ansistring;
begin
  s:=Str;
  res:=UpperAnsiString(s);
  if Length(res) > Length(s) then
    SetLength(res, Length(s));
  Move(PAnsiChar(res)^, Str, Length(res) + 1);
  Result:=Str;
end;

function CodePointLength(const Str: PChar; MaxLookAead: PtrInt): Ptrint;
var
  c: byte;
begin
  // Only UTF-8 encoding is supported
  c:=byte(Str^);
  if c =  0 then
    Result:=0
  else begin
    Result:=1;
    if c < $80 then
      exit; // 1-byte ASCII char
    while c and $C0 = $C0 do begin
      Inc(Result);
      c:=c shl 1;
    end;
    if Result > 6 then
      Result:=1 // Invalid code point
    else
      if Result > MaxLookAead then
        Result:=-1; // Incomplete code point
  end;
end;

function GetStandardCodePage(const stdcp: TStandardCodePageEnum): TSystemCodePage;
begin
  Result := CP_UTF8; // Android always uses UTF-8
end;

{$i textrec.inc}
procedure SetStdIOCodePage(var T: Text); inline;
begin
  case TextRec(T).Mode of
    fmInput:TextRec(T).CodePage:=DefaultSystemCodePage;
    fmOutput:TextRec(T).CodePage:=DefaultSystemCodePage;
  end;
end;

procedure SetStdIOCodePages; inline;
begin
  SetStdIOCodePage(Input);
  SetStdIOCodePage(Output);
  SetStdIOCodePage(ErrOutput);
  SetStdIOCodePage(StdOut);
  SetStdIOCodePage(StdErr);
end;

procedure Ansi2WideMove(source:pchar; cp:TSystemCodePage; var dest:widestring; len:SizeInt);
var
  us: UnicodeString;
begin
  Ansi2UnicodeMove(source,cp,us,len);
  dest:=us;
end;

function UpperWideString(const s : WideString) : WideString;
begin
  Result:=UpperUnicodeString(s);
end;

function LowerWideString(const s : WideString) : WideString;
begin
  Result:=LowerUnicodeString(s);
end;

function CompareWideString(const s1, s2 : WideString) : PtrInt;
begin
  Result:=CompareUnicodeString(s1, s2);
end;

function CompareTextWideString(const s1, s2 : WideString): PtrInt;
begin
  Result:=CompareTextUnicodeString(s1, s2);
end;

Procedure SetCWideStringManager;
Var
  CWideStringManager : TUnicodeStringManager;
begin
  CWideStringManager:=widestringmanager;
  With CWideStringManager do
    begin
      Wide2AnsiMoveProc:=@Unicode2AnsiMove;
      Ansi2WideMoveProc:=@Ansi2WideMove;
      UpperWideStringProc:=@UpperWideString;
      LowerWideStringProc:=@LowerWideString;
      CompareWideStringProc:=@CompareWideString;
      CompareTextWideStringProc:=@CompareTextWideString;

      UpperAnsiStringProc:=@UpperAnsiString;
      LowerAnsiStringProc:=@LowerAnsiString;
      CompareStrAnsiStringProc:=@CompareStrAnsiString;
      CompareTextAnsiStringProc:=@AnsiCompareText;
      StrCompAnsiStringProc:=@StrCompAnsi;
      StrICompAnsiStringProc:=@AnsiStrIComp;
      StrLCompAnsiStringProc:=@AnsiStrLComp;
      StrLICompAnsiStringProc:=@AnsiStrLIComp;
      StrLowerAnsiStringProc:=@AnsiStrLower;
      StrUpperAnsiStringProc:=@AnsiStrUpper;

      Unicode2AnsiMoveProc:=@Unicode2AnsiMove;
      Ansi2UnicodeMoveProc:=@Ansi2UnicodeMove;
      UpperUnicodeStringProc:=@UpperUnicodeString;
      LowerUnicodeStringProc:=@LowerUnicodeString;
      CompareUnicodeStringProc:=@CompareUnicodeString;
      CompareTextUnicodeStringProc:=@CompareTextUnicodeString;

      GetStandardCodePageProc:=@GetStandardCodePage;
      CodePointLengthProc:=@CodePointLength;
    end;
  SetUnicodeStringManager(CWideStringManager);
end;

procedure UnloadICU;
begin
  if hlibICUi18n <> 0 then begin
    if DefColl <> nil then
      ucol_close(DefColl);
    UnloadLibrary(hlibICUi18n);
    hlibICUi18n:=0;
  end;
  if hlibICU <> 0 then begin
    if DefConv <> nil then
      ucnv_close(DefConv);
    if LastConv <> nil then
      ucnv_close(LastConv);
    UnloadLibrary(hlibICU);
    hlibICU:=0;
  end;
end;

procedure LoadICU;
var
  LibVer: ansistring;

  function _GetProc(const Name: AnsiString; out ProcPtr; hLib: TLibHandle = 0): boolean;
  var
    p: pointer;
  begin
    if hLib = 0 then
      hLib:=hlibICU;
    p:=GetProcedureAddress(hlib, Name + LibVer);
    if p = nil then begin
      // unload lib on failure
      UnloadICU;
      Result:=False;
    end
    else begin
      pointer(ProcPtr):=p;
      Result:=True;
    end;
  end;

const
  ICUver: array [1..4] of ansistring = ('3_8', '4_2', '44', '46');
  TestProcName = 'ucnv_open';

var
  err: UErrorCode;
  i: longint;
  s: ansistring;
begin
  hlibICU:=LoadLibrary('libicuuc.so');
  hlibICUi18n:=LoadLibrary('libicui18n.so');
  if (hlibICU = 0) or (hlibICUi18n = 0) then begin
    UnloadICU;
    exit;
  end;
  // Finding ICU version using known versions table
  for i:=High(ICUver) downto Low(ICUver) do begin
    s:='_' + ICUver[i];
    if GetProcedureAddress(hlibICU, TestProcName + s) <> nil then begin
      LibVer:=s;
      break;
    end;
  end;

  if LibVer = '' then begin
    // Finding unknown ICU version
    Val(ICUver[High(ICUver)], i);
    for i:=i + 1 to 100 do begin
      Str(i, s);
      s:='_'  + s;
      if GetProcedureAddress(hlibICU, TestProcName + s) <> nil then begin
        LibVer:=s;
        break;
      end;
    end;
  end;

  if LibVer = '' then begin
    // Trying versionless name
    if GetProcedureAddress(hlibICU, TestProcName) = nil then begin
      // Unable to get ICU version
      UnloadICU;
      exit;
    end;
  end;

  if not _GetProc('ucnv_open', ucnv_open) then exit;
  if not _GetProc('ucnv_close', ucnv_close) then exit;
  if not _GetProc('ucnv_setSubstChars', ucnv_setSubstChars) then exit;
  if not _GetProc('ucnv_setFallback', ucnv_setFallback) then exit;
  if not _GetProc('ucnv_fromUChars', ucnv_fromUChars) then exit;
  if not _GetProc('ucnv_toUChars', ucnv_toUChars) then exit;
  if not _GetProc('u_strToUpper', u_strToUpper) then exit;
  if not _GetProc('u_strToLower', u_strToLower) then exit;
  if not _GetProc('u_strCompare', u_strCompare) then exit;
  if not _GetProc('u_strCaseCompare', u_strCaseCompare) then exit;

  if not _GetProc('u_errorName', u_errorName) then exit;

  if not _GetProc('ucol_open', ucol_open, hlibICUi18n) then exit;
  if not _GetProc('ucol_close', ucol_close, hlibICUi18n) then exit;
  if not _GetProc('ucol_strcoll', ucol_strcoll, hlibICUi18n) then exit;
  if not _GetProc('ucol_setStrength', ucol_setStrength, hlibICUi18n) then exit;

  DefConv:=OpenConverter('utf8');
  err:=0;
  DefColl:=ucol_open(nil, err);
  if DefColl <> nil then
    ucol_setStrength(DefColl, 2);
end;

initialization
  DefaultSystemCodePage:=GetStandardCodePage(scpAnsi);
  DefaultUnicodeCodePage:=CP_UTF16;
  LoadICU;
  SetCWideStringManager;
  SetStdIOCodePages;

finalization
  UnloadICU;

end.