{
    This file is part of the Free Pascal run time library.
    Copyright (c) 2008 by Giulio Bernardi

    Resource support for non-PECOFF targets (ELF, Mach-O)

    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.

 **********************************************************************}
const
{$if defined(CPUWASM)}
  { Since WebAssembly is a Harvard architecture, the code is invisible in linear
    memory and the data section starts at address 0. Resources reside after the
    initialized data section, just before the bss (uninitialized data) section,
    therefore it's perfectly possible that their data exist on a relatively low
    address (less than 64KB). So, for WebAssembly we check whether the pointer
    resides in the first 4KB of linear memory, instead of the first 64KB. Note
    that the first 4KB of linear memory in WebAssembly aren't used by Free
    Pascal. }
  MaxIntResource=4095;
{$else}
  MaxIntResource=65535;
{$endif}

type
  PResInfoNode = ^TResInfoNode;
  TResInfoNode = packed record
    nameid : PAnsiChar;             //name / integer ID / languageID
    ncounthandle : longword;    //named sub-entries count / resource handle
    idcountsize : longword;     //id sub-entries count / resource size
    subptr : PResInfoNode;      //first sub-entry pointer
  end;

  TResHdr = packed record
    rootptr     : PResInfoNode; //pointer to root node
    count       : longword;     //number of resources in the file
    usedhandles : longword;     //last resource handle used
    handles     : PPtrUint;     //pointer to handles
  end;
  PResHdr = ^TResHdr;
  PPResHdr = ^PResHdr;

  TLibGetResHdr=function():PResHdr;

var
{$ifdef FPC_HAS_WINLIKERESOURCES}
{$ifdef FPC_HAS_INDIRECT_ENTRY_INFORMATION}
  ResHeader : PPResHdr; external name '_FPC_ResLocation';
{$else}
  ResHeaderVar: PResHdr; external name 'FPC_RESLOCATION';
  ResHeader : PPResHdr = @ResHeaderVar;
{$endif}
{$else}
  ResHeaderVar : PResHdr = nil;
  ResHeader : PPResHdr= @ResHeaderVar;
{$endif}

(*****************************************************************************
                             Private Helper Functions
*****************************************************************************)

function ExtGetResHdr(ModuleHandle : TFPResourceHMODULE):PResHdr;
var
  p:TLibGetResHdr;
  pp:pointer;
begin
  ExtGetResHdr:=nil;
  if ModuleHandle=0 then
    ExtGetResHdr:=ResHeader^ // internal
  else
  begin
    // 1-st way to get resource location
    p:=TLibGetResHdr(GetProcAddress(ModuleHandle,'rsrc'));
    if p<>nil then // there is public
      ExtGetResHdr:=p();
    if ExtGetResHdr=nil then // try another way
    begin
      // 2-nd way to get resource location
      pp:=GetProcAddress(ModuleHandle,'FPC_RESLOCATION');
      if pp<>nil then
      ExtGetResHdr:=PResHDR(pp^);
    end;
  end;
end;


//resource functions are case insensitive... copied from genstr.inc
function ResStrIComp(Str1, Str2 : PAnsiChar): SizeInt;
var
  counter: SizeInt;
  c1, c2: AnsiChar;
begin
  counter := 0;
  c1 := upcase(str1[counter]);
  c2 := upcase(str2[counter]);
  while c1 = c2 do
  begin
    if (c1 = #0) or (c2 = #0) then break;
    inc(counter);
    c1 := upcase(str1[counter]);
    c2 := upcase(str2[counter]);
  end;
  ResStrIComp := ord(c1) - ord(c2);
end;

{!fixme!}
//function InternalIsIntResource(aStr : PAnsiChar; out aInt : PtrUint) : boolean;
function InternalIsIntResource(aStr : pansichar; var aInt : PtrUint) : boolean;
var i : integer;
    s : shortstring;
    code : word;
begin
  InternalIsIntResource:=PtrUInt(aStr)<=MaxIntResource;
  if InternalIsIntResource then aInt:=PtrUInt(aStr)
  else
  begin
    //a string like #number specifies an integer id
    if aStr[0]='#' then
    begin
      i:=1;
      while aStr[i]<>#0 do
        inc(i);
      if i>256 then i:=256;
      s[0]:=chr(i-1);
      Move(aStr[1],s[1],i-1);
      Val(s,aInt,code);
      InternalIsIntResource:=code=0;
    end;
  end;
end;

function BinSearchStr(arr : PResInfoNode; query : pansichar; left, right : integer)
: PResInfoNode;
var pivot, res : integer;
    resstr : pansichar;
begin
  BinSearchStr:=nil;
  while left<=right do
  begin
    pivot:=(left+right) div 2;
    resstr:=arr[pivot].nameid;
    res:=ResStrIComp(resstr,query);
    if res<0 then left:=pivot+1
    else if res>0 then right:=pivot-1
    else
    begin
      BinSearchStr:=@arr[pivot];
      exit;
    end;
  end;
end;

function BinSearchInt(arr : PResInfoNode; query : pansichar; left, right : integer)
: PResInfoNode;
var pivot : integer;
begin
  BinSearchInt:=nil;
  while left<=right do
  begin
    pivot:=(left+right) div 2;
    if PtrUint(arr[pivot].nameid)<PtrUInt(query) then left:=pivot+1
    else if PtrUint(arr[pivot].nameid)>PtrUInt(query) then right:=pivot-1
    else
    begin
      BinSearchInt:=@arr[pivot];
      exit;
    end;
  end;
end;

function BinSearchRes(root : PResInfoNode; aDesc : PAnsiChar) : PResInfoNode;
var aID : PtrUint;
begin
  if InternalIsIntResource(aDesc,aID) then
    BinSearchRes:=BinSearchInt(root^.subptr,PAnsiChar(aID),root^.ncounthandle,
      root^.ncounthandle+root^.idcountsize-1)
  else
    BinSearchRes:=BinSearchStr(root^.subptr,aDesc,0,root^.ncounthandle-1);
end;

//Returns a pointer to a name node.
function InternalFindResource(ResHdr:PResHdr;ResourceName, ResourceType: PAnsiChar):
 PResInfoNode;
begin
  InternalFindResource:=nil;
  if ResHdr=nil then exit;
  InternalFindResource:=ResHdr^.rootptr;

  InternalFindResource:=BinSearchRes(InternalFindResource,ResourceType);
  if InternalFindResource<>nil then
    InternalFindResource:=BinSearchRes(InternalFindResource,ResourceName);
end;

function FindSubLanguage(aPtr : PResInfoNode; aLangID : word; aMask: word) : PResInfoNode;
var arr : PResInfoNode;
    i : longword;
begin
  FindSubLanguage:=nil;
  arr:=aPtr^.subptr;
  i:=0;
  while i<aPtr^.idcountsize do
  begin
    if (PtrUInt(arr[i].nameid) and aMask)=(aLangID and aMask) then
    begin
      FindSubLanguage:=@arr[i];
      exit;
    end;
    inc(i);
  end;
end;




(*****************************************************************************
                             Public Resource Functions
*****************************************************************************)

Function IntHINSTANCE : TFPResourceHMODULE;
begin
  IntHINSTANCE:=0;
end;

Function IntEnumResourceTypes(ModuleHandle : TFPResourceHMODULE; EnumFunc : EnumResTypeProc; lParam : PtrInt) : LongBool;
var ptr : PResInfoNode;
    tot, i : integer;
    res_hdr:PResHdr;
begin
  IntEnumResourceTypes:=False;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  tot:=res_hdr^.rootptr^.ncounthandle+res_hdr^.rootptr^.idcountsize;
  ptr:=res_hdr^.rootptr^.subptr;
  IntEnumResourceTypes:=true;
  i:=0;
  while i<tot do
  begin
    if not EnumFunc(ModuleHandle,ptr[i].nameid,lParam) then exit;
    inc(i);
  end;
end;

Function IntEnumResourceNames(ModuleHandle : TFPResourceHMODULE; ResourceType : PAnsiChar; EnumFunc : EnumResNameProc; lParam : PtrInt) : LongBool;
var ptr : PResInfoNode;
    tot, i : integer;
    res_hdr:PResHdr;
begin
  IntEnumResourceNames:=False;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  ptr:=res_hdr^.rootptr;

  ptr:=BinSearchRes(ptr,ResourceType);
  if ptr=nil then exit;
  
  tot:=ptr^.ncounthandle+ptr^.idcountsize;
  ptr:=ptr^.subptr;
  IntEnumResourceNames:=true;
  i:=0;
  while i<tot do
  begin
    if not EnumFunc(ModuleHandle,ResourceType,ptr[i].nameid,lParam) then exit;
    inc(i);
  end;
end;

Function IntEnumResourceLanguages(ModuleHandle : TFPResourceHMODULE; ResourceType, ResourceName : PAnsiChar; EnumFunc : EnumResLangProc; lParam : PtrInt) : LongBool;
var ptr : PResInfoNode;
    tot, i : integer;
    res_hdr:PResHdr;
begin
  IntEnumResourceLanguages:=False;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  ptr:=InternalFindResource(res_hdr,ResourceName,ResourceType);
  if ptr=nil then exit;

  tot:=ptr^.idcountsize;
  ptr:=ptr^.subptr;
  IntEnumResourceLanguages:=true;
  i:=0;
  while i<tot do
  begin
    if not EnumFunc(ModuleHandle,ResourceType,ResourceName,PtrUInt(ptr[i].nameid),lParam) then exit;
    inc(i);
  end;
end;

Function IntFindResource(ModuleHandle: TFPResourceHMODULE; ResourceName,
  ResourceType: PAnsiChar): TFPResourceHandle;
var ptr : PResInfoNode;
    res_hdr: PresHdr;
begin
  IntFindResource:=0;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  ptr:=InternalFindResource(res_hdr,ResourceName,ResourceType);
  if ptr=nil then exit;

  //first language id
  ptr:=ptr^.subptr;
  if ptr^.ncounthandle=0 then
  begin
    res_hdr^.handles[res_hdr^.usedhandles]:=PtrUint(ptr);
    inc(res_hdr^.usedhandles);
    ptr^.ncounthandle:=res_hdr^.usedhandles;
  end;
  IntFindResource:=ptr^.ncounthandle;
end;

Function IntFindResourceEx(ModuleHandle: TFPResourceHMODULE; ResourceType,
  ResourceName: PAnsiChar; Language : word): TFPResourceHandle;
const LANG_NEUTRAL = 0;
      LANG_ENGLISH = 9;
var nameptr,ptr : PResInfoNode;
    res_hdr: PResHdr;
begin
  IntFindResourceEx:=0;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  nameptr:=InternalFindResource(res_hdr,ResourceName,ResourceType);
  if nameptr=nil then exit;

  //try exact match
  ptr:=FindSubLanguage(nameptr,Language,$FFFF);
  //try primary language
  if ptr=nil then
    ptr:=FindSubLanguage(nameptr,Language,$3FF);
  //try language neutral
  if ptr=nil then
    ptr:=FindSubLanguage(nameptr,LANG_NEUTRAL,$3FF);
  //try english
  if ptr=nil then
    ptr:=FindSubLanguage(nameptr,LANG_ENGLISH,$3FF);
  //nothing found, return the first one
  if ptr=nil then
    ptr:=nameptr^.subptr;

  if ptr^.ncounthandle=0 then
  begin
    res_hdr^.handles[res_hdr^.usedhandles]:=PtrUint(ptr);
    inc(res_hdr^.usedhandles);
    ptr^.ncounthandle:=res_hdr^.usedhandles;
  end;
  IntFindResourceEx:=ptr^.ncounthandle;
end;

Function IntLoadResource(ModuleHandle: TFPResourceHMODULE; ResHandle: TFPResourceHandle): TFPResourceHGLOBAL;
var res_hdr: PResHdr;
begin
  IntLoadResource:=0;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  if (ResHandle<=0) or (ResHandle>res_hdr^.usedhandles) then exit;
  IntLoadResource:=TFPResourceHGLOBAL(PResInfoNode(res_hdr^.handles[ResHandle-1])^.subptr);
end;

Function IntSizeofResource(ModuleHandle: TFPResourceHMODULE; ResHandle: TFPResourceHandle): LongWord;
var res_hdr: PResHdr;
begin
  IntSizeofResource:=0;
  res_hdr:=ExtGetResHdr(ModuleHandle);
  if res_hdr=nil then exit;
  if (ResHandle<=0) or (ResHandle>res_hdr^.usedhandles) then exit;
  IntSizeofResource:=PResInfoNode(res_hdr^.handles[ResHandle-1])^.idcountsize;
end;

Function IntLockResource(ResData: TFPResourceHGLOBAL): Pointer;
begin
  IntLockResource:=Nil;
  if ResHeader^=nil then exit;
  IntLockResource:=Pointer(ResData);
end;

Function IntUnlockResource(ResData: TFPResourceHGLOBAL): LongBool;
begin
  IntUnlockResource:=(ResHeader^<>nil);
end;

Function IntFreeResource(ResData: TFPResourceHGLOBAL): LongBool;
begin
  IntFreeResource:=(ResHeader^<>nil);
end;

const
  InternalResourceManager : TResourceManager =
  (
    HINSTANCEFunc : @IntHINSTANCE;
    EnumResourceTypesFunc : @IntEnumResourceTypes;
    EnumResourceNamesFunc : @IntEnumResourceNames;
    EnumResourceLanguagesFunc : @IntEnumResourceLanguages;
    FindResourceFunc : @IntFindResource;
    FindResourceExFunc : @IntFindResourceEx;
    LoadResourceFunc : @IntLoadResource;
    SizeofResourceFunc : @IntSizeofResource;
    LockResourceFunc : @IntLockResource;
    UnlockResourceFunc : @IntUnlockResource;
    FreeResourceFunc : @IntFreeResource;
  );