main.c

/*
    This file is part of "Filter Foundry", a filter plugin for Adobe Photoshop
    Copyright (C) 2003-2009 Toby Thain, toby@telegraphics.net
    Copyright (C) 2018-2023 Daniel Marschall, ViaThinkSoft

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    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.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

//#include <stdio.h>
//#include <sound.h>

#include "ff.h"

#include "str.h"
#include "node.h"
#include "funcs.h"
#include "y.tab.h"
#include "scripting.h"
#include <math.h>
#include "PIBufferSuite.h"

// GIMP (PSPI) and IrfanView preserve neither *data(gdata), nor pb->parameters between invocations!
// For debugging, we can simulate it here
//#define DEBUG_SIMULATE_GIMP

// Used to find out which host signatures and memory settings a plugin host has
//#define SHOW_HOST_DEBUG

// Here are working variables:

struct node *tree[4];
TCHAR *err[4];
int errpos[4],errstart[4],nplanes,cnvused,chunksize,toprow;
value_type cell[NUM_CELLS];

globals_t *gdata; // this is the only memory area that keeps preserved by Photoshop:
FilterRecordPtr gpb;

#ifdef MAC_ENV
#define HINSTANCE HANDLE
#define hDllInstance NULL /* fake this Windows-only global */
#endif

#ifdef WIN_ENV
#include "manifest.h"
#endif

extern struct sym_rec predefs[];
extern int nplanes,varused[];

int checkandinitparams(Handle params);

// MPW MrC requires prototype
DLLEXPORT MACPASCAL
void ENTRYPOINT(short selector,FilterRecordPtr pb,intptr_t *data,short *result);

unsigned long parm_hash(PARM_T *parm) {
	unsigned long hash;
	int i;

	hash = djb2(parm->szCategory);
	hash += djb2(parm->szTitle);
	hash += djb2(parm->szCopyright);
	hash += djb2(parm->szAuthor);
	for (i = 0; i < 4; i++) hash += djb2(parm->szMap[i]);
	for (i = 0; i < 8; i++) hash += djb2(parm->szCtl[i]);
	for (i = 0; i < 4; i++) hash += djb2(parm->szFormula[i]);

	return hash;
}

size_t get_temp_afs(TCHAR* outfilename, Boolean isStandalone, PARM_T *parm) {
	char* atempdir;
	int hash;
	size_t i, j;
	TCHAR out[MAX_PATH + 1];
	char ahash[20];

	// out = getenv("TMP")
	atempdir = getenv("TMP");
	for (i = 0; i < strlen(atempdir); i++) {
		out[i] = (TCHAR)atempdir[i];
		out[i + 1] = 0;
	}

	#ifdef WIN_ENV
	if (xstrlen(out) > 0) xstrcat(out, TEXT("\\"));
	#else
	if (xstrlen(out) > 0) xstrcat(out, TEXT("/"));
	#endif

	hash = (isStandalone) ? parm_hash(parm) : 0;

	// sprintf(outfilename, "%sFilterFoundry%d.afs", atempdir, hash);
	xstrcat(out, TEXT("FilterFoundry"));
	_itoa(hash, &ahash[0], 10);
	for (i = 0; i < strlen(ahash); i++) {
		j = xstrlen(out);
		out[j] = (TCHAR)ahash[i];
		out[j + 1] = 0;
	}
	xstrcat(out, TEXT(".afs"));
	if (outfilename != NULL) {
		xstrcpy(outfilename, out);
	}
	return xstrlen(out);
}

char* stristr(const char* str, const char* strSearch) {
	// Source: https://stackoverflow.com/questions/27303062/strstr-function-like-that-ignores-upper-or-lower-case
	char *sors, *subs, *res = NULL;
	if ((sors = _strdup(str)) != NULL) {
		if ((subs = _strdup(strSearch)) != NULL) {
			res = strstr(_strlwr(sors), _strlwr(subs));
			if (res != NULL)
				res = (char*)str + (res - sors);
			free(subs);
		}
		free(sors);
	}
	return res;
}

#ifdef WIN_ENV
BOOL CalledFromRunDLL32(HINSTANCE hinst) {
	char exename[MAX_PATH];
	if (GetModuleFileNameA(hinst, exename, MAX_PATH) == 0) return false;
	return stristr(exename, "rundll32") != NULL;
}
#endif

#ifdef WIN_ENV
void CALLBACK FakeRundll32(HWND hwnd, HINSTANCE hinst, LPSTR lpszCmdLine, int nCmdShow) {
	UNREFERENCED_PARAMETER(hwnd);
	UNREFERENCED_PARAMETER(hinst);
	UNREFERENCED_PARAMETER(lpszCmdLine);
	UNREFERENCED_PARAMETER(nCmdShow);

	/*
	char* tmp = (char*)malloc(512);
	if (tmp != 0) {
		sprintf(tmp, "hwnd: %p\nhinst: %p\nlpszCmdLine: %s\nCmdShow: %d", (void*)(hwnd), (void*)(hinst), lpszCmdLine, nCmdShow);
		MessageBoxA(0, tmp, 0, 0);
		free(tmp);
	}
	*/

	simplealert_id(MSG_RUNDLL_ERR_ID);

	return;
}
#endif

/**
Register the global variable `gdata` that contains the PARM information and other things which need to be persistant
and preserve them in `*data`.
This memory allocation is never freed, because the filter can always be invoked again.
The memory allocation will be kept for the lifetime of the Photoshop process and
freed together with the application termination.
*/
void CreateDataPointer(intptr_t* data) {
	// We have at least 5 options to allocate memory:

	// (Method 1)
	// 1. The deprecated Standard Buffer Suite (pb->bufferProcs) - works fine!
	/*
	BufferID tempId;
	if (gpb->bufferProcs->allocateProc(sizeof(globals_t), &tempId) != noErr) {
		*data = NULL;
	}
	else {
		*data = (void*)gpb->bufferProcs->lockProc(tempId, true);
		if (*data) memset((void*)*data, 0, sizeof(globals_t));
	}
	*/

	// (Method 2) *DOES NOT WORK*
	// 2. The recommended buffer suite (kPSBufferSuite),
	//    It does not work, since it causes memory corruption when the filter is invoked a second time.
	//    Probably the BufferSuite cannot be used to share data between filter invocations?
	//    Also, the buffer suite is only available on the Adobe Photoshop host application.
	/*
	FFBuffer buf;
	newBuffer(&buf, sizeof(globals_t));
	*data = (intptr_t)lockBuffer(&buf);
	if (*data) memset((void*)*data, 0, sizeof(globals_t));
	*/

	// (Method 3)
	// 3. Using malloc(), which works also fine and is more independent from the host. It is also easier.
	//    However, we do not know how malloc() is implemented, and it might cause problems if the
	//    DLL is unloaded between invocations.
	/*
	*data = (intptr_t)malloc(sizeof(globals_t));
	if (*data) memset((void*)*data, 0, sizeof(globals_t));
	*/

	// (Method 4)
	// 4. Using PLUGIN.DLL:NewPtr(). This does FilterFactory 3.0.4, but requires an Adobe host.
	//    In Plugin.dll, the function NewPtr() and NewPtrClear() are implemented as GlobalAlloc/GlobalLock.
	//    Nothing special.

	// (Method 5)
	// 5. Using GlobalAlloc/GlobalLock. This does FilterFactory 3.00 (Flags GHND = GMEM_MOVEABLE and GMEM_ZEROINIT).
	//    This is Windows dependant. (However, on Mac we will just call NewPtr.)
	//    GlobalAlloc and LocalAlloc are equal in 32-bit windows. The memory allocation is NOT global anymore,
	//    instead it is on the private heap of the application. (Therefore we do not cause a leak when
	//    Photoshop is closed).
	// In Filter Foundry 1.7.0.17 we define a function called NewPtrClear, which is natively supported by Mac,
	// and in Windows it will be implemented using GlobalAlloc/GlobalLock.
	*data = (intptr_t)NewPtrClear(sizeof(globals_t));
}

DLLEXPORT MACPASCAL
void ENTRYPOINT(short selector, FilterRecordPtr pb, intptr_t *data, short *result){
	static Boolean wantdialog = false;
	static Boolean premiereWarnedOnce = false;

	#ifdef SHOW_HOST_DEBUG
	char* tmp;
	#endif

	#ifdef WIN_ENV
	// For Windows, we use an activation context to enforce that our Manifest resource will
	// be used. This allows us to use Visual Styles, even if the host application does not
	// support it.
	ManifestActivationCtx manifestVars;
	BOOL activationContextUsed;
	#endif

	// ---------------------------------------------------------------------

	EnterCodeResource();

	#ifdef WIN_ENV
	activationContextUsed = ActivateManifest((HMODULE)hDllInstance, 1, &manifestVars);
	#endif

	#ifdef WIN_ENV
	if ((intptr_t)result == SW_SHOWDEFAULT && CalledFromRunDLL32((HINSTANCE)pb)) {
		// When the 8BF file is analyzed with VirusTotal.com, it will invoke each
		// exported function by calling
		// loaddll64.exe 'C:\Users\user\Desktop\attachment.dll'
		//	  ==>  rundll32.exe C:\Users\user\Desktop\attachment.dll,PluginMain
		//	     ==> C:\Windows\system32\WerFault.exe -u -p 6612 -s 480
		//
		// But RunDLL32 requires the following signature:
		//    void __stdcall EntryPoint(HWND hwnd,      HINSTANCE hinst,    LPSTR lpszCmdLine, int nCmdShow);
		// Our signature is:
		//    void           PluginMain(short selector, FilterRecordPtr pb, intptr_t *data,    short *result);
		//
		// Obviously, this will cause an Exception. (It crashes at *result=e because result is 0xA, which is SW_SHOWDEFAULT)
		// Here is the problem: The crash will be handled by WerFault.exe inside the
		// VirusTotal virtual machine. WerFault connects to various servers (9 DNS resolutions!) and does
		// a lot of weird things, but VirusTotal thinks that our plugin does all that stuff,
		// and so they mark our plugin as "malware"!
		// This is a problem with VirusTotal! It shall not assume that WerFault.exe actions are our actions!
		// Even actions from processes like "MicrosoftEdgeUpdate.exe" and "SpeechRuntime.exe" are reported to be our
		// actions, although they have nothing to do with us!
		// See https://www.virustotal.com/gui/file/1f1012c567208186be455b81afc1ee407ae6476c197d633c70cc70929113223a/behavior
		//
		// Note in re "*result": Usually, The first 64KB of address space are always invalid. However, in Win32s (Windows 3.11), the
		// variable "result" is <=0xFFFF. So we cannot assume that result<=0xFFFF means that the call came from RunDLL32.

		FakeRundll32((HWND)(intptr_t)selector, (HINSTANCE)pb, (LPSTR)data, (int)(intptr_t)result);
		// (I don't understand why this works! Aren't we __cdecl and rundll expected __stdcall? But why is the parameter order correct and not reversed?)

		goto endmain;
	}
	#endif

	// will be changed if an error happens
	*result = noErr;

	#ifdef SHOW_HOST_DEBUG
	tmp = (char*)malloc(512);
	sprintf(tmp, "Host signature: '%c%c%c%c' (%d)\nMaxSpace32 = %d\nMaxSpace64 = %lld\nNum buffer procs: %d", (pb->hostSig >> 24) & 0xFF, (pb->hostSig >> 16) & 0xFF, (pb->hostSig >> 8) & 0xFF, pb->hostSig & 0xFF, pb->hostSig, pb->maxSpace, pb->maxSpace64, pb->bufferProcs == 0 ? -999/*About has no BufferProcs*/ : pb->bufferProcs->numBufferProcs);
	simplealert(tmp);
	free(tmp);
	#endif

	if (pb->hostSig == HOSTSIG_ADOBE_PREMIERE) {
		// DM 19.07.2021 : Tried running the 8BF file in Adobe Premiere 5 + Win98
		// (yes, that's possible, and there is even a FilterFactory for Premiere!),
		// but it crashes in evalpixel() where there is write-access to the "outp".
		// DM 24.04.2022 : On Adobe Premiere 6 + Win10, the filter opens sometimes (and sometimes crashes inside DialogBoxParam),
		// but the filter is not applied when you click "OK" (because it crashes internally; only the debugger sees it)...
		// Maybe the canvas structure is different (maybe it contains frames to achieve transitions?)
		// TODO: make Filter Foundry compatible with Premiere!
		if (!premiereWarnedOnce) {
			simplealert_id(MSG_PREMIERE_COMPAT_ID);
		}
		premiereWarnedOnce = true;
		*result = errPlugInHostInsufficient;
		goto endmain;
	}

	#ifdef DEBUG_SIMULATE_GIMP
	*data = 0;
	pb->parameters = pb->handleProcs->newProc(1);
	#endif

	gpb = pb; // required for CreateDataPointer()

	if (selector != filterSelectorAbout && !*data) {
		// The filter was never called before. We allocate (zeroed) memory now.
		CreateDataPointer(data);
		if (!*data) {
			*result = memFullErr;
			goto endmain;
		}
	}

	gdata = (globals_t*)*data;

	nplanes = MIN(pb->planes,4);

	switch (selector){
	case filterSelectorAbout:
		if (!gdata) {
			Boolean parmReadOk;
			// This is a temporary gdata structure just for the About dialog!
			// Not to be confused with the "real" gdata during the filter invocation (containing more data).
			gdata = (globals_t*)malloc(sizeof(globals_t));
			if (!gdata) break;
			gdata->hWndMainDlg = (HWND)((PlatformData*)((AboutRecordPtr)pb)->platformData)->hwnd; // so that simplealert() works
			parmReadOk = (LOADING_OK == readPARMresource((HMODULE)hDllInstance));
			if (!parmReadOk) gdata->parm.standalone = false;
			if (parmReadOk && (gdata->parm.cbSize != PARM_SIZE) && (gdata->parm.cbSize != PARM_SIZE_PREMIERE) && (gdata->parm.cbSize != PARM_SIG_MAC)) {
				parm_reset(true, true, true, true);
				if (gdata->obfusc) {
					simplealert_id(MSG_INCOMPATIBLE_OBFUSCATION_ID);
				}
				else {
					simplealert_id(MSG_INVALID_PARAMETER_DATA_ID);
				}
			}
			else {
				DoAbout((AboutRecordPtr)pb);
			}
			free(gdata);
			gdata = NULL;
		} else {
			DoAbout((AboutRecordPtr)pb);
		}
		break;
	case filterSelectorParameters:
		wantdialog = true;
		break;
	case filterSelectorPrepare:
		gdata->hWndMainDlg = 0;
		DoPrepare(pb);
		init_symtab(predefs); // ready for parser calls
		init_trigtab();
		break;
	case filterSelectorStart:
		if (HAS_BIG_DOC(pb)) {
			// The BigDocument structure is required if the document is larger than 30,000 pixels
			// It deprecates imageSize, filterRect, inRect, outRect, maskRect, floatCoord, and wholeSize.
			// By setting it to nonzero, we communicate to Photoshop that we support the BigDocument structure.
			pb->bigDocumentData->PluginUsing32BitCoordinates = true;
		}

		/* initialise the parameter handle that Photoshop keeps for us */
		if(!pb->parameters)
			pb->parameters = PINEWHANDLE(1); // don't set initial size to 0, since some hosts (e.g. GIMP/PSPI) are incompatible with that.

		if (!pb->parameters) {
			*result = memFullErr;
		}
		else
		{
			wantdialog |= checkandinitparams(pb->parameters);

			/* wantdialog = false means that we never got a Parameters call, so we're not supposed to ask user */
			if (wantdialog && (!gdata->parm.standalone || gdata->parm.popDialog)) {
				if (maindialog(pb)) {
					if (!host_preserves_parameters()) {
						/* Workaround for GIMP/PSPI, to avoid that formulas vanish when you re-open the main window.
						   The reason is a bug in PSPI: The host should preserve the value of pb->parameters, which PSPI does not do.
						   Also, all global variables are unloaded, so the plugin cannot preserve any data.
						   Workaround in FF 1.7: If the host GIMP is detected, then a special mode will be activated.
						   This mode saves the filter data into a temporary file "FilterFoundryXX.afs" and loads it
						   when the window is opened again. */
						   // Workaround: Save settings in "FilterFoundryXX.afs" if the host does not preserve pb->parameters
						TCHAR outfilename[MAX_PATH + 1];
						StandardFileReply sfr;
						InternalState tmpState;
						FFSavingResult saveres;

						sfr.sfGood = true;
						sfr.sfReplacing = true;
						sfr.sfType = PS_FILTER_FILETYPE;

						get_temp_afs(&outfilename[0], gdata->parm.standalone, &gdata->parm);

						xstrcpy(sfr.sfFile.szName, outfilename);
						#ifdef WIN_ENV
						sfr.nFileExtension = (WORD)(xstrlen(outfilename) - strlen(".afs") + 1);
						#endif
						sfr.sfScript = smSystemScript;

						// We only want the parameters (ctl,map) in the temporary .afs file
						// It is important to remove the expressions, otherwise they would be
						// revealed in the temporary files (That might be bad for obfuscated filters).
						if (gdata->parm.standalone) {
							tmpState = saveInternalState();
							parm_reset(false, false, false, true);
						}

						saveres = savefile_afs_pff_picotxt_guf(&sfr);

						if (gdata->parm.standalone) {
							restoreInternalState(tmpState);
						}

						if (saveres != SAVING_OK) {
							TCHAR* reason = FF_GetMsg_Cpy(saveres);
							alertuser_id(MSG_CANNOT_SAVE_SETTINGS_ID, reason);
							FF_GetMsg_Free(reason);
							*result = filterBadParameters;
						}
					}
					else {
						/* update stored parameters from new user settings */
						if (pb->parameters)
							saveparams_afs_pff(pb->parameters, false);
					}
				}
				else
					*result = userCanceledErr;
			}
			wantdialog = false;
		}

		if(*result == noErr){
			if(setup(pb)){
				DoStart(pb);
			}else{
				simplealert_id(MSG_SAVED_EXPR_ERR_ID);
				*result = filterBadParameters;
			}
		}
		break;
	case filterSelectorContinue:
		*result = DoContinue(pb);
		break;
	case filterSelectorFinish:
		DoFinish(pb);
		break;
	default:
		*result = filterBadParameters;
	}

endmain:

	// TODO: Question: Is that OK to call this at every invocation, or should it be only around UI stuff?
	#ifdef WIN_ENV
	if (activationContextUsed) DeactivateManifest(&manifestVars);
	#endif

	ExitCodeResource();
}

void parm_reset(Boolean resetMetadata, Boolean resetSliderValues, Boolean resetSliderNames, Boolean resetFormulas) {
	gdata->parm.cbSize = PARM_SIZE;
	if (resetMetadata) {
		strcpy(gdata->parm.szCategory, "Filter Foundry");
		strcpy(gdata->parm.szTitle, "Untitled");
		strcpy(gdata->parm.szCopyright, ""); //"Filter Foundry Copyright (C) 2003-2009 Toby Thain, 2018-" RELEASE_YEAR " Daniel Marschall"
		strcpy(gdata->parm.szAuthor, "Anonymous");
	}
	if (resetSliderValues) {
		int i;
		for (i = 0; i < 8; ++i) {
			gdata->parm.val[i] = (uint8_t)(i * 10 + 100);
		}
	}
	if (resetSliderNames) {
		int i;
		for (i = 0; i < 8; ++i) {
			strcpy(gdata->parm.szCtl[i], "ctl(X)");
			gdata->parm.szCtl[i][4] = '0' + i;
		}
		for (i = 0; i < 4; ++i) {
			strcpy(gdata->parm.szMap[i], "Map X");
			gdata->parm.szMap[i][4] = '0' + i;
		}
	}
	if (resetFormulas) {
		if (gpb->imageMode == plugInModeRGBColor) {
			strcpy(gdata->parm.szFormula[0], "r");
			strcpy(gdata->parm.szFormula[1], "g");
			strcpy(gdata->parm.szFormula[2], "b");
			strcpy(gdata->parm.szFormula[3], "a");
		}
		else {
			strcpy(gdata->parm.szFormula[0], "c");
			strcpy(gdata->parm.szFormula[1], "c");
			strcpy(gdata->parm.szFormula[2], "c");
			strcpy(gdata->parm.szFormula[3], "c");
		}
	}
}

/**
Cleanup "PARM" resource by removing stuff after the null terminators, to avoid that parts of confidential formulas are leaked
*/
void parm_cleanup() {
	int i;

	{
		char tmp[256];

		strcpy(tmp, gdata->parm.szCategory);
		memset(gdata->parm.szCategory, 0, sizeof(gdata->parm.szCategory));
		strcpy(gdata->parm.szCategory, tmp);

		strcpy(tmp, gdata->parm.szTitle);
		memset(gdata->parm.szTitle, 0, sizeof(gdata->parm.szTitle));
		strcpy(gdata->parm.szTitle, tmp);

		strcpy(tmp, gdata->parm.szCopyright);
		memset(gdata->parm.szCopyright, 0, sizeof(gdata->parm.szCopyright));
		strcpy(gdata->parm.szCopyright, tmp);

		strcpy(tmp, gdata->parm.szAuthor);
		memset(gdata->parm.szAuthor, 0, sizeof(gdata->parm.szAuthor));
		strcpy(gdata->parm.szAuthor, tmp);
	}

	for (i = 0; i < 4; i++) {
		char tmp[256];
		strcpy(tmp, gdata->parm.szMap[i]);
		memset(gdata->parm.szMap[i], 0, sizeof(gdata->parm.szMap[i]));
		strcpy(gdata->parm.szMap[i], tmp);
	}

	for (i = 0; i < 8; i++) {
		char tmp[256];
		strcpy(tmp, gdata->parm.szCtl[i]);
		memset(gdata->parm.szCtl[i], 0, sizeof(gdata->parm.szCtl[i]));
		strcpy(gdata->parm.szCtl[i], tmp);
	}

	for (i = 0; i < 4; i++) {
		char tmp[1024];
		strcpy(tmp, gdata->parm.szFormula[i]);
		memset(gdata->parm.szFormula[i], 0, sizeof(gdata->parm.szFormula[i]));
		strcpy(gdata->parm.szFormula[i], tmp);
	}
}

int checkandinitparams(Handle params){
	int i;
	Boolean bUninitializedParams;
	Boolean showdialog;
	InternalState tmpState;

	if (!host_preserves_parameters()) {
		// Workaround: Load settings in "FilterFoundryXX.afs" if host does not preserve pb->parameters
		TCHAR outfilename[MAX_PATH + 1];
		Boolean parmReadOk;
		StandardFileReply sfr;
		char bakexpr[4][MAXEXPR];

		sfr.sfGood = true;
		sfr.sfReplacing = true;
		sfr.sfType = PS_FILTER_FILETYPE;

		parmReadOk = (LOADING_OK == readPARMresource((HMODULE)hDllInstance));
		if (!parmReadOk) gdata->parm.standalone = false;
		if (parmReadOk && (gdata->parm.cbSize != PARM_SIZE) && (gdata->parm.cbSize != PARM_SIZE_PREMIERE) && (gdata->parm.cbSize != PARM_SIG_MAC)) {
			parm_reset(true, true, true, true);
			if (gdata->obfusc) {
				simplealert_id(MSG_INCOMPATIBLE_OBFUSCATION_ID);
			}
			else {
				simplealert_id(MSG_INVALID_PARAMETER_DATA_ID);
			}
			return false;
		}

		get_temp_afs(&outfilename[0], parmReadOk, &gdata->parm);

		xstrcpy(sfr.sfFile.szName, outfilename);
		#ifdef WIN_ENV
		sfr.nFileExtension = (WORD)(xstrlen(outfilename) - strlen(".afs") + 1);
		#endif
		sfr.sfScript = smSystemScript;

		if (parmReadOk) {
			tmpState = saveInternalState();
		}

		if (LOADING_OK == loadfile(&sfr)) {
			if (parmReadOk) {
				// In the standalone filter, we only want the parameters (ctl,map) in the temporary .afs file, not the formulas
				// We do not need to care about the metadata, because the AFS does not touch the metadata anyway
				for (i = 0; i < 4; i++) {
					strcpy(bakexpr[i], gdata->parm.szFormula[i]);
				}
				restoreInternalState(tmpState);
				for (i = 0; i < 4; i++) {
					strcpy(gdata->parm.szFormula[i],bakexpr[i]);
				}
			}

			return true;
		}
	}

	if( (bUninitializedParams = !(params && (LOADING_OK == readparams_afs_pff(params, false)))) ){
		/* either the parameter handle was uninitialised,
		   or the parameter data couldn't be read; set default values */

		Boolean parmReadOk;

		// see if saved parameters exist
		parmReadOk = (LOADING_OK == readPARMresource((HMODULE)hDllInstance));
		if (!parmReadOk) gdata->parm.standalone = false;
		if (parmReadOk && (gdata->parm.cbSize != PARM_SIZE) && (gdata->parm.cbSize != PARM_SIZE_PREMIERE) && (gdata->parm.cbSize != PARM_SIG_MAC)) {
			parm_reset(true, true, true, true);
			if (gdata->obfusc) {
				simplealert_id(MSG_INCOMPATIBLE_OBFUSCATION_ID);
			}
			else {
				simplealert_id(MSG_INVALID_PARAMETER_DATA_ID);
			}
			return false;
		}

		if(!gdata->parm.standalone){
			// no saved settings (not standalone)
			parm_reset(true, true, true, true);
		}
	}

	// let scripting system change parameters, if we're scripted;
	// user may want to force display of dialog during scripting playback
	switch (ReadScriptParamsOnRead()) {
	case SCR_SHOW_DIALOG:
		showdialog = true;
		break;
	case SCR_HIDE_DIALOG:
		showdialog = false;
		break;
	default:
	case SCR_NO_SCRIPT:
		showdialog = bUninitializedParams;
		break;
	}

	if (params) saveparams_afs_pff(params, false);

	return showdialog;
}

Boolean host_preserves_parameters(void) {
	#ifdef DEBUG_SIMULATE_GIMP
	return false;
	#endif

	if (gpb->hostSig == HOSTSIG_GIMP) return false;
	if (gpb->hostSig == HOSTSIG_IRFANVIEW) return false;

	// We just assume the other hosts preserve the parameters
	return true;
}

/**
Please see "Hosts.md" for details about the MaxSpace implementations of tested plugins
*/
int64_t maxspace(void){

	// Plugins that don't support MaxSpace64 shall set the field to zero; then we will use MaxSpace instead.
	// Also check "gpb->bufferProcs->numBufferProcs" to see if 64 bit API is available
	if ((gpb->bufferProcs->numBufferProcs >= 8) && (gpb->maxSpace64 > 0)) {
		uint64_t maxSpace64 = gpb->maxSpace64;

		return maxSpace64;
	} else {
		// Note: If maxSpace gets converted from Int32 to unsigned int, we can reach up to 4 GB RAM. However, after this, there will be a wrap to 0 GB again.
		unsigned int maxSpace32 = (unsigned int) gpb->maxSpace;
		uint64_t maxSpace64 = maxSpace32;

		if (gpb->hostSig == HOSTSIG_IRFANVIEW) maxSpace64 *= 1024; // IrfanView is giving Kilobytes instead of Bytes
		//if (gpb->hostSig == HOSTSIG_SERIF_PHOTOPLUS) maxSpace64 *= 1024; // TODO: Serif PhotoPlus also gives Kilobytes instead of bytes. But since it uses not a unique host signature, there is nothing we can do???

		return maxSpace64;
	}
}

/**
Please see "Hosts.md" for details about the MaxSpace implementations of tested plugins
*/
Boolean maxspace_available(void) {
	// GIMP PSPI sets MaxSpace to hardcoded 100 MB
	if (gpb->hostSig == HOSTSIG_GIMP) return false;

	// HOSTSIG_PAINT_NET sets MaxSpace to hardcoded 1 GB, see https://github.com/0xC0000054/PSFilterPdn/issues/5
	// Comment by the host author "This was done to avoid any compatibility issues with plugins handling 2 GB - 1"
	if (gpb->hostSig == HOSTSIG_PAINT_NET) return false;

	return true;
}

void DoPrepare(FilterRecordPtr pb){
	int i;

	for(i = 4; i--;){
		tree[i] = NULL;
		err[i] = NULL;
	}

	// Commented out by DM, 18 Dec 2018:
	// This code did not work on systems with 8 GB RAM:
	/*
	long space = (pb->maxSpace*9)/10; // don't ask for more than 90% of available memory

	maxSpace = 512L<<10; // this is a wild guess, actually
	if(maxSpace > space)
			maxSpace = space;
	pb->maxSpace = maxSpace;
	*/

	// New variant:
	if (maxspace_available()) {
		// don't ask for more than 90% of available memory
		int64 ninetyPercent = (int64)ceil((maxspace() / 10.) * 9);
		if ((gpb->bufferProcs->numBufferProcs >= 8) && (gpb->maxSpace64 > 0)) {
			pb->maxSpace64 = ninetyPercent;
		}
		if (ninetyPercent <= 0x7FFFFFFF) {
			pb->maxSpace = (int32)ninetyPercent;
		}
	}
}

/**
Request next block of the image
*/
void RequestNext(FilterRecordPtr pb){

	pb->inLoPlane = pb->outLoPlane = 0;
	pb->inHiPlane = pb->outHiPlane = nplanes-1;

	if (HAS_BIG_DOC(pb)) {
		// if any of the formulae involve random access to image pixels,
		// ask for the entire image
		if (needall) {
			SETRECT(BIGDOC_IN_RECT(pb), 0, 0, BIGDOC_IMAGE_SIZE(pb).h, BIGDOC_IMAGE_SIZE(pb).v);
		} else {
			// TODO: This does not work with GIMP. So, if we are using GIMP, we should
			//       somehow always use "needall=true", and/or find out why this doesn't work
			//       with GIMP.

			// otherwise, process the filtered area, by chunksize parts
			BIGDOC_IN_RECT(pb).left = BIGDOC_FILTER_RECT(pb).left;
			BIGDOC_IN_RECT(pb).right = BIGDOC_FILTER_RECT(pb).right;
			BIGDOC_IN_RECT(pb).top = (int32)toprow;
			BIGDOC_IN_RECT(pb).bottom = (int32)MIN(toprow + chunksize, BIGDOC_FILTER_RECT(pb).bottom);

			if (cnvused) {
				// cnv() needs one extra pixel in each direction
				if (BIGDOC_IN_RECT(pb).left > 0)
					--BIGDOC_IN_RECT(pb).left;
				if (BIGDOC_IN_RECT(pb).right < BIGDOC_IMAGE_SIZE(pb).h)
					++BIGDOC_IN_RECT(pb).right;
				if (BIGDOC_IN_RECT(pb).top > 0)
					--BIGDOC_IN_RECT(pb).top;
				if (BIGDOC_IN_RECT(pb).bottom < BIGDOC_IMAGE_SIZE(pb).v)
					++BIGDOC_IN_RECT(pb).bottom;
			}
		}
		BIGDOC_OUT_RECT(pb) = BIGDOC_FILTER_RECT(pb);
		/*
		{char s[0x100];sprintf(s,"RequestNext needall=%d inRect=(%d,%d,%d,%d) filterRect=(%d,%d,%d,%d)",
				needall,
				BIGDOC_IN_RECT(pb).left,BIGDOC_IN_RECT(pb).top,BIGDOC_IN_RECT(pb).right,BIGDOC_IN_RECT(pb).bottom,
				BIGDOC_FILTER_RECT(pb).left,BIGDOC_FILTER_RECT(pb).top,BIGDOC_FILTER_RECT(pb).right,BIGDOC_FILTER_RECT(pb).bottom);dbg(s);}
		*/
	} else {
		// if any of the formulae involve random access to image pixels,
		// ask for the entire image
		if (needall) {
			SETRECT(IN_RECT(pb), 0, 0, IMAGE_SIZE(pb).h, IMAGE_SIZE(pb).v);
		}
		else {
			// TODO: This does not work with GIMP. So, if we are using GIMP, we should
			//       somehow always use "needall=true", and/or find out why this doesn't work
			//       with GIMP.

			// otherwise, process the filtered area, by chunksize parts
			IN_RECT(pb).left = FILTER_RECT(pb).left;
			IN_RECT(pb).right = FILTER_RECT(pb).right;
			IN_RECT(pb).top = (int16)toprow;
			IN_RECT(pb).bottom = (int16)MIN(toprow + chunksize, FILTER_RECT(pb).bottom);

			if (cnvused) {
				// cnv() needs one extra pixel in each direction
				if (IN_RECT(pb).left > 0)
					--IN_RECT(pb).left;
				if (IN_RECT(pb).right < IMAGE_SIZE(pb).h)
					++IN_RECT(pb).right;
				if (IN_RECT(pb).top > 0)
					--IN_RECT(pb).top;
				if (IN_RECT(pb).bottom < IMAGE_SIZE(pb).v)
					++IN_RECT(pb).bottom;
			}
		}
		OUT_RECT(pb) = FILTER_RECT(pb);
		/*
		{char s[0x100];sprintf(s,"RequestNext needall=%d inRect=(%d,%d,%d,%d) filterRect=(%d,%d,%d,%d)",
				needall,
				IN_RECT(pb).left,IN_RECT(pb).top,IN_RECT(pb).right,IN_RECT(pb).bottom,
				FILTER_RECT(pb).left,FILTER_RECT(pb).top,FILTER_RECT(pb).right,FILTER_RECT(pb).bottom);dbg(s);}
		*/
	}
}

void DoStart(FilterRecordPtr pb){
	/* Note about global variable "needall": if src() or rad() functions are used, random access to the image data is required,
	   so we must request the entire image in a single chunk, otherwise we will use chunksize "CHUNK_ROWS". */
	if (HAS_BIG_DOC(pb)) {
		chunksize = needall ? (BIGDOC_FILTER_RECT(pb).bottom - BIGDOC_FILTER_RECT(pb).top) : CHUNK_ROWS;
		toprow = BIGDOC_FILTER_RECT(pb).top;
	} else {
		chunksize = needall ? (FILTER_RECT(pb).bottom - FILTER_RECT(pb).top) : CHUNK_ROWS;
		toprow = FILTER_RECT(pb).top;
	}
	RequestNext(pb);
}

OSErr DoContinue(FilterRecordPtr pb){
	OSErr e = noErr;
	long outoffset;

	if (HAS_BIG_DOC(pb)) {
		VRect fr;
		if (needall) {
			fr = BIGDOC_FILTER_RECT(pb);  // filter whole selection at once
		} else if (cnvused) {
			// we've requested one pixel extra all around
			// (see RequestNext()), just for access purposes. But filter
			// original selection only.
			fr.left = BIGDOC_FILTER_RECT(pb).left;
			fr.right = BIGDOC_FILTER_RECT(pb).right;
			fr.top = toprow;
			fr.bottom = MIN(toprow + chunksize, BIGDOC_FILTER_RECT(pb).bottom);
		} else {  // filter whatever portion we've been given
			fr = BIGDOC_IN_RECT(pb);
		}

		outoffset = (long)pb->outRowBytes * (fr.top - BIGDOC_OUT_RECT(pb).top)
			+ (long)nplanes * (fr.left - BIGDOC_OUT_RECT(pb).left);

		if (!(e = process_scaled_bigdoc(pb, true, fr, fr,
			(Ptr)pb->outData + outoffset, pb->outRowBytes, 1.)))
		{
			toprow += chunksize;
			if (toprow < BIGDOC_FILTER_RECT(pb).bottom)
				RequestNext(pb);
			else {
				SETRECT(BIGDOC_IN_RECT(pb), 0, 0, 0, 0);
				BIGDOC_OUT_RECT(pb) = BIGDOC_MASK_RECT(pb) = BIGDOC_IN_RECT(pb);
			}
		}
	} else {
		Rect fr;
		if (needall) {
			fr = FILTER_RECT(pb);  // filter whole selection at once
		} else if (cnvused) {
			// we've requested one pixel extra all around
			// (see RequestNext()), just for access purposes. But filter
			// original selection only.
			fr.left = FILTER_RECT(pb).left;
			fr.right = FILTER_RECT(pb).right;
			fr.top = toprow;
			fr.bottom = MIN(toprow + chunksize, FILTER_RECT(pb).bottom);
		} else {  // filter whatever portion we've been given
			fr = IN_RECT(pb);
		}

		outoffset = (long)pb->outRowBytes*(fr.top - OUT_RECT(pb).top)
			+ (long)nplanes*(fr.left - OUT_RECT(pb).left);

		if(!(e = process_scaled_olddoc(pb, true, fr, fr,
			(Ptr)pb->outData+outoffset, pb->outRowBytes, 1.)))
		{
			toprow += chunksize;
			if(toprow < FILTER_RECT(pb).bottom)
				RequestNext(pb);
			else{
				SETRECT(IN_RECT(pb),0,0,0,0);
				OUT_RECT(pb) = MASK_RECT(pb) = IN_RECT(pb);
			}
		}
	}
	return e;
}

void DoFinish(FilterRecordPtr pb){
	int i;

	UNREFERENCED_PARAMETER(pb);

	WriteScriptParamsOnRead();

	for(i = 4; i--;){
		freetree(tree[i]);
	}
}

InternalState saveInternalState(void) {
	InternalState ret;
	ret.bak_obfusc = gdata->obfusc;
	memcpy(&ret.bak_parm, &gdata->parm, sizeof(PARM_T));

	return ret;
}

void restoreInternalState(InternalState state) {
	gdata->obfusc = state.bak_obfusc;
	memcpy(&gdata->parm, &state.bak_parm, sizeof(PARM_T));
}