Subversion Repositories filter_foundry

/*

    This file is part of "Filter Foundry", a filter plugin for Adobe Photoshop

    Copyright (C) 2003-2009 Toby Thain, toby@telegraphics.com.au

    Copyright (C) 2018-2022 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;

uint8_t slider[8]; // this is the "working data". We cannot always use gdata->parm, because parm will not be loaded if a AFS file is read

char* expr[4]; // this is the "working data". We cannot always use gdata->parm, because parm will not be loaded if a AFS file is read

value_type cell[NUM_CELLS];

// this is the only memory area that keeps preserved by Photoshop:

globals_t *gdata;

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 get_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(LPTSTR 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) ? get_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);

}

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;

}

void CreateDataPointer(intptr_t* data) {

        // Register "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.

        // 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 in a Adobe Photoshop host.

        /*

        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) {

                // 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 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)

                // 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 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

                //

                // TODO: Usually, The first 64KB of address space are always invalid. However, in Win32s (Windows 3.11), the

                //       variable "result" is <=0xFFFF ! Let's just hope that it is never 0x000A (SW_SHOWDEFAULT),

                //       otherwise we have a problem here!

                // 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?

                FakeRundll32((HWND)(intptr_t)selector, (HINSTANCE)pb, (LPSTR)data, (int)(intptr_t)result);

                goto endmain;

        }

        else {

                // will be changed if an error happens

                *result = noErr;

        }

        #endif

        #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)...

                // Probably the canvas structure is different (maybe it contains frames to achieve transitions?)

                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.

                // Note: gdata->standalone and gdata->parmloaded will be set later

                CreateDataPointer(data);

                if (!*data) {

                        *result = memFullErr;

                        goto endmain;

                }

        }

        gdata = (globals_t*)*data;

        nplanes = MIN(pb->planes,4);

        switch (selector){

        case filterSelectorAbout:

                if (!gdata) {

                        // 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

                        gdata->standalone = gdata->parmloaded = readPARMresource((HMODULE)hDllInstance, NULL);

                        if (gdata->parmloaded && (gdata->parm.cbSize != PARM_SIZE) && (gdata->parm.cbSize != PARM_SIZE_PREMIERE) && (gdata->parm.cbSize != PARM_SIG_MAC)) {

                                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->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;

                                                char* bakexpr[4];

                                                int i;

                                                sfr.sfGood = true;

                                                sfr.sfReplacing = true;

                                                sfr.sfType = PS_FILTER_FILETYPE;

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

                                                xstrcpy(sfr.sfFile.szName, outfilename);

                                                #ifdef WIN_ENV

                                                sfr.nFileExtension = (WORD)(xstrlen(outfilename) - strlen(".afs") + 1);

                                                #endif

                                                sfr.sfScript = 0; // FIXME: is that ok?

                                                // 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.

                                                for (i = 0; i < 4; i++) {

                                                        bakexpr[i] = expr[i]; // moved out of the if-definition to make the compiler happy

                                                }

                                                if (gdata->standalone) {

                                                        expr[0] = _strdup("r");

                                                        expr[1] = _strdup("g");

                                                        expr[2] = _strdup("b");

                                                        expr[3] = _strdup("a");

                                                }

                                                savefile_afs_pff_picotxt(&sfr);

                                                if (gdata->standalone) {

                                                        for (i = 0; i < 4; i++) {

                                                                if (expr[i]) free(expr[i]);

                                                                expr[i] = bakexpr[i];

                                                        }

                                                }

                                        }

                                        else {

                                                /* update stored parameters from new user settings */

                                                if (pb->parameters)

                                                        saveparams_afs_pff(pb->parameters);

                                        }

                                }

                                else

                                        *result = userCanceledErr;

                        }

                        wantdialog = false;

                }

                if(*result == noErr){

                        if(setup(pb)){

                                DoStart(pb);

                        }else{

                                *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 every invocation, or should it be only around UI stuff?

        #ifdef WIN_ENV

        if (activationContextUsed) DeactivateManifest(&manifestVars);

        #endif

        ExitCodeResource();

}

int checkandinitparams(Handle params){

        int i;

        Boolean bUninitializedParams;

        Boolean showdialog;

        if (!host_preserves_parameters()) {

                // Workaround: Load settings in "FilterFoundryXX.afs" if host does not preserve pb->parameters

                TCHAR outfilename[MAX_PATH + 1];

                Boolean isStandalone;

                StandardFileReply sfr;

                char* bakexpr[4];

                sfr.sfGood = true;

                sfr.sfReplacing = true;

                sfr.sfType = PS_FILTER_FILETYPE;

                // We need to set gdata->standalone after loadfile(), but we must call readPARMresource() before loadfile()

                // Reason: readPARMresource() reads parameters from the DLL while loadfile() reads parameters from the AFS file

                // But loadfile() will reset gdata->standalone ...

                isStandalone = readPARMresource((HMODULE)hDllInstance, NULL);

                if (isStandalone && (gdata->parm.cbSize != PARM_SIZE) && (gdata->parm.cbSize != PARM_SIZE_PREMIERE) && (gdata->parm.cbSize != PARM_SIG_MAC)) {

                        if (gdata->obfusc) {

                                simplealert_id(MSG_INCOMPATIBLE_OBFUSCATION_ID);

                        }

                        else {

                                simplealert_id(MSG_INVALID_PARAMETER_DATA_ID);

                        }

                        gdata->parmloaded = false;

                        return false;

                }

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

                xstrcpy(sfr.sfFile.szName, outfilename);

                #ifdef WIN_ENV

                sfr.nFileExtension = (WORD)(xstrlen(outfilename) - strlen(".afs") + 1);

                #endif

                sfr.sfScript = 0; // FIXME: is that ok?

                // We only want the parameters (ctl,map) in the temporary .afs file

                if (isStandalone) {

                        for (i = 0; i < 4; i++) {

                                bakexpr[i] = my_strdup(expr[i]);

                        }

                }

                if (loadfile(&sfr, NULL)) {

                        gdata->standalone = gdata->parmloaded = isStandalone;

                        if (isStandalone) {

                                for (i = 0; i < 4; i++) {

                                        if (expr[i]) free(expr[i]);

                                        expr[i] = bakexpr[i];

                                }

                        }

                        return true;

                }

        }

        if( (bUninitializedParams = !(params && readparams_afs_pff(params, NULL))) ){

                /* either the parameter handle was uninitialised,

                   or the parameter data couldn't be read; set default values */

                // see if saved parameters exist

                gdata->standalone = gdata->parmloaded = readPARMresource((HMODULE)hDllInstance, NULL);

                if (gdata->parmloaded && (gdata->parm.cbSize != PARM_SIZE) && (gdata->parm.cbSize != PARM_SIZE_PREMIERE) && (gdata->parm.cbSize != PARM_SIG_MAC)) {

                        if (gdata->obfusc) {

                                simplealert_id(MSG_INCOMPATIBLE_OBFUSCATION_ID);

                        }

                        else {

                                simplealert_id(MSG_INVALID_PARAMETER_DATA_ID);

                        }

                        gdata->parmloaded = false;

                        return false;

                }

                if(!gdata->standalone){

                        // no saved settings (not standalone)

                        for(i = 0; i < 8; ++i)

                                slider[i] = (uint8_t)(i*10+100);

                        for(i = 0; i < 4; ++i)

                                if(expr[i])

                                        free(expr[i]);

                        if(gpb->imageMode == plugInModeRGBColor){

                                expr[0] = _strdup("r");

                                expr[1] = _strdup("g");

                                expr[2] = _strdup("b");

                                expr[3] = _strdup("a");

                        }else{

                                expr[0] = _strdup("c");

                                expr[1] = _strdup("c");

                                expr[2] = _strdup("c");

                                expr[3] = _strdup("c");

                        }

                }

        }

        // 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);

        return showdialog;

}

Boolean host_preserves_parameters() {

        #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;

}

int64_t maxspace(){

        // Please see "Hosts.md" for details about the MaxSpace implementations of tested plugins

        // 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;

        }

}

Boolean maxspace_available() {

        // Please see "Hosts.md" for details about the MaxSpace implementations of tested plugins

        // 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--;){

                expr[i] = NULL;

                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;

                }

        }

}

void RequestNext(FilterRecordPtr pb){

        /* Request next block of the image */

        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){

        /* 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);

                }