/* $Xorg: xcmsdb.c,v 1.3 2000/08/17 19:54:13 cpqbld Exp $ */

/*
 * (c) Copyright 1990 Tektronix Inc.
 * 	All Rights Reserved
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appear in all copies and that
 * both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of Tektronix not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.
 *
 * Tektronix disclaims all warranties with regard to this software, including
 * all implied warranties of merchantability and fitness, in no event shall
 * Tektronix be liable for any special, indirect or consequential damages or
 * any damages whatsoever resulting from loss of use, data or profits,
 * whether in an action of contract, negligence or other tortious action,
 * arising out of or in connection with the use or performance of this
 * software.
 *
 *
 *	NAME
 *		xcmsdb.c
 *
 *	DESCRIPTION
 *		Program to load, query or remove the Screen Color
 *		Characterization Data from the root window of the screen.
 *
 */
/* $XFree86: xc/programs/xcmsdb/xcmsdb.c,v 1.5 2001/01/17 23:45:19 dawes Exp $ */

/*
 *      INCLUDES
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xos.h>
#include <ctype.h>

#include "SCCDFile.h"

static void QuerySCCDataRGB(Display *dpy, Window root);
static void RemoveSCCData(Display *dpy, Window root, int colorFlag);
static unsigned long _XcmsGetElement(int format, char **pValue,
                                     unsigned long *pCount);
static int _XcmsGetProperty(Display *pDpy, Window w, Atom property,
                            int *pFormat, unsigned long *pNItems,
                            unsigned long *pNBytes, char **pValue);

static char *ProgramName;

static void
Syntax(int exitcode)
{
    fprintf(stderr,
            "usage:  %s [-options ...] [filename]\n\n%s",
            ProgramName,
            "where options include:\n"
            "    -display host:dpy[.scrn]     display to use\n"
            "    -format [ 32 | 16 | 8 ]      property format\n"
            "    -query                       query Screen Color Characterization Data\n"
            "    -remove                      remove Screen Color Characterization Data\n"
#ifdef GRAY
            "    -color                       use color as default\n"
            "    -gray                        use gray-scale as default\n"
#endif                          /* GRAY */
            "    -version                     print program version\n" "\n");
    exit(exitcode);
}

static void
MissingArg(const char *option)
{
    fprintf(stderr, "%s: %s requires an argument\n", ProgramName, option);
    Syntax(1);
}

static Bool
optionmatch(const char *opt, const char *arg, int minlen)
{
    int arglen;

    if (strcmp(opt, arg) == 0) {
        return (True);
    }

    if ((arglen = strlen(arg)) >= (int) strlen(opt) || arglen < minlen) {
        return (False);
    }

    if (strncmp(opt, arg, arglen) == 0) {
        return (True);
    }

    return (False);
}

int
main(int argc, char *argv[])
{
    Display *dpy;
    char *displayname = NULL;
    char *filename = NULL;
    int query = 0;
    int remove = 0;
    int load = 0;
    int color = -1;
    int targetFormat = 32;

    ProgramName = argv[0];

    for (int i = 1; i < argc; i++) {
        char *arg = argv[i];

        if (arg[0] == '-') {
            if (arg[1] == '\0') {
                filename = NULL;
                continue;
            }
            else if (optionmatch("-help", arg, 1)) {
                Syntax(0);
                /* doesn't return */
            }
            else if (optionmatch("-display", arg, 1)) {
                if (++i >= argc)
                    MissingArg("-display");
                displayname = argv[i];
                continue;
            }
            else if (optionmatch("-format", arg, 1)) {
                if (++i >= argc)
                    MissingArg("-format");
                targetFormat = atoi(argv[i]);
                if (targetFormat != 32 && targetFormat != 16 &&
                    targetFormat != 8) {
                    fprintf(stderr, "%s: invalid value for -format: %d\n",
                            ProgramName, targetFormat);
                    Syntax(1);
                }
                continue;
            }
            else if (optionmatch("-query", arg, 1)) {
                query = 1;
                continue;
            }
            else if (optionmatch("-remove", arg, 1)) {
                remove = 1;
                continue;
#ifdef GRAY
            }
            else if (optionmatch("-color", arg, 1)) {
                color = 1;
                continue;
            }
            else if (optionmatch("-gray", arg, 1)) {
                color = 0;
                continue;
#endif                          /* GRAY */
            }
            else if (optionmatch("-version", arg, 1)) {
                puts(PACKAGE_STRING);
                exit(0);
            }
            fprintf(stderr, "%s: unrecognized option '%s'\n", ProgramName, arg);
            Syntax(1);
        }
        else {
            load = 1;
            filename = arg;
        }
    }

    /* Open display  */
    if (!(dpy = XOpenDisplay(displayname))) {
        fprintf(stderr, "%s:  Can't open display '%s'\n",
                ProgramName, XDisplayName(displayname));
        exit(1);
    }

    if (query || remove) {
        load = 0;
    }

    if (load) {
        LoadSCCData(dpy, DefaultScreen(dpy), filename, targetFormat);
    }

    if (query) {
        if (color != 0)
            QuerySCCDataRGB(dpy, RootWindow(dpy, DefaultScreen(dpy)));
#ifdef GRAY
        if (color != 1)
            QuerySCCDataGray(dpy, RootWindow(dpy, DefaultScreen(dpy)));
#endif /* GRAY */
    }

    if (remove) {
        RemoveSCCData(dpy, RootWindow(dpy, DefaultScreen(dpy)), color);
    }

    XCloseDisplay(dpy);
    exit(0);
    /*NOTREACHED*/
}

static Atom
ParseAtom(Display *dpy, const char *name, int only_flag)
{
    return (XInternAtom(dpy, name, only_flag));
}

/*
 *	NAME
 *		PrintTableType0
 *
 *	SYNOPSIS
 */
static void
PrintTableType0(int format, char **pChar, unsigned long *pCount)
/*
 *	DESCRIPTION
 *
 *	RETURNS
 *		XcmsFailure if failed.
 *		XcmsSuccess if succeeded.
 *
 */
{
    unsigned int nElements;
    unsigned short hValue;
    XcmsFloat fValue;

    nElements = _XcmsGetElement(format, pChar, pCount) + 1;
    printf("\t    length:%d\n", nElements);

    switch (format) {
    case 8:
        while (nElements--) {
            /* 0xFFFF/0xFF = 0x101 */
            hValue = _XcmsGetElement(format, pChar, pCount) * 0x101;
            fValue = _XcmsGetElement(format, pChar, pCount)
                / (XcmsFloat) 255.0;
            printf("\t\t0x%x\t%8.5f\n", hValue, fValue);
        }
        break;
    case 16:
        while (nElements--) {
            hValue = _XcmsGetElement(format, pChar, pCount);
            fValue = _XcmsGetElement(format, pChar, pCount)
                / (XcmsFloat) 65535.0;
            printf("\t\t0x%x\t%8.5f\n", hValue, fValue);
        }
        break;
    case 32:
        while (nElements--) {
            hValue = _XcmsGetElement(format, pChar, pCount);
            fValue = _XcmsGetElement(format, pChar, pCount)
                / (XcmsFloat) 4294967295.0;
            printf("\t\t0x%x\t%8.5f\n", hValue, fValue);
        }
        break;
    default:
        return;
    }
}

/*
 *	NAME
 *		PrintTableType1
 *
 *	SYNOPSIS
 */
static void
PrintTableType1(int format, char **pChar, unsigned long *pCount)
/*
 *	DESCRIPTION
 *
 *	RETURNS
 *		XcmsFailure if failed.
 *		XcmsSuccess if succeeded.
 *
 */
{
    unsigned int count;
    unsigned int max_index;
    unsigned short hValue;
    XcmsFloat fValue;

    max_index = _XcmsGetElement(format, pChar, pCount);
    printf("\t    length:%d\n", max_index + 1);

    switch (format) {
    case 8:
        for (count = 0; count < max_index + 1; count++) {
            hValue = (count * 65535) / max_index;
            fValue = _XcmsGetElement(format, pChar, pCount)
                / (XcmsFloat) 255.0;
            printf("\t\t0x%x\t%8.5f\n", hValue, fValue);
        }
        break;
    case 16:
        for (count = 0; count < max_index + 1; count++) {
            hValue = (count * 65535) / max_index;
            fValue = _XcmsGetElement(format, pChar, pCount)
                / (XcmsFloat) 65535.0;
            printf("\t\t0x%x\t%8.5f\n", hValue, fValue);
        }
        break;
    case 32:
        for (count = 0; count < max_index + 1; count++) {
            hValue = (count * 65535) / max_index;
            fValue = _XcmsGetElement(format, pChar, pCount)
                / (XcmsFloat) 4294967295.0;
            printf("\t\t0x%x\t%8.5f\n", hValue, fValue);
        }
        break;
    default:
        return;
    }
}

/*
 *      NAME
 *		QuerySCCData - Query for the SCC data on the root window
 *
 *      SYNOPSIS
 */
static void
QuerySCCDataRGB(Display * dpy, Window root)
/*
 *      DESCRIPTION
 *
 *      RETURNS
 *		None
 */
{
    char *property_return, *pChar;
    int i, j;
    int count, format, cType, nTables;
    unsigned long nitems, nbytes_return;
    Atom MatricesAtom, CorrectAtom;
    VisualID visualID;
    XVisualInfo vinfo_template, *vinfo_ret;
    int nvis;

    static const char *visual_strings[] = {
        "StaticGray",
        "GrayScale",
        "StaticColor",
        "PseudoColor",
        "TrueColor",
        "DirectColor"
    };

    /*
     * Get Matrices
     */
    MatricesAtom = ParseAtom(dpy, XDCCC_MATRIX_ATOM_NAME, True);
    if (MatricesAtom != None) {
        if (_XcmsGetProperty(dpy, root, MatricesAtom, &format, &nitems,
                             &nbytes_return, &property_return) == XcmsFailure) {
            format = 0;
        }
        else if (nitems != 18) {
            printf("Property %s had invalid length of %ld\n",
                   XDCCC_MATRIX_ATOM_NAME, nitems);
            if (property_return) {
                XFree(property_return);
            }
            return;
        }
    }
    if (MatricesAtom == None || !format) {
        printf("Could not find property %s\n", XDCCC_MATRIX_ATOM_NAME);
    }
    else if (format != 32) {
        printf("Data in property %s not in 32 bit format\n",
               XDCCC_MATRIX_ATOM_NAME);
    }
    else {
        pChar = property_return;
        printf("Screen: %d\n", DefaultScreen(dpy));
        printf("Querying property %s\n", XDCCC_MATRIX_ATOM_NAME);
        printf("\tXYZtoRGB matrix :\n");
        for (i = 0; i < 3; i++) {
            printf("\t");
            for (j = 0; j < 3; j++) {
                printf("\t%8.5f",
                       (long) _XcmsGetElement(format, &pChar, &nitems)
                       / (XcmsFloat) XDCCC_NUMBER);
            }
            printf("\n");
        }
        printf("\tRGBtoXYZ matrix :\n");
        for (i = 0; i < 3; i++) {
            printf("\t");
            for (j = 0; j < 3; j++) {
                printf("\t%8.5f",
                       (long) _XcmsGetElement(format, &pChar, &nitems)
                       / (XcmsFloat) XDCCC_NUMBER);
            }
            printf("\n");
        }
        XFree(property_return);
    }

    /*
     * Get Intensity Tables
     */
    CorrectAtom = XInternAtom(dpy, XDCCC_CORRECT_ATOM_NAME, True);
    if (CorrectAtom != None) {
        if (_XcmsGetProperty(dpy, root, CorrectAtom, &format, &nitems,
                             &nbytes_return, &property_return) == XcmsFailure) {
            format = 0;
        }
        else if (nitems <= 0) {
            printf("Property %s had invalid length of %ld\n",
                   XDCCC_CORRECT_ATOM_NAME, nitems);
            if (property_return) {
                XFree(property_return);
            }
            return;
        }
    }
    if (CorrectAtom == None || !format) {
        printf("Could not find property %s\n", XDCCC_CORRECT_ATOM_NAME);
    }
    else {
        printf("\nQuerying property %s\n", XDCCC_CORRECT_ATOM_NAME);
        pChar = property_return;

        while (nitems) {
            switch (format) {
            case 8:
                /*
                 * Must have at least:
                 *              VisualID0
                 *              VisualID1
                 *              VisualID2
                 *              VisualID3
                 *              type
                 *              count
                 *              length
                 *              intensity1
                 *              intensity2
                 */
                if (nitems < 9) {
                    goto IntensityTblError;
                }
                count = 3;
                break;
            case 16:
                /*
                 * Must have at least:
                 *              VisualID0
                 *              VisualID3
                 *              type
                 *              count
                 *              length
                 *              intensity1
                 *              intensity2
                 */
                if (nitems < 7) {
                    goto IntensityTblError;
                }
                count = 1;
                break;
            case 32:
                /*
                 * Must have at least:
                 *              VisualID0
                 *              type
                 *              count
                 *              length
                 *              intensity1
                 *              intensity2
                 */
                if (nitems < 6) {
                    goto IntensityTblError;
                }
                count = 0;
                break;
            default:
                goto IntensityTblError;
            }

            /*
             * Get VisualID
             */
            visualID = _XcmsGetElement(format, &pChar, &nitems);
            /* add the depth, class, and bits info in output */
            vinfo_template.visualid = visualID;
            vinfo_ret = XGetVisualInfo(dpy, VisualIDMask, &vinfo_template,
                                       &nvis);
            while (count--) {
                visualID = visualID << format;
                visualID |= _XcmsGetElement(format, &pChar, &nitems);
            }

            if (vinfo_ret != NULL) {
                printf
                    ("\n\tVisualID: 0x%lx class: %s depth: %d bits_per_rgb: %d\n",
                     visualID, visual_strings[vinfo_ret->class],
                     vinfo_ret->depth, vinfo_ret->bits_per_rgb);
            }
            else
                printf("\n\tVisualID: 0x%lx\n", visualID);
            XFree(vinfo_ret);
            cType = _XcmsGetElement(format, &pChar, &nitems);
            printf("\ttype: %d\n", cType);
            nTables = _XcmsGetElement(format, &pChar, &nitems);
            printf("\tcount: %d\n", nTables);

            switch (cType) {
            case 0:
                /* Red Table should always exist */
                printf("\tRed Conversion Table:\n");
                PrintTableType0(format, &pChar, &nitems);
                if (nTables > 1) {
                    printf("\tGreen Conversion Table:\n");
                    PrintTableType0(format, &pChar, &nitems);
                    printf("\tBlue Conversion Table:\n");
                    PrintTableType0(format, &pChar, &nitems);
                }
                break;
            case 1:
                /* Red Table should always exist */
                printf("\tRed Conversion Table:\n");
                PrintTableType1(format, &pChar, &nitems);
                if (nTables > 1) {
                    printf("\tGreen Conversion Table:\n");
                    PrintTableType1(format, &pChar, &nitems);
                    printf("\tBlue Conversion Table:\n");
                    PrintTableType1(format, &pChar, &nitems);
                }
                break;
            default:
                goto IntensityTblError;
            }
        }
        XFree(property_return);
    }
    return;

 IntensityTblError:
    XFree(property_return);
    printf("Fatal error in %s property\n", XDCCC_CORRECT_ATOM_NAME);
}

#ifdef GRAY

/*
 *      NAME
 *		QuerySCCDataGray - Query for the SCC data on the root window
 *
 *      SYNOPSIS
 */
int
QuerySCCDataGray(Display * dpy, Window root)
/*
 *      DESCRIPTION
 *
 *      RETURNS
 *		None
 */
{
    char *property_return, *pChar;
    int count, format, cType;
    unsigned long nitems, nbytes_return;
    Atom MatricesAtom, CorrectAtom;
    VisualID visualID;

    MatricesAtom = ParseAtom(dpy, XDCCC_SCREENWHITEPT_ATOM_NAME, True);
    if (MatricesAtom != None) {
        if (_XcmsGetProperty(dpy, root, MatricesAtom, &format, &nitems,
                             &nbytes_return, &property_return) == XcmsFailure) {
            format = 0;
        }
        else if (nitems != 3) {
            printf("Property %s had invalid length of %d\n",
                   XDCCC_SCREENWHITEPT_ATOM_NAME, nitems);
            if (property_return) {
                XFree(property_return);
            }
            return;
        }
    }
    if (MatricesAtom == None || !format) {
        printf("Could not find property %s\n", XDCCC_SCREENWHITEPT_ATOM_NAME);
    }
    else {
        pChar = property_return;
        printf("\nQuerying property %s\n", XDCCC_SCREENWHITEPT_ATOM_NAME);
        printf("\tWhite Point XYZ :\n");
        printf("\t");
        for (int j = 0; j < 3; j++) {
            printf("\t%8.5lf",
                   (long) _XcmsGetElement(format, &pChar, &nitems) /
                   (XcmsFloat) XDCCC_NUMBER);
        }
        printf("\n");
        XFree(property_return);
    }

    CorrectAtom = XInternAtom(dpy, XDCCC_GRAY_CORRECT_ATOM_NAME, True);
    if (CorrectAtom != None) {
        if (_XcmsGetProperty(dpy, root, CorrectAtom, &format, &nitems,
                             &nbytes_return, &property_return) == XcmsFailure) {
            format = 0;
        }
        else if (nitems <= 0) {
            printf("Property %s had invalid length of %d\n",
                   XDCCC_GRAY_CORRECT_ATOM_NAME, nitems);
            if (property_return) {
                XFree(property_return);
            }
            return;
        }
    }
    if (CorrectAtom == None || !format) {
        printf("Could not find property %s\n", XDCCC_GRAY_CORRECT_ATOM_NAME);
    }
    else {
        printf("\nQuerying property %s\n\n", XDCCC_GRAY_CORRECT_ATOM_NAME);
        pChar = property_return;

        while (nitems) {
            switch (format) {
            case 8:
                /*
                 * Must have at least:
                 *              VisualID0
                 *              VisualID1
                 *              VisualID2
                 *              VisualID3
                 *              type
                 *              count
                 *              length
                 *              intensity1
                 *              intensity2
                 */
                if (nitems < 9) {
                    goto IntensityTblError;
                }
                count = 3;
                break;
            case 16:
                /*
                 * Must have at least:
                 *              VisualID0
                 *              VisualID3
                 *              type
                 *              count
                 *              length
                 *              intensity1
                 *              intensity2
                 */
                if (nitems < 7) {
                    goto IntensityTblError;
                }
                count = 1;
                break;
            case 32:
                /*
                 * Must have at least:
                 *              VisualID0
                 *              type
                 *              count
                 *              length
                 *              intensity1
                 *              intensity2
                 */
                if (nitems < 6) {
                    goto IntensityTblError;
                }
                count = 0;
                break;
            default:
                goto IntensityTblError;
                break;
            }

            /*
             * Get VisualID
             */
            visualID = _XcmsGetElement(format, &pChar, &nitems);
            while (count--) {
                visualID = visualID << format;
                visualID |= _XcmsGetElement(format, &pChar, &nitems);
            }

            printf("\n\tVisualID: 0x%lx\n", visualID);
            cType = _XcmsGetElement(format, &pChar, &nitems);
            printf("\ttype: %d\n", cType);
            printf("\tGray Conversion Table:\n");
            switch (cType) {
            case 0:
                PrintTableType0(format, &pChar, &nitems);
                break;
            case 1:
                PrintTableType1(format, &pChar, &nitems);
                break;
            default:
                goto IntensityTblError;
            }
        }
        XFree(property_return);
    }
    return;
 IntensityTblError:
    XFree(property_return);
    printf("Fatal error in %s property\n", XDCCC_CORRECT_ATOM_NAME);
}
#endif                          /* GRAY */

/*
 *      NAME
 *		RemoveSCCData - Remove for the SCC data on the root window
 *
 *      SYNOPSIS
 */
static void
RemoveSCCData(Display *dpy, Window root, int colorFlag)
/*
 *      DESCRIPTION
 *
 *      RETURNS
 *		None
 */
{
    unsigned char *ret_prop;
    unsigned long ret_len, ret_after;
    int ret_format, status = -1;
    Atom MatricesAtom, CorrectAtom, ret_atom;

    if (colorFlag != 0) {
        MatricesAtom = ParseAtom(dpy, XDCCC_MATRIX_ATOM_NAME, True);
        if (MatricesAtom != None) {
            status = XGetWindowProperty(dpy, root, MatricesAtom, 0, 8192,
                                        False, XA_INTEGER, &ret_atom,
                                        &ret_format, &ret_len, &ret_after,
                                        &ret_prop);
        }
        if (MatricesAtom == None || status != Success || !ret_format) {
            printf("Could not find property %s\n", XDCCC_MATRIX_ATOM_NAME);
        }
        else {
            printf("Deleting property %s\n", XDCCC_MATRIX_ATOM_NAME);
            XDeleteProperty(dpy, root, MatricesAtom);
            XFree(ret_prop);
        }

        CorrectAtom = XInternAtom(dpy, XDCCC_CORRECT_ATOM_NAME, True);
        if (CorrectAtom != None) {
            status = XGetWindowProperty(dpy, root, CorrectAtom, 0, 8192,
                                        False, XA_INTEGER, &ret_atom,
                                        &ret_format, &ret_len, &ret_after,
                                        &ret_prop);
        }
        if (CorrectAtom == None || status != Success || !ret_format) {
            printf("Could not find property %s\n", XDCCC_CORRECT_ATOM_NAME);
        }
        else {
            printf("Deleting property %s\n", XDCCC_CORRECT_ATOM_NAME);
            XDeleteProperty(dpy, root, CorrectAtom);
            XFree(ret_prop);
        }
    }
#ifdef GRAY
    if (colorFlag != 1) {
        MatricesAtom = ParseAtom(dpy, XDCCC_SCREENWHITEPT_ATOM_NAME, True);
        if (MatricesAtom != None) {
            status = XGetWindowProperty(dpy, root, MatricesAtom, 0, 8192,
                                        False, XA_INTEGER, &ret_atom,
                                        &ret_format, &ret_len, &ret_after,
                                        &ret_prop);
        }
        if (MatricesAtom == None || status != Success || !ret_format) {
            printf("Could not find property %s\n",
                   XDCCC_SCREENWHITEPT_ATOM_NAME);
        }
        else {
            printf("Deleting property %s\n", XDCCC_SCREENWHITEPT_ATOM_NAME);
            XDeleteProperty(dpy, root, MatricesAtom);
            XFree(ret_prop);
        }

        CorrectAtom = XInternAtom(dpy, XDCCC_GRAY_CORRECT_ATOM_NAME, True);
        if (CorrectAtom != None) {
            status = XGetWindowProperty(dpy, root, CorrectAtom, 0, 8192,
                                        False, XA_INTEGER, &ret_atom,
                                        &ret_format, &ret_len, &ret_after,
                                        &ret_prop);
        }
        if (CorrectAtom == None || status != Success || !ret_format) {
            printf("Could not find property %s\n",
                   XDCCC_GRAY_CORRECT_ATOM_NAME);
        }
        else {
            printf("Deleting property %s\n", XDCCC_GRAY_CORRECT_ATOM_NAME);
            XDeleteProperty(dpy, root, CorrectAtom);
            XFree(ret_prop);
        }
    }
#endif                          /* GRAY */
}

static unsigned long
_XcmsGetElement(int format, char **pValue, unsigned long *pCount)
/*
 *	DESCRIPTION
 *	    Get the next element from the property and return it.
 *	    Also increment the pointer the amount needed.
 *
 *	Returns
 *	    unsigned long
 */
{
    unsigned long value;

    switch (format) {
    case 32:
        value = *((unsigned long *) (*pValue)) & 0xFFFFFFFF;
        *pValue += sizeof(unsigned long);
        *pCount -= 1;
        break;
    case 16:
        value = *((unsigned short *) (*pValue));
        *pValue += sizeof(unsigned short);
        *pCount -= 1;
        break;
    case 8:
        value = *((unsigned char *) (*pValue));
        *pValue += 1;
        *pCount -= 1;
        break;
    default:
        value = 0;
        break;
    }
    return (value);
}

/*
 *	NAME
 *		_XcmsGetProperty -- Determine the existence of a property
 *
 *	SYNOPSIS
 */
static int
_XcmsGetProperty(Display *pDpy, Window w, Atom property, int *pFormat,
                 unsigned long *pNItems, unsigned long *pNBytes, char **pValue)
/*
 *	DESCRIPTION
 *
 *	Returns
 *	    0 if property does not exist.
 *	    1 if property exists.
 */
{
    char *prop_ret;
    int format_ret;
    long len = 6516;
    unsigned long nitems_ret, after_ret;
    Atom atom_ret;
    int xgwp_ret;

    while (True) {
        xgwp_ret = XGetWindowProperty(pDpy, w, property, 0, len, False,
                                      XA_INTEGER, &atom_ret, &format_ret,
                                      &nitems_ret, &after_ret,
                                      (unsigned char **) &prop_ret);
        if (xgwp_ret == Success && after_ret > 0) {
            len += nitems_ret * (format_ret >> 3);
            XFree(prop_ret);
        }
        else {
            break;
        }
    }
    if (xgwp_ret != Success || format_ret == 0 || nitems_ret == 0) {
        /* the property does not exist or is of an unexpected type or
           getting window property failed */
        return (XcmsFailure);
    }

    *pFormat = format_ret;
    *pNItems = nitems_ret;
    *pNBytes = nitems_ret * (format_ret >> 3);
    *pValue = prop_ret;
    return (XcmsSuccess);
}