Re: 64-bit support for display device

Thanks, Russell.  

I'm glad you found a way to do this in a backward compatible manner. 
Kudos.   I'll merge this over so it gets into our next pcl release.  

./Stefan

On Wed, 2004-02-11 at 01:38, Russell Lang wrote:
> Ray,
> 
> Please review the following patch.  I have not tested it on a 64-
> bit platform (I don't have one).  I would like this added to 
> 8.14.  If all goes well it should be harmless.  Worst case is 
> probably some compiler warnings when compiled on a 64-bit 
> platform.    For HEAD, GS_8_1X and GS_8_0X.
> 
> Log message:
> 
> Change display device parameter DisplayHandle from an integer
> to a string, to add support for 64-bit platforms.
> 
> DETAILS:
> 
> The display device passes a (void *) handle to callback 
> functions.  The handle is set before the device is opened, and 
> attempting to change it afterwards is an error.  The handle may 
> be used by the caller to identify an instance of the display 
> device, for example it may point to the display instance object 
> in the caller. This handle was set using a PostScript integer 
> which is 32-bits long, typically with -dDisplayHandle.  The 
> existing code will not work correctly on 64-bit architectures.   
> 
> 
> The display device is changed to return a string as the
> DisplayHandle parameter.
> Previously the handle would be set using -dDisplayHandle=1234.
> The changed code allows it to be passed as
>  -dDisplayHandle=1234
>  -dDisplayHandle=(1234)
>  -sDisplayHandle=1234
>  -sDisplayHandle=10#1234
>  -sDisplayHandle=16#04d2
> This should be backward compatible, since users of the
> display device will most likely only set the DisplayHandle,
> not read its value.
> 
> The ghostscript example code in dw*.c, dx*.c and dp*.c
> does not use DisplayHandle, so is unaffected by this change.
> GSview does use DisplayHandle and will require this
> change for operation on 64-bit platforms.
> 
> It is assumed that size_t is an integer with the same size
> as a pointer.
> 
> 
> Russell Lang                   [email protected]
> Ghostgum Software Pty Ltd      http://www.ghostgum.com.au/
> 
> 
> 
> 
> ______________________________________________________________________
> diff -u l:src/gdevdsp.c src/gdevdsp.c
> --- l:src/gdevdsp.c	Wed Apr 30 09:34:53 2003
> +++ src/gdevdsp.c	Wed Feb 11 08:08:53 2004
> @@ -704,9 +704,33 @@
>  {
>      gx_device_display *ddev = (gx_device_display *) dev;
>      int code = gx_default_get_params(dev, plist);
> +    gs_param_string dhandle;
> +    int idx;
> +    int val;
> +    int i = 0;
> +    size_t dptr;
> +    char buf[64];
> +   
> +    idx = ((int)sizeof(size_t)) * 8 - 4;
> +    buf[i++] = '1';
> +    buf[i++] = '6';
> +    buf[i++] = '#';
> +    dptr = (size_t)(ddev->pHandle);
> +    while (idx >= 0) {
> +	val = (int)(dptr >> idx) & 0xf;
> +        if (val <= 9)
> +	    buf[i++] = '0' + val;
> +	else
> +	    buf[i++] = 'a' - 10 + val;
> +	idx -= 4;
> +    }
> +    buf[i] = '\0';
> +     
> +    param_string_from_transient_string(dhandle, buf);
> +    
>      (void)(code < 0 ||
> -	(code = param_write_long(plist, 
> -	    "DisplayHandle", (long *)(&ddev->pHandle))) < 0 ||
> +	(code = param_write_string(plist, 
> +	    "DisplayHandle", &dhandle)) < 0 ||
>  	(code = param_write_int(plist, 
>  	    "DisplayFormat", &ddev->nFormat)) < 0 );
>      return code;
> @@ -731,6 +755,8 @@
>  
>      int format;
>      void *handle;
> +    int found_string_handle = 0;
> +    gs_param_string dh = { 0 };
>  
>      /* Handle extra parameters */
>  
> @@ -757,24 +783,98 @@
>  	    break;
>      }
>  
> -    switch (code = param_read_long(plist, "DisplayHandle", (long *)(&handle))) {
> +    /* 64-bit systems need to use DisplayHandle as a string */
> +    switch (code = param_read_string(plist, "DisplayHandle", &dh)) {
>  	case 0:
> -	    if (dev->is_open) {
> -		if (ddev->pHandle != handle)
> -		    ecode = gs_error_rangecheck;
> -		else
> -		    break;
> -	    }
> -	    else
> -		ddev->pHandle = handle;
> -		break;
> -	    goto hdle;
> +    	    found_string_handle = 1;
> +	    break;
>  	default:
> +	    if ((code == gs_error_typecheck) && (sizeof(size_t) <= 4)) {
> +		/* 32-bit systems can use the older long type */
> +		switch (code = param_read_long(plist, "DisplayHandle", 
> +		    (long *)(&handle))) {
> +		    case 0:
> +			if (dev->is_open) {
> +			    if (ddev->pHandle != handle)
> +				ecode = gs_error_rangecheck;
> +			    else
> +				break;
> +			}
> +			else {
> +			    ddev->pHandle = handle;
> +			    break;
> +			}
> +			goto hdle;
> +		    default:
> +			ecode = code;
> +		      hdle:param_signal_error(plist, "DisplayHandle", ecode);
> +		    case 1:
> +			break;
> +		}
> +		break;
> +	    }
>  	    ecode = code;
> -	  hdle:param_signal_error(plist, "DisplayHandle", ecode);
> +	    param_signal_error(plist, "DisplayHandle", ecode);
> +	    /* fall through */
>  	case 1:
> +	    dh.data = 0;
>  	    break;
>      }
> +    if (found_string_handle) {
> +	/* 
> +	 * Convert from a string to a pointer.  
> +	 * It is assumed that size_t has the same size as a pointer.
> +	 * Allow formats (1234), (10#1234) or (16#04d2).
> +	 */
> +	size_t ptr = 0;
> + 	int i;
> +	int base = 10;
> + 	int val;
> +	code = 0;
> +	for (i=0; i<dh.size; i++) {
> +	    val = dh.data[i];
> +	    if ((val >= '0') && (val <= '9'))
> +		val = val - '0';
> +	    else if ((val >= 'A') && (val <= 'F'))
> +		val = val - 'A' + 10;
> +	    else if ((val >= 'a') && (val <= 'f'))
> +		val = val - 'a' + 10;
> +	    else if (val == '#') {
> +		base = (int)ptr;
> +		ptr = 0;
> +		if ((base != 10) && (base != 16)) {
> +		    code = gs_error_rangecheck;
> +		    break;
> +		}
> +		continue;
> +	    }
> +	    else {
> +		code = gs_error_rangecheck;
> +		break;
> +	    }
> +
> +	    if (base == 10)
> +		ptr = ptr * 10 + val;
> +	    else if (base == 16)
> +		ptr = ptr * 16 + val;
> +	    else {
> +		code = gs_error_rangecheck;
> +		break;
> +	    }
> +	}
> +	if (code == 0) {
> +	    if (dev->is_open) {
> +		if (ddev->pHandle != (void *)ptr)
> +		    code = gs_error_rangecheck;
> +	    }
> +	    else
> +		ddev->pHandle = (void *)ptr;
> +	}
> +	if (code < 0) {
> +	    ecode = code;
> +	    param_signal_error(plist, "DisplayHandle", ecode);
> +	}
> +    }
>  
>      if (ecode >= 0) {
>  	/* Prevent gx_default_put_params from closing the device. */
> Only in src: gdevdsp.c.orig
> diff -u l:src/gdevdsp.h src/gdevdsp.h
> --- l:src/gdevdsp.h	Thu Nov 21 08:36:43 2002
> +++ src/gdevdsp.h	Wed Feb 11 08:11:53 2004
> @@ -28,8 +28,10 @@
>   *  gsapi_init_with_args(minst, argc, argv);
>   *
>   * Supported parameters and default values are:
> - * -dDisplayHandle=0                      long
> - *    Caller supplied handle.
> + * -sDisplayHandle=16#04d2 or 1234        string
> + *    Caller supplied handle as a decimal or hexadecimal number
> + *    in a string.  On 32-bit platforms, it may be set
> + *    using -dDisplayHandle=1234 for backward compatibility.
>   *    Included as first parameter of all callback functions.
>   *
>   * -dDisplayFormat=0                      long
> 
> ______________________________________________________________________
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