Re: Switch in CSharp very slow?

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

I mean, could you repost a sample showing the time lags you mention, but
without code in the case statments?
I' not able to reproduce your slow behavior.

<aliostad@xxxxxxxxx> wrote in message
news:1132438149.752754.154170@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>I have started programming with .NET 2.0 using Microsoft Visual Studio
> 2005
> Version 8.0.50727.42 (RTM.050727-4200)
> Microsoft .NET Framework
> Version 2.0.50727
>
> and I was doing some image processing and it was taking a long time to
> process and finally I found that I used a switch and it made it slower:
>
> private static bool GetBitonalValue(byte[] buffer, int x, int y,
> int stride, PixelFormat pf, int threshold)
> {
>
> switch (pf)
> {
> case PixelFormat.Format1bppIndexed:
> throw new InvalidOperationException("Image is
> already bitonal.");
> case PixelFormat.Format8bppIndexed:
> byte b = buffer[(y * stride) + x];
> return (b >= threshold);
> case PixelFormat.Format24bppRgb:
> byte[] bb = new byte[4];
> bb[0] = 255;
> Array.Copy(buffer, (y * stride) + x, bb, 1, 3);
> Color clr = Color.FromArgb(BitConverter.ToInt32(bb,
> 0));
> return ((clr.B + clr.G + clr.R) >= (threshold *
> 3));
>
> case PixelFormat.Format32bppArgb:
> case PixelFormat.Format32bppPArgb:
> byte[] bbb = new byte[4];
> Array.Copy(buffer, (y * stride) + x, bbb, 0, 4);
> Color clr1 =
> Color.FromArgb(BitConverter.ToInt32(bbb, 0));
> return ((clr1.B + clr1.G + clr1.R) >= (threshold *
> 3));
>
> default:
> throw new NotImplementedException("Pixel format is
> not supported.");
> }
>
> }
>
> Regardless of the code itself, when I removed the switch it became 10
> times faster. For an image of nearly 1000000 pixels it was taking 400ms
> and after removing switch it took only 30ms for that part of code.
>
> Is there anyway to optimise switch?
>


.

Relevant Pages

  • [WATCHDOG] v2.6.27-rc patches
    ... [WATCHDOG] ... Re-structure the ioctl switch call for all drivers as follows: ... module_param(wdt_start, int, 0); ... +static long acq_ioctl(struct file *file, unsigned int cmd, unsigned long arg) ...
    (Linux-Kernel)
  • Switch in CSharp very slow?
    ... I have started programming with .NET 2.0 using Microsoft Visual Studio ... and I was doing some image processing and it was taking a long time to ... private static bool GetBitonalValue(bytebuffer, int x, int y, ... when I removed the switch it became 10 ...
    (microsoft.public.dotnet.languages.csharp)
  • [PATCH -mm 1/2] RapidIO: Use common destid storage for endpoints and switches
    ... switches use an associated destid because they do not have their own. ... * @rswitch: Switch device ... u16 table, u16 route_destid, u8 route_port, int lock) ... portnum, em_perrdet); ...
    (Linux-Kernel)
  • Re: Switch in CSharp very slow?
    ... >I have started programming with .NET 2.0 using Microsoft Visual Studio ... > process and finally I found that I used a switch and it made it slower: ... > private static bool GetBitonalValue(bytebuffer, int x, int y, ... > times faster. ...
    (microsoft.public.dotnet.languages.csharp)
  • Re: Switch in CSharp very slow?
    ... >I have started programming with .NET 2.0 using Microsoft Visual Studio ... > Microsoft .NET Framework ... > process and finally I found that I used a switch and it made it slower: ... > private static bool GetBitonalValue(bytebuffer, int x, int y, ...
    (microsoft.public.dotnet.languages.csharp)