Pack the pixel information to use less memory. More...

Public Member Functions
	Packing (int noise_w, int pedestal_w, int gain_w, int status_w)

Public Attributes
PackedPixDbType	gain_mask

int	gain_shift

PackedPixDbType	noise_mask

int	noise_shift

int	noise_width

PackedPixDbType	pedestal_mask

int	pedestal_shift

int	pedestal_width

PackedPixDbType	status_mask

int	status_shift

int	status_width

Detailed Description

Pack the pixel information to use less memory.

Definition at line 48 of file SiPixelDbItem.h.

Constructor & Destructor Documentation

SiPixelDbItem::Packing::Packing	(	int	noise_w,
		int	pedestal_w,
		int	gain_w,
		int	status_w
	)

Definition at line 79 of file SiPixelDbItem.cc.

References gather_cfg::cout, gain_mask, gain_shift, noise_mask, noise_shift, pedestal_mask, pedestal_shift, status_mask, and status_shift.

   : noise_width(noise_w), pedestal_width(pedestal_w), status_width(status_w) 
 {
   // Constructor: pre-computes masks and shifts from field widths
   // Order of fields (from right to left) is
   // noise, pedestal, gain, status count.
   
   if ( noise_w+pedestal_w+gain_w+status_w != 32) {
     std::cout << std::endl << "Error in SiPixelDbItem::Packing constructor:" 
           << "sum of field widths != 32" << std::endl;
     // TO DO: throw an exception?
   }
 
   // Fields are counted from right to left!
   
   noise_shift     = 0;
   pedestal_shift  = noise_shift + noise_w;
   gain_shift    = pedestal_shift + pedestal_w;
   status_shift     = gain_shift + gain_w;
 
   // Ensure the complement of the correct 
   // number of bits:
   PackedPixDbType zero32 = 0;  // 32-bit wide
 
   noise_mask     = ~(~zero32 << noise_w);
   pedestal_mask  = ~(~zero32 << pedestal_w);
   gain_mask    = ~(~zero32 << gain_w);
   status_mask     = ~(~zero32 << status_w);
 }