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/* Copyright (C) 2000-2005 Constantin Kaplinsky. All Rights Reserved.
*
* This 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 software 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 software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
//
// TightPalette class is a container for ordered color values. Colors
// are keys in a hash where values are frequency counts. Also, there
// is a list where colors are always sorted by these counts (more
// frequent first).
//
#ifndef __RFB_TIGHTPALETTE_H__
#define __RFB_TIGHTPALETTE_H__
#include <string.h>
#include <rdr/types.h>
namespace rfb {
struct TightColorList {
TightColorList *next;
int idx;
rdr::U32 rgb;
};
struct TightPaletteEntry {
TightColorList *listNode;
int numPixels;
};
class TightPalette {
protected:
// FIXME: Bigger hash table? Better hash function?
inline static int hashFunc(rdr::U32 rgb) {
return (rgb ^ (rgb >> 13)) & 0xFF;
}
public:
TightPalette(int maxColors = 254);
//
// Re-initialize the object. This does not change maximum number
// of colors.
//
void reset();
//
// Set limit on the number of colors in the palette. Note that
// this value cannot exceed 254.
//
void setMaxColors(int maxColors);
//
// Insert new color into the palette, or increment its counter if
// the color is already there. Returns new number of colors, or
// zero if the palette is full. If the palette becomes full, it
// reports zero colors and cannot be used any more without calling
// reset().
//
int insert(rdr::U32 rgb, int numPixels);
//
// Return number of colors in the palette.
//
inline int getNumColors() const {
return m_numColors;
}
//
// Return the color specified by its index in the palette.
//
inline rdr::U32 getEntry(int i) const {
return (i < m_numColors) ? m_entry[i].listNode->rgb : (rdr::U32)-1;
}
//
// Return the pixel counter of the color specified by its index.
//
inline int getCount(int i) const {
return (i < m_numColors) ? m_entry[i].numPixels : 0;
}
//
// Return the index of a specified color.
//
inline rdr::U8 getIndex(rdr::U32 rgb) const {
TightColorList *pnode = m_hash[hashFunc(rgb)];
while (pnode != NULL) {
if (pnode->rgb == rgb) {
return (rdr::U8)pnode->idx;
}
pnode = pnode->next;
}
return 0xFF; // no such color
}
protected:
int m_maxColors;
int m_numColors;
TightPaletteEntry m_entry[256];
TightColorList *m_hash[256];
TightColorList m_list[256];
};
} // namespace rfb
#endif // __RFB_TIGHTPALETTE_H__
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