// Copyright (C) 2009,2010,2011,2012 GlavSoft LLC.
// All rights reserved.
//
//-------------------------------------------------------------------------
// This file is part of the TightVNC software.  Please visit our Web site:
//
//                       http://www.tightvnc.com/
//
// This program 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 program 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 program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//-------------------------------------------------------------------------
//

//
// TightPalette class implementation.
//

#include "TightPalette.h"

TightPalette::TightPalette(int maxColors)
{
  setMaxColors(maxColors);
  reset();
}

void TightPalette::reset()
{
  m_numColors = 0;
  memset(m_hash, 0, 256 * sizeof(TightColorList *));
}

void TightPalette::setMaxColors(int maxColors)
{
  m_maxColors = maxColors;
  if (m_maxColors < 0) {
    m_maxColors = 0;
  } else if (m_maxColors > 254) {
    m_maxColors = 254;
  }
}

int TightPalette::insert(UINT32 rgb, int numPixels)
{
  TightColorList *pnode;
  TightColorList *prev_pnode = NULL;
  int hash_key, idx, new_idx, count;

  hash_key = hashFunc(rgb);

  pnode = m_hash[hash_key];

  while (pnode != NULL) {
    if (pnode->rgb == rgb) {
      // Such palette entry already exists.
      new_idx = idx = pnode->idx;
      count = m_entry[idx].numPixels + numPixels;
      if (new_idx && m_entry[new_idx-1].numPixels < count) {
        do {
          m_entry[new_idx] = m_entry[new_idx-1];
          m_entry[new_idx].listNode->idx = new_idx;
          new_idx--;
        }
        while (new_idx && m_entry[new_idx-1].numPixels < count);

        m_entry[new_idx].listNode = pnode;
        pnode->idx = new_idx;
      }
      m_entry[new_idx].numPixels = count;
      return m_numColors;
    }
    prev_pnode = pnode;
    pnode = pnode->next;
  }

  // Check if the palette is full.
  if (m_numColors == 256 || m_numColors == m_maxColors) {
    m_numColors = 0;
    return 0;
  }

  // Move palette entries with lesser pixel counts.
  for ( idx = m_numColors;
        idx > 0 && m_entry[idx-1].numPixels < numPixels;
        idx-- ) {
    m_entry[idx] = m_entry[idx-1];
    m_entry[idx].listNode->idx = idx;
  }

  // Add new palette entry into the freed slot.
  pnode = &m_list[m_numColors];
  if (prev_pnode != NULL) {
    prev_pnode->next = pnode;
  } else {
    m_hash[hash_key] = pnode;
  }
  pnode->next = NULL;
  pnode->idx = idx;
  pnode->rgb = rgb;
  m_entry[idx].listNode = pnode;
  m_entry[idx].numPixels = numPixels;

  return ++m_numColors;
}
