/*
 * tableinittctemplate.c - template for initialising lookup tables for
 * truecolour to truecolour translation.
 *
 * This file shouldn't be compiled.  It is included multiple times by
 * translate.c, each time with a different definition of the macro OUT.
 * For each value of OUT, this file defines two functions for initialising
 * lookup tables.  One is for truecolour translation using a single lookup
 * table, the other is for truecolour translation using three separate
 * lookup tables for the red, green and blue values.
 *
 * I know this code isn't nice to read because of all the macros, but
 * efficiency is important here.
 */

/* Copyright (C) 2017 D. R. Commander.  All Rights Reserved.
 * Copyright (C) 1999 AT&T Laboratories Cambridge.  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA.
 */

#if !defined(OUT)
#error "This file shouldn't be compiled."
#error "It is included as part of translate.c"
#endif

#define OUT_T CONCAT2E(CARD, OUT)
#define SwapOUT(x) CONCAT2E(Swap, OUT(x))
#define rfbInitTrueColourSingleTableOUT  \
  CONCAT2E(rfbInitTrueColourSingleTable, OUT)
#define rfbInitTrueColourRGBTablesOUT CONCAT2E(rfbInitTrueColourRGBTables, OUT)
#define rfbInitOneRGBTableOUT CONCAT2E(rfbInitOneRGBTable, OUT)

static void rfbInitOneRGBTableOUT(OUT_T *table, int inMax, int outMax,
                                  int outShift, int swap);


/*
 * rfbInitTrueColourSingleTable sets up a single lookup table for truecolour
 * translation.
 */

static void rfbInitTrueColourSingleTableOUT(char **table, rfbPixelFormat *in,
                                            rfbPixelFormat *out)
{
  int i;
  int inRed, inGreen, inBlue, outRed, outGreen, outBlue;
  OUT_T *t;
  int nEntries = 1 << in->bitsPerPixel;

  free(*table);
  *table = (char *)rfbAlloc(nEntries * sizeof(OUT_T));
  t = (OUT_T *)*table;

  for (i = 0; i < nEntries; i++) {
    inRed   = (i >> in->redShift)   & in->redMax;
    inGreen = (i >> in->greenShift) & in->greenMax;
    inBlue  = (i >> in->blueShift)  & in->blueMax;

    outRed   = (inRed   * out->redMax   + in->redMax / 2)   / in->redMax;
    outGreen = (inGreen * out->greenMax + in->greenMax / 2) / in->greenMax;
    outBlue  = (inBlue  * out->blueMax  + in->blueMax / 2)  / in->blueMax;

    t[i] = ((outRed   << out->redShift)   |
            (outGreen << out->greenShift) |
            (outBlue  << out->blueShift));
#if (OUT != 8)
    if (out->bigEndian != in->bigEndian)
      t[i] = SwapOUT(t[i]);
#endif
  }
}


/*
 * rfbInitTrueColourRGBTables sets up three separate lookup tables for the
 * red, green and blue values.
 */

static void rfbInitTrueColourRGBTablesOUT(char **table, rfbPixelFormat *in,
                                          rfbPixelFormat *out)
{
  OUT_T *redTable;
  OUT_T *greenTable;
  OUT_T *blueTable;

  free(*table);
  *table = (char *)rfbAlloc((in->redMax + in->greenMax + in->blueMax + 3) *
                            sizeof(OUT_T));
  redTable = (OUT_T *)*table;
  greenTable = redTable + in->redMax + 1;
  blueTable = greenTable + in->greenMax + 1;

  rfbInitOneRGBTableOUT(redTable, in->redMax, out->redMax,
                        out->redShift, (out->bigEndian != in->bigEndian));
  rfbInitOneRGBTableOUT(greenTable, in->greenMax, out->greenMax,
                        out->greenShift, (out->bigEndian != in->bigEndian));
  rfbInitOneRGBTableOUT(blueTable, in->blueMax, out->blueMax,
                        out->blueShift, (out->bigEndian != in->bigEndian));
}


static void rfbInitOneRGBTableOUT(OUT_T *table, int inMax, int outMax,
                                  int outShift, int swap)
{
  int i;
  int nEntries = inMax + 1;

  for (i = 0; i < nEntries; i++) {
    table[i] = ((i * outMax + inMax / 2) / inMax) << outShift;
#if (OUT != 8)
    if (swap)
      table[i] = SwapOUT(table[i]);
#endif
  }
}


#undef OUT_T
#undef SwapOUT
#undef rfbInitTrueColourSingleTableOUT
#undef rfbInitTrueColourRGBTablesOUT
#undef rfbInitOneRGBTableOUT
