/* Copyright (C) 1992, 1995, 1996, 1997, 1998, 1999 Aladdin Enterprises.  All rights reserved.
  
  This software is provided AS-IS with no warranty, either express or
  implied.
  
  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gdevm4.c,v 1.4 2002/02/21 22:24:51 giles Exp $ */
/* 4-bit-per-pixel "memory" (stored bitmap) device */
#include "memory_.h"
#include "gx.h"
#include "gxdevice.h"
#include "gxdevmem.h"		/* semi-public definitions */
#include "gdevmem.h"		/* private definitions */

/* ================ Standard (byte-oriented) device ================ */

#undef chunk
#define chunk byte
#define fpat(byt) mono_fill_make_pattern(byt)

/* Procedures */
declare_mem_procs(mem_mapped4_copy_mono, mem_mapped4_copy_color, mem_mapped4_fill_rectangle);

/* The device descriptor. */
const gx_device_memory mem_mapped4_device =
mem_device("image4", 4, 0,
	   mem_mapped_map_rgb_color, mem_mapped_map_color_rgb,
  mem_mapped4_copy_mono, mem_mapped4_copy_color, mem_mapped4_fill_rectangle,
	   mem_gray_strip_copy_rop);

/* Convert x coordinate to byte offset in scan line. */
#undef x_to_byte
#define x_to_byte(x) ((x) >> 1)

/* Define the 4-bit fill patterns. */
static const mono_fill_chunk tile_patterns[16] =
{fpat(0x00), fpat(0x11), fpat(0x22), fpat(0x33),
 fpat(0x44), fpat(0x55), fpat(0x66), fpat(0x77),
 fpat(0x88), fpat(0x99), fpat(0xaa), fpat(0xbb),
 fpat(0xcc), fpat(0xdd), fpat(0xee), fpat(0xff)
};


/* Fill a rectangle with a color. */
private int
mem_mapped4_fill_rectangle(gx_device * dev,
			   int x, int y, int w, int h, gx_color_index color)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;

    fit_fill(dev, x, y, w, h);
    bits_fill_rectangle(scan_line_base(mdev, y), x << 2, mdev->raster,
			tile_patterns[color], w << 2, h);
    return 0;
}

/* Copy a bitmap. */
private int
mem_mapped4_copy_mono(gx_device * dev,
	       const byte * base, int sourcex, int sraster, gx_bitmap_id id,
	int x, int y, int w, int h, gx_color_index zero, gx_color_index one)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;
    const byte *line;
    declare_scan_ptr(dest);
    byte invert, bb;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    setup_rect(dest);
    line = base + (sourcex >> 3);
    /* Divide into opaque and masked cases. */
    if (one == gx_no_color_index) {
	if (zero == gx_no_color_index)
	    return 0;		/* nothing to do */
	invert = 0xff;
	bb = ((byte) zero << 4) | (byte) zero;
    } else if (zero == gx_no_color_index) {
	invert = 0;
	bb = ((byte) one << 4) | (byte) one;
    } else {
	/* Opaque case. */
	int shift = ~(sourcex ^ x) & 1;
	byte oz[4];

	oz[0] = (byte)((zero << 4) | zero);
	oz[1] = (byte)((zero << 4) | one);
	oz[2] = (byte)((one << 4) | zero);
	oz[3] = (byte)((one << 4) | one);
	do {
	    register byte *dptr = (byte *) dest;
	    const byte *sptr = line;
	    register uint sbyte = *sptr++;
	    register int sbit = ~sourcex & 7;
	    int count = w;

	    /*
	     * If the first source bit corresponds to an odd X in the
	     * destination, process it now.
	     */
	    if (x & 1) {
		*dptr = (*dptr & 0xf0) |
		    ((sbyte >> sbit) & 1 ? one : zero);
		--count;	/* may now be 0 */
		if (--sbit < 0)
		    sbit = 7, sbyte = *sptr++;
		++dptr;
	    }
	    /*
	     * Now we know the next destination X is even.  We want to
	     * process 2 source bits at a time from now on, so set things up
	     * properly depending on whether the next source X (bit) is even
	     * or odd.  In both even and odd cases, the active source bits
	     * are in bits 8..1 of sbyte.
	     */
	    sbyte <<= shift;
	    sbit += shift - 1;
	    /*
	     * Now bit # sbit+1 is the most significant unprocessed bit
	     * in sbyte.  -1 <= sbit <= 7; sbit is odd.
	     * Note that if sbit = -1, all of sbyte has been processed.
	     *
	     * Continue processing pairs of bits in the first source byte.
	     */
	    while (count >= 2 && sbit >= 0) {
		*dptr++ = oz[(sbyte >> sbit) & 3];
		sbit -= 2, count -= 2;
	    }
	    /*
	     * Now sbit = -1 iff we have processed the entire first source
	     * byte.
	     *
	     * Process full source bytes.
	     */
	    if (shift) {
		sbyte >>= 1;	/* in case count < 8 */
		for (; count >= 8; dptr += 4, count -= 8) {
		    sbyte = *sptr++;
		    dptr[0] = oz[sbyte >> 6];
		    dptr[1] = oz[(sbyte >> 4) & 3];
		    dptr[2] = oz[(sbyte >> 2) & 3];
		    dptr[3] = oz[sbyte & 3];
		}
		sbyte <<= 1;
	    } else {
		for (; count >= 8; dptr += 4, count -= 8) {
		    sbyte = (sbyte << 8) | *sptr++;
		    dptr[0] = oz[(sbyte >> 7) & 3];
		    dptr[1] = oz[(sbyte >> 5) & 3];
		    dptr[2] = oz[(sbyte >> 3) & 3];
		    dptr[3] = oz[(sbyte >> 1) & 3];
		}
	    }
	    if (!count)
		continue;
	    /*
	     * Process pairs of bits in the final source byte.  Note that
	     * if sbit > 0, this is still the first source byte (the
	     * full-byte loop wasn't executed).
	     */
	    if (sbit < 0) {
		sbyte = (sbyte << 8) | (*sptr << shift);
		sbit = 7;
	    }
	    while (count >= 2) {
		*dptr++ = oz[(sbyte >> sbit) & 3];
		sbit -= 2, count -= 2;
	    }
	    /*
	     * If the final source bit corresponds to an even X value,
	     * process it now.
	     */
	    if (count) {
		*dptr = (*dptr & 0x0f) |
		    (((sbyte >> sbit) & 2 ? one : zero) << 4);
	    }
	} while ((line += sraster, inc_ptr(dest, draster), --h) > 0);
	return 0;
    }
    /* Masked case. */
    do {
	register byte *dptr = (byte *) dest;
	const byte *sptr = line;
	register int sbyte = *sptr++ ^ invert;
	register int sbit = 0x80 >> (sourcex & 7);
	register byte mask = (x & 1 ? 0x0f : 0xf0);
	int count = w;

	do {
	    if (sbyte & sbit)
		*dptr = (*dptr & ~mask) | (bb & mask);
	    if ((sbit >>= 1) == 0)
		sbit = 0x80, sbyte = *sptr++ ^ invert;
	    dptr += (mask = ~mask) >> 7;
	} while (--count > 0);
	line += sraster;
	inc_ptr(dest, draster);
    } while (--h > 0);
    return 0;
}

/* Copy a color bitmap. */
private int
mem_mapped4_copy_color(gx_device * dev,
	       const byte * base, int sourcex, int sraster, gx_bitmap_id id,
		       int x, int y, int w, int h)
{
    /* Use monobit copy_mono. */
    int code;

    /* Patch the width in the device temporarily. */
    dev->width <<= 2;
    code = (*dev_proc(&mem_mono_device, copy_mono))
	(dev, base, sourcex << 2, sraster, id,
	 x << 2, y, w << 2, h, (gx_color_index) 0, (gx_color_index) 1);
    /* Restore the correct width. */
    dev->width >>= 2;
    return code;
}

/* ================ "Word"-oriented device ================ */

/* Note that on a big-endian machine, this is the same as the */
/* standard byte-oriented-device. */

#if !arch_is_big_endian

/* Procedures */
declare_mem_procs(mem4_word_copy_mono, mem4_word_copy_color, mem4_word_fill_rectangle);

/* Here is the device descriptor. */
const gx_device_memory mem_mapped4_word_device =
mem_full_device("image4w", 4, 0, mem_open,
		mem_mapped_map_rgb_color, mem_mapped_map_color_rgb,
	mem4_word_copy_mono, mem4_word_copy_color, mem4_word_fill_rectangle,
		gx_default_map_cmyk_color, gx_default_strip_tile_rectangle,
		gx_no_strip_copy_rop, mem_word_get_bits_rectangle);

/* Fill a rectangle with a color. */
private int
mem4_word_fill_rectangle(gx_device * dev, int x, int y, int w, int h,
			 gx_color_index color)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;
    byte *base;
    uint raster;

    fit_fill(dev, x, y, w, h);
    base = scan_line_base(mdev, y);
    raster = mdev->raster;
    mem_swap_byte_rect(base, raster, x << 2, w << 2, h, true);
    bits_fill_rectangle(base, x << 2, raster,
			tile_patterns[color], w << 2, h);
    mem_swap_byte_rect(base, raster, x << 2, w << 2, h, true);
    return 0;
}

/* Copy a bitmap. */
private int
mem4_word_copy_mono(gx_device * dev,
	       const byte * base, int sourcex, int sraster, gx_bitmap_id id,
	int x, int y, int w, int h, gx_color_index zero, gx_color_index one)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;
    byte *row;
    uint raster;
    bool store;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    row = scan_line_base(mdev, y);
    raster = mdev->raster;
    store = (zero != gx_no_color_index && one != gx_no_color_index);
    mem_swap_byte_rect(row, raster, x << 2, w << 2, h, store);
    mem_mapped4_copy_mono(dev, base, sourcex, sraster, id,
			  x, y, w, h, zero, one);
    mem_swap_byte_rect(row, raster, x << 2, w << 2, h, false);
    return 0;
}

/* Copy a color bitmap. */
private int
mem4_word_copy_color(gx_device * dev,
	       const byte * base, int sourcex, int sraster, gx_bitmap_id id,
		     int x, int y, int w, int h)
{
    int code;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    /* Use monobit copy_mono. */
    /* Patch the width in the device temporarily. */
    dev->width <<= 2;
    code = (*dev_proc(&mem_mono_word_device, copy_mono))
	(dev, base, sourcex << 2, sraster, id,
	 x << 2, y, w << 2, h, (gx_color_index) 0, (gx_color_index) 1);
    /* Restore the correct width. */
    dev->width >>= 2;
    return code;
}

#endif /* !arch_is_big_endian */
