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  Every copy of AFPL Ghostscript must include a copy of the License, normally
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*/

/*$Id: gdevm2.c,v 1.2 2000/09/19 19:00:13 lpd Exp $ */
/* 2-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_mapped2_copy_mono, mem_mapped2_copy_color, mem_mapped2_fill_rectangle);

/* The device descriptor. */
const gx_device_memory mem_mapped2_device =
mem_device("image2", 2, 0,
	   mem_mapped_map_rgb_color, mem_mapped_map_color_rgb,
	   mem_mapped2_copy_mono, mem_mapped2_copy_color,
	   mem_mapped2_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) >> 2)

/* Define the 2-bit fill patterns. */
static const mono_fill_chunk tile_patterns[4] = {
    fpat(0x00), fpat(0x55), fpat(0xaa), fpat(0xff)
};

/* Fill a rectangle with a color. */
private int
mem_mapped2_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 << 1, mdev->raster,
			tile_patterns[color], w << 1, h);
    return 0;
}

/* Copy a bitmap. */
private int
mem_mapped2_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;
    int first_bit;
    byte first_mask, b0, b1, bxor, left_mask, right_mask;
    static const byte btab[4] = {0, 0x55, 0xaa, 0xff};
    static const byte bmask[4] = {0xc0, 0x30, 0xc, 3};
    static const byte lmask[4] = {0, 0xc0, 0xf0, 0xfc};

    declare_scan_ptr(dest);

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    setup_rect(dest);
    line = base + (sourcex >> 3);
    first_bit = 0x80 >> (sourcex & 7);
    first_mask = bmask[x & 3];
    left_mask = lmask[x & 3];
    right_mask = ~lmask[(x + w) & 3];
    if ((x & 3) + w <= 3)
	left_mask = right_mask = left_mask | right_mask;
    b0 = btab[zero & 3];
    b1 = btab[one & 3];
    bxor = b0 ^ b1;
    while (h-- > 0) {
	register byte *pptr = (byte *) dest;
	const byte *sptr = line;
	register int sbyte = *sptr++;
	register int bit = first_bit;
	register byte mask = first_mask;
	int count = w;

	/* We have 4 cases, of which only 2 really matter. */
	if (one != gx_no_color_index) {
	    if (zero != gx_no_color_index) {	/* Copying an opaque bitmap. */
		byte data = (*pptr & left_mask) | (b0 & ~left_mask);

		for ( ; ; ) {
		    if (sbyte & bit)
			data ^= bxor & mask;
		    if (--count <= 0)
			break;
		    if ((bit >>= 1) == 0)
			bit = 0x80, sbyte = *sptr++;
		    if ((mask >>= 2) == 0)
			mask = 0xc0, *pptr++ = data, data = b0;
		}
		if (mask != 0xc0)
		    *pptr =
			(*pptr & right_mask) | (data & ~right_mask);
	    } else {		/* Filling a mask. */
		for ( ; ; ) {
		    if (sbyte & bit)
			*pptr = (*pptr & ~mask) + (b1 & mask);
		    if (--count <= 0)
			break;
		    if ((bit >>= 1) == 0)
			bit = 0x80, sbyte = *sptr++;
		    if ((mask >>= 2) == 0)
			mask = 0xc0, pptr++;
		}
	    }
	} else {		/* Some other case. */
	    for ( ; ; ) {
		if (!(sbyte & bit)) {
		    if (zero != gx_no_color_index)
			*pptr = (*pptr & ~mask) + (b0 & mask);
		}
		if (--count <= 0)
		    break;
		if ((bit >>= 1) == 0)
		    bit = 0x80, sbyte = *sptr++;
		if ((mask >>= 2) == 0)
		    mask = 0xc0, pptr++;
	    }
	}
	line += sraster;
	inc_ptr(dest, draster);
    }
    return 0;
}

/* Copy a color bitmap. */
private int
mem_mapped2_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 <<= 1;
    code = (*dev_proc(&mem_mono_device, copy_mono))
	(dev, base, sourcex << 1, sraster, id,
	 x << 1, y, w << 1, h, (gx_color_index) 0, (gx_color_index) 1);
    /* Restore the correct width. */
    dev->width >>= 1;
    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(mem2_word_copy_mono, mem2_word_copy_color, mem2_word_fill_rectangle);

/* Here is the device descriptor. */
const gx_device_memory mem_mapped2_word_device =
mem_full_device("image2w", 2, 0, mem_open,
		mem_mapped_map_rgb_color, mem_mapped_map_color_rgb,
		mem2_word_copy_mono, mem2_word_copy_color,
		mem2_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
mem2_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 << 1, w << 1, h, true);
    bits_fill_rectangle(base, x << 1, raster,
			tile_patterns[color], w << 1, h);
    mem_swap_byte_rect(base, raster, x << 1, w << 1, h, true);
    return 0;
}

/* Copy a bitmap. */
private int
mem2_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 << 1, w << 1, h, store);
    mem_mapped2_copy_mono(dev, base, sourcex, sraster, id,
			  x, y, w, h, zero, one);
    mem_swap_byte_rect(row, raster, x << 1, w << 1, h, false);
    return 0;
}

/* Copy a color bitmap. */
private int
mem2_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 <<= 1;
    code = (*dev_proc(&mem_mono_word_device, copy_mono))
	(dev, base, sourcex << 1, sraster, id,
	 x << 1, y, w << 1, h, (gx_color_index) 0, (gx_color_index) 1);
    /* Restore the correct width. */
    dev->width >>= 1;
    return code;
}

#endif /* !arch_is_big_endian */
