/* Copyright (C) 2001-2019 Artifex Software, Inc.
   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.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/

/* 16-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 */

#undef chunk
#define chunk byte

/* The 16 bits are divided 5 for red, 6 for green, and 5 for blue. */
/* Note that the bits must always be kept in big-endian order. */

/* Procedures */
declare_mem_map_procs(mem_true16_map_rgb_color, mem_true16_map_color_rgb);
declare_mem_procs(mem_true16_copy_mono, mem_true16_copy_color, mem_true16_fill_rectangle);

/* The device descriptor. */
const gx_device_memory mem_true16_device =
    mem_device("image16", 16, 0,
               mem_true16_map_rgb_color, mem_true16_map_color_rgb,
               mem_true16_copy_mono, mem_true16_copy_color,
               mem_true16_fill_rectangle, mem_default_strip_copy_rop);

/* Map a r-g-b color to a color index. */
static gx_color_index
mem_true16_map_rgb_color(gx_device * dev, const gx_color_value cv[])
{
    return ((cv[0] >> (gx_color_value_bits - 5)) << 11) +
        ((cv[1] >> (gx_color_value_bits - 6)) << 5) +
        (cv[2] >> (gx_color_value_bits - 5));
}

/* Map a color index to a r-g-b color. */
static int
mem_true16_map_color_rgb(gx_device * dev, gx_color_index color,
                         gx_color_value prgb[3])
{
    ushort value = color >> 11;

    prgb[0] = ((value << 11) + (value << 6) + (value << 1) + (value >> 4))
                      >> (16 - gx_color_value_bits);
    value = (color >> 5) & 0x3f;
    prgb[1] = ((value << 10) + (value << 4) + (value >> 2))
                      >> (16 - gx_color_value_bits);
    value = color & 0x1f;
    prgb[2] = ((value << 11) + (value << 6) + (value << 1) + (value >> 4))
                      >> (16 - gx_color_value_bits);
    return 0;
}

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

/* Fill a rectangle with a color. */
static int
mem_true16_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;
#if ARCH_IS_BIG_ENDIAN
    const ushort color16 = (ushort)color;
#else
    const ushort color16 = (ushort)((color << 8) | (color >> 8));
#endif
    declare_scan_ptr(dest);

    fit_fill(dev, x, y, w, h);
    setup_rect(dest);
    if (w == 1) {
        while (h-- > 0) {
            *(ushort *)dest = color16;
            inc_ptr(dest, draster);
        }
    } else if ((color16 >> 8) == (color16 & 0xff)) {
        bytes_fill_rectangle(scan_line_base(mdev, y) + (x << 1), draster,
                             (byte)color, w << 1, h);
    } else {
        while (h-- > 0) {
            ushort *pptr = (ushort *) dest;
            int cnt = w;

            for (; cnt >= 4; pptr += 4, cnt -= 4)
                pptr[3] = pptr[2] = pptr[1] = pptr[0] = color16;
            switch (cnt) {
            case 3: pptr[2] = color16;
            case 2: pptr[1] = color16;
            case 1: pptr[0] = color16;
            case 0: DO_NOTHING;
            }
            inc_ptr(dest, draster);
        }
    }
    return 0;
}

/* Copy a monochrome bitmap. */
static int
mem_true16_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;
#if ARCH_IS_BIG_ENDIAN
    const ushort zero16 = (ushort)zero;
    const ushort one16 = (ushort)one;
#else
    ushort zero16 = ((uint) (byte) zero << 8) + ((ushort) zero >> 8);
    ushort one16 = ((uint) (byte) one << 8) + ((ushort) one >> 8);
#endif
    const byte *line;
    int first_bit;

    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);
    while (h-- > 0) {
        register ushort *pptr = (ushort *) dest;
        const byte *sptr = line;
        register int sbyte = *sptr++;
        register int bit = first_bit;
        int count = w;

        do {
            if (sbyte & bit) {
                if (one != gx_no_color_index)
                    *pptr = one16;
            } else {
                if (zero != gx_no_color_index)
                    *pptr = zero16;
            }
            if ((bit >>= 1) == 0)
                bit = 0x80, sbyte = *sptr++;
            pptr++;
        }
        while (--count > 0);
        line += sraster;
        inc_ptr(dest, draster);
    }
    return 0;
}

/* Copy a color bitmap. */
static int
mem_true16_copy_color(gx_device * dev,
               const byte * base, int sourcex, int sraster, gx_bitmap_id id,
                      int x, int y, int w, int h)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    mem_copy_byte_rect(mdev, base, sourcex, sraster, x, y, w, h);
    return 0;
}
