/*
 *  Fast C2P (Chunky-to-Planar) Conversion
 *
 *  Copyright (C) 2003-2008 Geert Uytterhoeven
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License. See the file COPYING in the main directory of this archive
 *  for more details.
 */

#include <linux/export.h>
#include <linux/module.h>
#include <linux/string.h>

#include <linux/unaligned.h>

#include "c2p.h"
#include "c2p_core.h"


    /*
     *  Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words
     *  containing
     *    - 32 8-bit chunky pixels on input
     *    - permutated planar data (1 plane per 32-bit word) on output
     */

static void c2p_32x8(u32 d[8])
{
        transp8(d, 16, 4);
        transp8(d, 8, 2);
        transp8(d, 4, 1);
        transp8(d, 2, 4);
        transp8(d, 1, 2);
}


    /*
     *  Array containing the permutation indices of the planar data after c2p
     */

static const int perm_c2p_32x8[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };


    /*
     *  Store a full block of planar data after c2p conversion
     */

static inline void store_planar(void *dst, u32 dst_inc, u32 bpp, u32 d[8])
{
        int i;

        for (i = 0; i < bpp; i++, dst += dst_inc)
                put_unaligned_be32(d[perm_c2p_32x8[i]], dst);
}


    /*
     *  Store a partial block of planar data after c2p conversion
     */

static inline void store_planar_masked(void *dst, u32 dst_inc, u32 bpp,
                                       u32 d[8], u32 mask)
{
        int i;

        for (i = 0; i < bpp; i++, dst += dst_inc)
                put_unaligned_be32(comp(d[perm_c2p_32x8[i]],
                                        get_unaligned_be32(dst), mask),
                                   dst);
}


    /*
     *  c2p_planar - Copy 8-bit chunky image data to a planar frame buffer
     *  @dst: Starting address of the planar frame buffer
     *  @dx: Horizontal destination offset (in pixels)
     *  @dy: Vertical destination offset (in pixels)
     *  @width: Image width (in pixels)
     *  @height: Image height (in pixels)
     *  @dst_nextline: Frame buffer offset to the next line (in bytes)
     *  @dst_nextplane: Frame buffer offset to the next plane (in bytes)
     *  @src_nextline: Image offset to the next line (in bytes)
     *  @bpp: Bits per pixel of the planar frame buffer (1-8)
     */

void c2p_planar(void *dst, const void *src, u32 dx, u32 dy, u32 width,
                u32 height, u32 dst_nextline, u32 dst_nextplane,
                u32 src_nextline, u32 bpp)
{
        union {
                u8 pixels[32];
                u32 words[8];
        } d;
        u32 dst_idx, first, last, w;
        const u8 *c;
        void *p;

        dst += dy*dst_nextline+(dx & ~31);
        dst_idx = dx % 32;
        first = 0xffffffffU >> dst_idx;
        last = ~(0xffffffffU >> ((dst_idx+width) % 32));
        while (height--) {
                c = src;
                p = dst;
                w = width;
                if (dst_idx+width <= 32) {
                        /* Single destination word */
                        first &= last;
                        memset(d.pixels, 0, sizeof(d));
                        memcpy(d.pixels+dst_idx, c, width);
                        c += width;
                        c2p_32x8(d.words);
                        store_planar_masked(p, dst_nextplane, bpp, d.words,
                                            first);
                        p += 4;
                } else {
                        /* Multiple destination words */
                        w = width;
                        /* Leading bits */
                        if (dst_idx) {
                                w = 32 - dst_idx;
                                memset(d.pixels, 0, dst_idx);
                                memcpy(d.pixels+dst_idx, c, w);
                                c += w;
                                c2p_32x8(d.words);
                                store_planar_masked(p, dst_nextplane, bpp,
                                                    d.words, first);
                                p += 4;
                                w = width-w;
                        }
                        /* Main chunk */
                        while (w >= 32) {
                                memcpy(d.pixels, c, 32);
                                c += 32;
                                c2p_32x8(d.words);
                                store_planar(p, dst_nextplane, bpp, d.words);
                                p += 4;
                                w -= 32;
                        }
                        /* Trailing bits */
                        w %= 32;
                        if (w > 0) {
                                memcpy(d.pixels, c, w);
                                memset(d.pixels+w, 0, 32-w);
                                c2p_32x8(d.words);
                                store_planar_masked(p, dst_nextplane, bpp,
                                                    d.words, last);
                        }
                }
                src += src_nextline;
                dst += dst_nextline;
        }
}
EXPORT_SYMBOL_GPL(c2p_planar);

MODULE_DESCRIPTION("Fast C2P (Chunky-to-Planar) Conversion");
MODULE_LICENSE("GPL");