path: root/gs/src/gsflip.c

/* Copyright (C) 1996, 1997, 1998 Aladdin Enterprises.  All rights reserved.

   This file is part of Aladdin Ghostscript.

   Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
   or distributor accepts any responsibility for the consequences of using it,
   or for whether it serves any particular purpose or works at all, unless he
   or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
   License (the "License") for full details.

   Every copy of Aladdin Ghostscript must include a copy of the License,
   normally in a plain ASCII text file named PUBLIC.  The License grants you
   the right to copy, modify and redistribute Aladdin Ghostscript, but only
   under certain conditions described in the License.  Among other things, the
   License requires that the copyright notice and this notice be preserved on
   all copies.
 */

/*$Id$ */
/* Routines for "flipping" image data */
#include "gx.h"
#include "gsbittab.h"
#include "gsflip.h"

#define arch_has_byte_regs 1

/* Transpose a block of bits between registers. */
#define transpose(r,s,mask,shift)\
  r ^= (temp = ((s << shift) ^ r) & mask);\
  s ^= temp >> shift

/* Define the size of byte temporaries.  On Intel CPUs, this should be */
/* byte, but on all other CPUs, it should be uint. */
#if arch_has_byte_regs
typedef byte byte_var;

#else
typedef uint byte_var;

#endif

#define vtab(v80,v40,v20,v10,v8,v4,v2,v1)\
  bit_table_8(0,v80,v40,v20,v10,v8,v4,v2,v1)

/* Convert 3Mx1 to 3x1. */
private void
flip3x1(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    uint n = nbytes;
    static const bits32 tab3x1[256] =
    {
	vtab(0x800000, 0x100000, 0x20000, 0x4000, 0x800, 0x100, 0x20, 4)
    };

    for (; n > 0; out += 3, ++in1, ++in2, ++in3, --n) {
	bits32 b24 =
	tab3x1[*in1] | (tab3x1[*in2] >> 1) | (tab3x1[*in3] >> 2);

	out[0] = (byte) (b24 >> 16);
	out[1] = (byte) (b24 >> 8);
	out[2] = (byte) b24;
    }
}

/* Convert 3Mx2 to 3x2. */
private void
flip3x2(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    uint n = nbytes;
    static const bits32 tab3x2[256] =
    {
	vtab(0x800000, 0x400000, 0x20000, 0x10000, 0x800, 0x400, 0x20, 0x10)
    };

    for (; n > 0; out += 3, ++in1, ++in2, ++in3, --n) {
	bits32 b24 =
	tab3x2[*in1] | (tab3x2[*in2] >> 2) | (tab3x2[*in3] >> 4);

	out[0] = (byte) (b24 >> 16);
	out[1] = (byte) (b24 >> 8);
	out[2] = (byte) b24;
    }
}

/* Convert 3Mx4 to 3x4. */
private void
flip3x4(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    uint n = nbytes;

    for (; n > 0; out += 3, ++in1, ++in2, ++in3, --n) {
	byte_var b1 = *in1, b2 = *in2, b3 = *in3;

	out[0] = (b1 & 0xf0) | (b2 >> 4);
	out[1] = (b3 & 0xf0) | (b1 & 0xf);
	out[2] = (byte) (b2 << 4) | (b3 & 0xf);
    }
}

/* Convert 3Mx8 to 3x8. */
private void
flip3x8(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    uint n = nbytes;

    for (; n > 0; out += 3, ++in1, ++in2, ++in3, --n) {
	out[0] = *in1;
	out[1] = *in2;
	out[2] = *in3;
    }
}

/* Convert 3Mx12 to 3x12. */
private void
flip3x12(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *pa = planes[0] + offset;
    const byte *pb = planes[1] + offset;
    const byte *pc = planes[2] + offset;
    uint n = nbytes;

    /* We are guaranteed that the input is an integral number of pixels. */
    /* This implies that n = 0 mod 3. */

    for (; n > 0; out += 9, pa += 3, pb += 3, pc += 3, n -= 3) {
	byte_var a1 = pa[1], b0 = pb[0], b1 = pb[1], b2 = pb[2], c1 = pc[1];

	out[0] = pa[0];
	out[1] = (a1 & 0xf0) | (b0 >> 4);
	out[2] = (byte) ((b0 << 4) | (b1 >> 4));
	out[3] = pc[0];
	out[4] = (c1 & 0xf0) | (a1 & 0xf);
	out[5] = pa[2];
	out[6] = (byte) ((b1 << 4) | (b2 >> 4));
	out[7] = (byte) ((b2 << 4) | (c1 & 0xf));
	out[8] = pc[2];
    }
}

/* Convert 4Mx1 to 4x1. */
private void
flip4x1(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    const byte *in4 = planes[3] + offset;
    uint n = nbytes;

    for (; n > 0; out += 4, ++in1, ++in2, ++in3, ++in4, --n) {
	byte_var b1 = *in1, b2 = *in2, b3 = *in3, b4 = *in4;
	byte_var temp;

	/* Transpose blocks of 1 */
	transpose(b1, b2, 0x55, 1);
	transpose(b3, b4, 0x55, 1);
	/* Transpose blocks of 2 */
	transpose(b1, b3, 0x33, 2);
	transpose(b2, b4, 0x33, 2);
	/* There's probably a faster way to do this.... */
	out[0] = (b1 & 0xf0) | (b2 >> 4);
	out[1] = (b3 & 0xf0) | (b4 >> 4);
	out[2] = (byte) ((b1 << 4) | (b2 & 0xf));
	out[3] = (byte) ((b3 << 4) | (b4 & 0xf));
    }
}

/* Convert 4Mx2 to 4x2. */
private void
flip4x2(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    const byte *in4 = planes[3] + offset;
    uint n = nbytes;

    for (; n > 0; out += 4, ++in1, ++in2, ++in3, ++in4, --n) {
	byte_var b1 = *in1, b2 = *in2, b3 = *in3, b4 = *in4;
	byte_var temp;

	/* Transpose blocks of 4x2 */
	transpose(b1, b3, 0x0f, 4);
	transpose(b2, b4, 0x0f, 4);
	/* Transpose blocks of 2x1 */
	transpose(b1, b2, 0x33, 2);
	transpose(b3, b4, 0x33, 2);
	out[0] = b1;
	out[1] = b2;
	out[2] = b3;
	out[3] = b4;
    }
}

/* Convert 4Mx4 to 4x4. */
private void
flip4x4(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    const byte *in4 = planes[3] + offset;
    uint n = nbytes;

    for (; n > 0; out += 4, ++in1, ++in2, ++in3, ++in4, --n) {
	byte_var b1 = *in1, b2 = *in2, b3 = *in3, b4 = *in4;

	out[0] = (b1 & 0xf0) | (b2 >> 4);
	out[1] = (b3 & 0xf0) | (b4 >> 4);
	out[2] = (byte) ((b1 << 4) | (b2 & 0xf));
	out[3] = (byte) ((b3 << 4) | (b4 & 0xf));
    }
}

/* Convert 4Mx8 to 4x8. */
private void
flip4x8(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *in1 = planes[0] + offset;
    const byte *in2 = planes[1] + offset;
    const byte *in3 = planes[2] + offset;
    const byte *in4 = planes[3] + offset;
    uint n = nbytes;

    for (; n > 0; out += 4, ++in1, ++in2, ++in3, ++in4, --n) {
	out[0] = *in1;
	out[1] = *in2;
	out[2] = *in3;
	out[3] = *in4;
    }
}

/* Convert 4Mx12 to 4x12. */
private void
flip4x12(byte * buffer, const byte ** planes, uint offset, uint nbytes)
{
    byte *out = buffer;
    const byte *pa = planes[0] + offset;
    const byte *pb = planes[1] + offset;
    const byte *pc = planes[2] + offset;
    const byte *pd = planes[3] + offset;
    uint n = nbytes;

    /* We are guaranteed that the input is an integral number of pixels. */
    /* This implies that n = 0 mod 3. */

    for (; n > 0; out += 12, pa += 3, pb += 3, pc += 3, pd += 3, n -= 3) {
	byte_var a1 = pa[1], b1 = pb[1], c1 = pc[1], d1 = pd[1];

	{
	    byte_var v0;

	    out[0] = pa[0];
	    v0 = pb[0];
	    out[1] = (a1 & 0xf0) | (v0 >> 4);
	    out[2] = (byte) ((v0 << 4) | (b1 >> 4));
	    out[3] = pc[0];
	    v0 = pd[0];
	    out[4] = (c1 & 0xf0) | (v0 >> 4);
	    out[5] = (byte) ((v0 << 4) | (d1 >> 4));
	}
	{
	    byte_var v2;

	    v2 = pa[2];
	    out[6] = (byte) ((a1 << 4) | (v2 >> 4));
	    out[7] = (byte) ((v2 << 4) | (b1 & 0xf));
	    out[8] = pb[2];
	    v2 = pc[2];
	    out[9] = (byte) ((c1 << 4) | (v2 >> 4));
	    out[10] = (byte) ((v2 << 4) | (d1 & 0xf));
	    out[11] = pd[2];
	}
    }
}

/* Flip data given number of planes and bits per pixel. */
typedef void (*image_flip_proc) (P4(byte *, const byte **, uint, uint));
private const image_flip_proc image_flip_procs[2][13] =
{
    {0, flip3x1, flip3x2, 0, flip3x4, 0, 0, 0, flip3x8, 0, 0, 0, flip3x12},
    {0, flip4x1, flip4x2, 0, flip4x4, 0, 0, 0, flip4x8, 0, 0, 0, flip4x12}
};

/* Here is the public interface to all of the above. */
int
image_flip_planes(byte * buffer, const byte ** planes, uint offset, uint nbytes,
		  int num_planes, int bits_per_sample)
{
    void (*proc) (P4(byte * buffer, const byte ** planes, uint offset, uint nbytes));

    if (num_planes < 3 || num_planes > 4 ||
	bits_per_sample < 1 || bits_per_sample > 12 ||
	(proc = image_flip_procs[num_planes - 3][bits_per_sample]) == 0
	)
	return -1;
    (*proc) (buffer, planes, offset, nbytes);
    return 0;
}