/* vim: set ts=8 sw=8 noexpandtab: */

//  qcms

//  Copyright (C) 2009 Mozilla Foundation

//  Copyright (C) 1998-2007 Marti Maria

//

// Permission is hereby granted, free of charge, to any person obtaining 

// a copy of this software and associated documentation files (the "Software"), 

// to deal in the Software without restriction, including without limitation 

// the rights to use, copy, modify, merge, publish, distribute, sublicense, 

// and/or sell copies of the Software, and to permit persons to whom the Software 

// is furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in 

// all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO 

// THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 

// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 

// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 

// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#include <stdlib.h>

#include "qcmsint.h"

#include "matrix.h"

struct vector matrix_eval(struct matrix mat, struct vector v)

{

  struct vector result;

  result.v[0] = mat.m[0][0]*v.v[0] + mat.m[0][1]*v.v[1] + mat.m[0][2]*v.v[2];

  result.v[1] = mat.m[1][0]*v.v[0] + mat.m[1][1]*v.v[1] + mat.m[1][2]*v.v[2];

  result.v[2] = mat.m[2][0]*v.v[0] + mat.m[2][1]*v.v[1] + mat.m[2][2]*v.v[2];

  return result;

}

//XXX: should probably pass by reference and we could

//probably reuse this computation in matrix_invert

float matrix_det(struct matrix mat)

{

  float det;

  det = mat.m[0][0]*mat.m[1][1]*mat.m[2][2] +

    mat.m[0][1]*mat.m[1][2]*mat.m[2][0] +

    mat.m[0][2]*mat.m[1][0]*mat.m[2][1] -

    mat.m[0][0]*mat.m[1][2]*mat.m[2][1] -

    mat.m[0][1]*mat.m[1][0]*mat.m[2][2] -

    mat.m[0][2]*mat.m[1][1]*mat.m[2][0];

  return det;

}

/* from pixman and cairo and Mathematics for Game Programmers */

/* lcms uses gauss-jordan elimination with partial pivoting which is

 * less efficient and not as numerically stable. See Mathematics for

 * Game Programmers. */

struct matrix matrix_invert(struct matrix mat)

{

  struct matrix dest_mat;

  int i,j;

  static int a[3] = { 2, 2, 1 };

  static int b[3] = { 1, 0, 0 };

  /* inv  (A) = 1/det (A) * adj (A) */

  float det = matrix_det(mat);

  if (det == 0) {

    dest_mat.invalid = true;

    return dest_mat;

  }

  dest_mat.invalid = false;

  det = 1/det;

  for (j = 0; j < 3; j++) {

    for (i = 0; i < 3; i++) {

      double p;

      int ai = a[i];

      int aj = a[j];

      int bi = b[i];

      int bj = b[j];

      p = mat.m[ai][aj] * mat.m[bi][bj] -

        mat.m[ai][bj] * mat.m[bi][aj];

      if (((i + j) & 1) != 0)

        p = -p;

      dest_mat.m[j][i] = det * p;

    }

  }

  return dest_mat;

}

struct matrix matrix_identity(void)

{

  struct matrix i;

  i.m[0][0] = 1;

  i.m[0][1] = 0;

  i.m[0][2] = 0;

  i.m[1][0] = 0;

  i.m[1][1] = 1;

  i.m[1][2] = 0;

  i.m[2][0] = 0;

  i.m[2][1] = 0;

  i.m[2][2] = 1;

  i.invalid = false;

  return i;

}

struct matrix matrix_invalid(void)

{

  struct matrix inv = matrix_identity();

  inv.invalid = true;

  return inv;

}

/* from pixman */

/* MAT3per... */

struct matrix matrix_multiply(struct matrix a, struct matrix b)

{

  struct matrix result;

  int dx, dy;

  int o;

  for (dy = 0; dy < 3; dy++) {

    for (dx = 0; dx < 3; dx++) {

      double v = 0;

      for (o = 0; o < 3; o++) {

        v += a.m[dy][o] * b.m[o][dx];

      }

      result.m[dy][dx] = v;

    }

  }

  result.invalid = a.invalid || b.invalid;

  return result;

}