/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef NSCOORD_H

#define NSCOORD_H

#include "mozilla/FloatingPoint.h"

#include "nsAlgorithm.h"

#include "nscore.h"

#include "nsMathUtils.h"

#include <math.h>

#include <float.h>

#include <stdlib.h>

#include "nsDebug.h"

#include <algorithm>

/*

 * Basic type used for the geometry classes.

 *

 * Normally all coordinates are maintained in an app unit coordinate

 * space. An app unit is 1/60th of a CSS device pixel, which is, in turn

 * an integer number of device pixels, such at the CSS DPI is as close to

 * 96dpi as possible.

 */

// This controls whether we're using integers or floats for coordinates. We

// want to eventually use floats.

//#define NS_COORD_IS_FLOAT

#ifdef NS_COORD_IS_FLOAT

typedef float nscoord;

#define nscoord_MAX (mozilla::PositiveInfinity<float>())

#else

typedef int32_t nscoord;

#define nscoord_MAX nscoord((1 << 30) - 1)

#endif

#define nscoord_MIN (-nscoord_MAX)

inline void VERIFY_COORD(nscoord aCoord) {

#ifdef NS_COORD_IS_FLOAT

  NS_ASSERTION(floorf(aCoord) == aCoord,

               "Coords cannot have fractions");

#endif

}

/**

 * Divide aSpace by aN.  Assign the resulting quotient to aQuotient and

 * return the remainder.

 */

inline nscoord NSCoordDivRem(nscoord aSpace, size_t aN, nscoord* aQuotient)

{

#ifdef NS_COORD_IS_FLOAT

  *aQuotient = aSpace / aN;

  return 0.0f;

#else

  div_t result = div(aSpace, aN);

  *aQuotient = nscoord(result.quot);

  return nscoord(result.rem);

#endif

}

inline nscoord NSCoordMulDiv(nscoord aMult1, nscoord aMult2, nscoord aDiv) {

#ifdef NS_COORD_IS_FLOAT

  return (aMult1 * aMult2 / aDiv);

#else

  return (int64_t(aMult1) * int64_t(aMult2) / int64_t(aDiv));

#endif

}

inline nscoord NSToCoordRound(float aValue)

{

#if defined(XP_WIN32) && defined(_M_IX86) && !defined(__GNUC__) && !defined(__clang__)

  return NS_lroundup30(aValue);

#else

  return nscoord(floorf(aValue + 0.5f));

#endif /* XP_WIN32 && _M_IX86 && !__GNUC__ */

}

inline nscoord NSToCoordRound(double aValue)

{

#if defined(XP_WIN32) && defined(_M_IX86) && !defined(__GNUC__) && !defined(__clang__)

  return NS_lroundup30((float)aValue);

#else

  return nscoord(floor(aValue + 0.5f));

#endif /* XP_WIN32 && _M_IX86 && !__GNUC__ */

}

inline nscoord NSToCoordRoundWithClamp(float aValue)

{

#ifndef NS_COORD_IS_FLOAT

  // Bounds-check before converting out of float, to avoid overflow

  if (aValue >= nscoord_MAX) {

    return nscoord_MAX;

  }

  if (aValue <= nscoord_MIN) {

    return nscoord_MIN;

  }

#endif

  return NSToCoordRound(aValue);

}

/**

 * Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as

 * appropriate for the signs of aCoord and aScale.  If requireNotNegative is

 * true, this method will enforce that aScale is not negative; use that

 * parametrization to get a check of that fact in debug builds.

 */

inline nscoord _nscoordSaturatingMultiply(nscoord aCoord, float aScale,

                                          bool requireNotNegative) {

  VERIFY_COORD(aCoord);

  if (requireNotNegative) {

    MOZ_ASSERT(aScale >= 0.0f,

               "negative scaling factors must be handled manually");

  }

#ifdef NS_COORD_IS_FLOAT

  return floorf(aCoord * aScale);

#else

  float product = aCoord * aScale;

  if (requireNotNegative ? aCoord > 0 : (aCoord > 0) == (aScale > 0))

    return NSToCoordRoundWithClamp(std::min<float>((float)nscoord_MAX, product));

  return NSToCoordRoundWithClamp(std::max<float>((float)nscoord_MIN, product));

#endif

}

/**

 * Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as

 * appropriate for the sign of aCoord.  This method requires aScale to not be

 * negative; use this method when you know that aScale should never be

 * negative to get a sanity check of that invariant in debug builds.

 */

inline nscoord NSCoordSaturatingNonnegativeMultiply(nscoord aCoord, float aScale) {

  return _nscoordSaturatingMultiply(aCoord, aScale, true);

}

/**

 * Returns aCoord * aScale, capping the product to nscoord_MAX or nscoord_MIN as

 * appropriate for the signs of aCoord and aScale.

 */

inline nscoord NSCoordSaturatingMultiply(nscoord aCoord, float aScale) {

  return _nscoordSaturatingMultiply(aCoord, aScale, false);

}

/**

 * Returns a + b, capping the sum to nscoord_MAX.

 *

 * This function assumes that neither argument is nscoord_MIN.

 *

 * Note: If/when we start using floats for nscoords, this function won't be as

 * necessary.  Normal float addition correctly handles adding with infinity,

 * assuming we aren't adding nscoord_MIN. (-infinity)

 */

inline nscoord

NSCoordSaturatingAdd(nscoord a, nscoord b)

{

  VERIFY_COORD(a);

  VERIFY_COORD(b);

#ifdef NS_COORD_IS_FLOAT

  // Float math correctly handles a+b, given that neither is -infinity.

  return a + b;

#else

  if (a == nscoord_MAX || b == nscoord_MAX) {

    // infinity + anything = anything + infinity = infinity

    return nscoord_MAX;

  } else {

    // a + b = a + b

    // Cap the result, just in case we're dealing with numbers near nscoord_MAX

    return std::min(nscoord_MAX, a + b);

  }

#endif

}

/**

 * Returns a - b, gracefully handling cases involving nscoord_MAX.

 * This function assumes that neither argument is nscoord_MIN.

 *

 * The behavior is as follows:

 *

 *  a)  infinity - infinity -> infMinusInfResult

 *  b)  N - infinity        -> 0  (unexpected -- triggers NOTREACHED)

 *  c)  infinity - N        -> infinity

 *  d)  N1 - N2             -> N1 - N2

 *

 * Note: For float nscoords, cases (c) and (d) are handled by normal float

 * math.  We still need to explicitly specify the behavior for cases (a)

 * and (b), though.  (Under normal float math, those cases would return NaN

 * and -infinity, respectively.)

 */

inline nscoord 

NSCoordSaturatingSubtract(nscoord a, nscoord b, 

                          nscoord infMinusInfResult)

{

  VERIFY_COORD(a);

  VERIFY_COORD(b);

  if (b == nscoord_MAX) {

    if (a == nscoord_MAX) {

      // case (a)

      return infMinusInfResult;

    } else {

      // case (b)

      MOZ_ASSERT_UNREACHABLE("Attempted to subtract [n - nscoord_MAX]");

      return 0;

    }

  } else {

#ifdef NS_COORD_IS_FLOAT

    // case (c) and (d) for floats.  (float math handles both)

    return a - b;

#else

    if (a == nscoord_MAX) {

      // case (c) for integers

      return nscoord_MAX;

    } else {

      // case (d) for integers

      // Cap the result, in case we're dealing with numbers near nscoord_MAX

      return std::min(nscoord_MAX, a - b);

    }

#endif

  }

}

inline float NSCoordToFloat(nscoord aCoord) {

  VERIFY_COORD(aCoord);

#ifdef NS_COORD_IS_FLOAT

  NS_ASSERTION(!mozilla::IsNaN(aCoord), "NaN encountered in float conversion");

#endif

  return (float)aCoord;

}

/*

 * Coord Rounding Functions

 */

inline nscoord NSToCoordFloor(float aValue)

{

  return nscoord(floorf(aValue));

}

inline nscoord NSToCoordFloor(double aValue)

{

  return nscoord(floor(aValue));

}

inline nscoord NSToCoordFloorClamped(float aValue)

{

#ifndef NS_COORD_IS_FLOAT

  // Bounds-check before converting out of float, to avoid overflow

  if (aValue >= nscoord_MAX) {

    return nscoord_MAX;

  }

  if (aValue <= nscoord_MIN) {

    return nscoord_MIN;

  }

#endif

  return NSToCoordFloor(aValue);

}

inline nscoord NSToCoordCeil(float aValue)

{

  return nscoord(ceilf(aValue));

}

inline nscoord NSToCoordCeil(double aValue)

{

  return nscoord(ceil(aValue));

}

inline nscoord NSToCoordCeilClamped(double aValue)

{

#ifndef NS_COORD_IS_FLOAT

  // Bounds-check before converting out of double, to avoid overflow

  if (aValue >= nscoord_MAX) {

    return nscoord_MAX;

  }

  if (aValue <= nscoord_MIN) {

    return nscoord_MIN;

  }

#endif

  return NSToCoordCeil(aValue);

}

// The NSToCoordTrunc* functions remove the fractional component of

// aValue, and are thus equivalent to NSToCoordFloor* for positive

// values and NSToCoordCeil* for negative values.

inline nscoord NSToCoordTrunc(float aValue)

{

  // There's no need to use truncf() since it matches the default

  // rules for float to integer conversion.

  return nscoord(aValue);

}

inline nscoord NSToCoordTrunc(double aValue)

{

  // There's no need to use trunc() since it matches the default

  // rules for float to integer conversion.

  return nscoord(aValue);

}

inline nscoord NSToCoordTruncClamped(float aValue)

{

#ifndef NS_COORD_IS_FLOAT

  // Bounds-check before converting out of float, to avoid overflow

  if (aValue >= nscoord_MAX) {

    return nscoord_MAX;

  }

  if (aValue <= nscoord_MIN) {

    return nscoord_MIN;

  }

#endif

  return NSToCoordTrunc(aValue);

}

inline nscoord NSToCoordTruncClamped(double aValue)

{

#ifndef NS_COORD_IS_FLOAT

  // Bounds-check before converting out of double, to avoid overflow

  if (aValue >= nscoord_MAX) {

    return nscoord_MAX;

  }

  if (aValue <= nscoord_MIN) {

    return nscoord_MIN;

  }

#endif

  return NSToCoordTrunc(aValue);

}

/*

 * Int Rounding Functions

 */

inline int32_t NSToIntFloor(float aValue)

{

  return int32_t(floorf(aValue));

}

inline int32_t NSToIntCeil(float aValue)

{

  return int32_t(ceilf(aValue));

}

inline int32_t NSToIntRound(float aValue)

{

  return NS_lroundf(aValue);

}

inline int32_t NSToIntRound(double aValue)

{

  return NS_lround(aValue);

}

inline int32_t NSToIntRoundUp(double aValue)

{

  return int32_t(floor(aValue + 0.5));

}

/* 

 * App Unit/Pixel conversions

 */

inline nscoord NSFloatPixelsToAppUnits(float aPixels, float aAppUnitsPerPixel)

{

  return NSToCoordRoundWithClamp(aPixels * aAppUnitsPerPixel);

}

inline nscoord NSIntPixelsToAppUnits(int32_t aPixels, int32_t aAppUnitsPerPixel)

{

  // The cast to nscoord makes sure we don't overflow if we ever change

  // nscoord to float

  nscoord r = aPixels * (nscoord)aAppUnitsPerPixel;

  VERIFY_COORD(r);

  return r;

}

inline float NSAppUnitsToFloatPixels(nscoord aAppUnits, float aAppUnitsPerPixel)

{

  return (float(aAppUnits) / aAppUnitsPerPixel);

}

inline double NSAppUnitsToDoublePixels(nscoord aAppUnits, double aAppUnitsPerPixel)

{

  return (double(aAppUnits) / aAppUnitsPerPixel);

}

inline int32_t NSAppUnitsToIntPixels(nscoord aAppUnits, float aAppUnitsPerPixel)

{

  return NSToIntRound(float(aAppUnits) / aAppUnitsPerPixel);

}

inline float NSCoordScale(nscoord aCoord, int32_t aFromAPP, int32_t aToAPP)

{

  return (NSCoordToFloat(aCoord) * aToAPP) / aFromAPP;

}

/// handy constants

#define TWIPS_PER_POINT_INT           20

#define TWIPS_PER_POINT_FLOAT         20.0f

#define POINTS_PER_INCH_INT           72

#define POINTS_PER_INCH_FLOAT         72.0f

#define CM_PER_INCH_FLOAT             2.54f

#define MM_PER_INCH_FLOAT             25.4f

/* 

 * Twips/unit conversions

 */

inline float NSUnitsToTwips(float aValue, float aPointsPerUnit)

{

  return aValue * aPointsPerUnit * TWIPS_PER_POINT_FLOAT;

}

inline float NSTwipsToUnits(float aTwips, float aUnitsPerPoint)

{

  return (aTwips * (aUnitsPerPoint / TWIPS_PER_POINT_FLOAT));

}

/// Unit conversion macros

//@{

#define NS_POINTS_TO_TWIPS(x)         NSUnitsToTwips((x), 1.0f)

#define NS_INCHES_TO_TWIPS(x)         NSUnitsToTwips((x), POINTS_PER_INCH_FLOAT)                      // 72 points per inch

#define NS_MILLIMETERS_TO_TWIPS(x)    NSUnitsToTwips((x), (POINTS_PER_INCH_FLOAT * 0.03937f))

#define NS_POINTS_TO_INT_TWIPS(x)     NSToIntRound(NS_POINTS_TO_TWIPS(x))

#define NS_INCHES_TO_INT_TWIPS(x)     NSToIntRound(NS_INCHES_TO_TWIPS(x))

#define NS_TWIPS_TO_INCHES(x)         NSTwipsToUnits((x), 1.0f / POINTS_PER_INCH_FLOAT)

#define NS_TWIPS_TO_MILLIMETERS(x)    NSTwipsToUnits((x), 1.0f / (POINTS_PER_INCH_FLOAT * 0.03937f))

//@}

#endif /* NSCOORD_H */