splash/SplashMath.h

//========================================================================
//
// SplashMath.h
//
//========================================================================

//========================================================================
//
// Modified under the Poppler project - http://poppler.freedesktop.org
//
// All changes made under the Poppler project to this file are licensed
// under GPL version 2 or later
//
// Copyright (C) 2009-2011 Albert Astals Cid <aacid@kde.org>
// Copyright (C) 2017 Adrian Johnson <ajohnson@redneon.com>
//
// To see a description of the changes please see the Changelog file that
// came with your tarball or type make ChangeLog if you are building from git
//
//========================================================================

#ifndef SPLASHMATH_H
#define SPLASHMATH_H

#include "poppler-config.h"

#ifdef USE_FIXEDPOINT
#include "goo/FixedPoint.h"
#else
#include <math.h>
#endif
#include "SplashTypes.h"

static inline SplashCoord splashAbs(SplashCoord x) {
#if defined(USE_FIXEDPOINT)
  return FixedPoint::abs(x);
#elif defined(USE_FLOAT)
  return fabsf(x);
#else
  return fabs(x);
#endif
}

static inline int splashFloor(SplashCoord x) {
#if defined(USE_FIXEDPOINT)
    return FixedPoint::floor(x);
#elif defined(USE_FLOAT)
    return (int)floorf(x);
#elif defined(__GNUC__) && defined(__i386__)
    // floor() and (int)() are implemented separately, which results
    // in changing the FPCW multiple times - so we optimize it with
    // some inline assembly
    unsigned short oldCW, newCW, t;
    int result;

    __asm__ volatile("fldl   %4\n"
		   "fnstcw %0\n"
		   "movw   %0, %3\n"
		   "andw   $0xf3ff, %3\n"
		   "orw    $0x0400, %3\n"
		   "movw   %3, %1\n"       // round down
		   "fldcw  %1\n"
		   "fistpl %2\n"
		   "fldcw  %0\n"
		   : "=m" (oldCW), "=m" (newCW), "=m" (result), "=r" (t)
		   : "m" (x));
    return result;
#elif defined(_WIN32) && defined(_M_IX86)
    // floor() and (int)() are implemented separately, which results
    // in changing the FPCW multiple times - so we optimize it with
    // some inline assembly
    unsigned short oldCW, newCW;
    int result;

    __asm fld QWORD PTR x
    __asm fnstcw WORD PTR oldCW
    __asm mov ax, WORD PTR oldCW
    __asm and ax, 0xf3ff
    __asm or ax, 0x0400
    __asm mov WORD PTR newCW, ax     // round down
    __asm fldcw WORD PTR newCW
    __asm fistp DWORD PTR result
    __asm fldcw WORD PTR oldCW
    return result;
#else
    if (x > 0) return (int)x;
    else return (int)floor(x);
#endif
}

static inline int splashCeil(SplashCoord x) {
#if defined(USE_FIXEDPOINT)
  return FixedPoint::ceil(x);
#elif defined(USE_FLOAT)
  return (int)ceilf(x);
#elif defined(__GNUC__) && defined(__i386__)
  // ceil() and (int)() are implemented separately, which results
  // in changing the FPCW multiple times - so we optimize it with
  // some inline assembly
  unsigned short oldCW, newCW, t;
  int result;

  __asm__ volatile("fldl   %4\n"
		   "fnstcw %0\n"
		   "movw   %0, %3\n"
		   "andw   $0xf3ff, %3\n"
		   "orw    $0x0800, %3\n"
		   "movw   %3, %1\n"       // round up
		   "fldcw  %1\n"
		   "fistpl %2\n"
		   "fldcw  %0\n"
		   : "=m" (oldCW), "=m" (newCW), "=m" (result), "=r" (t)
		   : "m" (x));
  return result;
#elif defined(_WIN32) && defined(_M_IX86)
  // ceil() and (int)() are implemented separately, which results
  // in changing the FPCW multiple times - so we optimize it with
  // some inline assembly
  unsigned short oldCW, newCW;
  int result;

  __asm fld QWORD PTR x
  __asm fnstcw WORD PTR oldCW
  __asm mov ax, WORD PTR oldCW
  __asm and ax, 0xf3ff
  __asm or ax, 0x0800
  __asm mov WORD PTR newCW, ax     // round up
  __asm fldcw WORD PTR newCW
  __asm fistp DWORD PTR result
  __asm fldcw WORD PTR oldCW
  return result;
#else
  return (int)ceil(x);
#endif
}

static inline int splashRound(SplashCoord x) {
#if defined(USE_FIXEDPOINT)
  return FixedPoint::round(x);
#elif defined(__GNUC__) && defined(__i386__)
  // this could use round-to-nearest mode and avoid the "+0.5",
  // but that produces slightly different results (because i+0.5
  // sometimes rounds up and sometimes down using the even rule)
  unsigned short oldCW, newCW, t;
  int result;

  x += 0.5;
  __asm__ volatile("fldl   %4\n"
		   "fnstcw %0\n"
		   "movw   %0, %3\n"
		   "andw   $0xf3ff, %3\n"
		   "orw    $0x0400, %3\n"
		   "movw   %3, %1\n"       // round down
		   "fldcw  %1\n"
		   "fistpl %2\n"
		   "fldcw  %0\n"
		   : "=m" (oldCW), "=m" (newCW), "=m" (result), "=r" (t)
		   : "m" (x));
  return result;
#elif defined(_WIN32) && defined(_M_IX86)
  // this could use round-to-nearest mode and avoid the "+0.5",
  // but that produces slightly different results (because i+0.5
  // sometimes rounds up and sometimes down using the even rule)
  unsigned short oldCW, newCW;
  int result;

  x += 0.5;
  __asm fld QWORD PTR x
  __asm fnstcw WORD PTR oldCW
  __asm mov ax, WORD PTR oldCW
  __asm and ax, 0xf3ff
  __asm or ax, 0x0400
  __asm mov WORD PTR newCW, ax     // round down
  __asm fldcw WORD PTR newCW
  __asm fistp DWORD PTR result
  __asm fldcw WORD PTR oldCW
  return result;
#else
  return (int)splashFloor(x + 0.5);
#endif
}

static inline SplashCoord splashAvg(SplashCoord x, SplashCoord y) {
#ifdef USE_FIXEDPOINT
  return FixedPoint::avg(x, y);
#else
  return 0.5 * (x + y);
#endif
}
 
static inline SplashCoord splashSqrt(SplashCoord x) {
#if defined(USE_FIXEDPOINT)
  return FixedPoint::sqrt(x);
#elif defined(USE_FLOAT)
  return sqrtf(x);
#else
  return sqrt(x);
#endif
}

static inline SplashCoord splashPow(SplashCoord x, SplashCoord y) {
#if defined(USE_FIXEDPOINT)
  return FixedPoint::pow(x, y);
#elif defined(USE_FLOAT)
  return powf(x, y);
#else
  return pow(x, y);
#endif
}

static inline SplashCoord splashDist(SplashCoord x0, SplashCoord y0,
				     SplashCoord x1, SplashCoord y1) {
  SplashCoord dx, dy;
  dx = x1 - x0;
  dy = y1 - y0;
#ifdef USE_FIXEDPOINT
  // this handles the situation where dx*dx or dy*dy is too large to
  // fit in the 16.16 fixed point format
  SplashCoord dxa, dya, d;
  dxa = splashAbs(dx);
  dya = splashAbs(dy);
  if (dxa == 0 && dya == 0) {
    return 0;
  } else if (dxa > dya) {
    d = dya / dxa;
    return dxa * FixedPoint::sqrt(d*d + 1);
  } else {
    d = dxa / dya;
    return dya * FixedPoint::sqrt(d*d + 1);
  }
#else
  return splashSqrt(dx * dx + dy * dy);
#endif
}

static inline bool splashCheckDet(SplashCoord m11, SplashCoord m12,
				   SplashCoord m21, SplashCoord m22,
				   SplashCoord epsilon) {
#ifdef USE_FIXEDPOINT
  return FixedPoint::checkDet(m11, m12, m21, m22, epsilon);
#else
  return fabs(m11 * m22 - m12 * m21) >= epsilon;
#endif
}

#endif