cairo-wideint.c

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2004 Keith Packard
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Keith Packard
 *
 * Contributor(s):
 *	Keith R. Packard <[e-mail]>
 */

#include "cairoint.h"

#if HAVE_UINT64_T

#define _cairo_uint32s_to_uint64(h,l) ((uint64_t) (h) << 32 | (l))

cairo_uquorem64_t
_cairo_uint64_divrem (cairo_uint64_t num, cairo_uint64_t den)
{
    cairo_uquorem64_t	qr;

    qr.quo = num / den;
    qr.rem = num % den;
    return qr;
}

#else

cairo_uint64_t
_cairo_uint32_to_uint64 (uint32_t i)
{
    cairo_uint64_t	q;

    q.lo = i;
    q.hi = 0;
    return q;
}

cairo_int64_t
_cairo_int32_to_int64 (int32_t i)
{
    cairo_uint64_t	q;

    q.lo = i;
    q.hi = i < 0 ? -1 : 0;
    return q;
}

static const cairo_uint64_t
_cairo_uint32s_to_uint64 (uint32_t h, uint32_t l)
{
    cairo_uint64_t	q;

    q.lo = l;
    q.hi = h;
    return q;
}

cairo_uint64_t
_cairo_uint64_add (cairo_uint64_t a, cairo_uint64_t b)
{
    cairo_uint64_t	s;

    s.hi = a.hi + b.hi;
    s.lo = a.lo + b.lo;
    if (s.lo < a.lo)
	s.hi++;
    return s;
}

cairo_uint64_t
_cairo_uint64_sub (cairo_uint64_t a, cairo_uint64_t b)
{
    cairo_uint64_t	s;

    s.hi = a.hi - b.hi;
    s.lo = a.lo - b.lo;
    if (s.lo > a.lo)
	s.hi--;
    return s;
}

#define uint32_lo(i)	((i) & 0xffff)
#define uint32_hi(i)	((i) >> 16)
#define uint32_carry16	((1) << 16)

cairo_uint64_t
_cairo_uint32x32_64_mul (uint32_t a, uint32_t b)
{
    cairo_uint64_t  s;

    uint16_t	ah, al, bh, bl;
    uint32_t	r0, r1, r2, r3;

    al = uint32_lo (a);
    ah = uint32_hi (a);
    bl = uint32_lo (b);
    bh = uint32_hi (b);

    r0 = (uint32_t) al * bl;
    r1 = (uint32_t) al * bh;
    r2 = (uint32_t) ah * bl;
    r3 = (uint32_t) ah * bh;

    r1 += uint32_hi(r0);    /* no carry possible */
    r1 += r2;		    /* but this can carry */
    if (r1 < r2)	    /* check */
	r3 += uint32_carry16;

    s.hi = r3 + uint32_hi(r1);
    s.lo = (uint32_lo (r1) << 16) + uint32_lo (r0);
    return s;
}

cairo_int64_t
_cairo_int32x32_64_mul (int32_t a, int32_t b)
{
    cairo_int64_t s;
    s = _cairo_uint32x32_64_mul ((uint32_t) a, (uint32_t) b);
    if (a < 0)
	s.hi -= b;
    if (b < 0)
	s.hi -= a;
    return s;
}

cairo_uint64_t
_cairo_uint64_mul (cairo_uint64_t a, cairo_uint64_t b)
{
    cairo_uint64_t	s;

    s = _cairo_uint32x32_64_mul (a.lo, b.lo);
    s.hi += a.lo * b.hi + a.hi * b.lo;
    return s;
}

cairo_uint64_t
_cairo_uint64_lsl (cairo_uint64_t a, int shift)
{
    if (shift >= 32)
    {
	a.hi = a.lo;
	a.lo = 0;
	shift -= 32;
    }
    if (shift)
    {
	a.hi = a.hi << shift | a.lo >> (32 - shift);
	a.lo = a.lo << shift;
    }
    return a;
}

cairo_uint64_t
_cairo_uint64_rsl (cairo_uint64_t a, int shift)
{
    if (shift >= 32)
    {
	a.lo = a.hi;
	a.hi = 0;
	shift -= 32;
    }
    if (shift)
    {
	a.lo = a.lo >> shift | a.hi << (32 - shift);
	a.hi = a.hi >> shift;
    }
    return a;
}

#define _cairo_uint32_rsa(a,n)	((uint32_t) (((int32_t) (a)) >> (n)))

cairo_int64_t
_cairo_uint64_rsa (cairo_int64_t a, int shift)
{
    if (shift >= 32)
    {
	a.lo = a.hi;
	a.hi = _cairo_uint32_rsa (a.hi, 31);
	shift -= 32;
    }
    if (shift)
    {
	a.lo = a.lo >> shift | a.hi << (32 - shift);
	a.hi = _cairo_uint32_rsa (a.hi, shift);
    }
    return a;
}

int
_cairo_uint64_lt (cairo_uint64_t a, cairo_uint64_t b)
{
    return (a.hi < b.hi ||
	    (a.hi == b.hi && a.lo < b.lo));
}

int
_cairo_uint64_eq (cairo_uint64_t a, cairo_uint64_t b)
{
    return a.hi == b.hi && a.lo == b.lo;
}

int
_cairo_int64_lt (cairo_int64_t a, cairo_int64_t b)
{
    if (_cairo_int64_negative (a) && !_cairo_int64_negative (b))
	return 1;
    if (!_cairo_int64_negative (a) && _cairo_int64_negative (b))
	return 0;
    return _cairo_uint64_lt (a, b);
}

cairo_uint64_t
_cairo_uint64_not (cairo_uint64_t a)
{
    a.lo = ~a.lo;
    a.hi = ~a.hi;
    return a;
}

cairo_uint64_t
_cairo_uint64_negate (cairo_uint64_t a)
{
    a.lo = ~a.lo;
    a.hi = ~a.hi;
    if (++a.lo == 0)
	++a.hi;
    return a;
}

/*
 * Simple bit-at-a-time divide.
 */
cairo_uquorem64_t
_cairo_uint64_divrem (cairo_uint64_t num, cairo_uint64_t den)
{
    cairo_uquorem64_t	qr;
    cairo_uint64_t	bit;
    cairo_uint64_t	quo;

    bit = _cairo_uint32_to_uint64 (1);

    /* normalize to make den >= num, but not overflow */
    while (_cairo_uint64_lt (den, num) && (den.hi & 0x80000000) == 0)
    {
	bit = _cairo_uint64_lsl (bit, 1);
	den = _cairo_uint64_lsl (den, 1);
    }
    quo = _cairo_uint32_to_uint64 (0);

    /* generate quotient, one bit at a time */
    while (bit.hi | bit.lo)
    {
	if (_cairo_uint64_le (den, num))
	{
	    num = _cairo_uint64_sub (num, den);
	    quo = _cairo_uint64_add (quo, bit);
	}
	bit = _cairo_uint64_rsl (bit, 1);
	den = _cairo_uint64_rsl (den, 1);
    }
    qr.quo = quo;
    qr.rem = num;
    return qr;
}

#endif /* !HAVE_UINT64_T */

cairo_quorem64_t
_cairo_int64_divrem (cairo_int64_t num, cairo_int64_t den)
{
    int			num_neg = _cairo_int64_negative (num);
    int			den_neg = _cairo_int64_negative (den);
    cairo_uquorem64_t	uqr;
    cairo_quorem64_t	qr;

    if (num_neg)
	num = _cairo_int64_negate (num);
    if (den_neg)
	den = _cairo_int64_negate (den);
    uqr = _cairo_uint64_divrem (num, den);
    if (num_neg)
	qr.rem = _cairo_int64_negate (uqr.rem);
    else
	qr.rem = uqr.rem;
    if (num_neg != den_neg)
	qr.quo = (cairo_int64_t) _cairo_int64_negate (uqr.quo);
    else
	qr.quo = (cairo_int64_t) uqr.quo;
    return qr;
}

#if HAVE_UINT128_T

cairo_uquorem128_t
_cairo_uint128_divrem (cairo_uint128_t num, cairo_uint128_t den)
{
    cairo_uquorem128_t	qr;

    qr.quo = num / den;
    qr.rem = num % den;
    return qr;
}

#else

cairo_uint128_t
_cairo_uint32_to_uint128 (uint32_t i)
{
    cairo_uint128_t	q;

    q.lo = _cairo_uint32_to_uint64 (i);
    q.hi = _cairo_uint32_to_uint64 (0);
    return q;
}

cairo_int128_t
_cairo_int32_to_int128 (int32_t i)
{
    cairo_int128_t	q;

    q.lo = _cairo_int32_to_int64 (i);
    q.hi = _cairo_int32_to_int64 (i < 0 ? -1 : 0);
    return q;
}

cairo_uint128_t
_cairo_uint64_to_uint128 (cairo_uint64_t i)
{
    cairo_uint128_t	q;

    q.lo = i;
    q.hi = _cairo_uint32_to_uint64 (0);
    return q;
}

cairo_int128_t
_cairo_int64_to_int128 (cairo_int64_t i)
{
    cairo_int128_t	q;

    q.lo = i;
    q.hi = _cairo_int32_to_int64 (_cairo_int64_negative(i) ? -1 : 0);
    return q;
}

cairo_uint128_t
_cairo_uint128_add (cairo_uint128_t a, cairo_uint128_t b)
{
    cairo_uint128_t	s;

    s.hi = _cairo_uint64_add (a.hi, b.hi);
    s.lo = _cairo_uint64_add (a.lo, b.lo);
    if (_cairo_uint64_lt (s.lo, a.lo))
	s.hi = _cairo_uint64_add (s.hi, _cairo_uint32_to_uint64 (1));
    return s;
}

cairo_uint128_t
_cairo_uint128_sub (cairo_uint128_t a, cairo_uint128_t b)
{
    cairo_uint128_t	s;

    s.hi = _cairo_uint64_sub (a.hi, b.hi);
    s.lo = _cairo_uint64_sub (a.lo, b.lo);
    if (_cairo_uint64_gt (s.lo, a.lo))
	s.hi = _cairo_uint64_sub (s.hi, _cairo_uint32_to_uint64(1));
    return s;
}

#if HAVE_UINT64_T

#define uint64_lo32(i)	((i) & 0xffffffff)
#define uint64_hi32(i)	((i) >> 32)
#define uint64_lo(i)	((i) & 0xffffffff)
#define uint64_hi(i)	((i) >> 32)
#define uint64_shift32(i)   ((i) << 32)
#define uint64_carry32	(((uint64_t) 1) << 32)

#else

#define uint64_lo32(i)	((i).lo)
#define uint64_hi32(i)	((i).hi)

static const cairo_uint64_t
uint64_lo (cairo_uint64_t i)
{
    cairo_uint64_t  s;

    s.lo = i.lo;
    s.hi = 0;
    return s;
}

static const cairo_uint64_t
uint64_hi (cairo_uint64_t i)
{
    cairo_uint64_t  s;

    s.lo = i.hi;
    s.hi = 0;
    return s;
}

static const cairo_uint64_t
uint64_shift32 (cairo_uint64_t i)
{
    cairo_uint64_t  s;

    s.lo = 0;
    s.hi = i.lo;
    return s;
}

static const cairo_uint64_t uint64_carry32 = { 0, 1 };

#endif

cairo_uint128_t
_cairo_uint64x64_128_mul (cairo_uint64_t a, cairo_uint64_t b)
{
    cairo_uint128_t	s;
    uint32_t		ah, al, bh, bl;
    cairo_uint64_t	r0, r1, r2, r3;

    al = uint64_lo32 (a);
    ah = uint64_hi32 (a);
    bl = uint64_lo32 (b);
    bh = uint64_hi32 (b);

    r0 = _cairo_uint32x32_64_mul (al, bl);
    r1 = _cairo_uint32x32_64_mul (al, bh);
    r2 = _cairo_uint32x32_64_mul (ah, bl);
    r3 = _cairo_uint32x32_64_mul (ah, bh);

    r1 = _cairo_uint64_add (r1, uint64_hi (r0));    /* no carry possible */
    r1 = _cairo_uint64_add (r1, r2);	    	    /* but this can carry */
    if (_cairo_uint64_lt (r1, r2))		    /* check */
	r3 = _cairo_uint64_add (r3, uint64_carry32);

    s.hi = _cairo_uint64_add (r3, uint64_hi(r1));
    s.lo = _cairo_uint64_add (uint64_shift32 (r1),
				uint64_lo (r0));
    return s;
}

cairo_int128_t
_cairo_int64x64_128_mul (cairo_int64_t a, cairo_int64_t b)
{
    cairo_int128_t  s;
    s = _cairo_uint64x64_128_mul (_cairo_int64_to_uint64(a),
				  _cairo_int64_to_uint64(b));
    if (_cairo_int64_negative (a))
	s.hi = _cairo_uint64_sub (s.hi,
				  _cairo_int64_to_uint64 (b));
    if (_cairo_int64_negative (b))
	s.hi = _cairo_uint64_sub (s.hi,
				  _cairo_int64_to_uint64 (a));
    return s;
}

cairo_uint128_t
_cairo_uint128_mul (cairo_uint128_t a, cairo_uint128_t b)
{
    cairo_uint128_t	s;

    s = _cairo_uint64x64_128_mul (a.lo, b.lo);
    s.hi = _cairo_uint64_add (s.hi,
				_cairo_uint64_mul (a.lo, b.hi));
    s.hi = _cairo_uint64_add (s.hi,
				_cairo_uint64_mul (a.hi, b.lo));
    return s;
}

cairo_uint128_t
_cairo_uint128_lsl (cairo_uint128_t a, int shift)
{
    if (shift >= 64)
    {
	a.hi = a.lo;
	a.lo = _cairo_uint32_to_uint64 (0);
	shift -= 64;
    }
    if (shift)
    {
	a.hi = _cairo_uint64_add (_cairo_uint64_lsl (a.hi, shift),
				    _cairo_uint64_rsl (a.lo, (64 - shift)));
	a.lo = _cairo_uint64_lsl (a.lo, shift);
    }
    return a;
}

cairo_uint128_t
_cairo_uint128_rsl (cairo_uint128_t a, int shift)
{
    if (shift >= 64)
    {
	a.lo = a.hi;
	a.hi = _cairo_uint32_to_uint64 (0);
	shift -= 64;
    }
    if (shift)
    {
	a.lo = _cairo_uint64_add (_cairo_uint64_rsl (a.lo, shift),
				    _cairo_uint64_lsl (a.hi, (64 - shift)));
	a.hi = _cairo_uint64_rsl (a.hi, shift);
    }
    return a;
}

cairo_uint128_t
_cairo_uint128_rsa (cairo_int128_t a, int shift)
{
    if (shift >= 64)
    {
	a.lo = a.hi;
	a.hi = _cairo_uint64_rsa (a.hi, 64-1);
	shift -= 64;
    }
    if (shift)
    {
	a.lo = _cairo_uint64_add (_cairo_uint64_rsl (a.lo, shift),
				    _cairo_uint64_lsl (a.hi, (64 - shift)));
	a.hi = _cairo_uint64_rsa (a.hi, shift);
    }
    return a;
}

int
_cairo_uint128_lt (cairo_uint128_t a, cairo_uint128_t b)
{
    return (_cairo_uint64_lt (a.hi, b.hi) ||
	    (_cairo_uint64_eq (a.hi, b.hi) &&
	     _cairo_uint64_lt (a.lo, b.lo)));
}

int
_cairo_int128_lt (cairo_int128_t a, cairo_int128_t b)
{
    if (_cairo_int128_negative (a) && !_cairo_int128_negative (b))
	return 1;
    if (!_cairo_int128_negative (a) && _cairo_int128_negative (b))
	return 0;
    return _cairo_uint128_lt (a, b);
}

int
_cairo_uint128_eq (cairo_uint128_t a, cairo_uint128_t b)
{
    return (_cairo_uint64_eq (a.hi, b.hi) &&
	    _cairo_uint64_eq (a.lo, b.lo));
}

#if HAVE_UINT64_T
#define _cairo_msbset64(q)  (q & ((uint64_t) 1 << 63))
#else
#define _cairo_msbset64(q)  (q.hi & ((uint32_t) 1 << 31))
#endif

cairo_uquorem128_t
_cairo_uint128_divrem (cairo_uint128_t num, cairo_uint128_t den)
{
    cairo_uquorem128_t	qr;
    cairo_uint128_t	bit;
    cairo_uint128_t	quo;

    bit = _cairo_uint32_to_uint128 (1);

    /* normalize to make den >= num, but not overflow */
    while (_cairo_uint128_lt (den, num) && !_cairo_msbset64(den.hi))
    {
	bit = _cairo_uint128_lsl (bit, 1);
	den = _cairo_uint128_lsl (den, 1);
    }
    quo = _cairo_uint32_to_uint128 (0);

    /* generate quotient, one bit at a time */
    while (_cairo_uint128_ne (bit, _cairo_uint32_to_uint128(0)))
    {
	if (_cairo_uint128_le (den, num))
	{
	    num = _cairo_uint128_sub (num, den);
	    quo = _cairo_uint128_add (quo, bit);
	}
	bit = _cairo_uint128_rsl (bit, 1);
	den = _cairo_uint128_rsl (den, 1);
    }
    qr.quo = quo;
    qr.rem = num;
    return qr;
}

cairo_int128_t
_cairo_int128_negate (cairo_int128_t a)
{
    a.lo = _cairo_uint64_not (a.lo);
    a.hi = _cairo_uint64_not (a.hi);
    return _cairo_uint128_add (a, _cairo_uint32_to_uint128 (1));
}

cairo_int128_t
_cairo_int128_not (cairo_int128_t a)
{
    a.lo = _cairo_uint64_not (a.lo);
    a.hi = _cairo_uint64_not (a.hi);
    return a;
}

#endif /* !HAVE_UINT128_T */

cairo_quorem128_t
_cairo_int128_divrem (cairo_int128_t num, cairo_int128_t den)
{
    int			num_neg = _cairo_int128_negative (num);
    int			den_neg = _cairo_int128_negative (den);
    cairo_uquorem128_t	uqr;
    cairo_quorem128_t	qr;

    if (num_neg)
	num = _cairo_int128_negate (num);
    if (den_neg)
	den = _cairo_int128_negate (den);
    uqr = _cairo_uint128_divrem (num, den);
    if (num_neg)
	qr.rem = _cairo_int128_negate (uqr.rem);
    else
	qr.rem = uqr.rem;
    if (num_neg != den_neg)
	qr.quo = _cairo_int128_negate (uqr.quo);
    else
	qr.quo = uqr.quo;
    return qr;
}