1 /* 2 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.java2d.marlin; 27 28 /** 29 * Faster Math ceil / floor routines derived from StrictMath 30 */ 31 public final class FloatMath implements MarlinConst { 32 33 // overflow / NaN handling enabled: 34 static final boolean CHECK_OVERFLOW = true; 35 static final boolean CHECK_NAN = true; 36 // Copied from sun.misc.FloatConsts: 37 public static final int FLOAT_SIGNIFICAND_WIDTH = 24; // sun.misc.FloatConsts.SIGNIFICAND_WIDTH 38 public static final int FLOAT_EXP_BIAS = 127; // sun.misc.FloatConsts.EXP_BIAS 39 public static final int FLOAT_EXP_BIT_MASK = 2139095040;// sun.misc.FloatConsts.EXP_BIT_MASK 40 public static final int FLOAT_SIGNIF_BIT_MASK = 8388607;// sun.misc.FloatConsts.SIGNIF_BIT_MASK 41 42 private FloatMath() { 43 // utility class 44 } 45 46 // faster inlined min/max functions in the branch prediction is high 47 static int max(final int a, final int b) { 48 return (a >= b) ? a : b; 49 } 50 51 static int min(final int a, final int b) { 52 return (a <= b) ? a : b; 53 } 54 55 /** 56 * Returns the smallest (closest to negative infinity) {@code float} value 57 * that is greater than or equal to the argument and is equal to a 58 * mathematical integer. Special cases: 59 * <ul><li>If the argument value is already equal to a mathematical integer, 60 * then the result is the same as the argument. <li>If the argument is NaN 61 * or an infinity or positive zero or negative zero, then the result is the 62 * same as the argument. <li>If the argument value is less than zero but 63 * greater than -1.0, then the result is negative zero.</ul> Note that the 64 * value of {@code StrictMath.ceil(x)} is exactly the value of 65 * {@code -StrictMath.floor(-x)}. 66 * 67 * @param a a value. 68 * @return the smallest (closest to negative infinity) floating-point value 69 * that is greater than or equal to the argument and is equal to a 70 * mathematical integer. 71 */ 72 public static float ceil_f(final float a) { 73 // Derived from StrictMath.ceil(double): 74 75 // Inline call to Math.getExponent(a) to 76 // compute only once Float.floatToRawIntBits(a) 77 final int doppel = Float.floatToRawIntBits(a); 78 79 final int exponent = ((doppel & FLOAT_EXP_BIT_MASK) 80 >> (FLOAT_SIGNIFICAND_WIDTH - 1)) 81 - FLOAT_EXP_BIAS; 82 83 if (exponent < 0) { 84 /* 85 * Absolute value of argument is less than 1. 86 * floorOrceil(-0.0) => -0.0 87 * floorOrceil(+0.0) => +0.0 88 */ 89 return ((a == 0.0f) ? a : 90 ( (a < 0.0f) ? -0.0f : 1.0f) ); 91 } 92 if (CHECK_OVERFLOW && (exponent >= 23)) { // 52 for double 93 /* 94 * Infinity, NaN, or a value so large it must be integral. 95 */ 96 return a; 97 } 98 // Else the argument is either an integral value already XOR it 99 // has to be rounded to one. 100 assert exponent >= 0 && exponent <= 22; // 51 for double 101 102 final int intpart = doppel 103 & (~(FLOAT_SIGNIF_BIT_MASK >> exponent)); 104 105 if (intpart == doppel) { 106 return a; // integral value (including 0) 107 } 108 109 // 0 handled above as an integer 110 // sign: 1 for negative, 0 for positive numbers 111 // add : 0 for negative and 1 for positive numbers 112 return Float.intBitsToFloat(intpart) + ((~intpart) >>> 31); 113 } 114 115 /** 116 * Returns the largest (closest to positive infinity) {@code float} value 117 * that is less than or equal to the argument and is equal to a mathematical 118 * integer. Special cases: 119 * <ul><li>If the argument value is already equal to a mathematical integer, 120 * then the result is the same as the argument. <li>If the argument is NaN 121 * or an infinity or positive zero or negative zero, then the result is the 122 * same as the argument.</ul> 123 * 124 * @param a a value. 125 * @return the largest (closest to positive infinity) floating-point value 126 * that less than or equal to the argument and is equal to a mathematical 127 * integer. 128 */ 129 public static float floor_f(final float a) { 130 // Derived from StrictMath.floor(double): 131 132 // Inline call to Math.getExponent(a) to 133 // compute only once Float.floatToRawIntBits(a) 134 final int doppel = Float.floatToRawIntBits(a); 135 136 final int exponent = ((doppel & FLOAT_EXP_BIT_MASK) 137 >> (FLOAT_SIGNIFICAND_WIDTH - 1)) 138 - FLOAT_EXP_BIAS; 139 140 if (exponent < 0) { 141 /* 142 * Absolute value of argument is less than 1. 143 * floorOrceil(-0.0) => -0.0 144 * floorOrceil(+0.0) => +0.0 145 */ 146 return ((a == 0.0f) ? a : 147 ( (a < 0.0f) ? -1.0f : 0.0f) ); 148 } 149 if (CHECK_OVERFLOW && (exponent >= 23)) { // 52 for double 150 /* 151 * Infinity, NaN, or a value so large it must be integral. 152 */ 153 return a; 154 } 155 // Else the argument is either an integral value already XOR it 156 // has to be rounded to one. 157 assert exponent >= 0 && exponent <= 22; // 51 for double 158 159 final int intpart = doppel 160 & (~(FLOAT_SIGNIF_BIT_MASK >> exponent)); 161 162 if (intpart == doppel) { 163 return a; // integral value (including 0) 164 } 165 166 // 0 handled above as an integer 167 // sign: 1 for negative, 0 for positive numbers 168 // add : -1 for negative and 0 for positive numbers 169 return Float.intBitsToFloat(intpart) + (intpart >> 31); 170 } 171 172 /** 173 * Faster alternative to ceil(float) optimized for the integer domain 174 * and supporting NaN and +/-Infinity. 175 * 176 * @param a a value. 177 * @return the largest (closest to positive infinity) integer value 178 * that less than or equal to the argument and is equal to a mathematical 179 * integer. 180 */ 181 public static int ceil_int(final float a) { 182 final int intpart = (int) a; 183 184 if (a <= intpart 185 || (CHECK_OVERFLOW && intpart == Integer.MAX_VALUE) 186 || CHECK_NAN && Float.isNaN(a)) { 187 return intpart; 188 } 189 return intpart + 1; 190 } 191 192 /** 193 * Faster alternative to ceil(double) optimized for the integer domain 194 * and supporting NaN and +/-Infinity. 195 * 196 * @param a a value. 197 * @return the largest (closest to positive infinity) integer value 198 * that less than or equal to the argument and is equal to a mathematical 199 * integer. 200 */ 201 public static int ceil_int(final double a) { 202 final int intpart = (int) a; 203 204 if (a <= intpart 205 || (CHECK_OVERFLOW && intpart == Integer.MAX_VALUE) 206 || CHECK_NAN && Double.isNaN(a)) { 207 return intpart; 208 } 209 return intpart + 1; 210 } 211 212 /** 213 * Faster alternative to floor(float) optimized for the integer domain 214 * and supporting NaN and +/-Infinity. 215 * 216 * @param a a value. 217 * @return the largest (closest to positive infinity) floating-point value 218 * that less than or equal to the argument and is equal to a mathematical 219 * integer. 220 */ 221 public static int floor_int(final float a) { 222 final int intpart = (int) a; 223 224 if (a >= intpart 225 || (CHECK_OVERFLOW && intpart == Integer.MIN_VALUE) 226 || CHECK_NAN && Float.isNaN(a)) { 227 return intpart; 228 } 229 return intpart - 1; 230 } 231 232 /** 233 * Faster alternative to floor(double) optimized for the integer domain 234 * and supporting NaN and +/-Infinity. 235 * 236 * @param a a value. 237 * @return the largest (closest to positive infinity) floating-point value 238 * that less than or equal to the argument and is equal to a mathematical 239 * integer. 240 */ 241 public static int floor_int(final double a) { 242 final int intpart = (int) a; 243 244 if (a >= intpart 245 || (CHECK_OVERFLOW && intpart == Integer.MIN_VALUE) 246 || CHECK_NAN && Double.isNaN(a)) { 247 return intpart; 248 } 249 return intpart - 1; 250 } 251 }