ToHexString.java revision 6073:cea72c2bf071 
1/*
2 * Copyright (c) 2003, 2011, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24/*
25 * @test
26 * @bug 4826774 4926547
27 * @summary Tests for {Float, Double}.toHexString methods
28 * @author Joseph D. Darcy
29 */
30
31import java.util.regex.*;
32import sun.misc.DoubleConsts;
33
34public class ToHexString {
35    private ToHexString() {}
36
37    /*
38     * Given a double value, create a hexadecimal floating-point
39     * string via an intermediate long hex string.
40     */
41    static String doubleToHexString(double d) {
42        return hexLongStringtoHexDoubleString(Long.toHexString(Double.doubleToLongBits(d)));
43    }
44
45    /*
46     * Transform the hexadecimal long output into the equivalent
47     * hexadecimal double value.
48     */
49    static String hexLongStringtoHexDoubleString(String transString) {
50        transString = transString.toLowerCase();
51
52        String zeros = "";
53        StringBuffer result = new StringBuffer(24);
54
55        for(int i = 0; i < (16 - transString.length()); i++, zeros += "0");
56        transString = zeros + transString;
57
58        // assert transString.length == 16;
59
60            char topChar;
61            // Extract sign
62            if((topChar=transString.charAt(0)) >= '8' ) {// 8, 9, a, A, b, B, ...
63                result.append("-");
64                // clear sign bit
65                transString =
66                    Character.toString(Character.forDigit(Character.digit(topChar, 16) - 8, 16)) +
67                    transString.substring(1,16);
68            }
69
70            // check for NaN and infinity
71            String signifString = transString.substring(3,16);
72
73            if( transString.substring(0,3).equals("7ff") ) {
74                if(signifString.equals("0000000000000")) {
75                    result.append("Infinity");
76                }
77                else
78                    result.append("NaN");
79            }
80            else { // finite value
81                // Extract exponent
82                int exponent = Integer.parseInt(transString.substring(0,3), 16) -
83                    DoubleConsts.EXP_BIAS;
84                result.append("0x");
85
86                if (exponent == DoubleConsts.MIN_EXPONENT - 1) { // zero or subnormal
87                    if(signifString.equals("0000000000000")) {
88                        result.append("0.0p0");
89                    }
90                    else {
91                        result.append("0." + signifString.replaceFirst("0+$", "").replaceFirst("^$", "0") +
92                                      "p-1022");
93                    }
94                }
95                else {  // normal value
96                    result.append("1." + signifString.replaceFirst("0+$", "").replaceFirst("^$", "0") +
97                                  "p" + exponent);
98                }
99            }
100            return result.toString();
101    }
102
103    public static int toHexStringTests() {
104        int failures = 0;
105        String [][] testCases1 = {
106            {"Infinity",                "Infinity"},
107            {"-Infinity",               "-Infinity"},
108            {"NaN",                     "NaN"},
109            {"-NaN",                    "NaN"},
110            {"0.0",                     "0x0.0p0"},
111            {"-0.0",                    "-0x0.0p0"},
112            {"1.0",                     "0x1.0p0"},
113            {"-1.0",                    "-0x1.0p0"},
114            {"2.0",                     "0x1.0p1"},
115            {"3.0",                     "0x1.8p1"},
116            {"0.5",                     "0x1.0p-1"},
117            {"0.25",                    "0x1.0p-2"},
118            {"1.7976931348623157e+308", "0x1.fffffffffffffp1023"},      // MAX_VALUE
119            {"2.2250738585072014E-308", "0x1.0p-1022"},                 // MIN_NORMAL
120            {"2.225073858507201E-308",  "0x0.fffffffffffffp-1022"},     // MAX_SUBNORMAL
121            {"4.9e-324",                "0x0.0000000000001p-1022"}      // MIN_VALUE
122        };
123
124        // Compare decimal string -> double -> hex string to hex string
125        for (int i = 0; i < testCases1.length; i++) {
126            String result;
127            if(! (result=Double.toHexString(Double.parseDouble(testCases1[i][0]))).
128               equals(testCases1[i][1])) {
129                failures ++;
130                System.err.println("For floating-point string " + testCases1[i][0] +
131                                   ", expected hex output " + testCases1[i][1] + ", got " + result +".");
132            }
133        }
134
135
136        // Except for float subnormals, the output for numerically
137        // equal float and double values should be the same.
138        // Therefore, we will explicitly test float subnormal values.
139        String [][] floatTestCases = {
140            {"Infinity",                "Infinity"},
141            {"-Infinity",               "-Infinity"},
142            {"NaN",                     "NaN"},
143            {"-NaN",                    "NaN"},
144            {"0.0",                     "0x0.0p0"},
145            {"-0.0",                    "-0x0.0p0"},
146            {"1.0",                     "0x1.0p0"},
147            {"-1.0",                    "-0x1.0p0"},
148            {"2.0",                     "0x1.0p1"},
149            {"3.0",                     "0x1.8p1"},
150            {"0.5",                     "0x1.0p-1"},
151            {"0.25",                    "0x1.0p-2"},
152            {"3.4028235e+38f",          "0x1.fffffep127"},      // MAX_VALUE
153            {"1.17549435E-38f",         "0x1.0p-126"},          // MIN_NORMAL
154            {"1.1754942E-38",           "0x0.fffffep-126"},     // MAX_SUBNORMAL
155            {"1.4e-45f",                "0x0.000002p-126"}      // MIN_VALUE
156        };
157        // Compare decimal string -> double -> hex string to hex string
158        for (int i = 0; i < floatTestCases.length; i++) {
159            String result;
160            if(! (result=Float.toHexString(Float.parseFloat(floatTestCases[i][0]))).
161               equals(floatTestCases[i][1])) {
162                failures++;
163                System.err.println("For floating-point string " + floatTestCases[i][0] +
164                                   ", expected hex output\n" + floatTestCases[i][1] + ", got\n" + result +".");
165            }
166        }
167
168        // Particular floating-point values and hex equivalents, mostly
169        // taken from fdlibm source.
170        String [][] testCases2 = {
171            {"+0.0",                                    "0000000000000000"},
172            {"-0.0",                                    "8000000000000000"},
173            {"+4.9e-324",                               "0000000000000001"},
174            {"-4.9e-324",                               "8000000000000001"},
175
176            // fdlibm k_sin.c
177            {"+5.00000000000000000000e-01",             "3FE0000000000000"},
178            {"-1.66666666666666324348e-01",             "BFC5555555555549"},
179            {"+8.33333333332248946124e-03",             "3F8111111110F8A6"},
180            {"-1.98412698298579493134e-04",             "BF2A01A019C161D5"},
181            {"+2.75573137070700676789e-06",             "3EC71DE357B1FE7D"},
182            {"-2.50507602534068634195e-08",             "BE5AE5E68A2B9CEB"},
183            {"+1.58969099521155010221e-10",             "3DE5D93A5ACFD57C"},
184
185            // fdlibm k_cos.c
186            {"+4.16666666666666019037e-02",             "3FA555555555554C"},
187            {"-1.38888888888741095749e-03",             "BF56C16C16C15177"},
188            {"+2.48015872894767294178e-05",             "3EFA01A019CB1590"},
189            {"-2.75573143513906633035e-07",             "BE927E4F809C52AD"},
190            {"+2.08757232129817482790e-09",             "3E21EE9EBDB4B1C4"},
191            {"-1.13596475577881948265e-11",             "BDA8FAE9BE8838D4"},
192
193            // fdlibm e_rempio.c
194            {"1.67772160000000000000e+07",              "4170000000000000"},
195            {"6.36619772367581382433e-01",              "3FE45F306DC9C883"},
196            {"1.57079632673412561417e+00",              "3FF921FB54400000"},
197            {"6.07710050650619224932e-11",              "3DD0B4611A626331"},
198            {"6.07710050630396597660e-11",              "3DD0B4611A600000"},
199            {"2.02226624879595063154e-21",              "3BA3198A2E037073"},
200            {"2.02226624871116645580e-21",              "3BA3198A2E000000"},
201            {"8.47842766036889956997e-32",              "397B839A252049C1"},
202
203
204            // fdlibm s_cbrt.c
205            {"+5.42857142857142815906e-01",             "3FE15F15F15F15F1"},
206            {"-7.05306122448979611050e-01",             "BFE691DE2532C834"},
207            {"+1.41428571428571436819e+00",             "3FF6A0EA0EA0EA0F"},
208            {"+1.60714285714285720630e+00",             "3FF9B6DB6DB6DB6E"},
209            {"+3.57142857142857150787e-01",             "3FD6DB6DB6DB6DB7"},
210        };
211
212        // Compare decimal string -> double -> hex string to
213        // long hex string -> double hex string
214        for (int i = 0; i < testCases2.length; i++) {
215            String result;
216            String expected;
217            if(! (result=Double.toHexString(Double.parseDouble(testCases2[i][0]))).
218               equals( expected=hexLongStringtoHexDoubleString(testCases2[i][1]) )) {
219                failures ++;
220                System.err.println("For floating-point string " + testCases2[i][0] +
221                                   ", expected hex output " + expected + ", got " + result +".");
222            }
223        }
224
225        // Test random double values;
226        // compare double -> Double.toHexString with local doubleToHexString
227        java.util.Random rand = new java.util.Random(0);
228        for (int i = 0; i < 1000; i++) {
229            String result;
230            String expected;
231            double d = rand.nextDouble();
232            if(! (expected=doubleToHexString(d)).equals(result=Double.toHexString(d)) ) {
233                failures ++;
234                System.err.println("For floating-point value " + d +
235                                   ", expected hex output " + expected + ", got " + result +".");
236            }
237        }
238
239        return failures;
240    }
241
242    public static void main(String argv[]) {
243        int failures = 0;
244
245        failures = toHexStringTests();
246
247        if (failures != 0) {
248            throw new RuntimeException("" + failures + " failures while testing Double.toHexString");
249        }
250    }
251}
252