source: trunk/src/org/expeditee/Util.java@ 1513

Last change on this file since 1513 was 1098, checked in by davidb, 6 years ago

New files from Corey's work on logic/graphics separation
File size: 5.8 KB
Line 
1package org.expeditee;
2
3import java.text.DateFormat;
4import java.text.ParseException;
5import java.text.SimpleDateFormat;
6import java.util.Collections;
7import java.util.Date;
8import java.util.HashSet;
9import java.util.LinkedList;
10import java.util.List;
11
12import org.expeditee.stats.Formatter;
13
14/**
15 * Static collection of various helper methods.
16 *
17 * @author cts16
18 *
19 */
20public class Util {
21
22 /**
23 * Using Microsofts commandline convention: Args seperated with white
24 * spaces. Options with white spaces enclosed with quotes. Args with quotes
25 * must be double quoted args1 args2=sfasas args3="option with spaces"
26 * arg""4""
27 *
28 * @param args
29 * Null and empty excepted
30 * @return An array of args. null if none provided
31 */
32 public static String[] parseArgs(String args) {
33
34 if (args == null)
35 return null;
36
37 args = args.trim();
38 if (args.length() == 0)
39 return null;
40
41 List<String> vargs = new LinkedList<String>();
42 StringBuilder sb = new StringBuilder();
43 boolean quoteOn = false;
44 for (int i = 0; i < args.length(); i++) {
45
46 char c = args.charAt(i);
47 if (c == ' ' && !quoteOn) {
48
49 // Extract arg
50 vargs.add(sb.toString());
51 sb = new StringBuilder();
52
53 // Consume white spaces
54 while (args.charAt(++i) == ' ' && i < args.length()) {
55 }
56 i--;
57
58 } else if (c == '\"') {
59 // If double quoted
60 if (args.length() >= (i + 2) && args.charAt(i + 1) == '\"') {
61
62 sb.append(c); // add escaped
63 i++;
64
65 } else {
66 quoteOn = !quoteOn;
67 }
68
69 } else {
70 sb.append(c);
71 }
72 }
73
74 if (sb.length() > 0)
75 vargs.add(sb.toString());
76
77 if (vargs.size() == 0)
78 return null;
79 else
80 return vargs.toArray(new String[vargs.size()]);
81 }
82
83 /**
84 * Reverse of parseArgs
85 *
86 * @return Null if args is null or empty / all whitespace
87 */
88 public static String formatArgs(String[] args) {
89 if (args == null)
90 return null;
91
92 StringBuilder sb = new StringBuilder();
93
94 for (String s : args) {
95 if (s == null)
96 continue;
97
98 // Escape quotes
99 StringBuilder formatted = new StringBuilder(s.replaceAll("\"",
100 "\"\""));
101
102 // Encapsulate spaces
103 int index = formatted.indexOf(" ");
104 if (index >= 0) {
105 formatted.insert(index, "\"");
106 formatted.append('\"');
107 }
108
109 if (sb.length() > 0)
110 sb.append(' ');
111 sb.append(formatted);
112 }
113
114 return sb.length() > 0 ? sb.toString() : null;
115 }
116
117 /**
118 * Parses a date from the given string.
119 *
120 * @param dateString
121 * The string to parse.
122 *
123 * @return
124 * The date parsed from the string.
125 *
126 * @throws ParseException
127 */
128 public static Date parseDate(String dateString) throws ParseException {
129 // Select the best match for a date or time format
130 DateFormat df = null;
131 if (dateString.length() > Formatter.DATE_FORMAT.length()) {
132 df = new SimpleDateFormat(Formatter.DATE_TIME_FORMAT);
133 } else if (dateString.length() <= Formatter.TIME_FORMAT.length()) {
134 df = new SimpleDateFormat(Formatter.TIME_FORMAT);
135 } else {
136 df = new SimpleDateFormat(Formatter.DATE_FORMAT);
137 }
138 Date date = df.parse(dateString);
139 return date;
140 }
141
142 /**
143 * Sets all members of the given array to the given value.
144 *
145 * @param arr
146 * The array to initialise.
147 *
148 * @param val
149 * The value to set each element to.
150 */
151 public static void initialiseBoolArray(boolean[] arr, boolean val)
152 {
153 for (int i = 0; i < arr.length; i++) arr[i] = val;
154 }
155
156 /** Whether or not the system has been checked to see if the Java version is >= 1.6 */
157 private static boolean _minimum_version6_checked = false;
158 /** Whether or not the Java version running is >= 1.6 */
159 private static boolean _minimum_version6 = false;
160
161 /**
162 * Checks if the running version of Java is >= 1.6.
163 *
164 * @return
165 * True if the Java version is >= 1.6, false otherwise.
166 */
167 public static boolean isMinimumVersion6()
168 {
169 // If we haven't checked yet, do so
170 if (!_minimum_version6_checked) {
171 String full_version = System.getProperty("java.version");
172 String[] version_parts = full_version.split("\\.");
173 if (version_parts.length>=2) {
174 String version_str = version_parts[0] + "." + version_parts[1];
175 double version = Double.parseDouble(version_str);
176 if (version >= 1.6) {
177 _minimum_version6 = true;
178 }
179 }
180
181 _minimum_version6_checked = true;
182 }
183
184 return _minimum_version6;
185 }
186
187 /**
188 * Returns an array of roots to the quadratic equation ax^2 + bx + c = 0.
189 * Will be null, or contain 1 or 2 values depending on the constants given.
190 */
191 public static double[] quadraticEquation(double a, double b, double c)
192 {
193 // Calculate the discriminant
194 double discriminant = b * b - 4 * a * c;
195
196 // See how many roots we have
197 if (discriminant < 0) {
198 return null;
199 } else if (discriminant == 0) {
200 double[] ret = new double[1];
201 ret[0] = -b / (2 * a);
202 return ret;
203 } else {
204 double[] ret = new double[2];
205 ret[0] = (-b + Math.sqrt(discriminant)) / (2 * a);
206 ret[1] = (-b - Math.sqrt(discriminant)) / (2 * a);
207 return ret;
208 }
209 }
210
211 public static double[] toDoubleArray(float[] floatArray)
212 {
213 if (floatArray == null) return null;
214
215 double[] ret = new double[floatArray.length];
216
217 for (int i = 0; i < floatArray.length; i++) {
218 ret[i] = floatArray[i];
219 }
220
221 return ret;
222 }
223
224 /** Creates a hash-set from an array. */
225 public static <T> HashSet<T> hashSetFromArray(T[] array)
226 {
227 if (array == null) return null;
228
229 HashSet<T> ret = new HashSet<T>();
230 for (T element : array) ret.add(element);
231
232 return ret;
233 }
234
235 /** Returns the string which is n concatenations of the given character. */
236 public static String nCopiesOf(int n, char character)
237 {
238 if (n < 0) {
239 return null;
240 } else if (n == 0) {
241 return "";
242 } else {
243 return String.join("", Collections.nCopies(n, Character.toString(character)));
244 }
245 }
246
247 /** Returns the linear interpolation between a and b. */
248 public static float lerp(float a, float b, float t)
249 {
250 return t * (b - a) + a;
251 }
252}
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