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1
4 package gnu.xquery.util;
5 import gnu.mapping.*;
6 import gnu.lists.*;
7 import gnu.xml.TextUtils;
8 import gnu.kawa.xml.*;
9 import gnu.kawa.functions.*;
10
11 public class MinMax
12 {
13 public static Object  min (Object arg, NamedCollator collation)
14 {
15 return minMax(arg, false, collation);
16 }
17
18 public static Object max (Object arg, NamedCollator collation)
19 {
20 return minMax(arg, true, collation);
21 }
22
23 public static Object minMax (Object arg, boolean returnMax,
24 NamedCollator collation)
25 {
26 if (arg instanceof Values)
27 {
28 TreeList tlist = (TreeList) arg;
29 int pos = 0;
30 int flags = returnMax ? Compare.TRUE_IF_GRT : Compare.TRUE_IF_LSS;
31 Object cur = tlist.getPosNext(pos);
32 if (cur == Sequence.eofValue)
33 return Values.empty;
34 Object result = convert(cur);
35 for (;;)
36 {
37 pos = tlist.nextPos(pos);
38 cur = tlist.getPosNext(pos);
39 if (cur == Sequence.eofValue)
40 return result;
41 cur = convert(cur);
42
43 if (result instanceof Number || cur instanceof Number )
44 {
45 int code1 = Arithmetic.classifyValue(result);
46 int code2 = Arithmetic.classifyValue(cur);
47 int rcode = NumberCompare.compare(result, code1,
48 cur, code2, false);
49 if (rcode == -3)
50 throw new IllegalArgumentException ("values cannot be compared");
51 int code = code1 < code2 ? code2 : code1;
52 boolean castNeeded;
53 if (rcode == -2)
54 {
55 result = NumberValue.NaN;
56 castNeeded = true; }
58 else if (! NumberCompare.checkCompareCode(rcode, flags))
59 {
60 castNeeded = code != code2;
61 result = cur;
62 }
63 else
64 {
65 castNeeded = code != code1;
66 }
67 if (castNeeded)
68 result = Arithmetic.convert(result, code);
69 }
70 else
71 {
72 if (! Compare.atomicCompare(flags, result, cur, collation))
73 result = cur;
74 }
75 }
76 }
77 else
78 {
79 arg = convert(arg);
80 Compare.atomicCompare(Compare.TRUE_IF_GRT, arg, arg, collation);
82 return arg;
83 }
84 }
85
86 static Object convert (Object arg)
87 {
88 arg = KNode.atomicValue(arg);
89 if (arg instanceof UntypedAtomic)
90 arg = (Double )
91 XDataType.doubleType.valueOf(TextUtils.stringValue(arg));
92 return arg;
93 }
94 }
95 |
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