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17 package org.apache.logging.log4j.core.helpers;
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23 public final class Transform {
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25 private static final String CDATA_START = "<![CDATA[";
26 private static final String CDATA_END = "]]>";
27 private static final String CDATA_PSEUDO_END = "]]>";
28 private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START;
29 private static final int CDATA_END_LEN = CDATA_END.length();
30
31 private Transform() {
32 }
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43 public static String escapeTags(final String input) {
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47 if (input == null
48 || input.length() == 0
49 || (input.indexOf('"') == -1 &&
50 input.indexOf('&') == -1 &&
51 input.indexOf('<') == -1 &&
52 input.indexOf('>') == -1)) {
53 return input;
54 }
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59 StringBuilder buf = new StringBuilder(input.length() + 6);
60 char ch = ' ';
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62 int len = input.length();
63 for (int i = 0; i < len; i++) {
64 ch = input.charAt(i);
65 if (ch > '>') {
66 buf.append(ch);
67 } else if (ch == '<') {
68 buf.append("<");
69 } else if (ch == '>') {
70 buf.append(">");
71 } else if (ch == '&') {
72 buf.append("&");
73 } else if (ch == '"') {
74 buf.append(""");
75 } else {
76 buf.append(ch);
77 }
78 }
79 return buf.toString();
80 }
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91 public static void appendEscapingCDATA(final StringBuilder buf, final String str) {
92 if (str != null) {
93 int end = str.indexOf(CDATA_END);
94 if (end < 0) {
95 buf.append(str);
96 } else {
97 int start = 0;
98 while (end > -1) {
99 buf.append(str.substring(start, end));
100 buf.append(CDATA_EMBEDED_END);
101 start = end + CDATA_END_LEN;
102 if (start < str.length()) {
103 end = str.indexOf(CDATA_END, start);
104 } else {
105 return;
106 }
107 }
108 buf.append(str.substring(start));
109 }
110 }
111 }
112 }