syslogd/src/main/java/biz/nellemann/syslogd/parser/JsonUtil.java

98 lines
3.2 KiB
Java

/*
This code is from https://gist.github.com/jjfiv/2ac5c081e088779f49aa, which is BSD licensed:
http://lemurproject.org/galago-license
*/
package biz.nellemann.syslogd.parser;
public class JsonUtil {
public static String encode(String input) {
StringBuilder output = new StringBuilder();
for (int i = 0; i < input.length(); i++) {
char ch = input.charAt(i);
// let's not put any nulls in our strings
if ((int) ch == 0) {
continue;
}
if (ch == '\n') {
output.append("\\n");
} else if (ch == '\t') {
output.append("\\t");
} else if (ch == '\r') {
output.append("\\r");
} else if (ch == '\\') {
output.append("\\\\");
} else if (ch == '"') {
output.append("\\\"");
} else if (ch == '\b') {
output.append("\\b");
} else if (ch == '\f') {
output.append("\\f");
} else if ((int) ch > 127) {
output.append(String.format("\\u%04x", (int) ch));
} else {
output.append(ch);
}
}
return output.toString();
}
public static String decode(String input) {
StringBuilder builder = new StringBuilder();
int i = 0;
while (i < input.length()) {
char delimiter = input.charAt(i);
i++; // consume letter or backslash
if (delimiter == '\\' && i < input.length()) {
// consume first after backslash
char ch = input.charAt(i);
i++;
if (ch == '\\' || ch == '/' || ch == '"' || ch == '\'') {
builder.append(ch);
} else if (ch == 'n') builder.append('\n');
else if (ch == 'r') builder.append('\r');
else if (ch == 't') builder.append('\t');
else if (ch == 'b') builder.append('\b');
else if (ch == 'f') builder.append('\f');
else if (ch == 'u') {
StringBuilder hex = new StringBuilder();
// expect 4 digits
if (i + 4 > input.length()) {
throw new RuntimeException("Not enough unicode digits! ");
}
for (char x : input.substring(i, i + 4).toCharArray()) {
if (!Character.isLetterOrDigit(x)) {
throw new RuntimeException("Bad character in unicode escape.");
}
hex.append(Character.toLowerCase(x));
}
i += 4; // consume those four digits.
int code = Integer.parseInt(hex.toString(), 16);
builder.append((char) code);
} else {
throw new RuntimeException("Illegal escape sequence: \\" + ch);
}
} else { // it's not a backslash, or it's the last character.
builder.append(delimiter);
}
}
return builder.toString();
}
}