/**
* Transforms this literal (which must be of type character) into a new one in which 4-digit
* Unicode escape sequences have been replaced with the corresponding Unicode characters.
*
* @param unicodeEscapeChar escape character (e.g. backslash) for Unicode numeric sequences; 0
* implies no transformation
* @return transformed literal
*/
public SqlLiteral unescapeUnicode(char unicodeEscapeChar) {
if (unicodeEscapeChar == 0) {
return this;
}
assert SqlTypeUtil.inCharFamily(getTypeName());
NlsString ns = (NlsString) value;
String s = ns.getValue();
StringBuilder sb = new StringBuilder();
int n = s.length();
for (int i = 0; i < n; ++i) {
char c = s.charAt(i);
if (c == unicodeEscapeChar) {
if (n > (i + 1)) {
if (s.charAt(i + 1) == unicodeEscapeChar) {
sb.append(unicodeEscapeChar);
++i;
continue;
}
}
if ((i + 5) > n) {
throw SqlUtil.newContextException(
getParserPosition(), RESOURCE.unicodeEscapeMalformed(i));
}
final String u = s.substring(i + 1, i + 5);
final int v;
try {
v = Integer.parseInt(u, 16);
} catch (NumberFormatException ex) {
throw SqlUtil.newContextException(
getParserPosition(), RESOURCE.unicodeEscapeMalformed(i));
}
sb.append((char) (v & 0xFFFF));
// skip hexits
i += 4;
} else {
sb.append(c);
}
}
ns = new NlsString(sb.toString(), ns.getCharsetName(), ns.getCollation());
return new SqlCharStringLiteral(ns, getParserPosition());
}
