@Override
public boolean evaluate(Tuple tuple, ImmutableBytesWritable ptr) {
// TODO: multi-byte characters
Expression offsetExpression = getOffsetExpression();
if (!offsetExpression.evaluate(tuple, ptr)) {
return false;
}
LongNative longNative = (LongNative) offsetExpression.getDataType().getNative();
int offset = (int) longNative.toLong(ptr);
int length = -1;
if (hasLengthExpression) {
Expression lengthExpression = getLengthExpression();
if (!lengthExpression.evaluate(tuple, ptr)) {
return false;
}
longNative = (LongNative) lengthExpression.getDataType().getNative();
length = (int) longNative.toLong(ptr);
if (length <= 0) {
return false;
}
}
if (!getStrExpression().evaluate(tuple, ptr)) {
return false;
}
try {
boolean isCharType = getStrExpression().getDataType() == PDataType.CHAR;
int strlen =
isCharType
? ptr.getLength()
: StringUtil.calculateUTF8Length(ptr.get(), ptr.getOffset(), ptr.getLength());
// Account for 1 versus 0-based offset
offset = offset - (offset <= 0 ? 0 : 1);
if (offset < 0) { // Offset < 0 means get from end
offset = strlen + offset;
}
if (offset < 0 || offset >= strlen) {
return false;
}
int maxLength = strlen - offset;
length = length == -1 ? maxLength : Math.min(length, maxLength);
int byteOffset =
isCharType
? offset
: StringUtil.getByteLengthForUtf8SubStr(ptr.get(), ptr.getOffset(), offset);
int byteLength =
isCharType
? length
: StringUtil.getByteLengthForUtf8SubStr(
ptr.get(), ptr.getOffset() + byteOffset, length);
ptr.set(ptr.get(), ptr.getOffset() + byteOffset, byteLength);
return true;
} catch (UnsupportedEncodingException e) {
return false;
}
}
