Method Lpad

be/src/exprs/string-functions-ir.cc:198–227

}

StringVal StringFunctions::Lpad(FunctionContext* context, const StringVal& str,
    const BigIntVal& len, const StringVal& pad) {
  if (str.is_null || len.is_null || pad.is_null || len.val < 0) return StringVal::null();
  // Corner cases: Shrink the original string, or leave it alone.
  // TODO: Hive seems to go into an infinite loop if pad.len == 0,
  // so we should pay attention to Hive's future solution to be compatible.
  if (len.val <= str.len || pad.len == 0) return StringVal(str.ptr, len.val);
  if (len.val > StringVal::MAX_LENGTH) {
    context->SetError(Substitute(ERROR_CHARACTER_LIMIT_EXCEEDED,
        "lpad() result",
        PrettyPrinter::Print(StringVal::MAX_LENGTH, TUnit::BYTES)).c_str());
    return StringVal::null();
  }
  StringVal result(context, len.val);
  if (UNLIKELY(result.is_null)) return StringVal::null();
  int padded_prefix_len = len.val - str.len;
  int pad_index = 0;
  int result_index = 0;
  uint8_t* ptr = result.ptr;

  // Prepend chars of pad.
  while (result_index < padded_prefix_len) {
    ptr[result_index++] = pad.ptr[pad_index++];
    pad_index = pad_index % pad.len;
  }

  // Append given string.
  memcpy(ptr + result_index, str.ptr, str.len);
  return result;
}

StringVal StringFunctions::Rpad(FunctionContext* context, const StringVal& str,
    const BigIntVal& len, const StringVal& pad) {