// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#include "exprs/mask-functions.h"

#include <gutil/strings/substitute.h>
#include <openssl/err.h>
#include <openssl/sha.h>

#include "exprs/anyval-util.h"
#include "exprs/math-functions.h"
#include "exprs/string-functions.h"
#include "util/ubsan.h"

#include "common/names.h"

using namespace impala;
using namespace impala_udf;

const static int CHAR_COUNT = 4;
const static int MASKED_UPPERCASE = 'X';
const static int MASKED_LOWERCASE = 'x';
const static int MASKED_DIGIT = 'n';
const static int MASKED_OTHER_CHAR = -1;
const static int MASKED_NUMBER = 1;
const static int MASKED_DAY_COMPONENT_VAL = 1;
const static int MASKED_MONTH_COMPONENT_VAL = 0;
const static int MASKED_YEAR_COMPONENT_VAL = 1;
const static int UNMASKED_VAL = -1;

/// Mask the given char depending on its type. UNMASKED_VAL(-1) means keeping the
/// original value.
static inline uint8_t MaskTransform(uint8_t val, int masked_upper_char,
    int masked_lower_char, int masked_digit_char, int masked_other_char) {
  if ('A' <= val && val <= 'Z') {
    if (masked_upper_char == UNMASKED_VAL) return val;
    return masked_upper_char;
  }
  if ('a' <= val && val <= 'z') {
    if (masked_lower_char == UNMASKED_VAL) return val;
    return masked_lower_char;
  }
  if ('0' <= val && val <= '9') {
    if (masked_digit_char == UNMASKED_VAL) return val;
    return masked_digit_char;
  }
  if (masked_other_char == UNMASKED_VAL) return val;
  return masked_other_char;
}

/// Mask the substring in range [start, end) of the given string value. Using rules in
/// 'MaskTransform'.
static StringVal MaskSubStr(FunctionContext* ctx, const StringVal& val,
    int start, int end, int masked_upper_char, int masked_lower_char,
    int masked_digit_char, int masked_other_char) {
  DCHECK_GE(start, 0);
  DCHECK_LT(start, end);
  DCHECK_LE(end, val.len);
  StringVal result(ctx, val.len);
  if (UNLIKELY(result.is_null)) return StringVal::null();
  Ubsan::MemCpy(result.ptr, val.ptr, start);
  if (end < val.len) Ubsan::MemCpy(result.ptr + end, val.ptr + end, val.len - end);
  for (int i = start; i < end; ++i) {
    result.ptr[i] = MaskTransform(val.ptr[i], masked_upper_char, masked_lower_char,
        masked_digit_char, masked_other_char);
  }
  return result;
}

/// Mask the given string except the first 'un_mask_char_count' chars. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskShowFirstN.
static inline StringVal MaskShowFirstNImpl(FunctionContext* ctx, const StringVal& val,
    int un_mask_char_count, int masked_upper_char, int masked_lower_char,
    int masked_digit_char, int masked_other_char) {
  // To be consistent with Hive, negative char_count is treated as 0.
  if (un_mask_char_count < 0) un_mask_char_count = 0;
  if (val.is_null || val.len == 0 || un_mask_char_count >= val.len) return val;
  return MaskSubStr(ctx, val, un_mask_char_count, val.len, masked_upper_char,
      masked_lower_char, masked_digit_char, masked_other_char);
}

/// Mask the given string except the last 'un_mask_char_count' chars. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskShowLastN.
static inline StringVal MaskShowLastNImpl(FunctionContext* ctx, const StringVal& val,
    int un_mask_char_count, int masked_upper_char, int masked_lower_char,
    int masked_digit_char, int masked_other_char) {
  // To be consistent with Hive, negative char_count is treated as 0.
  if (un_mask_char_count < 0) un_mask_char_count = 0;
  if (val.is_null || val.len == 0 || un_mask_char_count >= val.len) return val;
  return MaskSubStr(ctx, val, 0, val.len - un_mask_char_count, masked_upper_char,
      masked_lower_char, masked_digit_char, masked_other_char);
}

/// Mask the first 'mask_char_count' chars of the given string. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskFirstN.
static inline StringVal MaskFirstNImpl(FunctionContext* ctx, const StringVal& val,
    int mask_char_count, int masked_upper_char, int masked_lower_char,
    int masked_digit_char, int masked_other_char) {
  if (mask_char_count <= 0 || val.is_null || val.len == 0) return val;
  if (mask_char_count > val.len) mask_char_count = val.len;
  return MaskSubStr(ctx, val, 0, mask_char_count, masked_upper_char,
      masked_lower_char, masked_digit_char, masked_other_char);
}

/// Mask the last 'mask_char_count' chars of the given string. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskLastN.
static inline StringVal MaskLastNImpl(FunctionContext* ctx, const StringVal& val,
    int mask_char_count, int masked_upper_char, int masked_lower_char,
    int masked_digit_char, int masked_other_char) {
  if (mask_char_count <= 0 || val.is_null || val.len == 0) return val;
  if (mask_char_count > val.len) mask_char_count = val.len;
  return MaskSubStr(ctx, val, val.len - mask_char_count, val.len, masked_upper_char,
      masked_lower_char, masked_digit_char, masked_other_char);
}

/// Mask the whole given string. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMask.
static inline StringVal MaskImpl(FunctionContext* ctx, const StringVal& val,
    int masked_upper_char, int masked_lower_char, int masked_digit_char,
    int masked_other_char) {
  if (val.is_null || val.len == 0) return val;
  return MaskSubStr(ctx, val, 0, val.len, masked_upper_char,
      masked_lower_char, masked_digit_char, masked_other_char);
}

static inline int GetNumDigits(int64_t val) {
  if (val == 0) return 1;
  if (val < 0) val = -val;
  int num_digits = 0;
  while (val != 0) {
    num_digits++;
    val /= 10;
  }
  return num_digits;
}

/// Mask the numeric value by replacing the digits with 'masked_number'. The first
/// 'un_mask_char_count' digits will be kept unchanged. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskShowFirstN.
static inline BigIntVal MaskShowFirstNImpl(const BigIntVal& val, int un_mask_digit_count,
    int masked_number) {
  if (val.is_null) return val;
  // To be consistent with Hive, illegal masked_number is treated as default value.
  if (masked_number < 0 || masked_number > 9) masked_number = MASKED_NUMBER;
  if (un_mask_digit_count < 0) un_mask_digit_count = 0;
  if (val.val == 0) return un_mask_digit_count > 0 ? 0 : masked_number;
  int64_t unsigned_val = val.val;
  // The sign won't be masked.
  if (val.val < 0) unsigned_val = -unsigned_val;
  int num_digits = GetNumDigits(unsigned_val);
  // Number of digits to mask from the end
  int mask_count = num_digits - un_mask_digit_count;
  if (mask_count <= 0) return val;
  int64_t result = 0;
  int64_t base = 1;
  for (int i = 0; i < mask_count; ++i) { // loop from end to start
    result += masked_number * base;
    base *= 10;
    unsigned_val /= 10;
  }
  result += unsigned_val * base;
  return {val.val < 0 ? -result : result};
}

/// Mask the numeric value by replacing the digits with 'masked_number'. The last
/// 'un_mask_char_count' digits will be kept unchanged. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskShowLastN.
static inline BigIntVal MaskShowLastNImpl(const BigIntVal& val, int un_mask_char_count,
    int masked_number) {
  if (val.is_null) return val;
  // To be consistent with Hive, illegal masked_number is treated as default value.
  if (masked_number < 0 || masked_number > 9) masked_number = MASKED_NUMBER;
  if (un_mask_char_count < 0) un_mask_char_count = 0;
  if (val.val == 0) return un_mask_char_count > 0 ? 0 : masked_number;
  int64_t unsigned_val = val.val;
  // The sign won't be masked.
  if (val.val < 0) unsigned_val = -unsigned_val;
  int num_digits = GetNumDigits(unsigned_val);
  if (num_digits <= un_mask_char_count) return val;
  int64_t base = 1;
  for (int i = 0; i < un_mask_char_count; ++i) base *= 10;
  int64_t result = unsigned_val % base;
  for (int i = un_mask_char_count; i < num_digits; ++i) {
    // It's possible that result overflows, e.g. val is 2^63-1 and masked_number is 9.
    // Just continue with the overflowed result to be consistent with Hive.
    result += masked_number * base;
    base *= 10;
  }
  return {val.val < 0 ? -result : result};
}

/// Mask the numeric value by replacing the first 'mask_char_count' digits with
/// 'masked_number'. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskFirstN.
static inline BigIntVal MaskFirstNImpl(const BigIntVal& val, int mask_char_count,
    int masked_number) {
  if (val.is_null) return val;
  int num_digits = GetNumDigits(val.val);
  if (num_digits < mask_char_count) mask_char_count = num_digits;
  return MaskShowLastNImpl(val, num_digits - mask_char_count, masked_number);
}

/// Mask the numeric value by replacing the last 'mask_char_count' digits with
/// 'masked_number'. Ported from
/// org.apache.hadoop.hive.ql.udf.generic.GenericUDFMaskLastN.
static inline BigIntVal MaskLastNImpl(const BigIntVal& val, int mask_char_count,
    int masked_number) {
  if (val.is_null) return val;
  int num_digits = GetNumDigits(val.val);
  if (num_digits < mask_char_count) mask_char_count = num_digits;
  return MaskShowFirstNImpl(val, num_digits - mask_char_count, masked_number);
}

/// Mask the Date value by replacing the day by 'day_value', the month by 'month_value',
/// and the year by 'year_value'. UNMASKED_VAL(-1) means keeping the original value.
/// Ported from org.apache.hadoop.hive.ql.udf.generic.GenericUDFMask.
static DateVal MaskImpl(FunctionContext* ctx, const DateVal& val, int day_value,
    int month_value, int year_value) {
  if (val.is_null) return val;
  if (day_value != UNMASKED_VAL && !(1 <= day_value && day_value <= 31)) {
    day_value = MASKED_DAY_COMPONENT_VAL;
  }
  if (month_value != UNMASKED_VAL && !(0 <= month_value && month_value < 12)) {
    month_value = MASKED_MONTH_COMPONENT_VAL;
  }
  if (year_value != UNMASKED_VAL && (year_value <= 0 || year_value >= 9999)) {
    // Repalce illegal year for DateValue with default value.
    year_value = MASKED_YEAR_COMPONENT_VAL;
  }
  int year, month, day;
  DateValue dv = DateValue::FromDateVal(val);
  // Extract year, month, day.
  if (!dv.ToYearMonthDay(&year, &month, &day)) return DateVal::null();

  if (year_value != UNMASKED_VAL) year = year_value;
  // In DateValue, month starts from 1, so increase 'month_value' by 1.
  if (month_value != UNMASKED_VAL) month = month_value + 1;
  if (day_value != UNMASKED_VAL) day = day_value;
  return DateValue(year, month, day).ToDateVal();
}

static inline uint8_t GetFirstChar(const StringVal& str, uint8_t default_value) {
  // To be consistent with Hive, empty string is converted to default value. String with
  // length > 1 will only use its first char.
  return str.len == 0 ? default_value : str.ptr[0];
}

/// Get digit (masked_number) from StringVal. Only accept digits or -1.
static inline bool GetDigitFromString(FunctionContext* ctx, const StringVal& str,
    int* res) {
  if (str.len != 1 || str.ptr[0] < '0' || str.ptr[0] > '9') {
    ctx->SetError(Substitute(
        "Can't convert '$0' to a valid masked_number. Valid values: 0-9.",
        AnyValUtil::ToString(str)).c_str());
    return false;
  }
  *res = str.ptr[0] - '0';
  return true;
}

/// MaskShowFirstN overloads for string value
StringVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const StringVal& val) {
  return MaskShowFirstNImpl(ctx, val, CHAR_COUNT, MASKED_UPPERCASE, MASKED_LOWERCASE,
      MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count) {
  int un_mask_char_count = char_count.val;
  return MaskShowFirstNImpl(ctx, val, un_mask_char_count, MASKED_UPPERCASE,
      MASKED_LOWERCASE, MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char) {
  return MaskShowFirstNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      GetFirstChar(other_char, MASKED_OTHER_CHAR));
}
StringVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return MaskShowFirstN(ctx, val, char_count, upper_char, lower_char, digit_char,
      other_char);
}
StringVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  return MaskShowFirstNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      other_char.val);
}
StringVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return MaskShowFirstNImpl(ctx, val, char_count.val, upper_char.val, lower_char.val,
      digit_char.val, other_char.val);
}

/// MaskShowFirstN overloads for numeric value
BigIntVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const BigIntVal& val) {
  return {MaskShowFirstNImpl(val, CHAR_COUNT, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count) {
  return {MaskShowFirstNImpl(val, char_count.val, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return {MaskShowFirstNImpl(val, char_count.val, number_char.val)};
}
BigIntVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  int masked_number;
  if (!GetDigitFromString(ctx, number_char, &masked_number)) return BigIntVal::null();
  return {MaskShowFirstNImpl(val, char_count.val, masked_number)};
}
BigIntVal MaskFunctions::MaskShowFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return {MaskShowFirstNImpl(val, char_count.val, number_char.val)};
}

/// MaskShowLastN overloads for string value
StringVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const StringVal& val) {
  return MaskShowLastNImpl(ctx, val, CHAR_COUNT, MASKED_UPPERCASE, MASKED_LOWERCASE,
      MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count) {
  int un_mask_char_count = char_count.val;
  return MaskShowLastNImpl(ctx, val, un_mask_char_count, MASKED_UPPERCASE,
      MASKED_LOWERCASE, MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char) {
  return MaskShowLastNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      GetFirstChar(other_char, MASKED_OTHER_CHAR));
}
StringVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return MaskShowLastN(ctx, val, char_count, upper_char, lower_char, digit_char,
      other_char);
}
StringVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  return MaskShowLastNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      other_char.val);
}
StringVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return MaskShowLastNImpl(ctx, val, char_count.val, upper_char.val, lower_char.val,
      digit_char.val, other_char.val);
}

/// MaskShowLastN overloads for numeric value
BigIntVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const BigIntVal& val) {
  return {MaskShowLastNImpl(val, CHAR_COUNT, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count) {
  return {MaskShowLastNImpl(val, char_count.val, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return {MaskShowLastNImpl(val, char_count.val, number_char.val)};
}
BigIntVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  int masked_number;
  if (!GetDigitFromString(ctx, number_char, &masked_number)) return BigIntVal::null();
  return {MaskShowLastNImpl(val, char_count.val, masked_number)};
}
BigIntVal MaskFunctions::MaskShowLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return {MaskShowLastNImpl(val, char_count.val, number_char.val)};
}

/// MaskFirstN overloads for string value
StringVal MaskFunctions::MaskFirstN(FunctionContext *ctx, const StringVal &val) {
  return MaskFirstNImpl(ctx, val, CHAR_COUNT, MASKED_UPPERCASE, MASKED_LOWERCASE,
      MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count) {
  return MaskFirstNImpl(ctx, val, char_count.val, MASKED_UPPERCASE, MASKED_LOWERCASE,
      MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char) {
  return MaskFirstNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      GetFirstChar(other_char, MASKED_OTHER_CHAR));
}
StringVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return MaskFirstN(ctx, val, char_count, upper_char, lower_char, digit_char,
      other_char);
}
StringVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  return MaskFirstNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      other_char.val);
}
StringVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return MaskFirstNImpl(ctx, val, char_count.val, upper_char.val, lower_char.val,
      digit_char.val, other_char.val);
}

/// MaskFirstN overloads for numeric value
BigIntVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const BigIntVal& val) {
  return {MaskFirstNImpl(val, CHAR_COUNT, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count) {
  return {MaskFirstNImpl(val, char_count.val, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return {MaskFirstNImpl(val, char_count.val, number_char.val)};
}
BigIntVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  int masked_number;
  if (!GetDigitFromString(ctx, number_char, &masked_number)) return BigIntVal::null();
  return {MaskFirstNImpl(val, char_count.val, masked_number)};
}
BigIntVal MaskFunctions::MaskFirstN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return {MaskFirstNImpl(val, char_count.val, number_char.val)};
}

/// MaskLastN overloads for string value
StringVal MaskFunctions::MaskLastN(FunctionContext *ctx, const StringVal &val) {
  return MaskLastNImpl(ctx, val, CHAR_COUNT, MASKED_UPPERCASE, MASKED_LOWERCASE,
      MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count) {
  return MaskLastNImpl(ctx, val, char_count.val, MASKED_UPPERCASE, MASKED_LOWERCASE,
      MASKED_DIGIT, MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::MaskLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char) {
  return MaskLastNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      GetFirstChar(other_char, MASKED_OTHER_CHAR));
}
StringVal MaskFunctions::MaskLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return MaskLastN(ctx, val, char_count, upper_char, lower_char, digit_char,
      other_char);
}
StringVal MaskFunctions::MaskLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  return MaskLastNImpl(ctx, val, char_count.val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      other_char.val);
}
StringVal MaskFunctions::MaskLastN(FunctionContext* ctx, const StringVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return MaskLastNImpl(ctx, val, char_count.val, upper_char.val, lower_char.val,
      digit_char.val, other_char.val);
}

/// MaskLastN overloads for numeric value
BigIntVal MaskFunctions::MaskLastN(FunctionContext* ctx, const BigIntVal& val) {
  return {MaskLastNImpl(val, CHAR_COUNT, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count) {
  return {MaskLastNImpl(val, char_count.val, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::MaskLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return {MaskLastNImpl(val, char_count.val, number_char.val)};
}
BigIntVal MaskFunctions::MaskLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  int masked_number;
  if (!GetDigitFromString(ctx, number_char, &masked_number)) return BigIntVal::null();
  return {MaskLastNImpl(val, char_count.val, masked_number)};
}
BigIntVal MaskFunctions::MaskLastN(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& char_count, const IntVal& upper_char, const IntVal& lower_char,
    const IntVal& digit_char, const IntVal& other_char, const IntVal& number_char) {
  return {MaskLastNImpl(val, char_count.val, number_char.val)};
}

/// Mask() overloads for string value
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val) {
  return MaskImpl(ctx, val, MASKED_UPPERCASE, MASKED_LOWERCASE, MASKED_DIGIT,
      MASKED_OTHER_CHAR);
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char) {
  return MaskImpl(ctx, val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      GetFirstChar(other_char, MASKED_OTHER_CHAR));
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return Mask(ctx, val, upper_char, lower_char, digit_char, other_char);
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const IntVal& upper_char, const IntVal& lower_char, const IntVal& digit_char,
    const IntVal& other_char, const IntVal& number_char) {
  return MaskImpl(ctx, val, upper_char.val, lower_char.val, digit_char.val,
      other_char.val);
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  return MaskImpl(ctx, val,
      GetFirstChar(upper_char, MASKED_UPPERCASE),
      GetFirstChar(lower_char, MASKED_LOWERCASE),
      GetFirstChar(digit_char, MASKED_DIGIT),
      other_char.val);
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char, const IntVal& day_value, const IntVal& month_value,
    const IntVal& year_value) {
  return Mask(ctx, val, upper_char, lower_char, digit_char, other_char);
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char, const IntVal& day_value, const IntVal& month_value,
    const IntVal& year_value) {
  return Mask(ctx, val, upper_char, lower_char, digit_char, other_char, number_char);
}
StringVal MaskFunctions::Mask(FunctionContext* ctx, const StringVal& val,
    const IntVal& upper_char, const IntVal& lower_char, const IntVal& digit_char,
    const IntVal& other_char, const IntVal& number_char, const IntVal& day_value,
    const IntVal& month_value, const IntVal& year_value) {
  return MaskImpl(ctx, val, upper_char.val, lower_char.val, digit_char.val,
      other_char.val);
}

/// Mask() overloads for Date value
DateVal MaskFunctions::Mask(FunctionContext* ctx, const DateVal& val) {
  return MaskImpl(ctx, val, MASKED_DAY_COMPONENT_VAL, MASKED_MONTH_COMPONENT_VAL,
      MASKED_YEAR_COMPONENT_VAL);
}
DateVal MaskFunctions::Mask(FunctionContext* ctx, const DateVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char, const IntVal& day_value) {
  return MaskImpl(ctx, val, day_value.val, MASKED_MONTH_COMPONENT_VAL,
      MASKED_YEAR_COMPONENT_VAL);
}
DateVal MaskFunctions::Mask(FunctionContext* ctx, const DateVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char, const IntVal& day_value, const IntVal& month_value) {
  return MaskImpl(ctx, val, day_value.val, month_value.val, MASKED_YEAR_COMPONENT_VAL);
}
DateVal MaskFunctions::Mask(FunctionContext* ctx, const DateVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char, const IntVal& day_value, const IntVal& month_value,
    const IntVal& year_value) {
  return MaskImpl(ctx, val, day_value.val, month_value.val, year_value.val);
}
DateVal MaskFunctions::Mask(FunctionContext* ctx, const DateVal& val,
    const IntVal& upper_char, const IntVal& lower_char, const IntVal& digit_char,
    const IntVal& other_char, const IntVal& number_char, const IntVal& day_value,
    const IntVal& month_value, const IntVal& year_value) {
  return MaskImpl(ctx, val, day_value.val, month_value.val, year_value.val);
}
DateVal MaskFunctions::Mask(FunctionContext* ctx, const DateVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char, const IntVal& day_value, const IntVal& month_value,
    const IntVal& year_value) {
  return MaskImpl(ctx, val, day_value.val, month_value.val, year_value.val);
}

/// Mask() overloads for numeric value
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val) {
  return {MaskShowFirstNImpl(val, 0, MASKED_NUMBER)};
}
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char) {
  return {MaskShowFirstNImpl(val, 0, number_char.val)};
}
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char) {
  int masked_number;
  if (!GetDigitFromString(ctx, number_char, &masked_number)) return BigIntVal::null();
  return {MaskShowFirstNImpl(val, 0, masked_number)};
}
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& upper_char, const IntVal& lower_char, const IntVal& digit_char,
    const IntVal& other_char, const IntVal& number_char) {
  return {MaskShowFirstNImpl(val, 0, number_char.val)};
}
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const StringVal& other_char,
    const IntVal& number_char, const IntVal& day_value, const IntVal& month_value,
    const IntVal& year_value) {
  return {MaskShowFirstNImpl(val, 0, number_char.val)};
}
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val,
    const StringVal& upper_char, const StringVal& lower_char,
    const StringVal& digit_char, const IntVal& other_char,
    const StringVal& number_char, const IntVal& day_value, const IntVal& month_value,
    const IntVal& year_value) {
  int masked_number;
  if (!GetDigitFromString(ctx, number_char, &masked_number)) return BigIntVal::null();
  return {MaskShowFirstNImpl(val, 0, masked_number)};
}
BigIntVal MaskFunctions::Mask(FunctionContext* ctx, const BigIntVal& val,
    const IntVal& upper_char, const IntVal& lower_char, const IntVal& digit_char,
    const IntVal& other_char, const IntVal& number_char, const IntVal& day_value,
    const IntVal& month_value, const IntVal& year_value) {
  return {MaskShowFirstNImpl(val, 0, number_char.val)};
}

StringVal MaskFunctions::MaskHash(FunctionContext* ctx, const StringVal& val) {
  // Hive hash the value by sha256 and encoding it into a lower case hex string.
  StringVal sha256_hash(ctx, SHA256_DIGEST_LENGTH);
  if (UNLIKELY(sha256_hash.is_null)) return StringVal::null();
  discard_result(SHA256(val.ptr, val.len, sha256_hash.ptr));
  return StringFunctions::Lower(ctx, MathFunctions::HexString(ctx, sha256_hash));
}
// For other types, the hash values are always NULL.
BigIntVal MaskFunctions::MaskHash(FunctionContext* ctx, const BigIntVal& val) {
  return BigIntVal::null();
}
DoubleVal MaskFunctions::MaskHash(FunctionContext* ctx, const DoubleVal& val) {
  return DoubleVal::null();
}
BooleanVal MaskFunctions::MaskHash(FunctionContext* ctx, const BooleanVal& val) {
  return BooleanVal::null();
}
TimestampVal MaskFunctions::MaskHash(FunctionContext* ctx, const TimestampVal& val) {
  return TimestampVal::null();
}
DateVal MaskFunctions::MaskHash(FunctionContext* ctx, const DateVal& val) {
  return DateVal::null();
}