Line data    Source code

       1             : // Copyright 2019 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #include "src/objects/string-comparator.h"
       6             : 
       7             : #include "src/objects/string-inl.h"
       8             : 
       9             : namespace v8 {
      10             : namespace internal {
      11             : 
      12      123596 : void StringComparator::State::Init(String string) {
      13      123596 :   ConsString cons_string = String::VisitFlat(this, string);
      14      123596 :   iter_.Reset(cons_string);
      15      123596 :   if (!cons_string.is_null()) {
      16             :     int offset;
      17          43 :     string = iter_.Next(&offset);
      18          43 :     String::VisitFlat(this, string, offset);
      19             :   }
      20      123596 : }
      21             : 
      22   100664126 : void StringComparator::State::Advance(int consumed) {
      23             :   DCHECK(consumed <= length_);
      24             :   // Still in buffer.
      25   100664126 :   if (length_ != consumed) {
      26    50332063 :     if (is_one_byte_) {
      27    50332063 :       buffer8_ += consumed;
      28             :     } else {
      29           0 :       buffer16_ += consumed;
      30             :     }
      31    50332063 :     length_ -= consumed;
      32    50332063 :     return;
      33             :   }
      34             :   // Advance state.
      35             :   int offset;
      36   100664126 :   String next = iter_.Next(&offset);
      37             :   DCHECK_EQ(0, offset);
      38             :   DCHECK(!next.is_null());
      39    50332063 :   String::VisitFlat(this, next);
      40             : }
      41             : 
      42       61798 : bool StringComparator::Equals(String string_1, String string_2) {
      43             :   int length = string_1->length();
      44       61798 :   state_1_.Init(string_1);
      45       61798 :   state_2_.Init(string_2);
      46    50332063 :   while (true) {
      47    50393861 :     int to_check = Min(state_1_.length_, state_2_.length_);
      48             :     DCHECK(to_check > 0 && to_check <= length);
      49             :     bool is_equal;
      50    50393861 :     if (state_1_.is_one_byte_) {
      51    50332895 :       if (state_2_.is_one_byte_) {
      52             :         is_equal = Equals<uint8_t, uint8_t>(&state_1_, &state_2_, to_check);
      53             :       } else {
      54             :         is_equal = Equals<uint8_t, uint16_t>(&state_1_, &state_2_, to_check);
      55             :       }
      56             :     } else {
      57       60966 :       if (state_2_.is_one_byte_) {
      58             :         is_equal = Equals<uint16_t, uint8_t>(&state_1_, &state_2_, to_check);
      59             :       } else {
      60             :         is_equal = Equals<uint16_t, uint16_t>(&state_1_, &state_2_, to_check);
      61             :       }
      62             :     }
      63             :     // Looping done.
      64    50393861 :     if (!is_equal) return false;
      65    50393844 :     length -= to_check;
      66             :     // Exit condition. Strings are equal.
      67    50393844 :     if (length == 0) return true;
      68    50332063 :     state_1_.Advance(to_check);
      69    50332063 :     state_2_.Advance(to_check);
      70             :   }
      71             : }
      72             : 
      73             : }  // namespace internal
      74      120216 : }  // namespace v8