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      1 // Copyright 2009 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/regexp/regexp-stack.h"
      6 
      7 #include "src/isolate.h"
      8 
      9 namespace v8 {
     10 namespace internal {
     11 
     12 RegExpStackScope::RegExpStackScope(Isolate* isolate)
     13     : regexp_stack_(isolate->regexp_stack()) {
     14   // Initialize, if not already initialized.
     15   regexp_stack_->EnsureCapacity(0);
     16 }
     17 
     18 
     19 RegExpStackScope::~RegExpStackScope() {
     20   // Reset the buffer if it has grown.
     21   regexp_stack_->Reset();
     22 }
     23 
     24 
     25 RegExpStack::RegExpStack()
     26     : isolate_(NULL) {
     27 }
     28 
     29 
     30 RegExpStack::~RegExpStack() {
     31   thread_local_.Free();
     32 }
     33 
     34 
     35 char* RegExpStack::ArchiveStack(char* to) {
     36   size_t size = sizeof(thread_local_);
     37   MemCopy(reinterpret_cast<void*>(to), &thread_local_, size);
     38   thread_local_ = ThreadLocal();
     39   return to + size;
     40 }
     41 
     42 
     43 char* RegExpStack::RestoreStack(char* from) {
     44   size_t size = sizeof(thread_local_);
     45   MemCopy(&thread_local_, reinterpret_cast<void*>(from), size);
     46   return from + size;
     47 }
     48 
     49 
     50 void RegExpStack::Reset() {
     51   if (thread_local_.memory_size_ > kMinimumStackSize) {
     52     DeleteArray(thread_local_.memory_);
     53     thread_local_ = ThreadLocal();
     54   }
     55 }
     56 
     57 
     58 void RegExpStack::ThreadLocal::Free() {
     59   if (memory_size_ > 0) {
     60     DeleteArray(memory_);
     61     Clear();
     62   }
     63 }
     64 
     65 
     66 Address RegExpStack::EnsureCapacity(size_t size) {
     67   if (size > kMaximumStackSize) return NULL;
     68   if (size < kMinimumStackSize) size = kMinimumStackSize;
     69   if (thread_local_.memory_size_ < size) {
     70     Address new_memory = NewArray<byte>(static_cast<int>(size));
     71     if (thread_local_.memory_size_ > 0) {
     72       // Copy original memory into top of new memory.
     73       MemCopy(reinterpret_cast<void*>(new_memory + size -
     74                                       thread_local_.memory_size_),
     75               reinterpret_cast<void*>(thread_local_.memory_),
     76               thread_local_.memory_size_);
     77       DeleteArray(thread_local_.memory_);
     78     }
     79     thread_local_.memory_ = new_memory;
     80     thread_local_.memory_size_ = size;
     81     thread_local_.limit_ = new_memory + kStackLimitSlack * kPointerSize;
     82   }
     83   return thread_local_.memory_ + thread_local_.memory_size_;
     84 }
     85 
     86 
     87 }  // namespace internal
     88 }  // namespace v8
     89