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