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      1 // Copyright 2009 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #include "v8.h"
     29 #include "regexp-stack.h"
     30 
     31 namespace v8 {
     32 namespace internal {
     33 
     34 RegExpStackScope::RegExpStackScope(Isolate* isolate)
     35     : regexp_stack_(isolate->regexp_stack()) {
     36   // Initialize, if not already initialized.
     37   regexp_stack_->EnsureCapacity(0);
     38 }
     39 
     40 
     41 RegExpStackScope::~RegExpStackScope() {
     42   ASSERT(Isolate::Current() == regexp_stack_->isolate_);
     43   // Reset the buffer if it has grown.
     44   regexp_stack_->Reset();
     45 }
     46 
     47 
     48 RegExpStack::RegExpStack()
     49     : isolate_(NULL) {
     50 }
     51 
     52 
     53 RegExpStack::~RegExpStack() {
     54   thread_local_.Free();
     55 }
     56 
     57 
     58 char* RegExpStack::ArchiveStack(char* to) {
     59   size_t size = sizeof(thread_local_);
     60   OS::MemCopy(reinterpret_cast<void*>(to), &thread_local_, size);
     61   thread_local_ = ThreadLocal();
     62   return to + size;
     63 }
     64 
     65 
     66 char* RegExpStack::RestoreStack(char* from) {
     67   size_t size = sizeof(thread_local_);
     68   OS::MemCopy(&thread_local_, reinterpret_cast<void*>(from), size);
     69   return from + size;
     70 }
     71 
     72 
     73 void RegExpStack::Reset() {
     74   if (thread_local_.memory_size_ > kMinimumStackSize) {
     75     DeleteArray(thread_local_.memory_);
     76     thread_local_ = ThreadLocal();
     77   }
     78 }
     79 
     80 
     81 void RegExpStack::ThreadLocal::Free() {
     82   if (memory_size_ > 0) {
     83     DeleteArray(memory_);
     84     Clear();
     85   }
     86 }
     87 
     88 
     89 Address RegExpStack::EnsureCapacity(size_t size) {
     90   if (size > kMaximumStackSize) return NULL;
     91   if (size < kMinimumStackSize) size = kMinimumStackSize;
     92   if (thread_local_.memory_size_ < size) {
     93     Address new_memory = NewArray<byte>(static_cast<int>(size));
     94     if (thread_local_.memory_size_ > 0) {
     95       // Copy original memory into top of new memory.
     96       OS::MemCopy(
     97           reinterpret_cast<void*>(
     98               new_memory + size - thread_local_.memory_size_),
     99           reinterpret_cast<void*>(thread_local_.memory_),
    100           thread_local_.memory_size_);
    101       DeleteArray(thread_local_.memory_);
    102     }
    103     thread_local_.memory_ = new_memory;
    104     thread_local_.memory_size_ = size;
    105     thread_local_.limit_ = new_memory + kStackLimitSlack * kPointerSize;
    106   }
    107   return thread_local_.memory_ + thread_local_.memory_size_;
    108 }
    109 
    110 
    111 }}  // namespace v8::internal
    112