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 
RegExpStackScope(Isolate * isolate)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 
~RegExpStackScope()19 RegExpStackScope::~RegExpStackScope() {
20   // Reset the buffer if it has grown.
21   regexp_stack_->Reset();
22 }
23 
24 
RegExpStack()25 RegExpStack::RegExpStack()
26     : isolate_(NULL) {
27 }
28 
29 
~RegExpStack()30 RegExpStack::~RegExpStack() {
31   thread_local_.Free();
32 }
33 
34 
ArchiveStack(char * to)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 
RestoreStack(char * from)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 
Reset()50 void RegExpStack::Reset() {
51   if (thread_local_.memory_size_ > kMinimumStackSize) {
52     DeleteArray(thread_local_.memory_);
53     thread_local_ = ThreadLocal();
54   }
55 }
56 
57 
Free()58 void RegExpStack::ThreadLocal::Free() {
59   if (memory_size_ > 0) {
60     DeleteArray(memory_);
61     Clear();
62   }
63 }
64 
65 
EnsureCapacity(size_t size)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