michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef jit_FixedList_h
michael@0: #define jit_FixedList_h
michael@0: 
michael@0: #include <stddef.h>
michael@0: 
michael@0: #include "jit/Ion.h"
michael@0: #include "jit/IonAllocPolicy.h"
michael@0: 
michael@0: namespace js {
michael@0: namespace jit {
michael@0: 
michael@0: // List of a fixed length, but the length is unknown until runtime.
michael@0: template <typename T>
michael@0: class FixedList
michael@0: {
michael@0:     T *list_;
michael@0:     size_t length_;
michael@0: 
michael@0:   private:
michael@0:     FixedList(const FixedList&); // no copy definition.
michael@0:     void operator= (const FixedList*); // no assignment definition.
michael@0: 
michael@0:   public:
michael@0:     FixedList()
michael@0:       : list_(nullptr), length_(0)
michael@0:     { }
michael@0: 
michael@0:     // Dynamic memory allocation requires the ability to report failure.
michael@0:     bool init(TempAllocator &alloc, size_t length) {
michael@0:         length_ = length;
michael@0:         if (length == 0)
michael@0:             return true;
michael@0: 
michael@0:         if (length & mozilla::tl::MulOverflowMask<sizeof(T)>::value)
michael@0:             return false;
michael@0:         list_ = (T *)alloc.allocate(length * sizeof(T));
michael@0:         return list_ != nullptr;
michael@0:     }
michael@0: 
michael@0:     size_t length() const {
michael@0:         return length_;
michael@0:     }
michael@0: 
michael@0:     void shrink(size_t num) {
michael@0:         JS_ASSERT(num < length_);
michael@0:         length_ -= num;
michael@0:     }
michael@0: 
michael@0:     bool growBy(TempAllocator &alloc, size_t num) {
michael@0:         size_t newlength = length_ + num;
michael@0:         if (newlength < length_)
michael@0:             return false;
michael@0:         if (newlength & mozilla::tl::MulOverflowMask<sizeof(T)>::value)
michael@0:             return false;
michael@0:         T *list = (T *)alloc.allocate((length_ + num) * sizeof(T));
michael@0:         if (!list)
michael@0:             return false;
michael@0: 
michael@0:         for (size_t i = 0; i < length_; i++)
michael@0:             list[i] = list_[i];
michael@0: 
michael@0:         length_ += num;
michael@0:         list_ = list;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     T &operator[](size_t index) {
michael@0:         JS_ASSERT(index < length_);
michael@0:         return list_[index];
michael@0:     }
michael@0:     const T &operator [](size_t index) const {
michael@0:         JS_ASSERT(index < length_);
michael@0:         return list_[index];
michael@0:     }
michael@0: };
michael@0: 
michael@0: } // namespace jit
michael@0: } // namespace js
michael@0: 
michael@0: #endif /* jit_FixedList_h */