src/third_party/mozjs-45/js/src/jit/FixedList.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef jit_FixedList_h
#define jit_FixedList_h

#include <stddef.h>

#include "jit/Ion.h"
#include "jit/JitAllocPolicy.h"

namespace js {
namespace jit {

// List of a fixed length, but the length is unknown until runtime.
template <typename T>
class FixedList
{
    T* list_;
    size_t length_;

  private:
    FixedList(const FixedList&); // no copy definition.
    void operator= (const FixedList*); // no assignment definition.

  public:
    FixedList()
      : list_(nullptr), length_(0)
    { }

    // Dynamic memory allocation requires the ability to report failure.
    bool init(TempAllocator& alloc, size_t length) {
        length_ = length;
        if (length == 0)
            return true;

        size_t bytes;
        if (MOZ_UNLIKELY(!CalculateAllocSize<T>(length, &bytes)))
            return false;
        list_ = (T*)alloc.allocate(bytes);
        return list_ != nullptr;
    }

    size_t empty() const {
        return length_ == 0;
    }

    size_t length() const {
        return length_;
    }

    void shrink(size_t num) {
        MOZ_ASSERT(num < length_);
        length_ -= num;
    }

    bool growBy(TempAllocator& alloc, size_t num) {
        size_t newlength = length_ + num;
        if (newlength < length_)
            return false;
        size_t bytes;
        if (MOZ_UNLIKELY(!CalculateAllocSize<T>(newlength, &bytes)))
            return false;
        T* list = (T*)alloc.allocate(bytes);
        if (MOZ_UNLIKELY(!list))
            return false;

        for (size_t i = 0; i < length_; i++)
            list[i] = list_[i];

        length_ += num;
        list_ = list;
        return true;
    }

    T& operator[](size_t index) {
        MOZ_ASSERT(index < length_);
        return list_[index];
    }
    const T& operator [](size_t index) const {
        MOZ_ASSERT(index < length_);
        return list_[index];
    }

    T* begin() {
        return list_;
    }
    T* end() {
        return list_ + length_;
    }
};

} // namespace jit
} // namespace js

#endif /* jit_FixedList_h */