/*
 * Copyright 2011, The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef MEM_CHUNK_H
#define MEM_CHUNK_H

#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>

typedef void *(*AllocFunc) (size_t, uint32_t);
typedef void (*FreeFunc) (void *);

class MemChunk {
private:
  unsigned char *buf;
  size_t buf_size;
  bool bVendorBuf;

  static AllocFunc VendorAlloc;
  static FreeFunc VendorFree;

  bool invalidBuf() const;

public:
  MemChunk();

  ~MemChunk();

  bool allocate(size_t size);

  void print() const;

  bool protect(int prot);

  unsigned char const *getBuffer() const {
    return buf;
  }

  unsigned char *getBuffer() {
    return buf;
  }

  unsigned char &operator[](size_t index) {
    return buf[index];
  }

  unsigned char const &operator[](size_t index) const {
    return buf[index];
  }

  size_t size() const {
    return buf_size;
  }

  // The allocation function must return page-aligned memory or we will be
  // unable to mprotect the region appropriately.
  static void registerAllocFreeCallbacks(AllocFunc a, FreeFunc f) {
    VendorAlloc = a;
    VendorFree = f;
  }
};

#endif // MEM_CHUNK_H