// Copyright 2020 Google LLC

//

// 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_IMG_H

#define MEM_IMG_H

#include <stddef.h>

#include <stdint.h>

#include "tsk/tsk_tools_i.h"

#include "tsk/img/legacy_cache.h"

#include "tsk/img/tsk_img_i.h"

typedef struct {

  IMG_INFO img_info;

  const uint8_t *data;

  size_t size;

} IMG_MEM_INFO;

static ssize_t mem_read(TSK_IMG_INFO *img_info, TSK_OFF_T offset, char *buf,

                        size_t len) {

  IMG_MEM_INFO *mem_info = reinterpret_cast<IMG_MEM_INFO *>(img_info);

  // Bounds-checking exists in the real drivers.

  if ((offset < 0) || ((size_t) offset > mem_info->size)) {

    return -1;

  }

  ssize_t read_len = len;

  if (len > (mem_info->size - offset)) {

    read_len = mem_info->size - offset;

  }

  if ((read_len > 0) && memcpy(buf, mem_info->data + offset, read_len) == nullptr) {

    return -1;

  } else {

    return read_len;

  }

}

static void mem_close(TSK_IMG_INFO *img_info) {

  IMG_MEM_INFO *mem_info = reinterpret_cast<IMG_MEM_INFO *>(img_info);

  free(mem_info);

}

static void mem_imgstat(TSK_IMG_INFO *, FILE *) {}

IMG_INFO *mem_open(const uint8_t *data, size_t size) {

  IMG_MEM_INFO *inmemory_img =

      reinterpret_cast<IMG_MEM_INFO *>(malloc(sizeof(IMG_MEM_INFO)));

  TSK_IMG_INFO *img;

  if (inmemory_img == nullptr) {

    return nullptr;

  }

  inmemory_img->data = data;

  inmemory_img->size = size;

  auto base = &(inmemory_img->img_info.img_info);

  base->itype = TSK_IMG_TYPE_RAW;

  base->size = size;

  base->sector_size = 512;

  inmemory_img->img_info.read = mem_read;

  inmemory_img->img_info.close = mem_close;

  inmemory_img->img_info.imgstat = mem_imgstat;

  inmemory_img->img_info.cache = new LegacyCache();

  inmemory_img->img_info.cache_read = tsk_img_read_legacy;

  return (IMG_INFO*)inmemory_img;

}

#endif // # MEM_IMG_H