////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
////////////////////////////////////////////////////////////////////////////////

#include "vector.h"
#include <string.h>

////////////////////////////////////////////////////////////////////////////////
/// @brief grow rate
////////////////////////////////////////////////////////////////////////////////

#define GROW_FACTOR (1.2)

////////////////////////////////////////////////////////////////////////////////
/// @brief initializes a vector
////////////////////////////////////////////////////////////////////////////////

void TRI_InitVector(TRI_vector_t* vector, size_t elementSize) {
  vector->_buffer = nullptr;
  vector->_lengthX = 0;
  vector->_capacityX = 0;
  vector->_elementSizeX = static_cast<uint32_t>(elementSize);
}

////////////////////////////////////////////////////////////////////////////////
/// @brief initializes a vector, with user-definable settings
////////////////////////////////////////////////////////////////////////////////

int TRI_InitVector2(TRI_vector_t* vector, size_t elementSize, size_t initialCapacity) {
  // init vector as usual
  TRI_InitVector(vector, elementSize);

  if (initialCapacity != 0) {
    vector->_buffer = static_cast<char*>(TRI_Allocate(
        (initialCapacity * static_cast<size_t>(vector->_elementSizeX))));

    if (vector->_buffer == nullptr) {
      return TRI_ERROR_OUT_OF_MEMORY;
    }
  }

  vector->_capacityX = static_cast<uint32_t>(initialCapacity);

  return TRI_ERROR_NO_ERROR;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief destroys a vector, but does not free the pointer
////////////////////////////////////////////////////////////////////////////////

void TRI_DestroyVector(TRI_vector_t* vector) {
  if (vector->_buffer != nullptr) {
    TRI_Free(vector->_buffer);
  }
}

////////////////////////////////////////////////////////////////////////////////
/// @brief ensures a vector has space for extraCapacity more items
////////////////////////////////////////////////////////////////////////////////

int TRI_ReserveVector(TRI_vector_t* vector, size_t extraCapacity) {
  size_t oldLength = static_cast<size_t>(vector->_lengthX);
  size_t minLength = oldLength + extraCapacity;

  if (static_cast<size_t>(vector->_capacityX) >= minLength) {
    return TRI_ERROR_NO_ERROR;
  }

  size_t newSize = static_cast<size_t>(vector->_capacityX);
  while (newSize < minLength) {
    newSize = (size_t)(1 + GROW_FACTOR * newSize);
  }

  auto newBuffer = static_cast<char*>(
      TRI_Reallocate(vector->_buffer, newSize * static_cast<size_t>(vector->_elementSizeX)));

  if (newBuffer == nullptr) {
    return TRI_ERROR_OUT_OF_MEMORY;
  }

  vector->_buffer = newBuffer;
  vector->_capacityX = static_cast<uint32_t>(newSize);

  return TRI_ERROR_NO_ERROR;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief adjusts the length of the vector
////////////////////////////////////////////////////////////////////////////////

void TRI_SetLengthVector(TRI_vector_t* vector, size_t n) {
  vector->_lengthX = static_cast<uint32_t>(n);
}

////////////////////////////////////////////////////////////////////////////////
/// @brief resizes the vector
////////////////////////////////////////////////////////////////////////////////

int TRI_ResizeVector(TRI_vector_t* vector, size_t n) {
  if (static_cast<size_t>(vector->_lengthX) == n) {
    return TRI_ERROR_NO_ERROR;
  }

  if (static_cast<size_t>(vector->_capacityX) < n) {
    size_t newSize = n;
    auto newBuffer = static_cast<char*>(
        TRI_Reallocate(vector->_buffer, newSize * static_cast<size_t>(vector->_elementSizeX)));

    if (newBuffer == nullptr) {
      return TRI_ERROR_OUT_OF_MEMORY;
    }

    vector->_capacityX = static_cast<uint32_t>(n);
    vector->_buffer = newBuffer;
  }

  vector->_lengthX = static_cast<uint32_t>(n);
  return TRI_ERROR_NO_ERROR;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief adds an element at the end
////////////////////////////////////////////////////////////////////////////////

int TRI_PushBackVector(TRI_vector_t* vector, void const* element) {
  size_t const elementSize = static_cast<size_t>(vector->_elementSizeX);

  if (vector->_lengthX == vector->_capacityX) {
    size_t newSize =
        (size_t)(1 + (GROW_FACTOR * static_cast<size_t>(vector->_capacityX)));

    auto newBuffer =
        static_cast<char*>(TRI_Reallocate(vector->_buffer, newSize * elementSize));

    if (newBuffer == nullptr) {
      return TRI_ERROR_OUT_OF_MEMORY;
    }

    vector->_capacityX = static_cast<uint32_t>(newSize);
    vector->_buffer = newBuffer;
  }

  memcpy(vector->_buffer + static_cast<size_t>(vector->_lengthX) * elementSize,
         element, elementSize);

  vector->_lengthX++;

  return TRI_ERROR_NO_ERROR;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief removes an element
////////////////////////////////////////////////////////////////////////////////

void TRI_RemoveVector(TRI_vector_t* vector, size_t n) {
  if (n < static_cast<size_t>(vector->_lengthX)) {
    if (n + 1 < static_cast<size_t>(vector->_lengthX)) {
      size_t const elementSize = static_cast<size_t>(vector->_elementSizeX);

      memmove(vector->_buffer + n * elementSize, vector->_buffer + (n + 1) * elementSize,
              (static_cast<size_t>(vector->_lengthX) - n - 1) * elementSize);
    }

    --vector->_lengthX;
  }
}

////////////////////////////////////////////////////////////////////////////////
/// @brief returns an element to the vector after borrowing it via
/// TRI_NextVector. This will also decrease the vector length by one.
/// The caller must ensure that the element has been fetched from the vector
/// before.
////////////////////////////////////////////////////////////////////////////////

void TRI_ReturnVector(TRI_vector_t* vector) {
  TRI_ASSERT(vector->_lengthX > 0);

  vector->_lengthX--;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief increases vector length by one and returns the address of the
/// uninitialized element at the new position
////////////////////////////////////////////////////////////////////////////////

void* TRI_NextVector(TRI_vector_t* vector) {
  // ensure the vector has enough capacity for another element
  int res = TRI_ReserveVector(vector, 1);

  if (res != TRI_ERROR_NO_ERROR) {
    // out of memory
    return nullptr;
  }

  ++vector->_lengthX;
  TRI_ASSERT(vector->_lengthX <= vector->_capacityX);
  TRI_ASSERT(vector->_buffer != nullptr);

  return TRI_AtVector(vector, static_cast<size_t>(vector->_lengthX - 1));
}

////////////////////////////////////////////////////////////////////////////////
/// @brief returns the element at a given position
////////////////////////////////////////////////////////////////////////////////

void* TRI_AtVector(TRI_vector_t const* vector, size_t pos) {
  if (vector->_buffer == nullptr || pos >= static_cast<size_t>(vector->_lengthX)) {
    return nullptr;
  }

  return static_cast<void*>(vector->_buffer + pos * static_cast<size_t>(vector->_elementSizeX));
}

////////////////////////////////////////////////////////////////////////////////
/// @brief inserts an element at a given position
////////////////////////////////////////////////////////////////////////////////

int TRI_InsertVector(TRI_vector_t* vector, void const* element, size_t n) {
  size_t const elementSize = static_cast<size_t>(vector->_elementSizeX);

  // ...........................................................................
  // Check and see if we need to extend the vector
  // ...........................................................................

  if (vector->_lengthX >= vector->_capacityX || n >= static_cast<size_t>(vector->_capacityX)) {
    size_t newSize =
        (size_t)(1 + (GROW_FACTOR * static_cast<size_t>(vector->_capacityX)));

    if (n >= newSize) {
      newSize = n + 1;
    }

    TRI_ASSERT(newSize > n);

    auto newBuffer = static_cast<char*>(TRI_Allocate(newSize * elementSize));

    if (newBuffer == nullptr) {
      return TRI_ERROR_OUT_OF_MEMORY;
    }

    vector->_capacityX = static_cast<uint32_t>(newSize);

    if (vector->_buffer != nullptr) {
      memcpy(newBuffer, vector->_buffer, static_cast<size_t>(vector->_lengthX) * elementSize);
      TRI_Free(vector->_buffer);
    }

    vector->_buffer = newBuffer;
  }

  if (n < static_cast<size_t>(vector->_lengthX)) {
    memmove(vector->_buffer + (elementSize * (n + 1)),
            vector->_buffer + (elementSize * n),
            elementSize * (static_cast<size_t>(vector->_lengthX) - n));
    ++vector->_lengthX;
  } else {
    vector->_lengthX = static_cast<uint32_t>(n + 1);
  }

  memcpy(vector->_buffer + (elementSize * n), element, elementSize);

  return TRI_ERROR_NO_ERROR;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief sets an element at a given position
////////////////////////////////////////////////////////////////////////////////

void TRI_SetVector(TRI_vector_t* vector, size_t pos, void const* element) {
  if (pos < static_cast<size_t>(vector->_lengthX)) {
    size_t const elementSize = static_cast<size_t>(vector->_elementSizeX);
    memcpy((void*)(vector->_buffer + pos * elementSize), element, elementSize);
  }
}

////////////////////////////////////////////////////////////////////////////////
/// @brief returns the beginning
////////////////////////////////////////////////////////////////////////////////

void* TRI_BeginVector(TRI_vector_t const* vector) { return vector->_buffer; }