vertexDataBook.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file vertexDataBook.cxx
 * @author drose
 * @date 2007-05-16
 */

#include "vertexDataBook.h"
#include "mutexHolder.h"

/**
 *
 */
VertexDataBook::
VertexDataBook(size_t block_size) {
  // Make sure the block_size is an integer multiple of the system's page
  // size.
  _block_size = memory_hook->round_up_to_page_size(block_size);
}

/**
 *
 */
VertexDataBook::
~VertexDataBook() {
}

/**
 * Returns the total size of all bytes owned by all pages owned by this book.
 */
size_t VertexDataBook::
count_total_page_size() const {
  MutexHolder holder(_lock);

  size_t total = 0;
  Pages::const_iterator pi;
  for (pi = _pages.begin(); pi != _pages.end(); ++pi) {
    total += (*pi)->get_max_size();
  }
  return total;
}

/**
 * Returns the total size of all bytes owned by all pages owned by this book
 * that have the indicated ram class.
 */
size_t VertexDataBook::
count_total_page_size(VertexDataPage::RamClass ram_class) const {
  MutexHolder holder(_lock);

  size_t total = 0;
  Pages::const_iterator pi;
  for (pi = _pages.begin(); pi != _pages.end(); ++pi) {
    if ((*pi)->get_ram_class() == ram_class) {
      total += (*pi)->get_max_size();
    }
  }
  return total;
}

/**
 * Returns the total size of all bytes allocated within pages owned by this
 * book.
 */
size_t VertexDataBook::
count_allocated_size() const {
  MutexHolder holder(_lock);

  size_t total = 0;
  Pages::const_iterator pi;
  for (pi = _pages.begin(); pi != _pages.end(); ++pi) {
    total += (*pi)->get_total_size();
  }
  return total;
}

/**
 * Returns the total size of all bytes allocated within pages owned by this
 * book that have the indicated ram class.
 */
size_t VertexDataBook::
count_allocated_size(VertexDataPage::RamClass ram_class) const {
  MutexHolder holder(_lock);

  size_t total = 0;
  Pages::const_iterator pi;
  for (pi = _pages.begin(); pi != _pages.end(); ++pi) {
    if ((*pi)->get_ram_class() == ram_class) {
      total += (*pi)->get_total_size();
    }
  }
  return total;
}

/**
 * Writes all pages to disk immediately, just in case they get evicted later.
 * It makes sense to make this call just before taking down a loading screen,
 * to minimize chugs from saving pages inadvertently later.
 */
void VertexDataBook::
save_to_disk() {
  MutexHolder holder(_lock);

  Pages::iterator pi;
  for (pi = _pages.begin(); pi != _pages.end(); ++pi) {
    (*pi)->save_to_disk();
  }
}


/**
 * Allocates and returns a new VertexDataBuffer of the requested size.
 *
 * Assumes the lock is already held.
 */
VertexDataBlock *VertexDataBook::
do_alloc(size_t size) {
  // Look for an empty page of the appropriate size.  The _pages set is sorted
  // so that the pages with the smallest available blocks are at the front.

  // Create a dummy page to use to search the set.
  VertexDataPage size_page(size);
  Pages::iterator pi = _pages.lower_bound(&size_page);

  // Now we can start from the first element of the set that is possibly large
  // enough to contain this block, and work up from there.
  while (pi != _pages.end()) {
    Pages::iterator pnext = pi;
    ++pnext;

    VertexDataPage *page = (*pi);

    // Allocating a block may change the page's available contiguous size, and
    // thereby change its position in the set, invalidating the iterator pi.
    // This is why we've already computed pnext.
    VertexDataBlock *block = page->do_alloc(size);

    if (block != nullptr) {
      // This page worked.
      return block;
    }

    // Try the next page.
    pi = pnext;
  }

  // No page was good enough.  Create a new page.  Make it at least large
  // enough to hold this requested block.
  VertexDataPage *page = create_new_page(size);
  _pages.insert(page);

  VertexDataBlock *block = page->do_alloc(size);
  return block;
}