/src/FreeImage/Source/FreeImage/CacheFile.cpp
https://bitbucket.org/cabalistic/ogredeps/ · C++ · 271 lines · 164 code · 72 blank · 35 comment · 33 complexity · c7965be9b0f5a6f60afcff179ec20aeb MD5 · raw file
- // ==========================================================
- // Multi-Page functions
- //
- // Design and implementation by
- // - Floris van den Berg (flvdberg@wxs.nl)
- // - checkered (checkered@users.sourceforge.net)
- //
- // This file is part of FreeImage 3
- //
- // COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
- // OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
- // THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
- // OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
- // CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
- // THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
- // SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
- // PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
- // THIS DISCLAIMER.
- //
- // Use at your own risk!
- // ==========================================================
- #ifdef _MSC_VER
- #pragma warning (disable : 4786) // identifier was truncated to 'number' characters
- #endif
- #include "CacheFile.h"
- // ----------------------------------------------------------
- CacheFile::CacheFile(const std::string filename, BOOL keep_in_memory) :
- m_file(NULL),
- m_filename(filename),
- m_free_pages(),
- m_page_cache_mem(),
- m_page_cache_disk(),
- m_page_map(),
- m_page_count(0),
- m_current_block(NULL),
- m_keep_in_memory(keep_in_memory) {
- }
- CacheFile::~CacheFile() {
- }
- BOOL
- CacheFile::open() {
- if ((!m_filename.empty()) && (!m_keep_in_memory)) {
- m_file = fopen(m_filename.c_str(), "w+b");
- return (m_file != NULL);
- }
- return (m_keep_in_memory == TRUE);
- }
- void
- CacheFile::close() {
- // dispose the cache entries
- while (!m_page_cache_disk.empty()) {
- Block *block = *m_page_cache_disk.begin();
- m_page_cache_disk.pop_front();
- delete [] block->data;
- delete block;
- }
- while (!m_page_cache_mem.empty()) {
- Block *block = *m_page_cache_mem.begin();
- m_page_cache_mem.pop_front();
- delete [] block->data;
- delete block;
- }
- if (m_file) {
- // close the file
- fclose(m_file);
- // delete the file
- remove(m_filename.c_str());
- }
- }
- void
- CacheFile::cleanupMemCache() {
- if (!m_keep_in_memory) {
- if (m_page_cache_mem.size() > CACHE_SIZE) {
- // flush the least used block to file
- Block *old_block = m_page_cache_mem.back();
- fseek(m_file, old_block->nr * BLOCK_SIZE, SEEK_SET);
- fwrite(old_block->data, BLOCK_SIZE, 1, m_file);
- // remove the data
- delete [] old_block->data;
- old_block->data = NULL;
- // move the block to another list
- m_page_cache_disk.splice(m_page_cache_disk.begin(), m_page_cache_mem, --m_page_cache_mem.end());
- m_page_map[old_block->nr] = m_page_cache_disk.begin();
- }
- }
- }
- int
- CacheFile::allocateBlock() {
- Block *block = new Block;
- block->data = new BYTE[BLOCK_SIZE];
- block->next = 0;
- if (!m_free_pages.empty()) {
- block->nr = *m_free_pages.begin();
- m_free_pages.pop_front();
- } else {
- block->nr = m_page_count++;
- }
- m_page_cache_mem.push_front(block);
- m_page_map[block->nr] = m_page_cache_mem.begin();
- cleanupMemCache();
- return block->nr;
- }
- Block *
- CacheFile::lockBlock(int nr) {
- if (m_current_block == NULL) {
- PageMapIt it = m_page_map.find(nr);
- if (it != m_page_map.end()) {
- m_current_block = *(it->second);
- // the block is swapped out to disc. load it back
- // and remove the block from the cache. it might get cached
- // again as soon as the memory buffer fills up
- if (m_current_block->data == NULL) {
- m_current_block->data = new BYTE[BLOCK_SIZE];
- fseek(m_file, m_current_block->nr * BLOCK_SIZE, SEEK_SET);
- fread(m_current_block->data, BLOCK_SIZE, 1, m_file);
- m_page_cache_mem.splice(m_page_cache_mem.begin(), m_page_cache_disk, it->second);
- m_page_map[nr] = m_page_cache_mem.begin();
- }
- // if the memory cache size is too large, swap an item to disc
- cleanupMemCache();
- // return the current block
- return m_current_block;
- }
- }
- return NULL;
- }
- BOOL
- CacheFile::unlockBlock(int nr) {
- if (m_current_block) {
- m_current_block = NULL;
- return TRUE;
- }
- return FALSE;
- }
- BOOL
- CacheFile::deleteBlock(int nr) {
- if (!m_current_block) {
- PageMapIt it = m_page_map.find(nr);
- // remove block from cache
- if (it != m_page_map.end())
- m_page_map.erase(nr);
- // add block to free page list
- m_free_pages.push_back(nr);
- return TRUE;
- }
- return FALSE;
- }
- BOOL
- CacheFile::readFile(BYTE *data, int nr, int size) {
- if ((data) && (size > 0)) {
- int s = 0;
- int block_nr = nr;
- do {
- int copy_nr = block_nr;
- Block *block = lockBlock(copy_nr);
- block_nr = block->next;
- memcpy(data + s, block->data, (s + BLOCK_SIZE > size) ? size - s : BLOCK_SIZE);
- unlockBlock(copy_nr);
- s += BLOCK_SIZE;
- } while (block_nr != 0);
- return TRUE;
- }
- return FALSE;
- }
- int
- CacheFile::writeFile(BYTE *data, int size) {
- if ((data) && (size > 0)) {
- int nr_blocks_required = 1 + (size / BLOCK_SIZE);
- int count = 0;
- int s = 0;
- int stored_alloc;
- int alloc;
-
- stored_alloc = alloc = allocateBlock();
- do {
- int copy_alloc = alloc;
- Block *block = lockBlock(copy_alloc);
- block->next = 0;
- memcpy(block->data, data + s, (s + BLOCK_SIZE > size) ? size - s : BLOCK_SIZE);
- if (count + 1 < nr_blocks_required)
- alloc = block->next = allocateBlock();
- unlockBlock(copy_alloc);
- s += BLOCK_SIZE;
- } while (++count < nr_blocks_required);
- return stored_alloc;
- }
- return 0;
- }
- void
- CacheFile::deleteFile(int nr) {
- do {
- Block *block = lockBlock(nr);
- if (block == NULL)
- break;
- int next = block->next;
- unlockBlock(nr);
- deleteBlock(nr);
- nr = next;
- } while (nr != 0);
- }