manolas
/
vcglib
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Improved efficience in operator[]

This commit is contained in:
Federico Ponchio 2004-07-20 14:04:32 +00:00
parent f417270df1
commit c64c064b78
1 changed files with 17 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
apps/nexus/vfile.h
View File

@ -24,6 +24,9 @@
History
$Log: not supported by cvs2svn $
Revision 1.8 2004/07/15 14:32:49 ponchio
Debug.
Revision 1.7 2004/07/05 15:49:39 ponchio
Windows (DevCpp, mingw) port.
@ -101,6 +104,7 @@ template <class T> class VFile {
typedef typename std::list<Buffer>::iterator list_iterator;
std::map<unsigned int, list_iterator> index; //TODO move to hash_map
Buffer *last_buffer;
unsigned int chunk_size; //default buffer size (expressed in number of T)
unsigned int queue_size;
@ -118,13 +122,14 @@ template <class T> class VFile {
VFile *buffer;
};
VFile(): fp(NULL) {}
VFile(): fp(NULL), last_buffer(NULL) {}
~VFile() { Close(); }
bool Create(const std::string &filename,
unsigned int _chunk_size = 4096/sizeof(T),
unsigned int _queue_size = 1000) {
assert(_chunk_size > 0);
last_buffer = NULL;
chunk_size = _chunk_size;
queue_size = _queue_size;
n_elements = 0;
@ -147,6 +152,7 @@ template <class T> class VFile {
unsigned int _queue_size = 1000) {
assert(_chunk_size > 0);
last_buffer = NULL;
chunk_size = _chunk_size;
queue_size = _queue_size;
#ifdef WIN32
@ -186,6 +192,7 @@ template <class T> class VFile {
FlushBuffer(*i);
buffers.clear();
index.clear();
last_buffer = NULL;
}
void FlushBuffer(Buffer buffer) {
@ -248,8 +255,13 @@ template <class T> class VFile {
unsigned int offset = n - chunk*chunk_size;
assert(offset < chunk_size * sizeof(T));
if(index.count(chunk))
if(last_buffer && last_buffer->key == chunk)
return *(last_buffer->data + offset);
if(index.count(chunk)) {
last_buffer = &*index[chunk];
return *((*(index[chunk])).data + offset);
}
if(buffers.size() > queue_size) {
Buffer &buffer= buffers.back();
@ -270,9 +282,10 @@ template <class T> class VFile {
buffers.push_front(buffer);
index[buffer.key] = buffers.begin();
last_buffer = &*buffers.begin();
SetPosition(chunk);
ReadBuffer(buffer.data, buffer.size);
ReadBuffer(buffer.data, buffer.size);
return *(buffer.data + offset);
}