size_t BitmapEncoding::Bitmap::compress(void* dst, const ConstChunk& chunk, size_t chunkSize)
{
char const* dataSrc = (char const*)chunk.getData();
TypeId type = chunk.getAttributeDesc().getType();
_elementSize = TypeLibrary::getType(type).byteSize();
/* No more immutable arrays, to keep consistent with old code, always treat data as string
*/
_bitmapElements = chunkSize;
_elementSize = 1;
if(!_bitmapElements) { return chunkSize; }
char *readPos = const_cast<char *>(dataSrc);
ByteOutputItr out((uint8_t *) dst, chunkSize-1);
uint32_t i;
uint32_t bucketSize = (_bitmapElements + 7) >> 3;
uint32_t bucketCount = 0;
std::string key;
clearBitmapCache();
// make the key of our hash a string so that
// we can compare variable-length element sizes
size_t bitmapEntryLength = bucketSize + _elementSize;
assert(bitmapEntryLength);
uint32_t maxBuckets = floor(chunkSize / bitmapEntryLength);
if(maxBuckets * bitmapEntryLength == chunkSize)
{
// we want to beat the uncompressed case
--maxBuckets;
}
for(i = 0; i < _bitmapElements; ++i)
{
key.clear();
for(uint32_t j = 0; j < _elementSize; ++j)
{
key.push_back(*readPos);
++readPos;
}
uint8_t *bucket = NULL;
// check to see if a bucket exists, if so grab and pass on
std::map<std::string, uint8_t*>::iterator iter =
_bitmaps.find(key);
if(iter == _bitmaps.end() ) {
++bucketCount;
if(bucketCount > maxBuckets)
{
return chunkSize;
}
// create a new one
bucket = new uint8_t[bucketSize];
_bitmaps[key] = bucket;
for(uint32_t k = 0; k < bucketSize; ++k) { *(bucket+k) = 0;}
} else {
bucket = iter->second;
}
assert(bucket!=NULL);
setBit(bucket, i);
}
// drop all of bitmaps to dst
fillOutput(&out);
size_t compressedSize = out.close();
return compressedSize;
}
TextRendererPrivate::~TextRendererPrivate()
{
clearUsedTextures();
clearBitmapCache();
}
