U32 LASreadPoint::search_chunk_table(const U32 index, const U32 lower, const U32 upper)
{
if (lower + 1 == upper) return lower;
U32 mid = (lower+upper)/2;
if (index >= chunk_totals[mid])
return search_chunk_table(index, mid, upper);
else
return search_chunk_table(index, lower, mid);
}
BOOL LASreadPoint::seek(const U32 current, const U32 target)
{
if (!instream->isSeekable()) return FALSE;
U32 delta = 0;
if (dec)
{
if (chunk_starts)
{
U32 target_chunk;
if (chunk_totals)
{
target_chunk = search_chunk_table(target, 0, number_chunks);
chunk_size = chunk_totals[target_chunk+1]-chunk_totals[target_chunk];
delta = target - chunk_totals[target_chunk];
}
else
{
target_chunk = target/chunk_size;
delta = target%chunk_size;
}
if (current_chunk != target_chunk || current > target)
{
dec->done();
current_chunk = target_chunk;
instream->seek(chunk_starts[current_chunk]);
init(instream);
chunk_count = 0;
}
else
{
delta = target - current;
}
}
else if (current > target)
{
dec->done();
instream->seek(point_start);
init(instream);
delta = target;
}
else if (current < target)
{
delta = target - current;
}
while (delta)
{
read(seek_point);
delta--;
}
}
else
{
if (current != target)
{
instream->seek(point_start+point_size*target);
}
}
return TRUE;
}
