QGIS/external/lazperf/detail/field_byte10.cpp
2022-03-11 17:20:16 +01:00

109 lines
2.6 KiB
C++

/*
===============================================================================
PROGRAMMERS:
martin.isenburg@rapidlasso.com - http://rapidlasso.com
uday.karan@gmail.com - Hobu, Inc.
andrew.bell.ia@gmail.com - Hobu Inc.
COPYRIGHT:
(c) 2007-2014, martin isenburg, rapidlasso - tools to catch reality
(c) 2014, Uday Verma, Hobu, Inc.
This is free software; you can redistribute and/or modify it under the
terms of the GNU Lesser General Licence as published by the Free Software
Foundation. See the COPYING file for more information.
This software is distributed WITHOUT ANY WARRANTY and without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
CHANGE HISTORY:
===============================================================================
*/
#include "../las.hpp"
#include <deque>
namespace lazperf
{
namespace detail
{
Byte10Base::Byte10Base(size_t count) : count_(count), have_last_(false),
lasts_(count), diffs_(count), models_(count, models::arithmetic(256))
{}
// COMPRESSOR
Byte10Compressor::Byte10Compressor(encoders::arithmetic<OutCbStream>& encoder, size_t count) :
Byte10Base(count), enc_(encoder)
{}
const char *Byte10Compressor::compress(const char *buf)
{
if (count_ == 0)
return buf;
auto li = lasts_.begin();
auto di = diffs_.begin();
while (di != diffs_.end())
{
*di = *buf - *li;
*li = *buf;
di++; buf++; li++;
}
if (!have_last_)
{
enc_.getOutStream().putBytes(lasts_.data(), count_);
have_last_ = true;
}
else
{
di = diffs_.begin();
auto mi = models_.begin();
while (di != diffs_.end())
enc_.encodeSymbol(*mi++, *di++);
}
return buf;
}
// DECOMPRESSOR
Byte10Decompressor::Byte10Decompressor(decoders::arithmetic<InCbStream>& decoder, size_t count) :
Byte10Base(count), dec_(decoder)
{}
char *Byte10Decompressor::decompress(char *buf)
{
if (count_ == 0)
return buf;
if (!have_last_)
{
dec_.getInStream().getBytes((unsigned char *)buf, count_);
std::copy(buf, buf + count_, lasts_.data());
have_last_ = true;
return buf + count_;
}
// Use the diff vector for our current values.
auto& curs = diffs_;
auto ci = curs.begin();
auto li = lasts_.begin();
auto mi = models_.begin();
while (li != lasts_.end())
{
*ci = (uint8_t)(*li + dec_.decodeSymbol(*mi));
*li = *buf = *ci;
li++; buf++; ci++; mi++;
}
return buf;
}
} // namespace detail
} // namespace lazperf