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#pragma once
#include "coding/point_to_integer.hpp"
#include "coding/reader.hpp"
#include "coding/varint.hpp"
#include "coding/writer.hpp"
#include "geometry/latlon.hpp"
#include "base/checked_cast.hpp"
#include "std/limits.hpp"
#include "std/vector.hpp"
namespace coding
{
class TrafficGPSEncoder
{
public:
static uint32_t const kLatestVersion;
static uint32_t const kCoordBits;
static double const kMinDeltaLat;
static double const kMaxDeltaLat;
static double const kMinDeltaLon;
static double const kMaxDeltaLon;
struct DataPoint
{
// TODO(@m): document the version format
DataPoint() = default;
DataPoint(uint64_t timestamp, ms::LatLon latLon, uint8_t traffic)
: m_timestamp(timestamp), m_latLon(latLon), m_traffic(traffic)
{
}
// Uint64 should be enough for all our use cases.
// It is expected that |m_timestamp| stores time since epoch in seconds.
uint64_t m_timestamp = 0;
ms::LatLon m_latLon = ms::LatLon::Zero();
// A pod type instead of the traffic::SpeedGroup enum
// so as not to introduce a cyclic dependency.
// This field was added in Version 1 (and was the only addition).
uint8_t m_traffic = 0;
bool operator==(DataPoint const & p) const
{
return m_timestamp == p.m_timestamp && m_latLon == p.m_latLon;
}
};
// Serializes |points| to |writer| by storing delta-encoded points.
// Returns the number of bytes written.
// Version 0:
// Coordinates are truncated and stored as integers. All integers
// are written as varints.
template <typename Writer, typename Collection>
static size_t SerializeDataPoints(uint32_t version, Writer & writer, Collection const & points)
{
switch (version)
{
case 0: return SerializeDataPointsV0(writer, points);
case 1: return SerializeDataPointsV1(writer, points);
default: ASSERT(false, ("Unexpected serializer version:", version)); break;
}
return 0;
}
// Deserializes the points from |source| and appends them to |result|.
template <typename Source, typename Collection>
static void DeserializeDataPoints(uint32_t version, Source & src, Collection & result)
{
switch (version)
{
case 0: return DeserializeDataPointsV0(src, result);
case 1: return DeserializeDataPointsV1(src, result);
default: ASSERT(false, ("Unexpected serializer version:", version)); break;
}
}
private:
template <typename Writer, typename Collection>
static size_t SerializeDataPointsV0(Writer & writer, Collection const & points)
{
auto const startPos = writer.Pos();
if (!points.empty())
{
uint64_t const firstTimestamp = points[0].m_timestamp;
uint32_t const firstLat = DoubleToUint32(points[0].m_latLon.lat, ms::LatLon::kMinLat,
ms::LatLon::kMaxLat, kCoordBits);
uint32_t const firstLon = DoubleToUint32(points[0].m_latLon.lon, ms::LatLon::kMinLon,
ms::LatLon::kMaxLon, kCoordBits);
WriteVarUint(writer, firstTimestamp);
WriteVarUint(writer, firstLat);
WriteVarUint(writer, firstLon);
}
for (size_t i = 1; i < points.size(); ++i)
{
ASSERT_LESS_OR_EQUAL(points[i - 1].m_timestamp, points[i].m_timestamp, ());
uint64_t const deltaTimestamp = points[i].m_timestamp - points[i - 1].m_timestamp;
uint32_t deltaLat = DoubleToUint32(points[i].m_latLon.lat - points[i - 1].m_latLon.lat,
kMinDeltaLat, kMaxDeltaLat, kCoordBits);
uint32_t deltaLon = DoubleToUint32(points[i].m_latLon.lon - points[i - 1].m_latLon.lon,
kMinDeltaLon, kMaxDeltaLon, kCoordBits);
WriteVarUint(writer, deltaTimestamp);
WriteVarUint(writer, deltaLat);
WriteVarUint(writer, deltaLon);
}
ASSERT_LESS_OR_EQUAL(writer.Pos() - startPos, numeric_limits<size_t>::max(),
("Too much data."));
return static_cast<size_t>(writer.Pos() - startPos);
}
template <typename Writer, typename Collection>
static size_t SerializeDataPointsV1(Writer & writer, Collection const & points)
{
auto const startPos = writer.Pos();
if (!points.empty())
{
uint64_t const firstTimestamp = points[0].m_timestamp;
uint32_t const firstLat = DoubleToUint32(points[0].m_latLon.lat, ms::LatLon::kMinLat,
ms::LatLon::kMaxLat, kCoordBits);
uint32_t const firstLon = DoubleToUint32(points[0].m_latLon.lon, ms::LatLon::kMinLon,
ms::LatLon::kMaxLon, kCoordBits);
uint32_t const traffic = points[0].m_traffic;
WriteVarUint(writer, firstTimestamp);
WriteVarUint(writer, firstLat);
WriteVarUint(writer, firstLon);
WriteVarUint(writer, traffic);
}
for (size_t i = 1; i < points.size(); ++i)
{
ASSERT_LESS_OR_EQUAL(points[i - 1].m_timestamp, points[i].m_timestamp, ());
uint64_t const deltaTimestamp = points[i].m_timestamp - points[i - 1].m_timestamp;
uint32_t deltaLat = DoubleToUint32(points[i].m_latLon.lat - points[i - 1].m_latLon.lat,
kMinDeltaLat, kMaxDeltaLat, kCoordBits);
uint32_t deltaLon = DoubleToUint32(points[i].m_latLon.lon - points[i - 1].m_latLon.lon,
kMinDeltaLon, kMaxDeltaLon, kCoordBits);
uint32_t const traffic = points[i - 1].m_traffic;
WriteVarUint(writer, deltaTimestamp);
WriteVarUint(writer, deltaLat);
WriteVarUint(writer, deltaLon);
WriteVarUint(writer, traffic);
}
ASSERT_LESS_OR_EQUAL(writer.Pos() - startPos, numeric_limits<size_t>::max(),
("Too much data."));
return static_cast<size_t>(writer.Pos() - startPos);
}
template <typename Source, typename Collection>
static void DeserializeDataPointsV0(Source & src, Collection & result)
{
bool first = true;
uint64_t lastTimestamp = 0;
double lastLat = 0.0;
double lastLon = 0.0;
uint8_t traffic = 0;
while (src.Size() > 0)
{
if (first)
{
lastTimestamp = ReadVarUint<uint64_t>(src);
lastLat = Uint32ToDouble(ReadVarUint<uint32_t>(src), ms::LatLon::kMinLat,
ms::LatLon::kMaxLat, kCoordBits);
lastLon = Uint32ToDouble(ReadVarUint<uint32_t>(src), ms::LatLon::kMinLon,
ms::LatLon::kMaxLon, kCoordBits);
result.emplace_back(lastTimestamp, ms::LatLon(lastLat, lastLon), traffic);
first = false;
}
else
{
lastTimestamp += ReadVarUint<uint64_t>(src);
lastLat +=
Uint32ToDouble(ReadVarUint<uint32_t>(src), kMinDeltaLat, kMaxDeltaLat, kCoordBits);
lastLon +=
Uint32ToDouble(ReadVarUint<uint32_t>(src), kMinDeltaLon, kMaxDeltaLon, kCoordBits);
result.emplace_back(lastTimestamp, ms::LatLon(lastLat, lastLon), traffic);
}
}
}
template <typename Source, typename Collection>
static void DeserializeDataPointsV1(Source & src, Collection & result)
{
bool first = true;
uint64_t lastTimestamp = 0;
double lastLat = 0.0;
double lastLon = 0.0;
uint8_t traffic = 0;
while (src.Size() > 0)
{
if (first)
{
lastTimestamp = ReadVarUint<uint64_t>(src);
lastLat = Uint32ToDouble(ReadVarUint<uint32_t>(src), ms::LatLon::kMinLat,
ms::LatLon::kMaxLat, kCoordBits);
lastLon = Uint32ToDouble(ReadVarUint<uint32_t>(src), ms::LatLon::kMinLon,
ms::LatLon::kMaxLon, kCoordBits);
traffic = base::asserted_cast<uint8_t>(ReadVarUint<uint32_t>(src));
result.emplace_back(lastTimestamp, ms::LatLon(lastLat, lastLon), traffic);
first = false;
}
else
{
lastTimestamp += ReadVarUint<uint64_t>(src);
lastLat +=
Uint32ToDouble(ReadVarUint<uint32_t>(src), kMinDeltaLat, kMaxDeltaLat, kCoordBits);
lastLon +=
Uint32ToDouble(ReadVarUint<uint32_t>(src), kMinDeltaLon, kMaxDeltaLon, kCoordBits);
traffic = base::asserted_cast<uint8_t>(ReadVarUint<uint32_t>(src));
result.emplace_back(lastTimestamp, ms::LatLon(lastLat, lastLon), traffic);
}
}
}
};
} // namespace coding
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