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#pragma once
#include <cinttypes>
#include <numeric>
#include <vector>
#include "chunked-vector.hh"
#include "pos-idx.hh"
#include "position.hh"
#include "sync.hh"
namespace nix {
class PosTable
{
public:
class Origin
{
friend PosTable;
private:
uint32_t offset;
Origin(Pos::Origin origin, uint32_t offset, size_t size):
offset(offset), origin(origin), size(size)
{}
public:
const Pos::Origin origin;
const size_t size;
uint32_t offsetOf(PosIdx p) const
{
return p.id - 1 - offset;
}
};
private:
using Lines = std::vector<uint32_t>;
std::map<uint32_t, Origin> origins;
mutable Sync<std::map<uint32_t, Lines>> lines;
const Origin * resolve(PosIdx p) const
{
if (p.id == 0)
return nullptr;
const auto idx = p.id - 1;
/* we want the last key <= idx, so we'll take prev(first key > idx).
this is guaranteed to never rewind origin.begin because the first
key is always 0. */
const auto pastOrigin = origins.upper_bound(idx);
return &std::prev(pastOrigin)->second;
}
public:
Origin addOrigin(Pos::Origin origin, size_t size)
{
uint32_t offset = 0;
if (auto it = origins.rbegin(); it != origins.rend())
offset = it->first + it->second.size;
// +1 because all PosIdx are offset by 1 to begin with (because noPos == 0), and
// another +1 to ensure that all origins can point to EOF, eg on (invalid) empty inputs.
if (2 + offset + size < offset)
return Origin{origin, offset, 0};
return origins.emplace(offset, Origin{origin, offset, size}).first->second;
}
PosIdx add(const Origin & origin, size_t offset)
{
if (offset > origin.size)
return PosIdx();
return PosIdx(1 + origin.offset + offset);
}
Pos operator[](PosIdx p) const;
Pos::Origin originOf(PosIdx p) const
{
if (auto o = resolve(p))
return o->origin;
return std::monostate{};
}
};
}
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