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#include "TupleCodec.h"
#include <picosha2.h>
#include <algorithm>
#include <cstdint>
#include <cstring>
#include <numeric>
namespace nt::TupleCodec {
static std::vector<Attribute> Sorted(std::vector<Attribute> attrs) {
std::sort(attrs.begin(), attrs.end(),
[](const Attribute& a, const Attribute& b) { return a.name < b.name; });
return attrs;
}
std::string Hash(const std::vector<Attribute>& attrs) {
auto bytes = Serialize(attrs);
return picosha2::hash256_hex_string(bytes.begin(), bytes.end());
}
std::vector<uint8_t> Serialize(const std::vector<Attribute>& attrs) {
// Format: [uint32_le name_len][name][uint32_le value_len][value] ...
// Attributes are stored in sorted name order for determinism.
std::vector<uint8_t> out;
auto write_u32 = [&](uint32_t n) {
out.push_back(static_cast<uint8_t>(n));
out.push_back(static_cast<uint8_t>(n >> 8));
out.push_back(static_cast<uint8_t>(n >> 16));
out.push_back(static_cast<uint8_t>(n >> 24));
};
for (const auto& a : Sorted({attrs.begin(), attrs.end()})) {
write_u32(static_cast<uint32_t>(a.name.size()));
out.insert(out.end(), a.name.begin(), a.name.end());
write_u32(static_cast<uint32_t>(a.value.size()));
out.insert(out.end(), a.value.begin(), a.value.end());
}
return out;
}
std::vector<Attribute> Deserialize(const std::vector<uint8_t>& bytes) {
auto read_u32 = [&](size_t pos) -> uint32_t {
return static_cast<uint32_t>(bytes[pos]) |
(static_cast<uint32_t>(bytes[pos + 1]) << 8) |
(static_cast<uint32_t>(bytes[pos + 2]) << 16) |
(static_cast<uint32_t>(bytes[pos + 3]) << 24);
};
std::vector<Attribute> result;
size_t pos = 0;
while (pos + 8 <= bytes.size()) {
uint32_t name_len = read_u32(pos);
pos += 4;
std::string name(reinterpret_cast<const char*>(bytes.data() + pos), name_len);
pos += name_len;
uint32_t value_len = read_u32(pos);
pos += 4;
std::string value(reinterpret_cast<const char*>(bytes.data() + pos), value_len);
pos += value_len;
result.push_back({std::move(name), std::move(value)});
}
return result;
}
} // namespace nt::TupleCodec
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