#include <endian.h>
#include <algorithm>
#include <cstring>

#include "ffi_utils.h"

namespace starkware {

using ValueType = PrimeFieldElement::ValueType;

int HandleError(const char* msg, gsl::span<gsl::byte> out) {
  const size_t copy_len = std::min<size_t>(strlen(msg), out.size() - 1);
  memcpy(out.data(), msg, copy_len);
  memset(out.data() + copy_len, 0, out.size() - copy_len);
  return 1;
}

ValueType Deserialize(const gsl::span<const gsl::byte> span) {
  const size_t N = ValueType::LimbCount();
  ASSERT(span.size() == N * sizeof(uint64_t), "Source span size mismatches BigInt size.");
  std::array<uint64_t, N> value{};
  gsl::copy(span, gsl::byte_span(value));
  for (uint64_t& x : value) {
    x = le64toh(x);
  }
  return ValueType(value);
}

void Serialize(const ValueType& val, const gsl::span<gsl::byte> span_out) {
  const size_t N = ValueType::LimbCount();
  ASSERT(span_out.size() == N * sizeof(uint64_t), "Span size mismatches BigInt size.");
  for (size_t i = 0; i < N; ++i) {
    uint64_t limb = htole64(val[i]);
    gsl::copy(gsl::byte_span(limb), span_out.subspan(i * sizeof(uint64_t), sizeof(uint64_t)));
  }
}

}  // namespace starkware