Function strnlength

mlx/data/core/TARReader.cpp:12–15

namespace {
size_t strnlength(const char* s, size_t n) {
  const char* found = (const char*)std::memchr(s, '\0', n);
  return found ? (size_t)(found - s) : n;
}

size_t parse_payload_size(unsigned char* str, int len) {
  // "first bit set" means large file (GNU tar)