diff options
Diffstat (limited to 'src/libutil')
-rw-r--r-- | src/libutil/hash.cc | 2 | ||||
-rw-r--r-- | src/libutil/util.hh | 87 |
2 files changed, 88 insertions, 1 deletions
diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc index f447c80c5d81..a8bbcf8c1754 100644 --- a/src/libutil/hash.cc +++ b/src/libutil/hash.cc @@ -104,7 +104,7 @@ Hash parseHash(HashType ht, const string & s) string s2(s, i * 2, 2); if (!isxdigit(s2[0]) || !isxdigit(s2[1])) throw BadHash(format("invalid hash ‘%1%’") % s); - std::istringstream str(s2); + istringstream_nocopy str(s2); int n; str >> std::hex >> n; hash.hash[i] = n; diff --git a/src/libutil/util.hh b/src/libutil/util.hh index 2950f7daa5ec..7cb3e68b9ef1 100644 --- a/src/libutil/util.hh +++ b/src/libutil/util.hh @@ -449,4 +449,91 @@ struct ReceiveInterrupts }; +template <class CharT, class Traits = std::char_traits<CharT>, class Allocator = std::allocator<CharT>> +class basic_istringbuf_nocopy : public std::basic_streambuf<CharT, Traits> +{ +public: + typedef std::basic_string<CharT, Traits, Allocator> string_type; + + typedef typename std::basic_streambuf<CharT, Traits>::off_type off_type; + + typedef typename std::basic_streambuf<CharT, Traits>::pos_type pos_type; + + typedef typename std::basic_streambuf<CharT, Traits>::int_type int_type; + + typedef typename std::basic_streambuf<CharT, Traits>::traits_type traits_type; + +private: + const string_type & s; + + off_type off; + +public: + basic_istringbuf_nocopy(const string_type & s) : s{s}, off{0} + { + } + +private: + pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode which) + { + if (which & std::ios_base::in) { + this->off = dir == std::ios_base::beg + ? off + : (dir == std::ios_base::end + ? s.size() + off + : this->off + off); + } + return pos_type(this->off); + } + + pos_type seekpos(pos_type pos, std::ios_base::openmode which) + { + return seekoff(pos, std::ios_base::beg, which); + } + + std::streamsize showmanyc() + { + return s.size() - off; + } + + int_type underflow() + { + if (typename string_type::size_type(off) == s.size()) + return traits_type::eof(); + return traits_type::to_int_type(s[off]); + } + + int_type uflow() + { + if (typename string_type::size_type(off) == s.size()) + return traits_type::eof(); + return traits_type::to_int_type(s[off++]); + } + + int_type pbackfail(int_type ch) + { + if (off == 0 || (ch != traits_type::eof() && ch != s[off - 1])) + return traits_type::eof(); + + return traits_type::to_int_type(s[--off]); + } + +}; + +template <class CharT, class Traits = std::char_traits<CharT>, class Allocator = std::allocator<CharT>> +class basic_istringstream_nocopy : public std::basic_iostream<CharT, Traits> +{ + typedef basic_istringbuf_nocopy<CharT, Traits, Allocator> buf_type; + buf_type buf; +public: + basic_istringstream_nocopy(const typename buf_type::string_type & s) : + std::basic_iostream<CharT, Traits>(&buf), buf(s) {}; +}; + +/* A variant of std::istringstream that doesn't its string + argument. This is useful for large strings. The caller must ensure + that the string object is not destroyed while it's referenced by + this object. */ +typedef basic_istringstream_nocopy<char> istringstream_nocopy; + } |