#ifndef UTIL_FILE_PIECE__ #define UTIL_FILE_PIECE__ #include "util/ersatz_progress.hh" #include "util/exception.hh" #include "util/file.hh" #include "util/mmap.hh" #include "util/read_compressed.hh" #include "util/string_piece.hh" #include <cstddef> #include <iosfwd> #include <string> #include <assert.h> #include <stdint.h> namespace util { class ParseNumberException : public Exception { public: explicit ParseNumberException(StringPiece value) throw(); ~ParseNumberException() throw() {} }; extern const bool kSpaces[256]; // Memory backing the returned StringPiece may vanish on the next call. class FilePiece { public: // 1 MB default. explicit FilePiece(const char *file, std::ostream *show_progress = NULL, std::size_t min_buffer = 1048576); // Takes ownership of fd. name is used for messages. explicit FilePiece(int fd, const char *name = NULL, std::ostream *show_progress = NULL, std::size_t min_buffer = 1048576); /* Read from an istream. Don't use this if you can avoid it. Raw fd IO is * much faster. But sometimes you just have an istream like Boost's HTTP * server and want to parse it the same way. * name is just used for messages and FileName(). */ explicit FilePiece(std::istream &stream, const char *name = NULL, std::size_t min_buffer = 1048576); ~FilePiece(); char get() { if (position_ == position_end_) { Shift(); if (at_end_) throw EndOfFileException(); } return *(position_++); } // Leaves the delimiter, if any, to be returned by get(). Delimiters defined by isspace(). StringPiece ReadDelimited(const bool *delim = kSpaces) { SkipSpaces(delim); return Consume(FindDelimiterOrEOF(delim)); } // Unlike ReadDelimited, this includes leading spaces and consumes the delimiter. // It is similar to getline in that way. StringPiece ReadLine(char delim = '\n'); float ReadFloat(); double ReadDouble(); long int ReadLong(); unsigned long int ReadULong(); // Skip spaces defined by isspace. void SkipSpaces(const bool *delim = kSpaces) { assert(position_ <= position_end_); for (; ; ++position_) { if (position_ == position_end_) { Shift(); // And break out at end of file. if (position_ == position_end_) return; } assert(position_ < position_end_); if (!delim[static_cast<unsigned char>(*position_)]) return; } } uint64_t Offset() const { return position_ - data_.begin() + mapped_offset_; } const std::string &FileName() const { return file_name_; } private: void InitializeNoRead(const char *name, std::size_t min_buffer); // Calls InitializeNoRead, so don't call both. void Initialize(const char *name, std::ostream *show_progress, std::size_t min_buffer); template <class T> T ReadNumber(); StringPiece Consume(const char *to) { assert(to >= position_); StringPiece ret(position_, to - position_); position_ = to; return ret; } const char *FindDelimiterOrEOF(const bool *delim = kSpaces); void Shift(); // Backends to Shift(). void MMapShift(uint64_t desired_begin); void TransitionToRead(); void ReadShift(); const char *position_, *last_space_, *position_end_; scoped_fd file_; const uint64_t total_size_; const uint64_t page_; std::size_t default_map_size_; uint64_t mapped_offset_; // Order matters: file_ should always be destroyed after this. scoped_memory data_; bool at_end_; bool fallback_to_read_; ErsatzProgress progress_; std::string file_name_; ReadCompressed fell_back_; }; } // namespace util #endif // UTIL_FILE_PIECE__