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#ifndef UTIL_FILE_PIECE__
#define UTIL_FILE_PIECE__
#include "util/ersatz_progress.hh"
#include "util/exception.hh"
#include "util/mmap.hh"
#include "util/scoped.hh"
#include "util/string_piece.hh"
#include <string>
#include <cstddef>
namespace util {
class EndOfFileException : public Exception {
public:
EndOfFileException() throw();
~EndOfFileException() throw();
};
class ParseNumberException : public Exception {
public:
explicit ParseNumberException(StringPiece value) throw();
~ParseNumberException() throw() {}
};
int OpenReadOrThrow(const char *name);
// Return value for SizeFile when it can't size properly.
const off_t kBadSize = -1;
off_t SizeFile(int fd);
class FilePiece {
public:
// 32 MB default.
explicit FilePiece(const char *file, std::ostream *show_progress = NULL, off_t min_buffer = 33554432);
// Takes ownership of fd. name is used for messages.
explicit FilePiece(const char *name, int fd, std::ostream *show_progress = NULL, off_t min_buffer = 33554432);
char get() throw(EndOfFileException) {
if (position_ == position_end_) Shift();
return *(position_++);
}
// Memory backing the returned StringPiece may vanish on the next call.
// Leaves the delimiter, if any, to be returned by get().
StringPiece ReadDelimited() throw(EndOfFileException) {
SkipSpaces();
return Consume(FindDelimiterOrEOF());
}
// Unlike ReadDelimited, this includes leading spaces and consumes the delimiter.
// It is similar to getline in that way.
StringPiece ReadLine(char delim = '\n') throw(EndOfFileException);
float ReadFloat() throw(EndOfFileException, ParseNumberException);
void SkipSpaces() throw (EndOfFileException);
off_t Offset() const {
return position_ - data_.begin() + mapped_offset_;
}
// Only for testing.
void ForceFallbackToRead() {
fallback_to_read_ = true;
}
private:
void Initialize(const char *name, std::ostream *show_progress, off_t min_buffer);
StringPiece Consume(const char *to) {
StringPiece ret(position_, to - position_);
position_ = to;
return ret;
}
const char *FindDelimiterOrEOF() throw(EndOfFileException);
void Shift() throw (EndOfFileException);
// Backends to Shift().
void MMapShift(off_t desired_begin) throw ();
void ReadShift(off_t desired_begin) throw ();
const char *position_, *last_space_, *position_end_;
scoped_fd file_;
const off_t total_size_;
const off_t page_;
size_t default_map_size_;
off_t mapped_offset_;
// Order matters: file_ should always be destroyed after this.
scoped_memory data_;
bool at_end_;
bool fallback_to_read_;
ErsatzProgress progress_;
};
} // namespace util
#endif // UTIL_FILE_PIECE__
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