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#ifndef TENSORFLOW_LIB_IO_INPUTBUFFER_H_
#define TENSORFLOW_LIB_IO_INPUTBUFFER_H_
#include <string>
#include "tensorflow/core/public/env.h"
#include "tensorflow/core/platform/port.h"
#include "tensorflow/core/public/status.h"
namespace tensorflow {
namespace io {
// An InputBuffer provides a buffer on top of a RandomAccessFile.
// A given instance of an InputBuffer is NOT safe for concurrent use
// by multiple threads
class InputBuffer {
public:
// Create an InputBuffer for "file" with a buffer size of
// "buffer_bytes" bytes. Takes ownership of "file" and will
// delete it when the InputBuffer is destroyed.
InputBuffer(RandomAccessFile* file, size_t buffer_bytes);
~InputBuffer();
// Read one text line of data into "*result" until end-of-file or a
// \n is read. (The \n is not included in the result.) Overwrites
// any existing data in *result.
//
// If successful, returns OK. If we are already at the end of the
// file, we return an OUT_OF_RANGE error. Otherwise, we return
// some other non-OK status.
Status ReadLine(string* result);
// Reads bytes_to_read bytes into *result, overwriting *result.
//
// If successful, returns OK. If we there are not enough bytes to
// read before the end of the file, we return an OUT_OF_RANGE error.
// Otherwise, we return some other non-OK status.
Status ReadNBytes(int64 bytes_to_read, string* result);
// Like ReadNBytes() without returning the bytes read.
Status SkipNBytes(int64 bytes_to_skip);
// Returns the position in the file.
int64 Tell() const { return file_pos_ - (limit_ - pos_); }
private:
Status FillBuffer();
RandomAccessFile* file_; // Owned
int64 file_pos_; // Next position to read from in "file_"
size_t size_; // Size of "buf_"
char* buf_; // The buffer itself
// [pos_,limit_) hold the "limit_ - pos_" bytes just before "file_pos_"
char* pos_; // Current position in "buf"
char* limit_; // Just past end of valid data in "buf"
TF_DISALLOW_COPY_AND_ASSIGN(InputBuffer);
};
} // namespace io
} // namespace tensorflow
#endif // TENSORFLOW_LIB_IO_INPUTBUFFER_H_
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