diff options
Diffstat (limited to 'src/google/protobuf/io/zero_copy_stream_impl.h')
-rw-r--r-- | src/google/protobuf/io/zero_copy_stream_impl.h | 280 |
1 files changed, 1 insertions, 279 deletions
diff --git a/src/google/protobuf/io/zero_copy_stream_impl.h b/src/google/protobuf/io/zero_copy_stream_impl.h index 448aa216..d7cf73ff 100644 --- a/src/google/protobuf/io/zero_copy_stream_impl.h +++ b/src/google/protobuf/io/zero_copy_stream_impl.h @@ -45,6 +45,7 @@ #include <string> #include <iosfwd> #include <google/protobuf/io/zero_copy_stream.h> +#include <google/protobuf/io/zero_copy_stream_impl_lite.h> #include <google/protobuf/stubs/common.h> @@ -52,285 +53,6 @@ namespace google { namespace protobuf { namespace io { -// =================================================================== - -// A ZeroCopyInputStream backed by an in-memory array of bytes. -class LIBPROTOBUF_EXPORT ArrayInputStream : public ZeroCopyInputStream { - public: - // Create an InputStream that returns the bytes pointed to by "data". - // "data" remains the property of the caller but must remain valid until - // the stream is destroyed. If a block_size is given, calls to Next() - // will return data blocks no larger than the given size. Otherwise, the - // first call to Next() returns the entire array. block_size is mainly - // useful for testing; in production you would probably never want to set - // it. - ArrayInputStream(const void* data, int size, int block_size = -1); - ~ArrayInputStream(); - - // implements ZeroCopyInputStream ---------------------------------- - bool Next(const void** data, int* size); - void BackUp(int count); - bool Skip(int count); - int64 ByteCount() const; - - - private: - const uint8* const data_; // The byte array. - const int size_; // Total size of the array. - const int block_size_; // How many bytes to return at a time. - - int position_; - int last_returned_size_; // How many bytes we returned last time Next() - // was called (used for error checking only). - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ArrayInputStream); -}; - -// =================================================================== - -// A ZeroCopyOutputStream backed by an in-memory array of bytes. -class LIBPROTOBUF_EXPORT ArrayOutputStream : public ZeroCopyOutputStream { - public: - // Create an OutputStream that writes to the bytes pointed to by "data". - // "data" remains the property of the caller but must remain valid until - // the stream is destroyed. If a block_size is given, calls to Next() - // will return data blocks no larger than the given size. Otherwise, the - // first call to Next() returns the entire array. block_size is mainly - // useful for testing; in production you would probably never want to set - // it. - ArrayOutputStream(void* data, int size, int block_size = -1); - ~ArrayOutputStream(); - - // implements ZeroCopyOutputStream --------------------------------- - bool Next(void** data, int* size); - void BackUp(int count); - int64 ByteCount() const; - - private: - uint8* const data_; // The byte array. - const int size_; // Total size of the array. - const int block_size_; // How many bytes to return at a time. - - int position_; - int last_returned_size_; // How many bytes we returned last time Next() - // was called (used for error checking only). - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ArrayOutputStream); -}; - -// =================================================================== - -// A ZeroCopyOutputStream which appends bytes to a string. -class LIBPROTOBUF_EXPORT StringOutputStream : public ZeroCopyOutputStream { - public: - // Create a StringOutputStream which appends bytes to the given string. - // The string remains property of the caller, but it MUST NOT be accessed - // in any way until the stream is destroyed. - // - // Hint: If you call target->reserve(n) before creating the stream, - // the first call to Next() will return at least n bytes of buffer - // space. - explicit StringOutputStream(string* target); - ~StringOutputStream(); - - // implements ZeroCopyOutputStream --------------------------------- - bool Next(void** data, int* size); - void BackUp(int count); - int64 ByteCount() const; - - private: - static const int kMinimumSize = 16; - - string* target_; - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(StringOutputStream); -}; - -// Note: There is no StringInputStream. Instead, just create an -// ArrayInputStream as follows: -// ArrayInputStream input(str.data(), str.size()); - -// =================================================================== - - -// =================================================================== - -// A generic traditional input stream interface. -// -// Lots of traditional input streams (e.g. file descriptors, C stdio -// streams, and C++ iostreams) expose an interface where every read -// involves copying bytes into a buffer. If you want to take such an -// interface and make a ZeroCopyInputStream based on it, simply implement -// CopyingInputStream and then use CopyingInputStreamAdaptor. -// -// CopyingInputStream implementations should avoid buffering if possible. -// CopyingInputStreamAdaptor does its own buffering and will read data -// in large blocks. -class LIBPROTOBUF_EXPORT CopyingInputStream { - public: - virtual ~CopyingInputStream(); - - // Reads up to "size" bytes into the given buffer. Returns the number of - // bytes read. Read() waits until at least one byte is available, or - // returns zero if no bytes will ever become available (EOF), or -1 if a - // permanent read error occurred. - virtual int Read(void* buffer, int size) = 0; - - // Skips the next "count" bytes of input. Returns the number of bytes - // actually skipped. This will always be exactly equal to "count" unless - // EOF was reached or a permanent read error occurred. - // - // The default implementation just repeatedly calls Read() into a scratch - // buffer. - virtual int Skip(int count); -}; - -// A ZeroCopyInputStream which reads from a CopyingInputStream. This is -// useful for implementing ZeroCopyInputStreams that read from traditional -// streams. Note that this class is not really zero-copy. -// -// If you want to read from file descriptors or C++ istreams, this is -// already implemented for you: use FileInputStream or IstreamInputStream -// respectively. -class LIBPROTOBUF_EXPORT CopyingInputStreamAdaptor : public ZeroCopyInputStream { - public: - // Creates a stream that reads from the given CopyingInputStream. - // If a block_size is given, it specifies the number of bytes that - // should be read and returned with each call to Next(). Otherwise, - // a reasonable default is used. The caller retains ownership of - // copying_stream unless SetOwnsCopyingStream(true) is called. - explicit CopyingInputStreamAdaptor(CopyingInputStream* copying_stream, - int block_size = -1); - ~CopyingInputStreamAdaptor(); - - // Call SetOwnsCopyingStream(true) to tell the CopyingInputStreamAdaptor to - // delete the underlying CopyingInputStream when it is destroyed. - void SetOwnsCopyingStream(bool value) { owns_copying_stream_ = value; } - - // implements ZeroCopyInputStream ---------------------------------- - bool Next(const void** data, int* size); - void BackUp(int count); - bool Skip(int count); - int64 ByteCount() const; - - private: - // Insures that buffer_ is not NULL. - void AllocateBufferIfNeeded(); - // Frees the buffer and resets buffer_used_. - void FreeBuffer(); - - // The underlying copying stream. - CopyingInputStream* copying_stream_; - bool owns_copying_stream_; - - // True if we have seen a permenant error from the underlying stream. - bool failed_; - - // The current position of copying_stream_, relative to the point where - // we started reading. - int64 position_; - - // Data is read into this buffer. It may be NULL if no buffer is currently - // in use. Otherwise, it points to an array of size buffer_size_. - scoped_array<uint8> buffer_; - const int buffer_size_; - - // Number of valid bytes currently in the buffer (i.e. the size last - // returned by Next()). 0 <= buffer_used_ <= buffer_size_. - int buffer_used_; - - // Number of bytes in the buffer which were backed up over by a call to - // BackUp(). These need to be returned again. - // 0 <= backup_bytes_ <= buffer_used_ - int backup_bytes_; - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingInputStreamAdaptor); -}; - -// =================================================================== - -// A generic traditional output stream interface. -// -// Lots of traditional output streams (e.g. file descriptors, C stdio -// streams, and C++ iostreams) expose an interface where every write -// involves copying bytes from a buffer. If you want to take such an -// interface and make a ZeroCopyOutputStream based on it, simply implement -// CopyingOutputStream and then use CopyingOutputStreamAdaptor. -// -// CopyingOutputStream implementations should avoid buffering if possible. -// CopyingOutputStreamAdaptor does its own buffering and will write data -// in large blocks. -class LIBPROTOBUF_EXPORT CopyingOutputStream { - public: - virtual ~CopyingOutputStream(); - - // Writes "size" bytes from the given buffer to the output. Returns true - // if successful, false on a write error. - virtual bool Write(const void* buffer, int size) = 0; -}; - -// A ZeroCopyOutputStream which writes to a CopyingOutputStream. This is -// useful for implementing ZeroCopyOutputStreams that write to traditional -// streams. Note that this class is not really zero-copy. -// -// If you want to write to file descriptors or C++ ostreams, this is -// already implemented for you: use FileOutputStream or OstreamOutputStream -// respectively. -class LIBPROTOBUF_EXPORT CopyingOutputStreamAdaptor : public ZeroCopyOutputStream { - public: - // Creates a stream that writes to the given Unix file descriptor. - // If a block_size is given, it specifies the size of the buffers - // that should be returned by Next(). Otherwise, a reasonable default - // is used. - explicit CopyingOutputStreamAdaptor(CopyingOutputStream* copying_stream, - int block_size = -1); - ~CopyingOutputStreamAdaptor(); - - // Writes all pending data to the underlying stream. Returns false if a - // write error occurred on the underlying stream. (The underlying - // stream itself is not necessarily flushed.) - bool Flush(); - - // Call SetOwnsCopyingStream(true) to tell the CopyingOutputStreamAdaptor to - // delete the underlying CopyingOutputStream when it is destroyed. - void SetOwnsCopyingStream(bool value) { owns_copying_stream_ = value; } - - // implements ZeroCopyOutputStream --------------------------------- - bool Next(void** data, int* size); - void BackUp(int count); - int64 ByteCount() const; - - private: - // Write the current buffer, if it is present. - bool WriteBuffer(); - // Insures that buffer_ is not NULL. - void AllocateBufferIfNeeded(); - // Frees the buffer. - void FreeBuffer(); - - // The underlying copying stream. - CopyingOutputStream* copying_stream_; - bool owns_copying_stream_; - - // True if we have seen a permenant error from the underlying stream. - bool failed_; - - // The current position of copying_stream_, relative to the point where - // we started writing. - int64 position_; - - // Data is written from this buffer. It may be NULL if no buffer is - // currently in use. Otherwise, it points to an array of size buffer_size_. - scoped_array<uint8> buffer_; - const int buffer_size_; - - // Number of valid bytes currently in the buffer (i.e. the size last - // returned by Next()). When BackUp() is called, we just reduce this. - // 0 <= buffer_used_ <= buffer_size_. - int buffer_used_; - - GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(CopyingOutputStreamAdaptor); -}; // =================================================================== |