Package Orastream for XML C APIs

5 Package Orastream for XML C APIs

Orastream APIs support handling of text and binary nodes that exceed 64K in an XML document.

The data types used by Orastream are found in Datatypes for C; they include oracheck, oraerr, oraprop_id, oramemctx, oraprop, oraprop_t, oraprop_v, orastream, and orastreamhdl.

The error codes for the Orastream interfaces are described in Table 5-1.

Table 5-1 Orastream Error Codes for XML C Implementation

Error Code	Description
`ORASTREAM_ERR_NULL_POINTER`	Null pointer encountered.
`ORASTREAM_ERR_BAD_STREAM`	Invalid stream object.
`ORASTREAM_ERR_WRONG_DIRECTION`	Stream object is defined for the opposite I/O direction.
`ORASTREAM_ERR_UNKNOWN_PROPERTY`	Unknown creation property.
`ORASTREAM_ERR_NO_DIRECTION`	The I/O direction of the stream is undefined.
`ORASTREAM_ERR_BI_DIRECTION`	The stream direction is incorrectly defined as using both I/O directions.
`ORASTREAM_ERR_NOT_OPEN`	The stream is not open.
`ORASTREAM_ERR_WRONG_MODE`	The stream is defined for the opposite char/byte mode.
`ORASTREAM_ERR_CANT_OPEN`	The stream cannot be opened.
`ORASTREAM_ERR_CANT_CLOSE`	The stream cannot be closed.

The Orastream methods, listed in the following table, support unidirectional streams used to move data piecewise. The direction and mode of the stream is determined by the paramters that initialize the stream in the OraStreamInit() method.

Table 5-2 Summary of OraStream Methods for XML C Implementation

Function	Summary
OraStreamClose()	Closes the stream.
OraStreamHandle()	Returns the handle to the stream.
OraStreamInit()	Initializes the stream.
OraStreamIsOpen()	Determines if the stream is open.
OraStreamOpen()	Opens the stream.
OraStreamRead()	Reads bytes from the stream.
OraStreamReadable()	Determines if the stream is readable.
OraStreamReadChar()	Reads characters from the stream.
OraStreamSid()	Sets the SID of a stream.
OraStreamTerm()	Destroys the stream.
OraStreamWrite()	Writes bytes to the stream.
OraStreamWritable()	Determines if the stream is writable.
OraStreamWriteChar()	Writes characters to the stream.

OraStreamClose()

Closes the orastream object.

The function is used to close the given stream by calling the 'close' callback function of the stream.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamClose(
  orastream *stream);

Parameter	In/Out	Description
stream	IN	Stream that is closed

OraStreamHandle()

Returns the handle of the orastream object.

The handle contains the generic pointers and file descriptors.

Syntax

orastreamhdl *OraStreamHandle(
  orastream *stream);

Parameter	In/Out	Description
stream	IN	Stream whose handle is returned

OraStreamInit()

Creates and initializes a orastream object.

Syntax

orastream *OraStreamInit(
  void *sctx,
  void *sid,
  oraerr *err,
  list);

Parameter	In/Out	Description
sctx	IN	The input context; may be `NULL`
sid	IN	The user-defined stream context identifier
err	OUT	The error, if any. `ORAERR_OK` for success, or the error code for failure.
list	IN	`NULL`-terminated list of name-value pairs of arguments that specify the properties of the new `orastream` oject. These are: The `open` property name is for the open function, and its value follows. ORASTREAM_OPEN_F((), sctx, sid, hdl, length) The `close` property name is for the close function, and its value follows. ORASTREAM_CLOSE_F((), sctx, sid, hdl) The `read` property name is for reading byte data from the stream to the buffer. Note that `nread` returns the number of bytes actually read. ORASTREAM_READ_F((), sctx, sid, hdl, dest, size, start, nread, eoi) The `write` property name is for writing byte data from the buffer to the stream. Note that `written` returns the number of bytes actually written. ORASTREAM_WRITE_F((), sctx, sid, hdl, src, size, written) The `read_char` property name is for reading character data from the stream to the buffer. Note that `nread` returns the number of characters actually read. ORASTREAM_READ_F((), sctx, sid, hdl, dest, size, start, nread, eoi) The `write_char` property name is for writing character data from the buffer to the stream. Note that `written` returns the number of characters actually written. ORASTREAM_WRITE_F((), sctx, sid, hdl, src, size, written)

OraStreamIsOpen()

Determines if the orastream is open. Returns TRUE or FALSE.

Note that the stream must be open to perform read and write operations.

Syntax

boolean OraStreamIsOpen(
  orastream *stream);

Parameter	In/Out	Description
stream	IN	The stream that should be open for reads or writes.

OraStreamOpen()

Opens the orastream object.

The function opens the stream by calling the 'open' callback function of the stream.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamOpen(
  orastream *stream,
  ubig_ora *length)

Parameter	In/Out	Description
stream	IN	The stream that is open
length	OUT	Optional parameter; not used

OraStreamRead()

Reads bytes from the orastream object.

The function is used to read the data from the stream into the specified buffer. It also returns TRUE for the eoi parameter if the end of stream is reached.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamRead(
  orastream *stream,
  oratext *dest,
  ubig_ora size,
  oratext **start,
  ubig_ora *nread,
  ub1 *eoi);

Parameter	In/Out	Description
stream	IN	Stream that is being read
dest	IN	The destination buffer
size	IN	The size of the data to be read
start	OUT	Pointer to the start of data being read
nread	OUT	Number of bytes actually read from the stream
eoi	OUT	Returns `TRUE` if end of the stream is reached; `FALSE` otherwise

OraStreamReadable()

Determines if an existing orastream object is readable.

Returns TRUE or FALSE.

Syntax

boolean OraStreamReadable(
  orastream *stream);

Parameter	In/Out	Description
stream	IN	Stream that is checked for readability

OraStreamReadChar()

Reads chars from the orastream object.

The function is used to read the data from the stream into the specified buffer. It also returns TRUE for the eoi parameter if the end of stream is reached.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamReadChar(
  orastream *stream,
  oratext *dest, 
  ubig_ora size,
  oratext **start, 
  ubig_ora *nread, 
  ub1 *eoi);

Parameter	In/Out	Description
stream	IN	Stream that is being read
dest	IN	The destination buffer
size	IN	The size of the data to be read
start	OUT	Pointer to the start of data being read
nread	OUT	Number of characters actually read from the stream
eoi	OUT	Returns `TRUE` if end of the stream is reached; `FALSE` otherwise

OraStreamSid()

Assigns an SID to an existing orastream object. Returns the old SID through the OUT parameter osid.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamSid(
  orastream *stream,
  void *sid,
  void **osid);

Parameter	In/Out	Description
stream	IN	The stream whose SID is changed
sid	IN	The new SID
osid	OUT	The previous SID of the stream

OraStreamTerm()

Destroys a orastream object and frees its associated memory.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamTerm(
  orastream *stream);

Parameter	In/Out	Description
stream	IN	Stream that is destroyed

OraStreamWrite()

Writes bytes to the orastream object.

The number of bytes actually read are stored by the OUT parameter nwrote.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamWrite(
  orastream *stream, 
  oratext *src, 
  ubig_ora size,
  ubig_ora *nwrote);

Parameter	In/Out	Description
stream	IN	Stream where the data is written
src	IN	Buffer from which the data is written
size	IN	Size of data to be written
nwrote	OUT	Number of bytes written to the stream

OraStreamWritable()

Determines if an existing orastream object is writable.

Returns TRUE or FALSE.

Syntax

boolean OraStreamWritable(
  orastream *stream);

Parameter	In/Out	Description
stream	IN	Stream that is checked for writability.

OraStreamWriteChar()

Writes chars to the orastream object.

The number of characters actually written are stored by the OUT parameter nwrote.

Returns ORAERR_OK for success, or the error code for failure.

Syntax

oraerr OraStreamWriteChar(
  orastream *stream, 
  oratext *src, 
  ubig_ora size,
  ubig_ora *nwrote);

Parameter	In/Out	Description
stream	IN	Stream where the data is written
src	IN	Buffer from which the data is written
size	IN	Size of data to be written
nwrote	OUT	Number of characters written to the stream