NAME
BIO_f_buffer — buffering BIO
Synopsis
#include <openssl/bio.h>
BIO_METHOD
* BIO_f_buffer(void);
#define BIO_get_buffer_num_lines(b) BIO_ctrl(b,BIO_C_GET_BUFF_NUM_LINES,0,NULL)
#define
BIO_set_read_buffer_size(b,size)
BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,0)
#define
BIO_set_write_buffer_size(b,size)
BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,1)
#define
BIO_set_buffer_size(b,size) BIO_ctrl(b,BIO_C_SET_BUFF_SIZE,size,NULL)
#define
BIO_set_buffer_read_data(b,buf,num)
BIO_ctrl(b,BIO_C_SET_BUFF_READ_DATA,num,buf)
DESCRIPTION
BIO_f_buffer() returns the buffering BIO method.
Data written to a buffering BIO is buffered and periodically
written to the next BIO in the chain. Data read from a buffering
BIO comes from an internal buffer which is filled from the next
BIO in the chain. Both BIO_gets() and BIO_puts() are supported.
Calling BIO_reset() on a buffering BIO clears any buffered
data.
BIO_get_buffer_num_lines() returns the number of lines currently
buffered.
BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and
BIO_set_buffer_size() set the read, write or both read and write
buffer sizes to size. The initial buffer size
is DEFAULT_BUFFER_SIZE, currently 1024. Any attempt to reduce the
buffer size below DEFAULT_BUFFER_SIZE is ignored. Any buffered data
is cleared when the buffer is resized.
BIO_set_buffer_read_data() clears the read buffer and fills
it with num bytes of buf.
If num is larger than the current buffer size
the buffer is expanded.
NOTES
Buffering BIOs implement BIO_gets() by using BIO_read() operations
on the next BIO in the chain. By prepending a buffering BIO to a
chain it is therefore possible to provide BIO_gets() functionality
if the following BIOs do not support it (for example SSL BIOs).
Data is only written to the next BIO in the chain when the
write buffer fills or when BIO_flush() is called. It is therefore
important to call BIO_flush() whenever any pending data should be
written such as when removing a buffering BIO using BIO_pop(). BIO_flush()
may need to be retried if the ultimate source/sink BIO is non blocking.
RETURN VALUES
BIO_f_buffer() returns the buffering BIO method.
BIO_get_buffer_num_lines() returns the number of lines buffered
(may be 0).
BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and
BIO_set_buffer_size() return 1 if the buffer was successfully resized
or 0 for failure.
BIO_set_buffer_read_data() returns 1 if the data was set correctly
or 0 if there was an error.
