1*2175Sjp161948=pod 2*2175Sjp161948 3*2175Sjp161948=head1 NAME 4*2175Sjp161948 5*2175Sjp161948BIO_f_buffer - buffering BIO 6*2175Sjp161948 7*2175Sjp161948=head1 SYNOPSIS 8*2175Sjp161948 9*2175Sjp161948 #include <openssl/bio.h> 10*2175Sjp161948 11*2175Sjp161948 BIO_METHOD * BIO_f_buffer(void); 12*2175Sjp161948 13*2175Sjp161948 #define BIO_get_buffer_num_lines(b) BIO_ctrl(b,BIO_C_GET_BUFF_NUM_LINES,0,NULL) 14*2175Sjp161948 #define BIO_set_read_buffer_size(b,size) BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,0) 15*2175Sjp161948 #define BIO_set_write_buffer_size(b,size) BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,1) 16*2175Sjp161948 #define BIO_set_buffer_size(b,size) BIO_ctrl(b,BIO_C_SET_BUFF_SIZE,size,NULL) 17*2175Sjp161948 #define BIO_set_buffer_read_data(b,buf,num) BIO_ctrl(b,BIO_C_SET_BUFF_READ_DATA,num,buf) 18*2175Sjp161948 19*2175Sjp161948=head1 DESCRIPTION 20*2175Sjp161948 21*2175Sjp161948BIO_f_buffer() returns the buffering BIO method. 22*2175Sjp161948 23*2175Sjp161948Data written to a buffering BIO is buffered and periodically written 24*2175Sjp161948to the next BIO in the chain. Data read from a buffering BIO comes from 25*2175Sjp161948an internal buffer which is filled from the next BIO in the chain. 26*2175Sjp161948Both BIO_gets() and BIO_puts() are supported. 27*2175Sjp161948 28*2175Sjp161948Calling BIO_reset() on a buffering BIO clears any buffered data. 29*2175Sjp161948 30*2175Sjp161948BIO_get_buffer_num_lines() returns the number of lines currently buffered. 31*2175Sjp161948 32*2175Sjp161948BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and BIO_set_buffer_size() 33*2175Sjp161948set the read, write or both read and write buffer sizes to B<size>. The initial 34*2175Sjp161948buffer size is DEFAULT_BUFFER_SIZE, currently 1024. Any attempt to reduce the 35*2175Sjp161948buffer size below DEFAULT_BUFFER_SIZE is ignored. Any buffered data is cleared 36*2175Sjp161948when the buffer is resized. 37*2175Sjp161948 38*2175Sjp161948BIO_set_buffer_read_data() clears the read buffer and fills it with B<num> 39*2175Sjp161948bytes of B<buf>. If B<num> is larger than the current buffer size the buffer 40*2175Sjp161948is expanded. 41*2175Sjp161948 42*2175Sjp161948=head1 NOTES 43*2175Sjp161948 44*2175Sjp161948Buffering BIOs implement BIO_gets() by using BIO_read() operations on the 45*2175Sjp161948next BIO in the chain. By prepending a buffering BIO to a chain it is therefore 46*2175Sjp161948possible to provide BIO_gets() functionality if the following BIOs do not 47*2175Sjp161948support it (for example SSL BIOs). 48*2175Sjp161948 49*2175Sjp161948Data is only written to the next BIO in the chain when the write buffer fills 50*2175Sjp161948or when BIO_flush() is called. It is therefore important to call BIO_flush() 51*2175Sjp161948whenever any pending data should be written such as when removing a buffering 52*2175Sjp161948BIO using BIO_pop(). BIO_flush() may need to be retried if the ultimate 53*2175Sjp161948source/sink BIO is non blocking. 54*2175Sjp161948 55*2175Sjp161948=head1 RETURN VALUES 56*2175Sjp161948 57*2175Sjp161948BIO_f_buffer() returns the buffering BIO method. 58*2175Sjp161948 59*2175Sjp161948BIO_get_buffer_num_lines() returns the number of lines buffered (may be 0). 60*2175Sjp161948 61*2175Sjp161948BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and BIO_set_buffer_size() 62*2175Sjp161948return 1 if the buffer was successfully resized or 0 for failure. 63*2175Sjp161948 64*2175Sjp161948BIO_set_buffer_read_data() returns 1 if the data was set correctly or 0 if 65*2175Sjp161948there was an error. 66*2175Sjp161948 67*2175Sjp161948=head1 SEE ALSO 68*2175Sjp161948 69*2175Sjp161948TBA 70