#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)
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 4096. Any attempt to reduce the buffer size below DEFAULT_BUFFER_SIZE is ignored. Any buffered data is cleared when the buffer is resized.
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.
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.