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Diffstat (limited to 'doc/crypto/BIO_f_buffer.pod')
-rw-r--r-- | doc/crypto/BIO_f_buffer.pod | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/doc/crypto/BIO_f_buffer.pod b/doc/crypto/BIO_f_buffer.pod new file mode 100644 index 0000000..c9093c6 --- /dev/null +++ b/doc/crypto/BIO_f_buffer.pod @@ -0,0 +1,69 @@ +=pod + +=head1 NAME + +BIO_f_buffer - buffering BIO + +=head1 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) + +=head1 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 B<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 B<num> +bytes of B<buf>. If B<num> is larger than the current buffer size the buffer +is expanded. + +=head1 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. + +=head1 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. + +=head1 SEE ALSO + +TBA |