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Diffstat (limited to 'lib/libcrypto/man/BIO_f_buffer.3')
| -rw-r--r-- | lib/libcrypto/man/BIO_f_buffer.3 | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/lib/libcrypto/man/BIO_f_buffer.3 b/lib/libcrypto/man/BIO_f_buffer.3 new file mode 100644 index 00000000000..c01ab4809b1 --- /dev/null +++ b/lib/libcrypto/man/BIO_f_buffer.3 @@ -0,0 +1,110 @@ +.Dd July 17, 2014 +.Dt BIO_F_BUFFER 3 +.Os +.Sh NAME +.Nm BIO_f_buffer +.Nd buffering BIO +.Sh SYNOPSIS +.In openssl/bio.h +.Ft BIO_METHOD * +.Fo BIO_f_buffer +.Fa void +.Fc +.Bd -literal +#define BIO_get_buffer_num_lines(b) \e + BIO_ctrl(b,BIO_C_GET_BUFF_NUM_LINES,0,NULL) +#define BIO_set_read_buffer_size(b,size) \e + BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,0) +#define BIO_set_write_buffer_size(b,size) \e + BIO_int_ctrl(b,BIO_C_SET_BUFF_SIZE,size,1) +#define BIO_set_buffer_size(b,size) \e + BIO_ctrl(b,BIO_C_SET_BUFF_SIZE,size,NULL) +#define BIO_set_buffer_read_data(b,buf,num) \e + BIO_ctrl(b,BIO_C_SET_BUFF_READ_DATA,num,buf) +.Ed +.Sh DESCRIPTION +.Fn BIO_f_buffer +returns the buffering BIO method. +.Pp +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 +.Xr BIO_gets 3 +and +.Xr BIO_puts 3 +are supported. +.Pp +Calling +.Xr BIO_reset 3 +on a buffering BIO clears any buffered data. +.Pp +.Fn BIO_get_buffer_num_lines +returns the number of lines currently buffered. +.Pp +.Fn BIO_set_read_buffer_size , +.Fn BIO_set_write_buffer_size , +and +.Fn BIO_set_buffer_size +set the read, write or both read and write buffer sizes to +.Fa size . +The initial buffer size is +.Dv DEFAULT_BUFFER_SIZE , +currently 4096. +Any attempt to reduce the buffer size below +.Dv DEFAULT_BUFFER_SIZE +is ignored. +Any buffered data is cleared when the buffer is resized. +.Pp +.Fn BIO_set_buffer_read_data +clears the read buffer and fills it with +.Fa num +bytes of +.Fa buf . +If +.Fa num +is larger than the current buffer size the buffer is expanded. +.Sh NOTES +Buffering BIOs implement +.Xr BIO_gets 3 +by using +.Xr BIO_read 3 +operations on the next BIO in the chain. +By prepending a buffering BIO to a chain +it is therefore possible to provide +.Xr BIO_gets 3 +functionality if the following BIOs do not support it (for example SSL BIOs). +.Pp +Data is only written to the next BIO in the chain +when the write buffer fills or when +.Xr BIO_flush 3 +is called. +It is therefore important to call +.Xr BIO_flush 3 +whenever any pending data should be written +such as when removing a buffering BIO using +.Xr BIO_pop 3 . +.Xr BIO_flush 3 +may need to be retried if the ultimate source/sink BIO is non blocking. +.Sh RETURN VALUES +.Fn BIO_f_buffer +returns the buffering BIO method. +.Pp +.Fn BIO_get_buffer_num_lines +returns the number of lines buffered (may be 0). +.Pp +.Fn BIO_set_read_buffer_size , +.Fn BIO_set_write_buffer_size , +and +.Fn BIO_set_buffer_size +return 1 if the buffer was successfully resized or 0 for failure. +.Pp +.Fn BIO_set_buffer_read_data +returns 1 if the data was set correctly or 0 if there was an error. +.Sh SEE ALSO +.Xr BIO 3 , +.Xr BIO_ctrl 3 , +.Xr BIO_flush 3 , +.Xr BIO_pop 3 , +.Xr BIO_reset 3 |