man BIO_find_type () - BIO chain traversal
NAME
BIO_find_type, BIO_next - BIO chain traversal
SYNOPSIS
#include <openssl/bio.h>
BIO * BIO_find_type(BIO *b,int bio_type); BIO * BIO_next(BIO *b);
#define BIO_method_type(b) ((b)->method->type)
#define BIO_TYPE_NONE 0 #define BIO_TYPE_MEM (1|0x0400) #define BIO_TYPE_FILE (2|0x0400)
#define BIO_TYPE_FD (4|0x0400|0x0100) #define BIO_TYPE_SOCKET (5|0x0400|0x0100) #define BIO_TYPE_NULL (6|0x0400) #define BIO_TYPE_SSL (7|0x0200) #define BIO_TYPE_MD (8|0x0200) #define BIO_TYPE_BUFFER (9|0x0200) #define BIO_TYPE_CIPHER (10|0x0200) #define BIO_TYPE_BASE64 (11|0x0200) #define BIO_TYPE_CONNECT (12|0x0400|0x0100) #define BIO_TYPE_ACCEPT (13|0x0400|0x0100) #define BIO_TYPE_PROXY_CLIENT (14|0x0200) #define BIO_TYPE_PROXY_SERVER (15|0x0200) #define BIO_TYPE_NBIO_TEST (16|0x0200) #define BIO_TYPE_NULL_FILTER (17|0x0200) #define BIO_TYPE_BER (18|0x0200) #define BIO_TYPE_BIO (19|0x0400)
#define BIO_TYPE_DESCRIPTOR 0x0100 #define BIO_TYPE_FILTER 0x0200 #define BIO_TYPE_SOURCE_SINK 0x0400
DESCRIPTION
The BIO_find_type() searches for a BIO of a given type in a chain, starting at BIO b. If type is a specific type (such as BIO_TYPE_MEM) then a search is made for a BIO of that type. If type is a general type (such as BIO_TYPE_SOURCE_SINK) then the next matching BIO of the given general type is searched for. BIO_find_type() returns the next matching BIO or NULL if none is found.
Note: not all the BIO_TYPE_* types above have corresponding BIO implementations.
BIO_next() returns the next BIO in a chain. It can be used to traverse all BIOs in a chain or used in conjunction with BIO_find_type() to find all BIOs of a certain type.
BIO_method_type() returns the type of a BIO.
RETURN VALUES
BIO_find_type() returns a matching BIO or NULL for no match.
BIO_next() returns the next BIO in a chain.
BIO_method_type() returns the type of the BIO b.
NOTES
BIO_next() was added to OpenSSL 0.9.6 to provide a 'clean' way to traverse a BIO chain or find multiple matches using BIO_find_type(). Previous versions had to use:
next = bio->next_bio;
BUGS
BIO_find_type() in OpenSSL 0.9.5a and earlier could not be safely passed a NULL pointer for the b argument.
EXAMPLE
Traverse a chain looking for digest BIOs:
BIO *btmp; btmp = in_bio; /* in_bio is chain to search through */
do {
btmp = BIO_find_type(btmp, BIO_TYPE_MD);
if(btmp == NULL) break; /* Not found */
/* btmp is a digest BIO, do something with it ...*/
...
btmp = BIO_next(btmp); } while(btmp);
SEE ALSO
TBA