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Diffstat (limited to 'doc/crypto/BIO_s_mem.pod')
-rw-r--r-- | doc/crypto/BIO_s_mem.pod | 115 |
1 files changed, 0 insertions, 115 deletions
diff --git a/doc/crypto/BIO_s_mem.pod b/doc/crypto/BIO_s_mem.pod deleted file mode 100644 index 7663d8bf5ffd..000000000000 --- a/doc/crypto/BIO_s_mem.pod +++ /dev/null @@ -1,115 +0,0 @@ -=pod - -=head1 NAME - -BIO_s_mem, BIO_set_mem_eof_return, BIO_get_mem_data, BIO_set_mem_buf, -BIO_get_mem_ptr, BIO_new_mem_buf - memory BIO - -=head1 SYNOPSIS - - #include <openssl/bio.h> - - BIO_METHOD * BIO_s_mem(void); - - BIO_set_mem_eof_return(BIO *b,int v) - long BIO_get_mem_data(BIO *b, char **pp) - BIO_set_mem_buf(BIO *b,BUF_MEM *bm,int c) - BIO_get_mem_ptr(BIO *b,BUF_MEM **pp) - - BIO *BIO_new_mem_buf(const void *buf, int len); - -=head1 DESCRIPTION - -BIO_s_mem() return the memory BIO method function. - -A memory BIO is a source/sink BIO which uses memory for its I/O. Data -written to a memory BIO is stored in a BUF_MEM structure which is extended -as appropriate to accommodate the stored data. - -Any data written to a memory BIO can be recalled by reading from it. -Unless the memory BIO is read only any data read from it is deleted from -the BIO. - -Memory BIOs support BIO_gets() and BIO_puts(). - -If the BIO_CLOSE flag is set when a memory BIO is freed then the underlying -BUF_MEM structure is also freed. - -Calling BIO_reset() on a read write memory BIO clears any data in it. On a -read only BIO it restores the BIO to its original state and the read only -data can be read again. - -BIO_eof() is true if no data is in the BIO. - -BIO_ctrl_pending() returns the number of bytes currently stored. - -BIO_set_mem_eof_return() sets the behaviour of memory BIO B<b> when it is -empty. If the B<v> is zero then an empty memory BIO will return EOF (that is -it will return zero and BIO_should_retry(b) will be false. If B<v> is non -zero then it will return B<v> when it is empty and it will set the read retry -flag (that is BIO_read_retry(b) is true). To avoid ambiguity with a normal -positive return value B<v> should be set to a negative value, typically -1. - -BIO_get_mem_data() sets *B<pp> to a pointer to the start of the memory BIOs data -and returns the total amount of data available. It is implemented as a macro. - -BIO_set_mem_buf() sets the internal BUF_MEM structure to B<bm> and sets the -close flag to B<c>, that is B<c> should be either BIO_CLOSE or BIO_NOCLOSE. -It is a macro. - -BIO_get_mem_ptr() places the underlying BUF_MEM structure in *B<pp>. It is -a macro. - -BIO_new_mem_buf() creates a memory BIO using B<len> bytes of data at B<buf>, -if B<len> is -1 then the B<buf> is assumed to be nul terminated and its -length is determined by B<strlen>. The BIO is set to a read only state and -as a result cannot be written to. This is useful when some data needs to be -made available from a static area of memory in the form of a BIO. The -supplied data is read directly from the supplied buffer: it is B<not> copied -first, so the supplied area of memory must be unchanged until the BIO is freed. - -=head1 NOTES - -Writes to memory BIOs will always succeed if memory is available: that is -their size can grow indefinitely. - -Every read from a read write memory BIO will remove the data just read with -an internal copy operation, if a BIO contains a lot of data and it is -read in small chunks the operation can be very slow. The use of a read only -memory BIO avoids this problem. If the BIO must be read write then adding -a buffering BIO to the chain will speed up the process. - -=head1 BUGS - -There should be an option to set the maximum size of a memory BIO. - -There should be a way to "rewind" a read write BIO without destroying -its contents. - -The copying operation should not occur after every small read of a large BIO -to improve efficiency. - -=head1 EXAMPLE - -Create a memory BIO and write some data to it: - - BIO *mem = BIO_new(BIO_s_mem()); - BIO_puts(mem, "Hello World\n"); - -Create a read only memory BIO: - - char data[] = "Hello World"; - BIO *mem; - mem = BIO_new_mem_buf(data, -1); - -Extract the BUF_MEM structure from a memory BIO and then free up the BIO: - - BUF_MEM *bptr; - BIO_get_mem_ptr(mem, &bptr); - BIO_set_close(mem, BIO_NOCLOSE); /* So BIO_free() leaves BUF_MEM alone */ - BIO_free(mem); - - -=head1 SEE ALSO - -TBA |