mirror of
https://github.com/moparisthebest/curl
synced 2024-11-17 15:05:02 -05:00
34cf40321c
A struct bufref holds a buffer pointer, a data size and a destructor. When freed or its contents are changed, the previous buffer is implicitly released by the associated destructor. The data size, although not used internally, allows binary data support. A unit test checks its handling methods: test 1661 Closes #6654
82 lines
2.2 KiB
Markdown
82 lines
2.2 KiB
Markdown
# bufref
|
|
|
|
This is an internal module for handling buffer references. A referenced
|
|
buffer is associated with its destructor function that is implicitly called
|
|
when the reference is invalidated. Once referenced, a buffer cannot be
|
|
reallocated.
|
|
|
|
A data length is stored within the reference for binary data handling
|
|
purpose; it is not used by the bufref API.
|
|
|
|
The `struct bufref` is used to hold data referencing a buffer. The members of
|
|
that structure **MUST NOT** be accessed or modified without using the dedicated
|
|
bufref API.
|
|
|
|
## init
|
|
|
|
```c
|
|
void Curl_bufref_init(struct bufref *br);
|
|
```
|
|
|
|
Initialises a `bufref` structure. This function **MUST** be called before any
|
|
other operation is performed on the structure.
|
|
|
|
Upon completion, the referenced buffer is `NULL` and length is zero.
|
|
|
|
This function may also be called to bypass referenced buffer destruction while
|
|
invalidating the current reference.
|
|
|
|
## free
|
|
|
|
```c
|
|
void Curl_bufref_free(struct bufref *br);
|
|
```
|
|
|
|
Destroys the previously referenced buffer using its destructor and
|
|
reinitialises the structure for a possible subsequent reuse.
|
|
|
|
## set
|
|
|
|
```c
|
|
void Curl_bufref_set(struct bufref *br, const void *buffer, size_t length,
|
|
void (*destructor)(void *));
|
|
```
|
|
|
|
Releases the previouly referenced buffer, then assigns the new `buffer` to
|
|
the structure, associated with its `destructor` function. The later can be
|
|
specified as `NULL`: this will be the case when the referenced buffer is
|
|
static.
|
|
|
|
if `buffer` is NULL, `length`must be zero.
|
|
|
|
## memdup
|
|
|
|
```c
|
|
CURLcode Curl_bufref_memdup(struct bufref *br, const void *data, size_t length);
|
|
```
|
|
|
|
Releases the previouly referenced buffer, then duplicates the `length`-byte
|
|
`data` into a buffer allocated via `malloc()` and references the later
|
|
associated with destructor `curl_free()`.
|
|
|
|
An additional trailing byte is allocated and set to zero as a possible
|
|
string zero-terminator; it is not counted in the stored length.
|
|
|
|
Returns `CURLE_OK` if successful, else `CURLE_OUT_OF_MEMORY`.
|
|
|
|
## ptr
|
|
|
|
```c
|
|
const unsigned char *Curl_bufref_ptr(const struct bufref *br);
|
|
```
|
|
|
|
Returns a `const unsigned char *` to the referenced bufffer.
|
|
|
|
## len
|
|
|
|
```c
|
|
size_t Curl_bufref_len(const struct bufref *br);
|
|
```
|
|
|
|
Returns the stored length of the referenced buffer.
|