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<!--
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
-->
# 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
purposes; 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);
```
Initializes 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
reinitializes 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 previously referenced buffer, then assigns the new `buffer` to
the structure, associated with its `destructor` function. The latter can be
specified as `NULL`: this is the case when the referenced buffer is static.
if `buffer` is NULL, `length` must be zero.
## `memdup0`
```c
CURLcode Curl_bufref_memdup0(struct bufref *br, const void *data,
size_t length);
```
Releases the previously referenced buffer, then duplicates the `length`-byte
`data` into a buffer allocated via `malloc()` and references the latter
associated with destructor `curl_free()`.
An additional trailing byte is allocated and set to zero as a possible string
null-terminator; it is not counted in the stored length.
Returns `CURLE_OK` if successful, else `CURLE_OUT_OF_MEMORY`.
## `ptr`
```c
const char *Curl_bufref_ptr(const struct bufref *br);
```
Returns a `const char *` to the referenced buffer.
## `uptr`
```c
const unsigned char *Curl_bufref_uptr(const struct bufref *br);
```
Returns a `const unsigned char *` to the referenced buffer.
## `len`
```c
size_t Curl_bufref_len(const struct bufref *br);
```
Returns the stored length of the referenced buffer.
## `dup`
```c
char *Curl_bufref_dup(const struct bufref *br);
```
Returns a strdup() version of the buffer. Note that this assumes that the
bufref is null terminated.
|
