1<!-- 2Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3 4SPDX-License-Identifier: curl 5--> 6 7# bufref 8 9This is an internal module for handling buffer references. A referenced 10buffer is associated with its destructor function that is implicitly called 11when the reference is invalidated. Once referenced, a buffer cannot be 12reallocated. 13 14A data length is stored within the reference for binary data handling 15purposes; it is not used by the bufref API. 16 17The `struct bufref` is used to hold data referencing a buffer. The members of 18that structure **MUST NOT** be accessed or modified without using the dedicated 19bufref API. 20 21## `init` 22 23```c 24void Curl_bufref_init(struct bufref *br); 25``` 26 27Initializes a `bufref` structure. This function **MUST** be called before any 28other operation is performed on the structure. 29 30Upon completion, the referenced buffer is `NULL` and length is zero. 31 32This function may also be called to bypass referenced buffer destruction while 33invalidating the current reference. 34 35## `free` 36 37```c 38void Curl_bufref_free(struct bufref *br); 39``` 40 41Destroys the previously referenced buffer using its destructor and 42reinitializes the structure for a possible subsequent reuse. 43 44## `set` 45 46```c 47void Curl_bufref_set(struct bufref *br, const void *buffer, size_t length, 48 void (*destructor)(void *)); 49``` 50 51Releases the previously referenced buffer, then assigns the new `buffer` to 52the structure, associated with its `destructor` function. The latter can be 53specified as `NULL`: this is the case when the referenced buffer is static. 54 55if `buffer` is NULL, `length` must be zero. 56 57## `memdup` 58 59```c 60CURLcode Curl_bufref_memdup(struct bufref *br, const void *data, size_t length); 61``` 62 63Releases the previously referenced buffer, then duplicates the `length`-byte 64`data` into a buffer allocated via `malloc()` and references the latter 65associated with destructor `curl_free()`. 66 67An additional trailing byte is allocated and set to zero as a possible string 68null-terminator; it is not counted in the stored length. 69 70Returns `CURLE_OK` if successful, else `CURLE_OUT_OF_MEMORY`. 71 72## `ptr` 73 74```c 75const unsigned char *Curl_bufref_ptr(const struct bufref *br); 76``` 77 78Returns a `const unsigned char *` to the referenced buffer. 79 80## `len` 81 82```c 83size_t Curl_bufref_len(const struct bufref *br); 84``` 85 86Returns the stored length of the referenced buffer. 87
