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