mirror of
https://github.com/moparisthebest/curl
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109 lines
2.5 KiB
Markdown
109 lines
2.5 KiB
Markdown
# dynbuf
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This is the internal module for creating and handling "dynamic buffers". This
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means buffers that can be appended to, dynamically and grow in size to adapt.
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There will always be a terminating zero put at the end of the dynamic buffer.
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The `struct dynbuf` is used to hold data for each instance of a dynamic
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buffer. The members of that struct **MUST NOT** be accessed or modified
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without using the dedicated dynbuf API.
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## init
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```c
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void Curl_dyn_init(struct dynbuf *s, size_t toobig);
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```
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This inits a struct to use for dynbuf and it can't fail. The `toobig` value
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**must** be set to the maximum size we allow this buffer instance to grow to.
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The functions below will return `CURLE_OUT_OF_MEMORY` when hitting this limit.
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## free
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```c
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void Curl_dyn_free(struct dynbuf *s);
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```
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Free the associated memory and clean up. After a free, the `dynbuf` struct can
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be re-used to start appending new data to.
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## addn
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```c
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CURLcode Curl_dyn_addn(struct dynbuf *s, const void *mem, size_t len);
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```
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Append arbitrary data of a given length to the end of the buffer.
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## add
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```c
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CURLcode Curl_dyn_add(struct dynbuf *s, const char *str);
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```
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Append a C string to the end of the buffer.
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## addf
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```c
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CURLcode Curl_dyn_addf(struct dynbuf *s, const char *fmt, ...);
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```
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Append a `printf()`-style string to the end of the buffer.
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## vaddf
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```c
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CURLcode Curl_dyn_vaddf(struct dynbuf *s, const char *fmt, va_list ap);
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```
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Append a `vprintf()`-style string to the end of the buffer.
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## reset
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```c
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void Curl_dyn_reset(struct dynbuf *s);
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```
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Reset the buffer length, but leave the allocation.
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## tail
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```c
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CURLcode Curl_dyn_tail(struct dynbuf *s, size_t length);
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```
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Keep `length` bytes of the buffer tail (the last `length` bytes of the
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buffer). The rest of the buffer is dropped. The specified `length` must not be
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larger than the buffer length.
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## ptr
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```c
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char *Curl_dyn_ptr(const struct dynbuf *s);
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```
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Returns a `char *` to the buffer if it has a length, otherwise a NULL. Since
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the buffer may be reallocated, this pointer should not be trusted or used
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anymore after the next buffer manipulation call.
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## uptr
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```c
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unsigned char *Curl_dyn_uptr(const struct dynbuf *s);
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```
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Returns an `unsigned char *` to the buffer if it has a length, otherwise a
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NULL. Since the buffer may be reallocated, this pointer should not be trusted
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or used anymore after the next buffer manipulation call.
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## len
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```c
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size_t Curl_dyn_len(const struct dynbuf *s);
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```
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Returns the length of the buffer in bytes. Does not include the terminating
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zero byte.
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